The Lasting Impact of Childhood Circumstance on Obesity in ... · obesity was rarely a problem in...

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1 The Lasting Impact of Childhood Circumstance on Obesity in Korea: Results from the Korean National Health and Nutrition Examination Survey 2007-2011 Yeonjin Lee Introduction In 2005, World Health Organization (WHO) published an annual report that sparked considerable debate on global obesity epidemic that is posing drastic public health threats worldwide (add reference to the report). In non-western societies such as those in East Asia obesity was rarely a problem in the past, but the prevalence of obesity and chronic diseases associated with obesity have increased rapidly with recent industrialization (Popkin 2002; Popkin & Gordon-Larsen, 2004). Therefore an emerging challenge for researchers and public health specialists is to gain a better understanding of factors that have contributed to the recent rise in obesity worldwide and how environmental changes may play a role. Many researchers have documented a relationship between socioeconomic status (SES) and obesity. Accessibility to high-quality foods, autonomy to manage one’s social life, knowledge, and maintenance of healthy behaviors such as physical activities influence individuals’ weight patterns over the life course (Levi et al. 2010; Joshu et al. 2008). Obesity may be more sensitive to early life conditions (i.e. physical and social environment) than other health epidemics as many of its risk factors may date to childhood experiences. Questions remain concerning the cumulative or relative impact of early life socioeconomic circumstances and the influence of intergenerational social mobility on adult obesity especially among the societies in process of fast transition. Thus, examining socioeconomic inequalities in early life in the trajectory of obesity may

Transcript of The Lasting Impact of Childhood Circumstance on Obesity in ... · obesity was rarely a problem in...

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    The Lasting Impact of Childhood Circumstance on Obesity in Korea:

    Results from the Korean National Health and Nutrition Examination

    Survey 2007-2011

    Yeonjin Lee

    Introduction

    In 2005, World Health Organization (WHO) published an annual report that sparked

    considerable debate on global obesity epidemic that is posing drastic public health threats

    worldwide (add reference to the report). In non-western societies such as those in East Asia

    obesity was rarely a problem in the past, but the prevalence of obesity and chronic diseases

    associated with obesity have increased rapidly with recent industrialization (Popkin 2002; Popkin

    & Gordon-Larsen, 2004). Therefore an emerging challenge for researchers and public health

    specialists is to gain a better understanding of factors that have contributed to the recent rise in

    obesity worldwide and how environmental changes may play a role.

    Many researchers have documented a relationship between socioeconomic status (SES)

    and obesity. Accessibility to high-quality foods, autonomy to manage one’s social life, knowledge,

    and maintenance of healthy behaviors such as physical activities influence individuals’ weight

    patterns over the life course (Levi et al. 2010; Joshu et al. 2008). Obesity may be more sensitive

    to early life conditions (i.e. physical and social environment) than other health epidemics as many

    of its risk factors may date to childhood experiences. Questions remain concerning the

    cumulative or relative impact of early life socioeconomic circumstances and the influence of

    intergenerational social mobility on adult obesity especially among the societies in process of fast

    transition.

    Thus, examining socioeconomic inequalities in early life in the trajectory of obesity may

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    reveal mechanisms underlying socioeconomic gradients in obesity in later life. The current study

    examines whether respondents’ childhood socioeconomic conditions are associated with obesity

    with and without controls for adult SES and health behaviors in South Korea (Korea hereafter)

    as a representative of newly developed countries.

    Mechanisms Underlying Early life Condition and Obesity in Later Life

    Early life conditions may influence adult obesity through biological (i.e. metabolic

    syndrome and increased number of fat cells), psychological and behavioral mechanisms (self-

    regulation of weight, eating disorders and physical activities) operating across the life course.

    Furthermore, childhood circumstances generally determined by parental socioeconomic

    condition are correlated with adult SES that may influence various health outcomes (i.e. children

    from higher socioeconomic families are more likely to achieve higher educational attainment and

    better health outcomes that are negatively associated with obesity in developed countries). Over

    the past few decades, pseudo-experimental and clinical studies have examined associations

    between utero and early life conditions, metabolic syndrome and obesity in later life (Gluckman

    & Hanson 2008). Deprivation during fetal and prenatal periods is thought to affect early neuro-

    endocrine development and cause long-term changes in the levels of major hormone systems

    such as an increase in adrenal glucocorticoid secretion. These factors are highly correlated with

    the predisposition to diabetes, metabolic syndrome and obesity when followed by nutritional

    abundance (Reilly et al. 2005). For instance, according to the studies based on cohorts born

    during the Dutch famine (1944–1945), malnutrition during early gestation was associated with

    higher obesity prevalence in later life among women, but not among men (Ravelli et al. 1999;

    Stein et al. 2007). Luo et al. (2006) investigated adult obesity among the Chinese who were born

    during the Great Famine (1959–1962) and found that the association between early life

    deprivation and adult metabolic syndrome was statistically significant for women.

    Parents may influence children’s obesity risk in later life via shared obesogenic

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    circumstances such as sedentary lifestyles, eating disorders, and poor emotional regulation along

    with genetic transmission (Reilly et al. 2005; Newby, 2007). Parental SES is a key factor in

    childhood for determining family resources and culture such as choice of foods, value of exercise,

    eating patterns and habits (Ball & Mishra, 2005). Previous studies from developed countries

    show that children from the socioeconomically vulnerable households are more likely to face

    psychological challenges sometimes exhibiting as obesogenic behaviors such as binge eating and

    drinking (Repetti et al. 2002; Lynch et al., 1997; Power et al., 2005). Some studies further show

    that mothers’ educational attainment is highly correlated with children’s food choices such as

    fruits and vegetables, which may continue to influence food choices in adulthood (Lytle et al.

    2003; Kremers et al. 2003; Neumark et al. 2003). Other studies report that consumption of fast

    food among adolescents increases when the frequency with which families eat together at home

    decreases (Gillman et al. 2000; Neumark et al. 2003).

    Intergenerational transmission of SES may be another important contributor for the

    association between early life conditions and obesity risk in later life through its relationship with

    adult SES (Case, Fertig, & Paxson, 2005; Huang & Elo, 2009). In industrialized societies low-

    SES adults are at a greater risk of being obese and having chronic diseases than high-SES adults

    (Case, Fertig, & Paxson, 2005). Thus, adult SES may serve as an important connection linking

    childhood disadvantage represented by parental SES to adult health outcomes (Hayward &

    Gorman 2004).

    Social Gradients in Obesity across Gender

    Findings from previous studies address that the biological impact of early-life condition

    on metabolic system, which is intimately related with obesity in later life varies by gender (Luo,

    2006). Other studies suggest that since men and women have different psychological and

    behavioral responses to socioeconomic status (e.g. girls with high SES family background is

    more likely to be educated to care about weight compared to boys) it is necessary to investigate

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    whether early life socioeconomic risk factors which may determine obesity is gender-specific. For

    example, Robinson et al. (2009) examined health behaviors among U.S. black adolescents in

    2007 and found that the relationship between childhood SES and the likelihood of adopting

    obesity-promoting behaviors was gender-specific. Others have argued that early life conditions

    may have long lasting gender-specific impacts on appetite regulation, eating behaviors, and body

    weight gain patterns (Case & Menendez, 2009).

