Adherence to healthy dietary guidelines and future depressive symptoms: evidence for sex differentials in the Whitehall II study

Abstract

Background: It has been suggested that dietary patterns are associated with future risk of depressive symptoms. However, there is a paucity of prospective data that have examined the temporality of this relation.

Objective: We examined whether adherence to a healthy diet, as defined by using the Alternative Healthy Eating Index (AHEI), was prospectively associated with depressive symptoms assessed over a 5-y period.

Design: Analyses were based on 4215 participants in the Whitehall II Study. AHEI scores were computed in 1991-1993 and 2003-2004. Recurrent depressive symptoms were defined as having a Center for Epidemiologic Studies Depression Scale score ≥16 or self-reported use of antidepressants in 2003-2004 and 2008-2009.

Results: After adjustment for potential confounders, the AHEI score was inversely associated with recurrent depressive symptoms in a dose-response fashion in women (P-trend < 0.001; for 1 SD in AHEI score; OR: 0.59; 95% CI: 0.47, 0.75) but not in men. Women who maintained high AHEI scores or improved their scores during the 10-y measurement period had 65% (OR: 0.35%; 95% CI: 0.19%, 0.64%) and 68% (OR: 0.32%; 95% CI: 0.13%, 0.78%) lower odds of subsequent recurrent depressive symptoms than did women who maintained low AHEI scores. Among AHEI components, vegetable, fruit, trans fat, and the ratio of polyunsaturated fat to saturated fat components were associated with recurrent depressive symptoms in women.

Conclusion: In the current study, there was a suggestion that poor diet is a risk factor for future depression in women.

FIGURE 1.

Derivation of the analytic sample. Compared with participants excluded from the current analytic sample (n = 2728), included participants (n = 4215) were more likely to be men, white, younger, and with a high socioeconomic status (all P < 0.001) and less likely to report recurrent depressive symptoms (P < 0.001). Furthermore, a higher mean total energy intake (P < 0.001) and AHEI score (P < 0.001) were observed in included than excluded participants because of missing data on depressive symptoms or covariates. AHEI, Alternative Healthy Eating Index.

FIGURE 2.

Associations between AHEI-component scores assessed at phase 7 and onset of recurrent depressive symptoms over 5 y in women. ORs for the development of recurrent depression symptoms associated with an increase of 1 SD in AHEI-component scores at phase 7. M1 was adjusted for age, ethnicity, and total energy intake at phase 7. M2 was adjusted as for M1 and for socioeconomic status, retirement status, marital status, smoking, physical activity, coronary artery disease, type 2 diabetes, hypertension, HDL cholesterol, use of lipid-lowering drugs, central obesity, and cognitive impairment assessed at phase 7. M3 was adjusted as for M2 and for the 8 other AHEI-component scores. AHEI, Alternative Healthy Eating Index; M1, model 1; M2, model 2; M3, model 3.

FIGURE 3.

Associations [ORs (95% CIs)] between changes in AHEI components over the 10-y exposure period and subsequent recurrent depressive symptoms over 5 y in women. To analyze the 10-y change in AHEI-component scores, the AHEI-component scores were categorized as high or low according to the median value of AHEI-component scores at phase 3. Median values at phase 3 for AHEI-component scores were, respectively, 6, 6, 3, 5, 10, 10, 5, 2.5, and 5 for vegetables, fruit, nuts and soy, the ratio of white to red meat, fiber, trans fat, the ratio of PUFA to saturated fat, multivitamin use, and alcohol. Four categories in the 10-y change in AHEI components were defined as follows: participants who maintained a high AHEI-component score [phase 3 and 7 scores of at least the median value at phase 3 (eg, 6 for vegetables)], participants who maintained a low AHEI-component score (phase 3 and 7 scores <6), participants who improved their AHEI-component score (phase 3 score <6 and phase 7 score ≥6), and participants who decreased their AHEI-component score (phase 3 score ≥6 and phase 7 score <6). Odds of 5-y recurrent depressive symptoms were estimated for 1) participants who maintained a high AHEI-component score (compared with individuals who maintained a low score), 2) participants who improved their AHEI-component score (compared with individuals who maintained a low score), and 3) participants who decreased their AHEI-component score (compared with individuals who maintained a high score). This procedure was applied to the 9 AHEI components. ORs were adjusted for age, ethnicity, total energy intake, SES, retirement status, marital status, smoking, physical activity, HDL cholesterol, coronary artery disease, hypertension, and central obesity assessed at phase 3. AHEI, Alternative Healthy Eating Index; SES, socioeconomic status.