Overweight and Obesity:Prevalence and Health

RisksDr. David L. Gee

FCSN/PE 446

Overweight vs. ObeseTraditional Definitions

– Obese: Body fatness above population norm

– Overweight: Body weight above population norm

Current NIH Definition– Obese is a more severe form of

overweight

Body Mass IndexBMI = BW / H2

where: –BW = kilograms

–H = meters

Body Mass IndexExample:

– BW = 165 lbs / 2.2 lbs/kg = 75 kg

– H = 70 in x 2.54 cm/in = 178 cm = 1.78 m

BMI = 75 / 1.782 = 24BMI is not a direct measure of body

fatness

1998 NIH-NHLBI Clinical Guidelines

Expert Panel (24 members)Systematic Literature Review (1980-

1997)394 randomized controlled trialsExecutive summary 1998Arch Int Med (Sept ‘98), JADA (Oct

‘98), NHLBI Web page

1998 NIH-NHLBI Guidelines

Overweight: BMI 25 - 29.9Obese: BMI > 30

–Obesity Class I: 30 - 34.9

–Obesity Class II: 35 - 39.9

–Extreme Obesity: >40

Prevalence of Overweight and Obesity in the United States, 1999-2004

JAMA 295: 1549-1555 (2006)

2003-2004 NHANESAll adults Males Females

OverweightBMI > 25

66% 71% 62%

ObeseBMI > 30

32% 31% 33%

Severely ObeseBMI > 40

5% 3% 7%

Obesity Trends Among U.S. Adults between 1985 and 2005

Obesity Trends Among U.S. Adults between 1985 and 2005

Source of the data: CDC’s Behavioral Risk Factor Surveillance

System (BRFSS). – state health departments – monthly telephone interviews with U.S. adults.

Source of the data: CDC’s Behavioral Risk Factor Surveillance

System (BRFSS). – state health departments – monthly telephone interviews with U.S. adults.

Is being overweight really that dangerous?

Excess Deaths Associated with Underweight, Overweight, and Obesity

JAMA 2005:293:1861-1867 “Underweight and obesity… were

associated with increased mortality…” “Overweight was not associated with

excess mortality.” “Study finds government overstated danger

of obesity” – USA Today – 4/19/05– http://www.usatoday.com/news/health/2005-04

-19-obesity-danger_x.htm

For adults ages 25-59, increased mortality in underweight and obese categories, but not overweight category.

Is being overweight really that dangerous?

Other interpretations: While risk of mortality may not be greater in

overweight subjects, risk of chronic disease is greater in overweight and obese subjects– Improved detection and treatment of risk factors result

in reduced mortality in overweight subjects Hypertension, diabetes, dyslipidemia Quality of life

Overweight is a temporary state– Most/many overweight become obese– Obese state is clearly a health risk

Prevalence and Trends in Obesity Among US Adults, 1999-2000

JAMA 288(14)1723-1727 (2002)

Childhood Obesity

Overweight Prevalence in

Children & Adolescents: Definitions

Criteria based on NHANES 1976-1980

Higher BMI criteria– >95th percentile = overweight, medical

follow-up (~BMI=30 in adults)– 85-95th pct = risk of overweight (~BMI=25

adults)

American children are getting fatter…

Prevalence of Overweight* Among U.S. Children and Adolescents (Aged 2 –19 Years)National Health and Nutrition Examination Surveys

American boys of all ethnicities are getting fatter

Adolescent Boys Prevalence of Overweight* by Race/Ethnicity (Aged 12–19 Years)

National Health and Nutrition Examination Surveys

American girls, especially African-American girls, are getting fatter

Adolescent Girls Prevalence of Overweight* by Race/Ethnicity (Aged 12–19 Years)

National Health and Nutrition Examination Surveys

The Spread of the Obesity Epidemic in the US, 1991-1998JAMA 282: 1519-1522 (1999)cross sectional random telephone

survey>100,000 subjectsobesity = BMI > 30self-reported data

– probable underestimation of obesity

Changes of Obesity Prevalence:Gender

1991 1998 %increase

men 11.7% 17.7% 51.5%

women 12.2% 18.1% 47.1%Although the prevalence of obesity is higher in women than in men,

The rate of increase in obesity is greater in men than in women.

