Racial discrimination, body mass index, and insulin resistance: A longitudinal analysis

Abstract

Objective: To examine prospective relations of perceived racial discrimination at ages 16-18 with body mass index (BMI) at ages 19-21 and insulin resistance (IR) at ages 25 and 27 among Black youth in the rural South, and to determine whether BMI connected discrimination to IR as a mediator.

Method: Participants were 315 African American adolescents in rural counties in Georgia who provided data on their perceptions of discrimination during adolescence. BMI was measured during a yearly home visit, and a certified phlebotomist drew a fasting blood sample from which IR was measured.

Results: The data analysis, with all confounding variables controlled, revealed that, over time, (a) discrimination was associated positively with both BMI and IR; (b) BMI was associated positively with IR; and (c) BMI acted as a mediator connecting discrimination with IR.

Conclusions: The findings are consistent with the hypothesis that exposure to discrimination presages IR through its effects on BMI. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Figure 1.

The estimated trajectories of racial discrimination for each class.

Figure 2.

Means of (a) IR levels at ages 25 to 27 and (b) BMI at ages 19 to 21 for the racial discrimination trajectory groups. Error bars = ±1 standard error. Analyses controlled for gender, family SES disadvantage, depressive symptoms, life stress, drug use, and exercise.

Figure 3.

BMI at ages 19 to 21 as a mediator of the relation between racial discrimination at ages 16 to 18 and IR at ages 25 to 27. Family socioeconomic-related risk at ages 16 to 18, gender, youth depressive symptoms at ages 16 to 17, youth personal life stress at ages 17 to 18, and youth substance use and exercise at ages 19 to 21 were controlled (not shown). Unstandardized coefficients with 95% confident intervals (CI) are presented. N = 337. *p < .05; **p < .01; ***p < .001.