Background: Low vitamin B-6 status has been linked to depressive symptomatology. However, most studies have been cross-sectional and may not have controlled for relevant confounders. Few studies have examined this association in Latino populations at high risk for major depression. Design: We used two-level hierarchical linear regression models (HLM) for continuous outcomes. Level-1 data included three measures of participant’s depressive symptomatology collected at baseline, 2y follow-up and 5y follow-up. Participants constituted level-2 data. Vitamin B-6 was associated with depressive symptomatology across these time points. Objective: We examined the longitudinal association of vitamin B-6 status with depressive symptomatology across 3 time points over ~ 5-7 y in a cohort of older Puerto Rican adults, a population previously identified to be at high risk for depressive symptomatology and clinical depression. Results: Plasma pyridoxyl-5’-phosphate (PLP) concentration, a time-varying predictor, was significantly associated with depressive symptomatology. Study participants with PLP deficiency, vs. optimal PLP, had higher baseline depressive symptoms (22±14, vs. 20±13); this differential remained constant over time and persisted after controlling for age, sex, education, BMI, smoking and alcohol use, other relevant nutritional factors, perceived stress, stressful life events and allostatic load; and use of antidepressant medication. However, PLP concentration was not associated with the rate of change in depressive symptomatology over time. Conclusions: Suboptimal plasma PLP is associated with higher depressive symptomatology in older Puerto Rican adults and this appears to persist over time. Our data suggest that identification and treatment of vitamin B-6 deficiency may be a useful preventive and intervention approach in this population.

Objectives: To examine the association between red blood cell (RBC) ω-6 and ω-3 fatty acid (FA) composition and cognitive function over 2-y follow-up among older U.S. mainland Puerto Ricans. Methods: Data are from the Boston Puerto Rican Health Study (74% female; 57±8 y). RBC membrane FA status was ascertained at baseline. Individual FA were expressed as a percentage of total FA identified. Cognitive function was measured at baseline and at 2-y using the Mini-Mental State Exam (MMSE), where a higher score ranging from 0-30 indicates better function. Cognitive impairment was defined as MMSE scores ≤21, ≤23, and ≤24 for those with less than a 9th grade education, a 9th to 12th grade education, and some college education or higher, respectively. Relations between FA and MMSE scores were examined in 946 participants and incidence of cognitive impairment among those considered to be cognitively normal at baseline (n=639). Results: In multivariate models additionally adjusted for baseline MMSE, total ω-6 FA (quartiles) were associated with lower MMSE score at 2-y (P-trend=0.003). Total ω-3 FA were positively (P-trend=0.04) and the ω-6:ω-3 ratio inversely (P-trend=0.007) related to 2-y MMSE, but these relationships attenuated with adjustment for baseline score. The incidence of cognitive impairment at follow-up was 22%. In multivariate models, a 1% increase in total ω-6 FA related to a 9% greater incidence of cognitive impairment [RR=1.09 (95% CI: 1.00, 1.18), P=0.04]. Total ω-3 FA were inversely related to incident cognitive impairment [RR=0.92 (0.81 to 1.05), P=0.21], whereas the ω-6:ω-3 ratio was positively associated [RR=1.12 (95% CI: 0.98, 1.26), P=0.08]. Conclusions: An objective biomarker of ω-6 FA consumption was associated with poorer cognitive function and incidence of cognitive impairment over 2-y follow-up, suggesting that greater intakes of food sources of ω-6 FA may play a role in cognitive decline among older U.S. mainland Puerto Ricans.