    Men and women may have different socioeconomic gradient in obesity and the

    association can vary by countries. According to the studies from developed countries, the

    association between SES and obesity tends to be negative both for men and women. Data from

    United State, Britain, Sweden, and Finland show that both men and women with less education

    were more likely to be obese than were those with more education (Flegal et al. 1989). Wardle

    and Griffith studied the effect of occupational status on obesity in Britain (2001). A negative

    association between professional job status and obesity prevalence has been well documented in

    women while not clearly observed for men (Ibid). The result suggests that gender difference in

    sensitivity to body image may be the reason for gender differences in SES gradient in BMI.

    Women especially in professional occupations tend to be more sensitive to weight related stigma

    and pressure to preserve a specific body shape (Sobal & Stunkard 1989). Women having weight

    problems are more likely to face social discrimination and more burdens of psychological

    diseases attributable to overweight and obesity (e.g. depression) and hard to obtain higher social

    status compared to men (Carpenter et al. 2000).

    Obesity in Newly Industrialized Societies

    Despite of global concern about obesity, much of the prior literature evaluating the

    association between SES over the life course and obesity has been limited to high-income

    countries, although the findings from these countries may not be applicable to low- and middle-

    income countries (Monasta et al. 2010). Many newly developed societies experienced

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    considerable “nutrition and epidemiology transitions” followed by rapid economic development.

    This makes people grown up during social transitions have faced complicated socioeconomic

    profiles in health consequences (Swinburn et al. 2011). For example, under-nutrition during early

    childhood followed by over-nutrition under the certain environmental exposures may emphasize

    a link between early life disadvantage and the risk of obesity and chronic diseases in later life

    independent of own adult SES (Barker et al. 1989). A study by Case and Menendez (2009) on

    BMI patterns of 975 individuals residing in Cape Town in South Africa in 2004- 2005, found

    that South African women who spent their childhood in poverty and hunger were significantly

    more likely to be obese as adults than other women after adjusting for their current social status.

    As for the populations in newly developed countries, comparisons of impact of early life

    condition across cohorts may help study the mechanisms through which environment and

    historical conditions affect social gradients in obesity in later life (Bell, Ge, & Popkin, 2001).

    During the period in process of economic growth children born to higher SES families were

    selectively exposed to risk of over nutrition such as diets high in fat and sugar (Westernized diet)

    and thus faced greater risks of gaining weight than children born to lower SES families; a

    direction of the association between SES and obesity tended to shift from positive to negative as

    countries’ level of socioeconomic development increased (Kapoor, & Anand, 2002; Kim,

    Symons, & Popkin, 2004; McLaren, 2007). A study from Brazil by the end of 1980s obesity had

    been positively associated with income and the relationship between income and obesity has

    begun to reverse after industrialization especially among women (Monteiro et al. 2000). In Accra,

    Ghana, centre in West Africa that recently urbanized, a burden related with obesity was more

    likely to be found in places of high SES. In areas where people with lower SES reside in, both

    high prevalence of infectious and non-communicable disease burdens were observed (de-Graft

    Aikins, 2007). Studies on Chinese population showed that macro migration to urban areas in

    China is significantly related with increased risk of obesity and chronic diseases as people

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    changed their traditional lifestyles and diets into westernized one and passed them on to

    descendents (Gong et al. 2012). Ng and colleagues (2009) evaluated the impact of community-

    level urbanization on average weekly physical activity among Chinese young men and women

    and found that for both gender, physical activity per a week declined as the level of urbanization

    increased (Ng, Norton & Popkin 2009). At the same time, industrialization has introduced young

    generations to cultural values from western societies, including ideal body images favoring

    thinness which in pre-industrialized countries was viewed as a sign of poverty and unhealthiness

    (Chen & Meltzer 2008). For example, adolescents in Fiji where people traditionally preferred

    chubbiness to thinness as an aesthetic ideal developed an interest in diet as a means of emulating

    television characters after several years of exposure to western culture (Becker 2004; Becker et al.

    2002). The findings suggest the importance of identifying groups that are most susceptible to the

    obesity in newly developed countries concerned with changes in a group’s demographic and SES

    characteristics over time. Therefore, obesity epidemic in newly developed societies can be

    hypothesized to be dynamic within an individual’s life course and across generations as

    socioeconomic, environmental, and historical contexts change together with individuals’

    behaviors over time (Kuh et al. 2003).

    Little is known about gender differences in the relationship between social

    circumstances and obesity over the life trajectory in low- and middle-income countries. Previous

    studies argue that the biological and behavioral responses to the early life disadvantage

    potentially impacting on obesity in later life may vary by gender (Sobal & Stunkard 1989; Luo

    2006). Luo et al. (2006) investigate adult obesity among the Chinese who were born during the

    Great Famine (1959–1962) and found that the association between childhood deprivation and

    adult metabolic syndrome was statistically significant but only for the women. According to Lee

    (2011) due to the strong gender role segregation in Korean society it is usual that boys and girls

    are educated separately in schools and home with different topics from their junior high school

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    (e.g. nutrition, home economics only for girls vs. carpentry only for boys) while the difference

    has reduced for the recent cohorts. Thus with the same or less level of educational attainment,

    women can have more knowledge on metabolism and nutritional balance and more likely to

    adopt behaviors which protect against obesity than men.

    Gender specific cultural values such as weight perception may pattern the differences in

    obesity across SES varying by gender and the association may be distinct from that of western

    societies (Sobal & Stunkard 1989; Luo 2006). Case and Menendez (2009), for example, found

    that in South Africa, a cultural preference for a larger body size is more common among women

    than men, and that women of higher SES are considerably more likely to be obese than lower

    SES women, a pattern that is not observed among men. A preference for a larger body size

    among women than men is also observed in Thailand where there is also a higher prevalence of

    obesity among women with higher education and semi-professional occupation than other

    women, whereas this pattern is not found among men (McraLen, 2007). However, as

    industrialization proceeds apace under the influence of western countries, recent women

    generations have started to favor thinness and stigmatize ‘being fat’ (Becker, 2004; Becker et al.

    2002). Thus, the risk of obesity may be related to socio-cultural mechanisms different upon the

    birth cohorts while resulting in gender-specific obesity gradients across SES in this society.

    Korean Setting

    Although Korea is not the most obese nation in the world, obesity in Korea has been an

    increasing public health concern during the last decade. (Kim et al. 2004). According to the

    Korean National Health Examination and Nutrition Survey (KNHANES) from 1998 to 2011,

    there was a nearly 50% increase in the prevalence of overweight and obesity among Korean men

    in a recent 10-year period, whereas there was no significant increase among women (Korean

    Centers for Disease Control and Prevention). Considering that a population level genetic shift is

    not likely to happen within a decade, the large increase in obesity prevalence, especially among

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    Korean men, might be attributable to environmental and individual behavioral changes.

