Low serum 25-hydroxyvitamin D concentrations are associated with increased likelihood of having depressive symptoms among Japanese workers.
BACKGROUND
Accumulating evidence suggests a protective role of vitamin D against mood disorders; however, epidemiologic studies are scarce in working populations.


OBJECTIVE
We investigated cross-sectionally the association of serum vitamin D status and depressive symptoms among Japanese workers.


METHODS
Participants were 1786 employees (9% women), aged 19-69 y, who received health check-ups and participated in a nutrition and health survey. Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured with the use of a competitive protein binding assay. Depressive symptoms were assessed by using the Center for Epidemiologic Studies Depression (CES-D) scale. Logistic regression was used to estimate ORs with adjustment for potential confounding variables including dietary factors.


RESULTS
Overall, 92% of study participants had suboptimal vitamin D status [25(OH)D <30 μg/L]. Depressive symptoms were inversely associated with 25(OH)D. Compared with those with a 25(OH)D concentration of <20 μg/L, multivariable-adjusted ORs (95% CIs) for depressive symptoms (CES-D scale score ≥16) were 0.75 (0.59, 0.95) and 0.66 (0.41, 1.06) for those with a 25(OH)D concentration of 20-29 μg/L and ≥30 μg/L, respectively (P-trend = 0.01). After further adjustment for leisure-time physical activity and shift work (factors closely related to photo-initiated vitamin D production), the OR (95% CI) for the highest category of 25(OH)D was 0.70 (0.43, 1.14). The association between 25(OH)D and depressive symptoms appears to be linear, according to restricted cubic spline regression.


CONCLUSIONS
Results suggest that lower concentrations of circulating vitamin D are associated with increased likelihood of having depressive symptoms among apparently healthy workers.
Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan mizoue@ri.ncgm.go.jp.
Tetsuya
T
Mizoue
Department of Health Administration, Furukawa Electric Corporation, Tokyo, Japan; and.
Takeshi
T
Kochi
Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan.
Shamima
S
Akter
Department of Health Administration, Furukawa Electric Corporation, Tokyo, Japan; and.
Masafumi
M
Eguchi
Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan.
Kayo
K
Kurotani
Department of Health Administration, Furukawa Electric Corporation, Tokyo, Japan; and.
Hiroko
H
Tsuruoka
Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan Teikyo University Graduate School of Public Health, Tokyo, Japan.
Keisuke
K
Kuwahara
Department of Health Administration, Furukawa Electric Corporation, Tokyo, Japan; and.
Rie
R
Ito
Department of Health Administration, Furukawa Electric Corporation, Tokyo, Japan; and.
Isamu
I
Kabe
Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan.
Akiko
A
Nanri
D000328:Adult; D000368:Aged; D044466:Asian People; D003430:Cross-Sectional Studies; D003863:Depression / Q000097:blood* / Q000150:complications; D005260:Female; D006306:Health Surveys; D006801:Humans; D007564:Japan; D016015:Logistic Models; D008875:Middle Aged; D009752:Nutritional Status; D011336:Probability; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications; D055815:Young Adult
D014807:Vitamin D; C104450:25-hydroxyvitamin D
25-hydroxyvitamin D; Japanese; cross-sectional studies; depressive symptoms; worker