title: Vitamin D status in the Chinese population in the Netherlands: The DRAGON study.
abstract: Vitamin D is essential for bone health since it stimulates the intestinal absorption of calcium and phosphorus from the gut, both necessary for bone mineralization. However, vitamin D deficiency is highly prevalent among several non-Western immigrant populations in the Netherlands. To date, there are no data available of the vitamin D status in the Chinese population residing in the Netherlands. Therefore, an observational study was performed to determine 25-hydroxyvitamin D (25(OH)D) concentrations and to assess potential determinants of low vitamin D status.
  
  
  
  Subjects, aged 18 years and older, with a Chinese background and residing in the Netherlands were invited to participate in the study. A questionnaire was used to assess general characteristics and lifestyle habits. Fasting blood samples were obtained in March 2014 to measure serum 25(OH)D concentration, and analysed by liquid chromatography tandem mass spectrometry.
  
  
  
  418 subjects participated in the study, 104 men and 314 women. The mean age for both men and women was 56 years. Serum 25(OH)D concentration <50nmol/L was more prevalent in men than in women (67.9% and 53.1%, respectively; p=0.008). The percentage of serum 25(OH)D concentration<25nmol/L in men and women was 5.8% and 10.9%, respectively. Multiple logistic regression analysis, adjusted for age and gender, revealed that non-use of vitamin D supplements and fewer days per week of physical activity were significant predictors of serum 25(OH)D levels below 50nmol/L.
  
  
  
  Within the Chinese population living in the Netherlands, serum 25(OH)D concentration was below 50nmol/L in 68% of men and 53% of women. Use of vitamin D supplements by Chinese people in the Netherlands was highly protective against low 25(OH)D levels.
authors.affiliation: Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: p.w.man@lumc.nl.
authors.forename: Ping Wai
authors.initials: PW
authors.lastname: Man
authors.affiliation: Medical Center Balans, The Hague, The Netherlands.
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Lin
authors.affiliation: Department of Epidemiology, Municipal Health Service Haaglanden, The Hague, The Netherlands.
authors.forename: Irene M
authors.initials: IM
authors.lastname: van der Meer
authors.affiliation: Department of Clinical Chemistry, Endocrine Laboratory, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Annemieke C
authors.initials: AC
authors.lastname: Heijboer
authors.affiliation: Department of Medical Statistics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Ron
authors.initials: R
authors.lastname: Wolterbeek
authors.affiliation: Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Mattijs E
authors.initials: ME
authors.lastname: Numans
authors.affiliation: Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands; Department of Epidemiology, Municipal Health Service Haaglanden, The Hague, The Netherlands.
authors.forename: Barend J C
authors.initials: BJC
authors.lastname: Middelkoop
authors.affiliation: Department of Internal Medicine, Endocrine Section, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Paul
authors.initials: P
authors.lastname: Lips
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D019587:Dietary Supplements / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D014815:Vitamins / Q000097:blood*
chemical_list: D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25(OH)D; Chinese; Netherlands; Non-Western immigrant; Vitamin D status