    Given that Korea has experienced both a rapid industrialization during the last few

    decades and a large increase in obesity in recent years, the Korean case offers a useful

    opportunity to explore how social transition may shape the way in which childhood and adult

    socioeconomic conditions are associated with obesity in later life (Caballero, 2001; Popkin, 1994).

    Koreans, who were children during early phases of industrialization (e.g. Koreans born 1954-

    1963), were subsequently exposed to very different nutritional and socioeconomic environments

    in adulthood: under-nutrition in childhood and over-nutrition in adulthood. Koreans born

    around the mid 1960s spent their childhood and adolescence during a period when Korea was

    undergoing rapid industrialization and democratization. During this period new cultural values

    from western societies and benefits from the advanced technology began to be widespread.

    More recently, Korea is beginning to focus attention and raise awareness of the risk of obesity

    and its association with chronic diseases and these efforts have led more recent generations to

    adopt lifestyles that help maintain healthy weight, especially among professional women who

    experience the most social pressure for weight control. Along with industrialization, ideal body

    image and awareness of weight control that have been prevalent in western countries have also

    increasingly permeated Korean society (Joh et al. 2013). Obesity might have been a symbol of

    “affluence” and “health” in the past, but as social awareness of maintaining proper body weight

    is heightened and Western culture is actively introduced, fatness has become stigmatized

    especially among women (Joh et al. 2013). On the other hand, Korean men prefer a larger body

    size, which is a symbol of masculinity, dependableness and wealth. There is rarely discrimination

    against overweight and obese men. These different gender-specific cultural norms make Korean

    women with higher SES more conscious of their body weight than higher SES men. The roles of

    other behavioral determinants of weight such as drinking are also potentially important in its

    social patterning. Korean society values collectivism and thus, drinking is considered to be an

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    extension of work especially for male professional workers. This alerts men in higher

    occupational status to be exposed to risk of obesity. Given the rapid social changes and unique

    cultural norms in Korean society, the association between childhood and adult SES and obesity

    prevalence may differ by birth cohort and gender. However, it is not known well whether

    different socioeconomic risk factors dominate at different life stages, or if the impacts of these

    are similar in other western societies. The primary aim of this study is to determine the extent to

    which the socioeconomic patterning of obesity stratified by birth cohort and gender, with the

    greatest emphasis on residual impact of early life SES. I hypothesized that the social patterning

    of obesity during early life time would be stronger at older cohort. The secondary aim was to

    examine variations by gender in the extent to which the social patterning of obesity is explained

    by measures of childhood precursors (parental SES), adult SES, and modifiable behavioral risk

    factor (drinking).

    Data

    The data for this study came from the Korean National Health and Nutrition

    Examination Survey (KNHANES). Korean Centers for Disease Control and Prevention has

    conducted periodical data collection since 1998 to assess health and nutritional status of the

    civilian, non-institutionalized population in Korea (KCDC 2000). The KNHANES is a

    nationally representative survey in Korea, a combination of a health interview, nutritional survey,

    and health examinations with comprehensive information on biochemical and anthropometric

    measurements, health status, health behaviors and socio-demographic characteristics. Therefore,

    the data offer special benefits for studies that need accurate measures of a variety of health

    outcomes along with information on socioeconomic backgrounds of individuals.

    Standardized health examinations are directly carried out in a specially equipped mobile

    examination center. Similar to the U.S. NHANES, the KNHANES is a repetitive cross-sectional

    survey of Korean individuals chosen in a multistage clustered sampling frame based on

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    geographical unit, sex and age, which were provided by the 2005 National Census Registry, the

    latest 5-year national household census in Korea. Since the KNHANES examines independent

    sets of randomly selected individuals, it rarely happens to select the same person repeatedly in

    the following year (Lim et al. 2011).

    The current study utilizes five of the most recent waves of KNHANES from 2007 to

    2011 because key variables measuring parental SES are not available in previous years. I restrict

    the sample to individuals ages over 25-57. By age 25 most people have completed their highest

    level of education. I also exclude individuals who belong to cohorts born before the end of the

    Korean War (1950-1953). The number of 18,217 pooled 2007-2011 KNHANES sample consists

    of 6,995 males and 9,392 females. From this sample, I excluded individuals who were missing

    information on BMI (N=1,242) and on core SES explanatory variables (N=431). Women who

    are pregnant at the time of examination were also excluded (N=147). Missing data in parental

    education and drinking variables are imputed by using multiple imputation procedure with the

    Markov chain Monte Carlo algorithm. Imputed values are estimated based on the individual

    information on socio-demographic characteristics and replace missing values (Allison, 2000).

    Measuring Overweight and Obesity

    Current study uses body mass index (BMI = weight in kg/ (height in meters)2) as an

    indicator of overweight and obesity. Height and weight were measured in light indoor clothing

    without shoes to the nearest 0.1 kg and 0.1 cm respectively. BMI is categorized based on the

    criteria recommended by the World Health Organization (WHO) for the study of obesity among

    Asians as follows: underweight (BMI

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    lowering BMI cutoff points for Asians because compared to Caucasians, Asians have greater

    abdominal fat distribution and higher prevalence of obesity-related diseases (type-2 diabetes and

    cardiovascular diseases) at lower levels of BMI 25 kg/m2 (Hubbard 2000; Snijder et al. 2005;

    Villareal et al. 2005). In addition, populations with short stature may be considered “obese” at

    lower levels of BMI because those with small body structure have higher proportion of body fat

    at each level of BMI (Villareal et al. 2005). The Korean Society for the Study of Obesity and

    Korean medical institutions also use the lower BMI cutoff value (obesity≥25kg/m2) to define

    obesity. In Singapore, many studies defined overweight based on BMI of ≥23 kg/m2 and obesity

    based on BMI > 27 kg/m2. In Hong Kong, working aged individuals whose BMI is greater than

    24 kg/m2 are considered to be obese (Deurenberg-Yap et al. 2001; Ko et al. 1999). Even though

    there is some controversy about what BMI cutoff points should be used to define overweight or

    obesity among all Asians, a systematic review of obesity-related health problems among Asian

    populations reveals that the BMI correlated with the prevalence of obesity-related complications

    are between 22 kg/m2 to 31 kg/m2 (Serena Low et al. 2009). Therefore, in this study we use the

    BMI cutoff points to define overweight and obesity recommended for use in Asian populations

    by the WHO (WHO 2000). Furthermore, through subsequent sensitivity tests with alternative

    measures: continuous standardized score of BMI and relative values of BMI based on quintiles,

    we will evaluate whether and to what extent the BMI cutoff points affect our conclusions.

