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Analyzing Age and Gender Relationship Stratified by Race, Region and Poverty level in Asthma Population Estimates

(2009)

By: Veatasha H. Dorsey

Research Background and Significance

According to CDCs National Center for Health Statistics:

8.2% of the U.S. population has asthma, or about 25 million people 3,395 asthma deaths were reported in 2008 Asthma accounted for 10.5 million lost school days and 14.2 million lost work days in 2008 4.2% of the population in 2009 reported at least one asthma attack in the previous year Asthma is a very frequent respiratory disease with roughly 8.2% of children and adolescents having asthma. During childhood, it is more frequent in males. However, during adulthood, it is more frequent in females. The prevalence (people who suffer asthma at the same moment) is on the rise, especially among children.

Given these statistics, I wish to see if there is a statistically significant relationship between the age and gender of

asthma sufferers delineated by race, region and economic status. A relationship, and particularly the strength (not

analyzed in this study) is important in the field of public health given the increased focus on health disparities commonly

associated with these three census markers.

Research Question: Stratified by race, region and economic status, is there a statistically significant relationship

between gender and age of current asthma sufferers?

Method:

The method that I used was a Chi Square Test for Independence. This test was most appropriate given my data set

included random sampling, a large sample size, categorical variables, and an expected frequency count > 5 in each cell of

the contingency table ( > 2x2 contingency table). My null and alternative Hypotheses are as follows. H0: There is not a

statistically significant relationship between age and gender (meaning gender and age are independent) and Ha: There is

a statistically significant relationship between age and gender (gender and age are not independent or related). I used a

dataset from the CDC on the current national asthma population in 2009.I chose the CDC based on its national

reputability and rigorous attention to sample size estimation and efficacious statistical analyses. The categories from this

particular data set that I used are as follows:

Categories

Race: White, Black, Hispanic , Mexican (Subset of Hispanic)

Region: Northeast, Midwest, South, West

Family Income: Poverty Threshold

The family income-poverty threshold is the ratio of income to poverty is a family's or person's income divided by their

poverty threshold. The Frequency ratios are < 1.00 (below 100 percent of poverty) are below the official poverty

definition and > 1.00 or greater (100 percent of poverty or greater) indicate income above the poverty level.

http://www.cdc.gov/asthma/nhis/09/table3-1.htmhttp://www.cdc.gov/asthma/nhis/09/table3-1.htm

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Results-Chi Square Test

Conclusions

At the 0.05 level of significance we reject the null hypothesis and conclude that there is a relationship between age

and gender of asthma sufferers in the stratified by race, region and economic status. A graphical depiction of the

categories (shown in the Appendix below) is generally representative of the idea that male children have increased

asthma rates among children sampled and adult females have increased asthma rates among the sampled adults.

However, we see that the gap between black male and female children with asthma sampled is closer than any other

race. An interesting finding is that among lower income children the asthma rate is higher, however, among higher

income adults the asthma rate is also higher. This can possibly be explained by a childs respiratory system being more

susceptible to environmental pollutants (a major contributor to asthma), especially in poorer areas, than adults who

develop asthma during adulthood.

Limitations

This study was largely delimited by time. In addition, the testing method used could have caused a limitation to

gathering the most information from this study. While Chi Square shows us statistical significance (as respresented by

the table above and the rejection of the null hypothesis) it does not give us much information about the strength of the

relationship or substantive significance, much like if the Odds Ratio was calculated once a dependency was found.

Region and Economic Status were not stratified by race within the sample. If it was, it could have possibly given moreinsight spatially (for region) in the analysis.

Chi Square Test

Asthma Sufferers df X2

P(X2) P(X

2) Round

Race* White 1 790.4 6.73E-174 0Black 1 197.5 7.20E-45 0

Hispanic 1 141.0 1.64E-32 0

Mexican 1 93.3 4.55E-22 0

Region 2 99.0 2.61E-21 0

Income:Poverty Threshold 2 602.7 2.67E-130 0

* Yates Continuity Correction for X2

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References

World Health Organization. Global surveillance, prevention and control of chronic respiratory diseases: a comprehensive

approach [database on the Internet]. http://www.who.int/gard/publications/GARD_Manual/en/index.html

Centers for Disease Control and Prevention. 2008 adult asthma data: prevalence tables and maps [database on the

Internet]. 2008. http://www.cdc.gov/asthma/brfss/08/lifetime/tableL1.htm

American Lung Association. Trends in asthma morbidity and mortality [database on the Internet]. 2010.http://www.lungusa.org/finding-cures/our-research/trend-reports/asthma-trend-report.pdf.

Centers for Disease Control and Prevention. Adult self-reported current asthma prevalence rate by sex and state or

territory: BRFSS 2008 [database on the Internet]. http://www.cdc.gov/asthma/brfss/08/current/tableC21.htm

Barnes PM, Heyman KM, Freeman G, et al. Early release of selected estimates based on data from the 2009 National

Health Interview Survey. Hyattsville, MD: National Center for Health Statistics; 2010.

http://www.cdc.gov/nchs/nhis.htm.

Appendix (Contingency Tables and Graphs)

White Children (< 18 yrs) Adult (> 18 yrs) Total

Male 2135 4364 6499

Female 1338 8120 9458

Total 3473 12484 15957

Black Children (< 18 yrs) Adult (> 18 yrs) Total

Male 972 739 1711

Female 816 1542 2358

Total 1788 2281 4069

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2009 National Health Interview Survey (NHIS)DataPrevious Table|Next Table

Table 3-1Current Asthma Population Estimates -- in thousands

by Age, United States: National Health Interview Survey, 2009Age (years)

15-34

Characteristic

AllagesTotal

ChildrenAge

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Table 3-1Current Asthma Population Estimates -- in thousands

by Age, United States: National Health Interview Survey, 2009

Age (years)

15-34

Characteristic

All

agesTotal

Children

Age