title: Impact of demographic, environmental, and lifestyle factors on vitamin D sufficiency in 9084 Japanese adults.
abstract: BACKGROUND
  Little is known about correlates of vitamin D status in Asian populations. In this study, we established the prevalence of vitamin D sufficiency in the Murakami region (latitude N38°13') in Niigata, Japan, and examined demographic, environmental, and lifestyle factors that might be associated with vitamin D sufficiency, with the aim of clarifying the relative contributions of previously described determinants of vitamin D status as well as identifying new determinants in this Japanese population.
  
  
  METHODS
  This study involved a cross-sectional analysis of baseline data obtained from a cohort study conducted in 2011-2013. Participants were 9084 individuals aged between 40 and 74 years who provided blood samples for the determination of plasma 25-hydroxyvitamin D [25(OH)D] concentrations. Lifestyle information was obtained from 8498 participants, with some missing values regarding different lifestyle factors. Multiple logistic regression analysis was used to obtain odds ratios for vitamin D sufficiency, which was defined as a plasma 25(OH)D concentration ≥ 75 nmol/L.
  
  
  RESULTS
  The prevalence of vitamin D sufficiency (i.e., plasma 25(OH)D concentration ≥ 75 nmol/L) was 9.1%, and significant associations were observed with male gender (P<0.0001; OR=2.37, 95% CI: 1.84-3.05), older age (P for trend <0.0001), lower BMI (P for trend <0.0001), higher METs score (P for trend=0.0138), higher vitamin D intake (P for trend=0.0467), summer season (P for trend <0.0001), longer duration outdoors (P for trend=0.0026), no sunscreen use (P=0.0135; OR=1.40, 95% CI: 1.07-1.82), higher salmon consumption (P for trend <0.0001), higher alcohol consumption (P for trend <0.0001), and lower coffee consumption (P for trend=0.0025). Unlike other populations previously reported, vitamin D sufficiency was associated with older age.
  
  
  CONCLUSIONS
  The prevalence of vitamin D sufficiency (i.e., 25[OH]D ≥ 75 nmol/L) was low (9.1%) in this Japanese population. A number of demographic, environmental, and lifestyle factors are associated with vitamin D sufficiency, and thus lifestyle modification may present an opportunity to achieve vitamin D sufficiency.
authors.affiliation: Division of Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata City 951-8510, Japan. Electronic address: kazun@med.niigata-u.ac.jp.
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Division of Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata City 951-8510, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kitamura
authors.affiliation: Division of Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata City 951-8510, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Takachi
authors.affiliation: Department of Health and Nutrition, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata City 951-3198, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Saito
authors.affiliation: Department of Physical Therapy, Niigata University of Health and Welfare, 1398 Shimami-cho, Niigata City 951-3198, Kita-ku, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Kobayashi
authors.affiliation: Department of Physical Therapy, Niigata University of Health and Welfare, 1398 Shimami-cho, Niigata City 951-3198, Kita-ku, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Oshiki
authors.affiliation: Division of Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata City 951-8510, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tsugane
authors.affiliation: Murakami Public Health Center, 10-15 Sakanamachi, Murakami, Niigata 958-0864, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Sasaki
authors.affiliation: Niigata Prefectural Office, 4-1 Shinkocho, Chuo-ku, Niigata City 950-0965, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Yamazaki
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D003710:Demography; D004777:Environment; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Asian; Cross-sectional study; Lifestyle; Odds ratio; Vitamin D deficiency; Vitamin D sufficiency