    Explanatory Variables

    Among the demographic characteristics, I control for age in all analyses. I also control

    for current marital status (married, separated/divorced/widowed, never married). Survey years

    are controlled for.

    Because the survey does not have a direct measure of the respondents’ socioeconomic

    circumstances and nutritional status in childhood, I use parental educational attainment when the

    respondents were 14 years old as a measure of childhood SES. Respondents were asked: What is

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    your father’s highest degree? And what is your mother’s highest degree? Education level of the

    father and the mother are combined into one variable named ‘parental education’ given their

    high correlation. Higher educational attainment of either mother or father is used to address

    respondents’ parental SES. Parental education is grouped into quartiles based on their birth

    cohorts.

    I also include several indicators of current SES: educational attainment, household

    income, occupation, and place of residence. Education is coded as follows: less than elementary

    school (12 years). Household income is derived from the income of all household members and

    divided into tertiles per a month:

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    (8) frequency of inability to remember after drinking, (9) injury because of drinking, and (10) any

    suggestion to cut down by family members, friends, or doctors. Scores for the each item were

    summed up into a continuous variable and categorized into three groups based on the cut-offs as

    follows: 0–7, 8–14, and ≥15. These cut-off points were based on previous studies about

    detecting hazardous drinkers (Flegal et al. 2010). Each survey year from the five waves (from

    2007 to 2011) also controlled in all models. Table 1 provides descriptive statistics for all variables

    used in the analysis by gender.

    Methods and Model Description

    To estimate the associations between childhood and adult SES and underweight,

    overweight, and obesity, I estimate multinomial logistic regression models. I assessed differential

    obesity–social status associations for those individuals born from 1954 to 1963 (the initial stage

    of economic growth), those born in 1964-1973 and those born after 1974 by testing for an age–

    SES interaction and considering historical changes in Korean context and undertook the main

    analyses split by birth cohort. All models are estimated separately for men and women as well

    and the results are presented as relative risk ratios (RRRs) with standard errors (S.E.). All

    equations are weighted to represent the national sample of Korea.

    Model 1 I control for parental education (indicators of early-life conditions), age at the

    time of interview, and survey years. In Model 2, I introduce indicators of adult socio-

    demographic variables to see whether introducing current SES changes the association between

    childhood SES and risk of obesity. In Model 3, I add health behavior to model 2 and examine

    whether health behaviors are mediators of the impact of SES on overweight and obesity. In

    model 4, I interact parental educational attainment with current SES to evaluate whether current

    SES modifies the impact of childhood SES on the risk of obesity among men and women. I use

    Wald statistics and their p-values for testing for whether the interaction is significant. The 0.1

    significance level is used because the aim of the paper is to study the associations between

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    several potential predictors of obesity, and all included characteristics have a theoretical

    connection with the dependent variable. However, I mostly report and discuss associations

    significant at the p

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    SES (higher parental educational attainment) are more likely to be obese (RRRs for oldest cohort

    = 1.24; second oldest cohort = 1.23, p

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    individuals with lowest level of educational attainment become less likely to be obese than

    individuals with highest degree with marginal statistical power to explain (RRR= 0.58, p

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    lowest educational attainment = 1.91, p

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    considerably change the association between childhood and adult SES and weight just as found

    in older cohorts.

    I introduce interaction terms between childhood SES and current SES factors to the

    model adjusted for childhood- and adult- SES and related covariates to investigate whether

    childhood SES modifies the association of current socioeconomic conditions with weight after

    controlling for other related covariates. Three interaction terms are included into the final model

    in preliminary test: parental education*current education, parental education*household income,

    parental education*occupation. Statistical significance from the multivariate Wald test is found in

    the interaction effect between parental education and current occupational status among men

    with respect to improvement of model fit (p = 0.03). The result shows that higher level of

    parental educational attainment is associated with reduced prevalence of obesity especially

    among professional males and females of the latest cohort (Figure 1 & 2). For example, although

    professional male workers are likely to be exposed to higher risk factors to be obese compared to

    manual worker counterpart, if he has been raised by highly educated parents, the risks of being

    obese seem to be reduced by around 20% (p

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    association between childhood SES and obesity among women but it has a limited impact on

    men across the birth cohorts. The explanatory role of current SES in the association between

    childhood SES and obesity seems apparently more important for those who spent their early

    childhood in the process of industrialization (born from 1964 to 1973) than other cohorts,

    particularly among women with the greatest emphasis on those of education and income. For

    earlier cohorts of men, positive social gradients in obesity were observed and the gradients began

    to shift into negative direction for the youngest cohort. In a society with high level of gender

    inequality like in Korea, strong and negative association between adulthood SES and obesity may

    indicate that women are more likely to be vulnerable to socioeconomic disadvantages given that

    they have less economic power to control their own resources. They may be also more sensitive

    to the effects of socioeconomic disadvantages which usually closely related with risk factors of

    being obese (Doyal, 2001; Rogers, 2006).

    The findings of gender difference in SES gradients in obesity over the life trajectory

    partially concur with earlier studies (Doyal, 2001; Rogers, 2006; Wells et al., 2012). Past studies

    have found stronger negative relationships between early-life SES and adult obesity risk in

    women than men (Heraclides et al., 2008; Khlat et al., 2009; Langenberg et al., 2003; Case &

    Menendez, 2009), addressing greater sensitivity of females to such early life disadvantage; girls in

    poverty tend to be more stunted (Borooah, 2004; Ghosh et al., 2002; Moestue, 2009). The result

    from comparison of models of the youngest cohort supports the argument that parental SES in

    early life is negatively related with overweight only for women after controlling for other

    covariates. However, across birth cohorts, a residual impact of childhood SES on weight later in

    life was much stronger for men than women in Korea. Strong and positive relationship between

    childhood SES and obesity found only among men can be explained as follows. Given that

    Korea was agrarian society before the industrialization started during the 1960s, dairy products

    and foods containing high animal fat and low fiber were allowable only for the wealthiest people

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    and thus “chubbiness” of children is a sign of prosperity. Before the end of 1980s, having a car and

    using elevator are unusual for middle-class Korean families and only children with highest SES

    could enjoy the benefit of technology. Promotion of knowledge of metabolism and nutritional

    balance to educate mother to reduce obesity risk among children was not initiated until a few

    years ago (Lim, 2011). Therefore, many Koreans from higher SES origin adopted and maintain

    dietary habits and behaviors conducive to the development of obesity during their early life

    which may influence BMI trajectory over their life-course. The shift in economic structure from

    light industry to electronic industry expanded mass media market which transplanted the western

    culture into Korea. Introduced culture idealized westernized features such as tallness and

    slimness and generated new body awareness in post-industrialized Korean society (after 1970s).

    The new body awareness has become the social beauty norm in the highly competitive job and

    marriage markets especially for women (Jang, 2013). Women who fail to fit the socially defined

    body standards are easily marginalized and discriminated against major competitions. The recent

    awareness spread out among the young women that “slim body” gives an advantage over the life

    spheres encourages Korean women to eagerly manipulate their bodies toward the desired ideal

    by investing their money and time for dieting, exercising and/or medical (or pseudo medical)

    treatment. The result found among the youngest female cohort that higher SES women are more

    likely to be underweight give an empirical evidence support the trend. On the other hand,

    western culture makes people prefer bigger body of male to smaller one as they consider big

    body a symbol of masculinity, power and wealth. Social attitudes are more lenient and relatively

    neutral for obese men (Ibid). In Korea, the extent of social pressure and stigmatization against

    gaining weight is disproportionately concentrated on women and this tendency is consistent with

    previous reports in other developed countries in that there is a clear social gradient in overweight

    and obesity among women (Waldle & Griffith, 2001). For Korean men, heavy drinking habits

    are likely to be the most important factor increasing BMI. Heavy drinking can cause obesity by

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    increasing calorie intakes from alcohol as well as by hindering healthy weight control behaviors

    such as exercising. Traditionally in Korea, men (especially who are in professional job) tend to

    place high value on sociality and consider drinking gathering as an extension of formal work. The

    finding is in the same direction with previous studies showing that heavy male drinkers were less

    active in controlling their weight, even though their weight perceptions were not different from

    those of non- or moderate drinkers (Ko et al., 2013). Given the high prevalence of and rising

    trends in heavy drinking among Korean men (KHNES 2012), result of current study should be

    seriously considered to develop effective public intervention.

    Individuals belong to the youngest cohort, whose parents are highly educated, seem to

    have less likelihood to be obese for both men and women. When medical knowledge spread out

    after industrialization children grown up under highly educated parents easily obtain knowledge

    concerned with maintaining healthy weight and integrate the knowledge into their life styles such

    as foods with less sugar and physical activities on a regular base. In other words, knowledge and

    life habits passed by parents seem to have strong effect on protecting adult obesity especially for

    the men and women achieved higher adult SES via professional job. For example men in

    professional jobs can use their knowledge to offset negative impact of traditional working culture

    including frequent social gathering with heavy drinks and severe stress. In this sense, the result is

    consistent with the previous findings of Ball and Mishra (2005) that mother’s socioeconomic

    status might be more influential on weight control patterns of people with high SES. People are

    more likely to respond to or model their dieting or weight loss attempts on the suggestions or

    behaviors of their care givers.

    Conclusion

    Using data from South Korean KHNES (2007-2011), the study is able to identify the

    relationship between childhood SES and current SES and obesity prevalence by gender and birth

    cohorts. I find that men with higher SES origin and with greater nutritional catch up during the

  • 22

    social transition are more likely to be at significantly greater risk of obesity and the gradient

    decreases as the society develops. On the other hand, higher SES is related with less likelihood of

    being overweight and obesity among women regardless of their childhood SES. Women having

    more resources seem to use these resources to get and maintain slim body fit to meet social

    expectation while men with more resources do not seem to have this tendency. This might be

    intimately related with the Korean socioeconomic shift and the culture of gender norms and

    body images.

    With interesting findings the study has several limitations. Cross-sectional data do not

    provide information on the direction of causality between SES and obesity. Although an

    apparent cross-sectional relationship between obesity and SES has been found, it is possibly also

    affected by a reverse causation: obesity leads to downward SES. In this case, the relationship

    between SES and adulthood obesity may be confounded by obesity in childhood or adolescent,

    which I was not able to control for in our study. Due to the limitation in data availability, I can

    only use maternal and paternal education as indicators of childhood SES. However, many

    previous studies argue that education is a proper and consistent measurement of general SES

    (Ball & Mishra, 2005). Given the fact that Korea has experienced educational expansion, the

    future steps should be needed to consider variations by cohorts and periods with respect to the

    effect of education of both parents and respondents on obesity prevalence.

    Understanding the differences that men and women face in their risks of obesity is a

    necessary and important first step for developing effective policy and public health intervention.

    The result shows that men with higher SES are highly likely to be obese but not women in Korea.

    In this case, campaign that spread information on the necessity of regular exercise, fat and

    nutrition content of food toward general target would not that be efficient to reduce obesity risk

    that current Korean society is facing. One way to address the high prevalence among men in

    higher SES is to better educate employers about the relevant risks related with obesity and

  • 23

    encourage them to change occupational culture (i.e. do not force drinking etc.). In that way,

    men’s perceptions of healthy BMI may change. There may be an upper bound on the extent to

    which such campaigns will be successful, however, if a man’s ability to regulate his appetite is

    compromised by the eating and exercise behaviors he already adopted and has maintained from

    his early life. As current results emphasize potential role of parents in reducing obesity later in

    life, comprehensive evaluation about the socioeconomic conditions over the life-course

    trajectory is necessary to understand obesity risk the society is facing and develop effective health

    intervention.

  • 24

    Table1. Sample Characteristics by Gender Ages 25-57, Cohort 1954-1989, 2007–2011 Korean National Health and Nutrition Examination Survey (KNHANES), (N=16,371)

    Men Women p-value

    Characteristics (N= 6,985) (N= 9,386)

    Weight status N % N %

    Underweight (0

  • 25

    Table1. Sample Characteristics by Gender Ages 25-57, Cohort 1954-1989, 2007–2011 Korean National Health and Nutrition Examination Survey (KNHANES), (N=16,371)

    Region of current residence

    Metropolitan area

    3,193

    45.7

    4,406

    46.9

    0.12

    Outside metropolitan area 3,792 54.3 4,980 53.1

    Health Behaviors Alcohol consumption

    Light 2,698 38.7 7,834 83.5 0.00

    Middle 2,148 30.7 1,131 12.1

    Heavy 2,139 30.5 421 4.5

    1. Parental education coded based on the percentage by respondents’ generation given the large change in Korean educational system.

  • 26

    Table 2-1. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among male born from 1954 to 1963 (N=2,303)

    Under Over Obesity Under Over Obesity Under Over Obesity Under Over Obesity

    VARIABLES weight weight weight weight weight weight weight weight

    Early life conditions

    Parental education 1.07 1.12* 1.24*** 1.04 1.03 1.16** 1.04 1.03 1.16** 0.81 1.04 1.20**

    (0.20) (0.07) (0.08) (0.21) (0.07) (0.08) (0.21) (0.07) (0.08) (0.20) (0.09) (0.10)

    Adult socio-demographic conditions

    Educational attainment

    (College and abovea)

    Elementary 0.49 0.80 0.91 0.56 0.80 0.91 0.49 0.80 0.92

    (0.29) (0.17) (0.18) (0.33) (0.17) (0.18) (0.30) (0.18) (0.19)

    Middle school 0.34* 0.77 0.98 0.36* 0.77 0.98 0.34* 0.77 0.98

    (0.20) (0.15) (0.18) (0.22) (0.15) (0.18) (0.21) (0.15) (0.18)

