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.
Zhang
Qi
Q
School of Community and Environmental Health, Old Dominion University, Norfolk, VA, USA. qzhang@odu.edu
Wang
Youfa
Y
Huang
Elbert S
ES
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