Changes of Obesity Prevalence:Age

Age 1991 1998 % increase

18-29 7.1% 12.1% 69.9%30-39 11.3% 16.9% 49.5%40-49 15.8% 21.2% 34.3%50-59 16.1% 23.8% 47.9%60-69 14.7% 21.3% 44.9%> 70 11.4% 14.6% 28.6%

Although the prevalence of obesity is greater in older Americans,The rate of increase in obesity is rising faster among younger Americans

Changes of Obesity Prevalence:Ethnicity

Ethnicity 1991 1998 % increase

White 11.3% 16.6% 47.3%

Black 19.3% 26.9% 39.2%

Hispanic 11.6% 20.8% 80.0%

Other 7.3% 11.9% 62.0%

Prevalence of obesity is highest among African-Americans,The rate of obesity rising fastest in the Hispanic population.

Changes of Obesity Prevalence:Education Level

EducationLevel

1991 1998 %increase

< Highschool

16.5% 24.1% 46.0%

Highschool

13.3% 19.4% 46.1%

Somecollege

10.6% 17.8% 67.5%

>College

8.0% 13.1% 62.9%

Prevalence of obesity is higher in less educated Americans, butThe rate of obesity is faster among more educated Americans.

Obesity is growing worldwideScience: 7 January 2005: vol. 307. no. 5706, p. 38

Obesity and HealthContributes to over half of Western

chronic diseases.– Coronary heart disease

– All major cancers except lung cancer

– Diabetes

– Stroke

Obesity and Mortality Rate

Lowest mortality–BMI = 19-25–10% to 20% under average BW

Mortality rate increases exponentially above BMI of 25–CDC 2005 study, above 30

Overweight and Coronary Heart Disease

70% of CHD cases are overweight Being overweight

– increases CHD mortality risk

– increases Total Cholesterol & LDL-C

– decreases HDL-C

– increases VLDL-TG

BMI and Prevalence of HypercholesterolemiaNHANES III

BMI and Prevalence of Low HDLNHANES III

Obesity and Diabetes Mellitus

80% of diabetics are overweightPrevalence

– 7th most frequent cause of death

– 11 million cases in US

Diabetes Prevalence1994 & 2002

Millions of Cases of Diabetes in 2000 and Projections for 2030, with Projected Percent Changes. NEJM 356:213-215(2007)

Obesity and Diabetes Mellitus

Type 1 DM (IDDM) (10-15%)– absolute deficiency of insulin

– not associated with obesityType 2 DM (NIDDM) (80%)

– peripheral insulin resistance

– highly associated with overweight

– weight loss cornerstone of treatment

Complications of Diabetes

Micro-angiopathies– blindness– renal failure– amputations

uncontrolled infections, numbness

Macro-angiopathies– coronary heart disease

Diagnostic Criteria for Diabetes (2005)

Fasting blood glucose > 126 mg/dl– 110-125mg/dl impaired glucose tolerance

Testing for all adults over 45 years every 3 years Testing earlier or more frequently

– if BMI > 25 plus CVD risk factors At risk ethnicity Family history Chronic inactivity History of gestational diabetes

Obesity and StrokeHypertension and StrokeObesity and Hypertension Prevalence

– 35% of obese have hpt

– 17% of desirable BMI have hpt

Diagnostic Criteria– systolic BP > 140 or– diastolic BP > 90

BMI and Prevalence of Hypertension

Prevalence of the Metabolic Syndrome Among US AdultsJAMA, 287: 356-359 (2002)

Definition– Cluster of risk factors resulting in substantial increased

risk for developing diabetes and cardiovascular disease (NCEP-ATP III)

Criteria: three or more of the following– Abdominal obesity (m>40”, f>35”)– Hypertriglyceridemia (>150mg/dl)– Low HDL-C (m<40mg/dl, f<50mg/dl)– Hi blood pressure (>130/85)– Hi fasting blood glucose (>110 mg/dl)

Prevalence of the Metabolic Syndrome Among US AdultsJAMA, 287: 356-359 (2002)

NHANES III (1988-1994)– 8814 adults

Results:– Age adjusted prevalence: 24%– Prevalence increased with age– Prevalence increased in Hispanic-Americans– Prevalence similar in white males & females

Higher in black and Hispanic females than males

Obesity and CancerPositive association with:

– Breast Cancer (post menopause)– Colon Cancer– Prostate Cancer– Endometrial Cancer

Essentially all except lung cancer

Overweight, Obesity, and Mortality from Cancer in a Prospectively

Studied Cohort of U.S. Adults NEJM 348:1625(April 2003)

900,000 adults – Prospective study, free of cancer

Self reported height/body weight in beginning

– 16 year follow up– ~57,000 cancer deaths

Obesity and Mortality from CancerNEJM April 2003

Under Fitness vs Over Fatness?