    High school 0.53 0.92 0.97 0.56 0.92 0.97 0.58 0.92 0.96

    (0.23) (0.14) (0.14) (0.24) (0.14) (0.14) (0.26) (0.14) (0.14)

    Occupation (Manual workera)

    Service worker 1.13 1.38* 1.79*** 1.17 1.38* 1.79*** 1.21 1.38* 1.79***

    (0.63) (0.24) (0.30) (0.65) (0.24) (0.30) (0.68) (0.24) (0.30)

    Professional worker 0.78 0.98 1.61*** 0.77 0.98 1.61*** 0.07* 1.02 1.96**

    (0.38) (0.15) (0.23) (0.38) (0.15) (0.23) (0.10) (0.38) (0.66)

    Not in the labor market 3.15*** 0.83 0.87 3.07** 0.83 0.87 3.06** 0.83 0.87

    (1.36) (0.17) (0.17) (1.33) (0.17) (0.17) (1.33) (0.17) (0.17)

    Household income (Highest incomea)

    Low income 1.54 0.76* 1.01 1.51 0.76* 1.02 1.49 0.76* 1.02

    (0.68) (0.11) (0.14) (0.67) (0.11) (0.14) (0.66) (0.11) (0.14)

    Middle income 1.31 0.73** 1.10 1.34 0.73** 1.10 1.32 0.73** 1.10

    (0.57) (0.10) (0.14) (0.59) (0.10) (0.14) (0.58) (0.10) (0.14)

    Current residence(Metropolitan areaa)

    Rural 1.26 0.86 1.03 1.26 0.86 1.03 1.22 0.86 1.03

    (0.42) (0.10) (0.11) (0.42) (0.10) (0.11) (0.41) (0.10) (0.11)

  • 27

    Table 2-1. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among male born from 1954 to 1963 (N=2,303)

    Health behaviors

    Alcohol consumption (Lighta)

    Middle 0.52 1.12 1.07 0.52 1.12 1.07

    (0.25) (0.16) (0.14) (0.25) (0.16) (0.14)

    Heavy 0.59 0.94 0.97 0.62 0.94 0.97

    (0.25) (0.13) (0.12) (0.26) (0.13) (0.12) Interaction

    Parental education*Professional workers 2.51* 0.98 0.92

    (1.20) (0.15) (0.12)

    *** p

  • 28

    Table 2-2. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among male born from 1964 to 1973 (N=2,564)

    Under Over Obesity Under Over Obesity Under Over Obesity Under Over Obesity

    VARIABLES weight weight weight weight weight weight weight weight

    Early life conditions

    Parental education 1.10 1.13* 1.23*** 1.06 1.04 1.14* 1.08 1.04 1.14* 1.19 0.93 1.11

    (0.21) (0.08) (0.08) (0.21) (0.08) (0.08) (0.22) (0.08) (0.08) (0.30) (0.10) (0.10)

    Adult socio-demographic conditions

    Educational attainment

    (College and abovea)

    Elementary 0.29 0.57 0.60 0.28 0.55 0.58* 0.29 0.53* 0.58*

    (0.37) (0.22) (0.19) (0.36) (0.21) (0.19) (0.38) (0.20) (0.19)

    Middle school 0.95 0.71 1.08 0.90 0.68 1.04 0.93 0.65 1.03

    (0.58) (0.21) (0.25) (0.55) (0.20) (0.25) (0.56) (0.19) (0.24)

    High school 0.58 1.02 0.90 0.57 1.01 0.89 0.57 1.02 0.89

    (0.20) (0.13) (0.10) (0.20) (0.13) (0.10) (0.20) (0.13) (0.10)

    Occupation (Manual workera)

    Service worker 1.12 2.40*** 1.95*** 1.10 2.33*** 1.91*** 1.06 2.41*** 1.92***

    (0.50) (0.30) (0.49) (0.39) (0.29) (0.48) (0.41) (0.30) (0.30)

    Professional worker 0.67 1.26 1.16 0.68 1.23 1.14 1.45 0.65 1.00

    (0.26) (0.15) (0.26) (0.18) (0.15) (1.59) (0.27) (0.36) (0.66)

    Not in the labor market 0.45 1.53* 1.13 0.45 1.60* 1.19 0.44 1.64* 1.20

    (0.33) (0.27) (0.33) (0.41) (0.29) (0.33) (0.42) (0.29) (0.17)

    Household income (Highest incomea)

    Low income 1.52 0.81 0.67*** 1.57 0.84 0.70*** 1.57 0.84 0.70***

    (0.62) (0.12) (0.09) (0.64) (0.12) (0.09) (0.64) (0.12) (0.09)

    Middle income 1.49 0.91 0.79* 1.57 0.93 0.81* 1.57 0.93 0.81*

    (0.59) (0.09) (0.63) (0.13) (0.10) (0.63) (0.13) (0.10) (0.10)

    Current residence(Metropolitan areaa)

    Rural 0.77 1.06 1.15 0.78 1.06 1.14 0.79 1.06 1.14

    (0.23) (0.11) (0.11) (0.23) (0.12) (0.11) (0.23) (0.12) (0.11)

  • 29

    Table 2-2. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among male born from 1964 to 1973 (N=2,564)

    Health behaviors

    Alcohol consumption (Lighta)

    Middle 0.93 1.46*** 1.60*** 0.93 1.46*** 1.60***

    (0.35) (0.19) (0.19) (0.35) (0.20) (0.19)

    Heavy 1.62 1.81*** 1.66*** 1.63 1.80*** 1.66***

    (0.56) (0.25) (0.20) (0.57) (0.25) (0.20) Interaction

    Parental education*Professional workers 0.75 1.28 1.05

    (0.30) (0.19) (0.14)

    *** p

  • 30

    Table 2-3. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among male born from 1974 to 1983 (N=2,118)

    Under Over Obesity Under Over Obesity Under Over Obesity Under Over Obesity

    VARIABLES weight weight weight weight weight weight weight weight

    Early life conditions

    Parental education 1.12 1.11* 1.14** 1.13 1.09 1.13** 1.14 1.10 1.13** 1.34 1.10 1.24***

    (0.16) (0.06) (0.06) (0.17) (0.07) (0.06) (0.17) (0.07) (0.06) (0.26) (0.08) (0.09)

    Adult socio-demographic conditions

    Educational attainment

    (College and abovea)

    Elementary 0.00 1.44 1.63 0.00 1.39 1.54 0.00 1.39 1.61

    (0.00) (1.75) (1.98) (0.00) (1.69) (1.88) (0.00) (1.69) (1.97)

    Middle school 0.00 0.93 1.77 0.00 0.91 1.72 0.00 0.90 1.75

    (0.00) (0.41) (0.66) (0.00) (0.41) (0.64) (0.00) (0.41) (0.65)

