Association between serum 25-hydroxyvitamin D and depressive symptoms in Japanese: analysis by survey season

Abstract

Both depressive symptoms and vitamin D insufficiency are common during winter. This study examined the association between serum 25-hydroxyvitamin D and depressive symptoms by survey season. Subjects were 527 municipal employees aged 21-67 years of two municipal offices in Japan. Overall, there was no measurable association. However, in the workplace surveyed in November, multivariate-adjusted odds ratios (95% confidence interval) of having depressive symptoms (Center for Epidemiologic Studies Depression score of X16) for the lowest through highest quartiles of serum 25-hydroxyvitamin D were 1.00 (reference), 0.84 (0.45-1.58), 0.83 (0.44-1.58) and 0.59 (0.30-1.15), respectively (trend P ¼ 0.14). The association with the severe depressive state was more pronounced. By contrast, there was no such association in the workplace surveyed in July. Overall, this study did not provide evidence linking higher blood vitamin D levels with decreased depressive symptoms. The suggestive inverse association in sun-deprived season warrants further investigation.

Association between vitamin D and depressive symptoms varies by season: Results from the German Health Interview and Examination Survey for Adults (DEGS1)

“…Analyses showed an inverse association between vitamin D concentrations and levels of depressive symptoms but no effect modification by season (interaction term: p=0.39). Similarly, although using different methods, a study of 527 office workers in Japan aged 21 to 67 years (Nanri et al, 2009) Conflicting results found across previous studies are likely to be underpinned by diverse study methodology. Several differences including the observed population and age groups, definitions of seasons, heterogenity in instruments used to assess depressive symptoms, and various methods to analyse vitamin D and cut-offs to determine depression and vitamin D deficiency make direct comparisons with previous studies challenging.…”

“…Remarkably, relatively few studies have examined the influence of season on the association between vitamin D and depression (Brandenbarg et al, 2012;Hoang et al, 2011;Kjaergaard et al, 2011;Nanri et al, 2009;Stewart and Hirani, 2010). Results from these studies were mixed; three studies did not observe an influence of season (Brandenbarg et al, 2012;Nanri et al, 2009;Stewart and Hirani, 2010), while the other two studies reported conflicting evidence for an inverse association between vitamin D and depressive symptoms in winter (Hoang et al, 2011) and in summer (Kjaergaard et al, 2011).…”

“…Lee et al, 2011;Milaneschi et al, 2010;Polak et al, 2014;Williams et al, 2014) and others finding no relationship (Almeida et al, 2015;Pan et al, 2009;Zhao et al, 2010). Although depressive symptoms are common during winter times in northern latitudes, only a few studies specifically examined the influence of season on the association (Brandenbarg et al, 2012;Hoang et al, 2011;Kjaergaard et al, 2011;Nanri et al, 2009;Stewart and Hirani, 2010).…”

Association Between Low Serum 25-Hydroxyvitamin D and Depression in a Large Sample of Healthy Adults: The Cooper Center Longitudinal Study

“…This subset analysis may shed light on why there were conflicting results in earlier studies because the populations were not assessed on the basis of prior history of depression. [20][21][22][23][24] These findings may potentially have clinical importance in the evaluation of patients with a prior history of depression.…”

“…[26][27][28] Previous observational studies also used the CES-D to assess depressive symptoms in large populations. [20][21][22][23][24]31 History of depression was based on patient report and confirmed by the physician but not further defined. In addition, although we controlled for many known confounds, some may have remained.…”