title: Lifestyle and Dietary Factors Associated with Serum 25-Hydroxyvitamin D Levels in Korean Young Adults.
abstract: Inadequate vitamin D status is highly prevalent in the Korean population, especially among young adults. Nonetheless, correlates of suboptimal vitamin D levels in young adults are not well defined. This study aimed to investigate potentially modifiable determinants of vitamin D levels in young adults in Korea. This cross-sectional study was based on health check-up data from 3,450 healthy male and female university students aged 18-29 yr in Seoul between April and May 2013. Serum 25-hydroxyvitamin D [25(OH)D] levels were determined using chemiluminescent immunoassay. Anthropometric data were measured, and lifestyle, dietary, and sociodemographic factors were obtained through self-administered questionnaires. General linear regression was used to assess correlates of serum 25(OH)D levels. The mean serum 25(OH)D level was 11.1 ng/mL, and the prevalence of 25(OH)D levels less than 10 ng/mL was 44.7% (39.5% in men, 50.2% in women). In a final multivariable model, significant positive correlates of serum 25(OH)D were older age, male sex, increased physical activity, sunlight exposure ≥ 30 min/day, eating breakfast regularly, consumption of dairy and fatty fish, and use of vitamin D-containing supplements. In contrast, significant inverse correlates were obesity (body mass index, BMI ≥ 25 kg/m(2)) or underweight (BMI < 18.5 kg/m(2)), abdominal obesity, increased sedentary time, and frequent consumption of instant noodles and sugar-sweetened beverages. In conclusion, many modifiable lifestyle and dietary factors were associated with low serum 25(OH)D levels in Korean young adults. Further studies on potential mechanisms of the correlates and optimal strategies to improve vitamin D status in this vulnerable subpopulation are warranted.
authors.affiliation: Department of Medicine, Seoul National University College of Medicine, Seoul, Korea. ; Department of Family Medicine, Seoul National University Health Service Center, Seoul, Korea.
authors.forename: Hee-Kyung
authors.initials: HK
authors.lastname: Joh
authors.affiliation: Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Chun Soo
authors.initials: CS
authors.lastname: Lim
authors.affiliation: Department of Family Medicine and Health Promotion Center, Seoul National University Hospital, Seoul, Korea. ; Advanced Institutes of Convergence Technology, Seoul National University, Seoul, Korea. ; Institute on Aging, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: BeLong
authors.initials: B
authors.lastname: Cho
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D005247:Feeding Behavior; D005260:Female; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D008297:Male; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment; D017678:Sex Distribution; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology* / Q000517:prevention & control; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Breakfast; Instant Noodle; Life Style; Obesity; Sugar-sweetened Beverage; Thinness; Vitamin D; Young Adult