Metropolitan Area Socioeconomic Status and Depression - A Multilevel Study

WU, Yun-Hsuan

INTRODUCTION:

Depression is one of the most common mental illnesses worldwide, affecting 3.2% of the world’s population annually. Lower individual-level socioeconomic status (SES) is associated with higher levels of depression. However, it is not clear how the broader social environment affects mental health. The aim of this study is to explore the association of SES at the metropolitan statistical area (MSA) with depression in the U.S., with particular attention to education, income, and employment.

METHODS:

We used the 1999 National Health Interview Survey, which was the most recent year that used the Composite International Diagnostic Interview Short Form to measure depression. Census data from 2000 were used to measure three MSA-level markers of SES: % of population 25 years and over that had less than high school education, % of population 16 years and over that was unemployed, and % of households with income < $20,000. We used generalized estimating equations to investigate the association between MSA-level SES markers on depression, after controlling for individual-level covariates.

RESULTS:

16,402 adults with complete information on depression and MSA-level SES were included in the analysis. The annual prevalence of depression was 6.0 %. MSA-level markers of education (OR=1.01, 95% CI=0.99, 1.04) and income (OR=1.01, 95% CI=0.98, 1.04) were not associated with depression. However, individuals living in MSAs with a higher percentage of unemployed people had lower levels of depression (OR=0.95, 95% CI=0.92, 0.98).

CONCLUSIONS:

Our results suggested that MSA-level education and income were not associated with depression, while higher MSA-level unemployment was associated with less depression. The unexpected result for MSA-level employment, and the null results for the other SES markers, may be due to a high amount of missingness for MSA-level information, or that the MSA level might not be the most relevant geographic area when considering individual-level depression.