Association between folate intake and melancholic depressive symptoms. A Finnish population-based study

An association between low blood folate levels and depressive symptoms (DS) has been reported in several epidemiological studies, but no studies have examined folate intake in melancholic or non-melancholic DS in population-based samples.

The aim of the study was to evaluate folate intake in DS with or without melancholic characteristics as a part of the Finnish diabetes prevention program (FIN-D2D). Altogether, 4500 randomly selected subjects aged 45-74 years were selected from the National Population Register. The study population (N=2806, participation rate 62%) consisted of 1328 men and 1478 women. The health examinations were carried out in 2007 according to the WHO MONICA project. The assessment of DS was based on the Beck Depression Inventory (BDI, cut-off≥10 points). A summary score of melancholic items in the BDI was used in dividing the participants with DS (N=429) into melancholic (N=138) and non-melancholic DS (N=291) subgroups. Folate intake was assessed using a validated food frequency questionnaire (FFQ).

DS associated linearly with gender specific tertiles of folate intake (p for linearity=0.003). The OR for melancholic DS was 0.55 (95%CI 0.34 to 0.90) for the high tertile of folate intake versus the low (p for linearity=0.018), while the ORs for non-melancholic DS were nonsignificant.

Assessment of DS was based on a self-rating scale, and the population was in advanced middle-aged.

A low folate intake was associated with DS through its effect on melancholic DS.