Association of Physical Activity and Body Mass Index With Novel and Traditional Cardiovascular Biomarkers in Women Samia Mora, MD, MHS; I-Min Lee, MBBS, ScD; Julie E. Buring, ScD; Paul M Ridker, MD, MPH JAMA. 2006;295:1412-1419.

Women’s Health Study– 27,158 healthy women (mean age = 55yrs)– Randomized, placebo controlled for low-dose asprin

and vitamin E in primary prevention of CVD and Cancer.

– Main outcome measures of this study: Association of physical activity and BMI on CVD risk factors

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Mora, S. et al. JAMA 2006;295:1412-1419.

Adjusted Odds Ratios for the Association of Quintiles of Physical Activity and Quintiles of Body Mass Index With Elevated Biomarker Levels*

After adjusting for age, race, smoking, systolic blood pressure, diabetes, menopausal status, hormone use, and eitherBMI or physical activity, both physical activity and BMI remained significantly associated in a linear manner with most biomarker levels, with greater odds ratios (ORs) for BMI compared with physical activity

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Mora, S. et al. JAMA 2006;295:1412-1419.

Association of Physical Activity and Body Mass Index Categories With Cardiovascular Biomarkers

High BMI showed stronger associations with these biomarkers than physical inactivity,but within BMI categories, physical activity was generally associated with more favorable cardiovascular biomarker levels than inactivity.

Association of Physical Activity and Body Mass Index With Novel and Traditional Cardiovascular

Biomarkers in Women Samia Mora, MD, MHS; I-Min Lee, MBBS, ScD; Julie E. Buring, ScD; Paul M Ridker, MD, MPH JAMA. 2006;295:1412-1419.

Conclusions: Both lower levels of physical activity and higher levels of

BMI were strongly and independently associated with adverse inflammatory and lipid biomarker levels.

BMI showed greater magnitude of association with the biomarkers

A modest level of physical activity was significantly associated with more favorable biomarker profiles, even in overweight or obese individuals.

The most favorable inflammatory and lipid levels were found in women who had at least moderate physical activity levels and were normal weight.

Another view:Cardiorespiratory Fitness, Macronutrient Intake,

and the Metabolic Syndrome: The Aerobics Center Longitudinal StudyJADA 2006; 106:673-679

~12,000 adult men and women enrolled in prospective trial at the Cooper Clinic, Dallas, TX

Cross-sectional epidemiological study

Odds of prevalent m etabolic syndrom e by fitness groups and BMI categories

0

0.2

0.4

0.6

0.8

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1.2

Normal w eight Overw eight

Odd

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atio Low f itness

Moderate f itness

High f itness

Fitness was significantly and inversely associated withprevalent metabolic syndrome in both normal and overweight subjects. (however, researchers did notreport absolute risk of normal and overweight subjects)

The Cost of ObesityHealth Affairs, Aug 2006

Year % of Medicare Patients with

obesity

% of Medicare spending on

obese patients

1987 11.7% 9.4%

2002 22.5% 24.8%

$336 billion 2005 total Medicare expenses

Effects of Weight Loss on HealthThe good news!

Reduces overall mortalityReduces risk factors

– decreases plasma TG– decreases blood pressure– increases HDL-C, decreases LDL-C– decreases fasting blood glucose

The Effect of Weight Loss on Left Ventricular Mass

NEJM 314: 334-339 (1986)

21 week, randomized control trial, n=41, young overweight patients

Hypertension and Weight Loss in Men

Conclusion:– modest weight loss results in

lowering of blood pressure in obese men.