    High school 1.54 0.81 1.09 1.59 0.80* 1.07 1.58 0.80* 1.08

    (0.47) (0.11) (0.13) (0.49) (0.10) (0.13) (0.48) (0.10) (0.13)

    Occupation (Manual workera)

    Service worker 1.17 1.15 1.59*** 1.22 1.11 1.51** 1.14 1.11 1.47**

    (0.53) (0.22) (0.27) (0.56) (0.21) (0.26) (0.53) (0.21) (0.26)

    Professional worker 1.25 1.16 1.58*** 1.27 1.15 1.56*** 4.05* 1.16 2.70***

    (0.49) (0.18) (0.23) (0.50) (0.18) (0.23) (3.35) (0.39) (0.82)

    Not in the labor market 1.12 0.88 1.06 1.08 0.90 1.09 0.96 0.89 1.03

    (0.47) (0.16) (0.18) (0.46) (0.17) (0.19) (0.42) (0.17) (0.18)

    Household income (Highest incomea)

    Low income 0.98 0.96 1.09 0.98 0.96 1.09 1.02 0.96 1.10

    (0.39) (0.14) (0.15) (0.38) (0.14) (0.15) (0.40) (0.14) (0.15)

    Middle income 2.06** 0.92 1.10 2.06** 0.93 1.11 2.08** 0.93 1.10

    (0.71) (0.13) (0.14) (0.71) (0.13) (0.14) (0.72) (0.13) (0.14)

    Current residence(Metropolitan areaa)

    Rural 0.59* 1.22* 0.93 0.58* 1.22* 0.93 0.58* 1.22* 0.93

    (0.17) (0.14) (0.10) (0.17) (0.14) (0.10) (0.17) (0.14) (0.10)

  • 31

    Table 2-3. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among male born from 1974 to 1983 (N=2,118)

    Health behaviors

    Alcohol consumption (Lighta)

    Middle 0.68 1.15 1.27* 0.66 1.15 1.26*

    (0.26) (0.16) (0.16) (0.26) (0.16) (0.16)

    Heavy 0.66 1.29* 1.47*** 0.65 1.29* 1.47***

    (0.27) (0.20) (0.20) (0.26) (0.20) (0.20) Interaction

    Parental education*Professional workers 0.63 0.99 0.80**

    (0.19) (0.12) (0.09)

    *** p

  • 32

    Table 3-1. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among female born from 1954 to 1963 (N=3,179)

    Under Over Obesity Under Over Obesity Under Over Obesity Under Over Obesity

    VARIABLES weight weight weight weight weight weight weight weight

    Early life conditions

    Parental education 1.09 0.93 0.91** 1.07 1.00 1.12* 1.06 0.99 1.11* 1.12 0.96 1.12*

    (0.17) (0.05) (0.04) (0.18) (0.06) (0.06) (0.18) (0.06) (0.06) (0.20) (0.06) (0.06)

    Adult socio-demographic conditions

    Educational attainment

    (College and abovea)

    Elementary 0.91 1.92*** 3.51*** 0.85 1.87*** 3.44*** 0.87 1.88*** 3.41***

    (0.48) (0.36) (0.66) (0.46) (0.36) (0.65) (0.47) (0.36) (0.65)

    Middle school 0.88 1.50** 2.51*** 0.91 1.48** 2.51*** 0.92 1.51** 2.48***

    (0.42) (0.26) (0.44) (0.43) (0.26) (0.44) (0.44) (0.27) (0.44)

    High school 0.69 1.35** 1.48** 0.69 1.34* 1.48** 0.68 1.38** 1.46**

    (0.27) (0.20) (0.23) (0.27) (0.20) (0.23) (0.27) (0.21) (0.23)

    Occupation (Manual workera)

    Service worker 1.66 1.25* 1.12 1.61 1.23 1.11 1.59 1.25 1.10

    (0.67) (0.16) (0.14) (0.66) (0.16) (0.14) (0.65) (0.16) (0.14)

    Professional worker 0.88 1.08 1.00 0.89 1.08 0.99 3.23 0.41* 1.26

    (0.51) (0.20) (0.18) (0.52) (0.20) (0.18) (4.36) (0.21) (0.60)

    Not in the labor market 1.35 0.97 0.92 1.29 0.96 0.91 1.27 0.97 0.91

    (0.51) (0.12) (0.10) (0.49) (0.12) (0.10) (0.48) (0.12) (0.10)

    Household income (Highest incomea)

    Low income 0.89 0.92 1.07 0.88 0.92 1.06 0.87 0.93 1.06

    (0.30) (0.10) (0.12) (0.30) (0.10) (0.12) (0.29) (0.11) (0.12)

    Middle income 0.72 0.80** 1.01 0.70 0.79* 1.00 0.70 0.80* 1.00

    (0.26) (0.09) (0.11) (0.25) (0.09) (0.11) (0.25) (0.09) (0.11)

    Current residence(Metropolitan areaa)

    Rural 2.31*** 1.07 1.25** 2.35*** 1.07 1.25** 2.32*** 1.08 1.25**

    (0.66) (0.10) (0.11) (0.67) (0.10) (0.11) (0.66) (0.10) (0.11)

  • 33

    Table 3-1. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among female born from 1954 to 1963 (N=3,179)

    Health behaviors

    Alcohol consumption (Lighta)

    Middle 0.00 1.02 0.85 0.00 1.02 0.85

    (1.03) (0.16) (0.15) (0.01) (0.16) (0.15)

    Heavy 3.51** 1.39 1.61 3.50** 1.39 1.61

    (1.87) (0.41) (0.46) (1.86) (0.41) (0.46) Interaction

    Parental education*Professional workers 0.59 1.45** 0.91

    (0.31) (0.26) (0.16)

    *** p

  • 34

    Table 3-2. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among female born from 1964 to 1973 (N=3,304)

    Under Over Obesity Under Over Obesity Under Over Obesity Under Over Obesity

    VARIABLES weight weight weight weight weight weight weight weight

    Early life conditions

    Parental education 1.08 0.92 0.90* 1.08 0.97 1.06 1.09 0.98 1.06 0.97 0.96 1.00

    (0.12) (0.06) (0.05) (0.12) (0.06) (0.07) (0.12) (0.06) (0.06) (0.12) (0.07) (0.07)

    Adult socio-demographic conditions

    Educational attainment

    (College and abovea)

    Elementary 2.72** 1.97** 3.03*** 3.10** 2.01** 3.02*** 2.86** 1.98** 2.92***

    (1.18) (0.61) (0.88) (1.37) (0.63) (0.88) (1.26) (0.62) (0.85)

    Middle school 0.17** 1.53** 2.65*** 0.20** 1.56** 2.63*** 0.19** 1.55** 2.58***

    (0.12) (0.31) (0.50) (0.14) (0.32) (0.50) (0.13) (0.32) (0.50)

