Alternative pathway analyses indicate bidirectional relations between depressive symptoms, diet quality, and central adiposity in a sample of urban US adults

Abstract

Background: Temporality between socioeconomic status (SES), depressive symptoms (DS), dietary quality (DQ), and central adiposity (CA) is underexplored. Objectives: Alternative pathways linking SES to DQ, DS, and CA were tested and models compared, stratified by race and sex. Methods: With the use of data from the Healthy Aging in Neighborhoods of Diversity across the Life Span (baseline age: 30-64 y; 2 visits; mean follow-up: 4.9 y), 12 structural equationmodels (SM) were conducted and compared. Timedependent factors included the Center for Epidemiologic Studies-Depression [CES-D total score, baseline or visit 1 (v1), follow-up or visit 2 (v2), mean across visits (m), and annual rate of change (Δ)], 2010 Healthy Eating Index (HEI) (same notation), and central adiposity principal components' analysis score of waist circumference and trunk fat (kg) (Adipcent) (same notation). Sample sizes were white women (WW, n = 236), white men (WM, n = 159), African American women (AAW, n = 395), and African American men (AAM, n = 274), and a multigroup analysis within the SM framework was also conducted. Results: In the best-fitting model, overall, ~31% of the total effect of SES → Adipcent(v2) (α ± SE: -0.10 ± 0.03, P < 0.05) was mediated through a combination of CES-D(v1) and ΔHEI. Two dominant pathways contributed to the indirect effect: SES→(-)CES-D(v1)→ (+)Adipcent(v2) (-0.015) and SES → (+) ΔHEI → (-)Adipcent(v2) (-0.017), with a total indirect effect of -0.031 (P < 0.05). In a second best-fitting model, SES independently predicted Adipcent(v1, 20.069), ΔHEI(+0.037) and CES-D(v2, -2.70) (P < 0.05), with Adipcent(v1) marginally predicting ΔHEI(-0.014) and CES-D(v2, +0.67) (P < 0.10). These findings were indicative of DS's and CA's marginally significant bidirectional association (P < 0.10). Although best-fit- selected models were consistent across race 3 sex categories, path coefficients differed significantly between groups. Specifically, SES→Adipcent[v1(+0.11), v2(+0.14)] was positive among AAM (P < 0.05), and the overall positive association of Adipcent(v1)/CES-D(v2) was specific to AAW (+0.97, P < 0.10). Conclusions: Despite consistent model fit, pathways linking SES to DQ, DS, and CA differed markedly among the race 3 sex groups. Our findings can inform the potential effectiveness of various mental health and dietary interventions. J Nutr 2016;146:1241-9.