– effect of weight loss is comparable if not better than with medication

Women, Weight Change, & Hypertension

Ann. Internal Med. 128: 81-88 (1998)

Nurse’s Health Study– 1976 – 1992 (16 yr)

– 82,473 healthy females– 16,395 new cases of hypertension

Women, Weight Change, & Hypertension

no change mod wt loss sig wt loss mod wt gain severe wt gain

1 0.85 0.74

1.74

5.21

0

1

2

3

4

5

6

RR

no change mod wt loss sig wt loss mod wt gain severe wt gain

Long-term effects of modest weight loss in Type II diabetic patients.Arch. Int. Med. 147:1749-1753 (1987)

1 year,Behavioral weight controlprogram,N=114 type 2diabetics

Long-term effects of modest weight loss in Type II diabetic

patients.Conclusions:

–Modest weight loss results in improved glucose control improved insulin sensitivity reduced triglycerides increased HDL-C

Prevention of Type 2 Diabetes Mellitus by Changes in Lifestyle among Subjects with

Impaired Glucose Tolerance NEJM - May 2001 522 middle age males

– BMI = 31– w/ impaired glucose tolerance

3.2 year follow-up– Intervention group

individualized wt. loss counseling

– Control group standard advice

Prevention of Type 2 Diabetes Mellitus by Changes in Lifestyle among Subjects with

Impaired Glucose ToleranceWeight Loss

– Intervention = 4.2 kg– Control = 0.8 kg

Diabetes Incidence @ 3 years– Intervention = 11%– Control = 23%

“The reduction in the incidence of diabetes was directly associated with changes in lifestyle”

Weight Cycling - Risk Factor?

Significant and deliberate fluctuations in body weight– Yo-yo dieting

Framingham Studies (1991)– individuals with greatest weight fluctuations

had highest risk of overall mortality and mortality & morbidity to coronary heart disease.

Variability of body weight and health outcomes in the Framingham population.

NEJM 324: 1839-1844 (1991)

Weight Cycling and Cholecystectomy in Women

Ann. Internal Med. (Mar 1999) Nurse’s Health Study

– (47,153 women, 30-55yr, w/o gall bladder disease, 1972-1988)

Weight cycling history (1 episode intentional)– light = 5-9 lbs (20.1% of subjects)– moderate = 10-19 lbs (18.8%)– severe = >20 lbs (16%)

Weight Cycling and Cholecystectomy in Women

Adjusted relative risk for cholecystectomy compared to women who maintained their weight:– 1.20 for light cyclers– 1.31 for moderate cyclers– 1.68 for severe cyclers

Caused by:– weight cycling?– severity of obesity?

Intentional vs Unintentional Weight Loss and Mortality in

Older Women.Iowa Women’s Health Study

– 25,897 women (55-69 yrs)

– questionnaire regarding wt loss since 18 yrs old

– followed 4 years

Intentional vs Unintentional Weight Loss and Mortality in

Older Women.Intentional wt loss (> 20 lbs):

– risk of total or CHD mortality not affectedUnintentional wt loss:

– 26-57% greater mortality risk, – 51-114% greater CHD risk

Increased mortality due to wt loss due to pre-existing disease.

Weight Cycling: Health Risk Factor?

NIH/NIDDK/WIN statementsrisk of remaining obese vs.

risk(?) of weight cyclingunderscores importance of life-

long changes in behaviors to attain a healthy weight.

A Prospective Study of Weight Change and Health-Related Quality of Life in

WomenJAMA Dec. 1999Nurse’s Health Study

– 40,098 women, 4 yr longitudinal study– Weight changes– Quality of life questionnaire

Physical function Vitality Freedom from bodily pain Mental health

The effect of weight gain/loss on:Vitality Score

Weight gain:– associated with

declines in vitality scores in all BMI categories

Weight loss– associated with

improved vitality scores only in women with BMI>25

The effect of weight gain/loss on:Mental Health Score

Weight gain– associated with a

decline in mental health scores in all weight categories

Weight loss– associated with

improved mental health scores only in obese class I women and declined in normal weight women.

A Prospective Study of Weight Change and Health-Related Quality of Life in Women.

Conclusions: For women at all BMI categories:

– Don’t gain weight– Reduced quality of life

For overweight and obese women:– Weight loss is generally associated with

improved quality of life For normal weight women

– Weight loss does not improve quality of life May actually reduce quality of life

Lose weight to improve health– Optimal health attained at BMI = 18,5-25

Avoid trying to lose weight to look like a media star– Media stars often may

Be genetically thin Lose weight in unhealthy ways Actually not be all that thin

Jamie Lee CurtisBefore and after work with 13 experts & 3 hours

“True Thighs” More magazine, August 2002

"The retouching is excessive. I do not look like that and more importantly I don't desire to look like that," she said. "I actually have a Polaroid that the photographer gave me on the day of the shoot… I can tell you they've reduced the size of my legs by about a third. For my money it looks pretty good the way it was taken."