Changes in racial/ethnic disparities in the prevalence of Type 2 diabetes by obesity level among US adults.
OBJECTIVE
Ethnic minority status and obesity are two independent risk factors for Type 2 diabetes (T2D). There is no clear understanding of how they may have interacted and influenced disparities in T2D prevalence over time. This study examined the trends in racial/ethnic disparities in the prevalence of T2D by weight status among US adults.


METHODS
We used nationally representative data from the National Health and Nutrition Examination Surveys I (1971-1975), II (1976-1980), and III (1988-1994), and 1999-2004 among 49,574 adults aged 20-74 years. The prevalences of diagnosed and undiagnosed T2D were estimated by race/ethnicity groups (non-Hispanic White, non-Hispanic Black, and Mexican American) and body mass index (BMI) groups (normal, 18.5-24.9; overweight, 25-29.9; obese, 30-34.9; severely obese, >or=35). We used logistic regression controlling for age, gender, and education to estimate the odds ratio of T2D across race/ethnicity and BMI groups.


RESULTS
Trends in racial/ethnic disparities in prevalence of diagnosed T2D varied by BMI. Normal weight group saw increasing racial disparities. In the overweight group, ethnic disparities worsened as diabetes prevalence increased 33.3% in Whites, compared to 60.0% in Blacks, and 227.3% in Mexican Americans. Minimal racial/ethnic disparities were observed in obese and severely obese groups over time. In contrast to diagnosed diabetes, overall racial/ethnic disparities in undiagnosed T2D declined in all BMI groups.


CONCLUSIONS
Racial/ethnic disparities in diabetes prevalence have become most pronounced among normal and overweight groups. Eliminating racial/ethnic disparities in diabetes will require prevention efforts not only in obese minority individuals, but also in normal and overweight minority individuals.
School of Community and Environmental Health, Old Dominion University, Norfolk, VA, USA. qzhang@odu.edu
Qi
Q
Zhang
Youfa
Y
Wang
Elbert S
ES
Huang
D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D015992:Body Mass Index; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000209:etiology; D005006:Ethnicity; D005260:Female; D054624:Health Status Disparities; D006306:Health Surveys; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D016017:Odds Ratio; D011287:Prejudice; D015995:Prevalence; D012307:Risk Factors; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology