Experiences of Discrimination and Incident Type 2 Diabetes Mellitus

The Multi-Ethnic Study of Atherosclerosis (MESA)

Kara M. Whitaker; Susan A. Everson-Rose; James S. Pankow; Carlos J. Rodriguez; Tené T. Lewis; Kiarri N. Kershaw; Ana V. Diez Roux; Pamela L. Lutsey

Disclosures

Am J Epidemiol. 2017;186(4):445-455. 

In This Article

Results

Participant Characteristics

As seen in Table 1, nearly 58% of the population reported no major experiences of discrimination, 23% reported discrimination in one situation, and 20% discrimination in 2 or more situations. All participant characteristics significantly differed by discrimination category (P < 0.001). Participants reporting greater levels of discrimination were more likely to be younger, African American, male, never married or divorced/separated, and have greater levels of education and income. Those reporting higher levels of discrimination were also more likely to be smokers, have higher levels of alcohol use, more depressive symptoms and chronic stress, higher levels of physical activity, greater mean BMI and waist circumference, and lower diet quality.

Approximately 18% of the total sample attributed at least 1 experience of discrimination to race/ethnicity (n = 973), and 31% attributed experience of discrimination to other causes (n = 1,636). Discrimination attributed to race/ethnicity was reported most frequently for African Americans (44.8%), followed by Hispanics (20.2%), Chinese (11.9%), and non-Hispanic whites (4.1%). Discrimination attributed to other causes was reported most frequently for non-Hispanic whites (35.9%), followed by African Americans (35.0%), Hispanics (27.3%), and Chinese (14.4%; data not shown).

Major Experiences of Discrimination and Incident Diabetes

A total of 654 cases of incident diabetes were confirmed during a median follow-up of 9.4 years (range, 0.87–11.38). The incidence per 1,000 person-years was 21.7 in Hispanics, 19.8 in African Americans, 16.1 in Chinese, and 11.6 in non-Hispanic whites. The hazard ratios and 95% confidence intervals of incident diabetes according to the number of major experiences of discrimination are presented in Table 2. For each additional experience of overall discrimination reported, there was a 12% increased risk of incident diabetes after controlling for demographic factors (hazard ratio (HR) = 1.12, 95% confidence interval (CI): 1.04, 1.19). This association remained significant after additionally controlling for psychosocial factors (model 2), behavioral factors (model 3), and obesity (model 4), although the strength of the association was slightly attenuated (model 4: HR = 1.09, 95% CI: 1.01, 1.17). When modeled categorically, individuals reporting discrimination in ≥2 situations had a 40% increased risk of incident diabetes compared with those reporting no discrimination after controlling for demographic factors. This association remained significant after additionally controlling for psychosocial and behavioral factors, as well as obesity (model 4: HR = 1.34, 95% CI: 1.08, 1.66).

When examining the association of discrimination attributed to race/ethnicity with incident diabetes, there was a positive trend and consistent association across all continuous models (model 1: HR = 1.09, 95% CI: 0.99, 1.21; model 4: HR = 1.09, 95% CI: 0.98, 1.21). When modeled categorically, individuals reporting race/ethnicity discrimination in 2 or more situations had a 36% greater risk of developing diabetes compared with those who reported no race/ethnicity discrimination after controlling for demographic factors (HR = 1.36, 95% CI: 1.02, 1.80). The association was not attenuated after additionally controlling for psychosocial factors, behavioral factors, and obesity (HR = 1.36, 95% CI: 1.01, 1.84). There were no statistically significant interactions by age, sex, or race/ethnicity (data not shown). However, in exploratory analyses, we further examined associations of racial/ethnic discrimination and incident diabetes by racial/ethnic group (see Web Table 2). Although precision was low in subgroup analyses, individuals who self-identified as Chinese, Hispanic, and non-Hispanic white, but not African American, reporting discrimination in 2 or more situations tended to have higher risk of developing diabetes, although the associations were not always statistically significant.

When examining major experiences of discrimination attributed to causes other than race/ethnicity, for each additional experience of discrimination reported, there was a 13% increased risk of incident diabetes (HR = 1.13, 95% CI: 1.02, 1.25). This association remained significant after additionally controlling for psychosocial and behavioral factors but was attenuated after controlling for obesity (HR = 1.08, 95% CI: 0.97, 1.20). Individuals reporting discrimination attributed to other causes in 2 or more situations were also at increased risk of incident diabetes, although the association was attenuated after additionally controlling for behavioral factors and obesity (model 4: HR = 1.22, 95% CI: 0.93, 1.60).

Everyday Discrimination and Incident Diabetes

Everyday discrimination, modeled as a continuous or categorical variable, was not associated with incident diabetes in any of the tested models (see Table 3).

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