Additive Effects of Anxiety and Depression on Body Mass Index among Blacks: Role of Ethnicity and Gender.

Background: Most studies on mental health associates of obesity have focused on depression and less is known about the role of anxiety in obesity.

Objectives: This study compared the additive effects of General Anxiety Disorder (GAD) and Major Depressive Disorder (MDD) on Body Mass Index (BMI) across sub-populations of Blacks based on the intersection of ethnicity and gender.

Methods: Data came from the National Survey of American Life (NSAL), 2001 - 2003. The participants consisted of 3,570 African Americans and 1,621 Caribbean Blacks. Twelve-month MDD and GAD were determined using the World Mental Health Composite International Diagnostic Interview (CIDI). Levels of BMI were categorized based on being equal to or larger than 25, 30, 35, and 40 kg/m(2). We fitted linear regression models specific for our groups, which were defined based on the intersection of ethnicity and gender. Additionally, age, education, marital status, employment, and region were controlled.

Results: Among Caribbean Black men and African American women, lifetime GAD, but not MDD, was associated with high BMI. Among Caribbean Black women, lifetime MDD, but not GAD, was associated with high BMI.

Conclusions: Intersection of ethnicity and gender may determine how anxiety and depression are associated with BMI among Blacks. Sub-populations of Blacks (e.g. based on ethnicity and gender) may have specific mental health determinants or consequences of obesity. Future research should investigate how and why the additive effects of anxiety and depression on obesity vary across ethnic and gender groups of Blacks.