Abstract P228: The Relationship Between Obesity and Cardiometabolic Risk Factors Differs by Race/Ethnicity
Obesity is a major public health problem in the US, and is associated with several adverse health outcomes such as cardiovascular disease (CVD), diabetes and cancer. Research suggests that the association between obesity and certain diseases may not be similar in all racial/ethnic groups. To our knowledge, no published study has assessed the association of obesity with cardiometabolic risk factors simultaneously for Hispanics, non-Hispanic Whites (NHW) and African-Americans.
Methods We used data from the 2007-2008 National Health and Nutrition Examination Survey (NHANES) to examine, cross-sectionally, whether race/ethnicity modifies the relationship between body mass index (BMI) and: high sensitivity C-reactive protein (hsCRP), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), apoB, 2-hr glucose (OGTT) and insulin levels. Study subjects (age 20-75 ys) included 1508 Hispanics, 2192 NHWs and 1078 African-Americans (~50% women).
Results Hispanics had higher LDL-C, TG, apoB, insulin and OGTT, and lower HDL-C levels than NHWs and African-Americans. Both overweight and obesity were more prevalent among Hispanics, while morbid obesity was more prevalent among African-Americans. In univariate linear regression analysis, BMI significantly predicted all the studied biomarkers. The association between BMI and all biomarkers, with the exception of LDL-C, remained significant in multivariable linear regression analysis, independent of age, sex, smoking, physical activity, and diabetes (depending on the biomarker). There was a significant positive interaction between Hispanic ethnicity and BMI indicating that the increase in OGTT (B=0.13, p=0.02) and insulin (B=0.34, p=0.003) associated with obesity was higher for Hispanics than for others. Additionally, there was a significant negative interaction between Black race and BMI on TG levels indicating that the increase in TG with increasing BMI was significantly lower for African-Americans than for Hispanics and NHWs (B= -3.87, p=0.0007).
Conclusion In this study, ethnicity modified the effect of obesity on several biomarkers/CVD risk factors. The interactions between BMI and both OGTT and insulin levels are consistent with the higher prevalence of both obesity and type 2 diabetes in Hispanics. The negative interaction between black race and BMI on TG levels is also consistent with the fact that most of the excess fat depots in African-Americans are subcutaneous, rather than visceral. Caution should be exercised when interpreting these findings given the cross-sectional nature of the study where survival bias is common and temporal relationships are unclear.
- © 2013 by American Heart Association, Inc.