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 equation models (SM) were conducted and compared. Time-dependent 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, -0.069), 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 × 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 × sex groups. Our findings can inform the potential effectiveness of various mental health and dietary interventions.

Keywords: central adiposity; depression; dietary quality; socioeconomic status; urban adults.

FIGURE 1

Best-fit model [(A) model 3] and second best-fit model [(B) model 11] out of the 12 SMs and compared within race × sex with the use of the lowest AIC/BIC criteria. (A) Model 3. All: AIC/BIC = 38,751/38,999; n = 1064; total effects: SES→ΔHEI: +0.037* SES→Adip_cent(v2): −0.10* CES-D(v1)→Adip_cent(v2): 0.07; indirect effects: SES→ΔHEI: +0.004* SES→Adip_cent(v2): −0.031* CES-D(v1)→Adip_cent(v2): −0.001* mediation proportions: SES→ΔHEI: −10.8%; SES→Adip_cent(v2): +31.0%; CES-D(v1)→Adip_cent(v2): NA. WW: AIC/BIC = 8030/8176; n = 236. WM: AIC/BIC = 5108/5237; n = 159. AAW: AIC/BIC = 12,463/12,630; n = 395. AAM: AIC/BIC = 9313/9465; n = 274. (B) Model 11. All: AIC/BIC = 39,044/39,293; n = 1064; total effects: SES→ΔHEI: +0.038* SES→CES-D(v2): −2.73* Adip_cent(v1)→CES-D(v2): +0.66^~; indirect effects: SES→ΔHEI: +0.0010* SES→CES-D(v2): −0.030^~; Adip_cent(v1)→CES-D(v2): −0.006^~; mediation proportions: SES→ΔHEI: +2.6; SES→CES-D(v2): 1.1; Adip_cent(v1)→CES-D(v2): −0.9. WW: AIC/BIC = 8037/8182; n = 236. WM: AIC/BIC = 5148/5277; n = 159. AAW: AIC/BIC = 12,563/12,729; n = 395. AAM: AIC/BIC = 9464/9616; n = 274. ^~P < 0.10, *P < 0.05 for null hypothesis that path coefficient = 0 or that total/indirect effect = 0. Detailed findings are presented in Supplemental Tables 1–4. ^aP < 0.05 based on Wald test for path equality constraint after multigroup analysis. AAM, African American men; AAW, African American women; Adip_cent, central adiposity; AIC, Akaike information criterion; BIC, Bayesian information criterion; CES-D, Center for Epidemiologic Studies–Depression; HEI, Healthy Eating Index; NA, not applicable; SES, socioeconomic status; SM, structural equations model; WM, white men; WW, white women; Δ, annual rate of change.