    High school 0.69* 1.23* 1.75*** 0.73 1.23* 1.75*** 0.73 1.23* 1.76***

    (0.13) (0.13) (0.20) (0.14) (0.13) (0.20) (0.14) (0.13) (0.20)

    Occupation (Manual workera)

    Service worker 0.88 1.13 1.00 0.89 1.13 1.00 0.90 1.13 1.01

    (0.28) (0.18) (0.15) (0.28) (0.18) (0.15) (0.29) (0.18) (0.15)

    Professional worker 0.58* 1.01 0.79 0.57* 1.00 0.80 0.11** 0.83 0.30***

    (0.19) (0.13) (0.19) (0.17) (0.13) (0.10) (0.35) (0.14) (0.66)

    Not in the labor market 0.80 0.93 0.84 0.78 0.93 0.85 0.80 0.93 0.86

    (0.22) (0.14) (0.12) (0.22) (0.14) (0.12) (0.23) (0.14) (0.12)

    Household income (Highest incomea)

    Low income 1.17 0.87 1.30** 1.15 0.87 1.30** 1.17 0.88 1.31**

    (0.25) (0.11) (0.15) (0.25) (0.11) (0.15) (0.25) (0.11) (0.16)

    Middle income 0.58** 0.99 1.08 0.58** 1.00 1.08 0.58** 1.00 1.08

    (0.13) (0.11) (0.12) (0.13) (0.11) (0.12) (0.13) (0.11) (0.12)

    Current residence(Metropolitan areaa)

    Rural 1.12 1.06 1.06 1.12 1.06 1.06 1.13 1.06 1.07

    (0.19) (0.10) (0.10) (0.19) (0.10) (0.10) (0.19) (0.10) (0.10)

  • 35

    Table 3-2. Relative Risk Ratios from Multinomial Logit Models: Underweight, overweight and obesity versus normal weight among female born from 1964 to 1973 (N=3,304)

    Health behaviors

    Alcohol consumption (Lighta)

    Middle 0.43** 0.90 0.99 0.43** 0.90 0.99

    (0.17) (0.14) (0.15) (0.17) (0.14) (0.15)

    Heavy 0.77 0.84 1.15 0.77 0.84 1.16

    (0.42) (0.22) (0.28) (0.43) (0.22) (0.28) Interaction

    Parental education*Professional workers 1.81** 1.07 1.44**

    (0.51) (0.16) (0.23)

    *** p

  • 36

    Table 3-3. Relative Risk Ratios from Multinomial Logit Models: Underweight overweight and obesity versus Normal weight among female born from 1974 to 1983 (N=2,903)

    Under Over Obesity Under Over Obesity Under Over Obesity Under Over Obesity

    VARIABLES weight weight weight weight weight weight weight weight

    Early life conditions

    Parental education 1.15** 0.85*** 0.85*** 1.11 0.90* 0.97 1.11 0.90* 0.97 1.18* 0.94 1.07

    (0.07) (0.05) (0.04) (0.08) (0.05) (0.06) (0.08) (0.05) (0.06) (0.10) (0.07) (0.07)

    Adult socio-demographic conditions

    Educational attainment

    (College and abovea)

    Elementary 0.32 0.73 2.12* 0.31 0.70 2.06 0.32 0.72 2.14*

    (0.39) (0.48) (0.96) (0.38) (0.47) (0.94) (0.39) (0.48) (0.97)

    Middle school 0.73 0.79 1.88* 0.72 0.77 1.82* 0.75 0.80 1.91*

    (0.41) (0.35) (0.62) (0.41) (0.35) (0.60) (0.43) (0.36) (0.64)

    High school 1.01 1.16 1.75*** 1.00 1.15 1.71*** 1.02 1.16 1.73***

    (0.14) (0.15) (0.20) (0.15) (0.15) (0.20) (0.15) (0.15) (0.21)

    Occupation (Manual workera)

    Service worker 1.24 0.54** 0.69 1.23 0.53** 0.67 1.21 0.52** 0.65

    (0.52) (0.15) (0.19) (0.52) (0.15) (0.19) (0.51) (0.14) (0.18)

    Professional worker 1.50 0.53** 0.70 1.50 0.53** 0.70 2.19 0.78 1.69

    (0.58) (0.18) (0.58) (0.14) (0.18) (1.14) (0.31) (0.67) (0.82)

    Not in the labor market 1.63 0.56** 1.09 1.63 0.56** 1.09 1.60 0.55** 1.06

    (0.62) (0.16) (0.18) (0.46) (0.17) (0.19) (0.42) (0.17) (0.18)

    Household income (Highest incomea)

    Low income 0.80 1.45** 1.75*** 0.80 1.45** 1.75*** 0.80 1.45** 1.73***

    (0.12) (0.22) (0.26) (0.12) (0.22) (0.26) (0.12) (0.22) (0.25)

    Middle income 0.64*** 1.24 1.40** 0.64*** 1.24 1.40** 0.63*** 1.23 1.38**

    (0.09) (0.18) (0.20) (0.09) (0.18) (0.20) (0.09) (0.18) (0.20)

    Current residence(Metropolitan areaa)

    Rural 1.26* 0.87 1.15 1.27* 0.87 1.15 1.27* 0.88 1.16

    (0.16) (0.10) (0.12) (0.16) (0.10) (0.12) (0.16) (0.10) (0.12)

  • 37

    Table 3-3. Relative Risk Ratios from Multinomial Logit Models: Underweight overweight and obesity versus Normal weight among female born from 1974 to 1983 (N=2,903)

    Health behaviors

    Alcohol consumption (Lighta)

    Middle 0.96 0.92 1.15 0.95 0.91 1.14

    (0.17) (0.15) (0.18) (0.17) (0.15) (0.17)

    Heavy 1.11 1.19 1.16 1.10 1.18 1.13

    (0.29) (0.26) (0.26) (0.29) (0.26) (0.25) Interaction

    Parental education*Professional workers 0.86 0.85 0.69***

    (0.11) (0.11) (0.09)

    *** p

  • 38

    Figure 1. Moderating Effects of Professional Jobs and Parental Educational Attainment on the Predicted Value of Obesity for Men

    -.4

    -.3

    -.2

    -.1

    0.1

    Pre

    dic

    ted V

    alu

    e o

    f O

    besity

    less

    than

    ele

    men

    tary

    sch

    ool

    mid

    dle

    scho

    ol

    mor

    e th

    an c

    ollege

    high

    sch

    ool

    Parental Education

    professional worker=0 professional worker=1

  • 39

    Figure 2. Moderating Effects of Professional Jobs and Parental Educational Attainment on the Predicted Value of Obesity for Women

    -2.5

    -2-1

    .5-1

    -.5

    0

    Pre

    dic

    ted V

    alu

    e o

    f O

    besity

    less

    than

    ele

    men

    tary

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    ool

    mid

    dle

    scho

    ol

    mor

    e th

    an c

    ollege

    high

    sch

    ool

    Parental Education

    professional worker=0 professional worker=1

  • 40

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