FIGURE 1.

Multivariate relative risks (RR; 95% CIs) of clinical depression with increased intake of α-linolenic acid (ALA) according to stratification by quintiles (Q) of linoleic acid (LA). Values are RRs from Cox proportional hazards models. The RR is for each 0.5-g/d increase of ALA. The ALA × LA interaction was significant for clinical depression risk (P = 0.02). Multivariate analysis included the following covariates: age (continuous); time interval; hormonal status (postmenopausal without or with hormonal therapy, premenopausal); white race (binary); obesity (binary); smoking status (never smoked; past smoker; currently smoke 1–14 cigarettes/d, 15–24 cigarettes/d, or ≥25 cigarettes/d); physical activity (quintiles); reported diagnosis of diabetes (binary), cancer (binary), or myocardial infarction or angina (binary); multivitamin use (binary); and cumulative average intake (all continuous) of energy (kcal/d), protein (g/d), trans fatty acids (g/d), saturated fatty acids (g/d), monounsaturated fatty acids (g/d), alcohol (g/d), eicosapentaenoic acid plus docosahexaenoic acid (g/d), arachidonic acid (g/d), and fish oil (never, 1990 only, 1994 only, or both 1990 and 1994).