Adult ; Aged ; Aged, 80 and over ; Calcifediol/blood ; Calcifediol/deficiency* ; Cross-Sectional Studies ; Environmental Exposure/statistics & numerical data ; Female ; Global Health ; Humans ; Middle Aged ; Osteoporosis, Postmenopausal/blood ; Osteoporosis, Postmenopausal/epidemiology* ; Residence Characteristics ; Risk Factors ; Skin Pigmentation ; Sunlight ; Vitamin D Deficiency/blood ; Vitamin D Deficiency/epidemiology*
Keywords
25‐Hydroxyvitamin D ; inadequacy ; osteoporotic ; postmenopausal ; risk factors ; vitamin D
Abstract
A serum 25-hydroxyvitamin D [25(OH)D] level of 75 nmol/l (30 ng/ml) has been proposed as the minimum for adequate vitamin D nutrition as lower levels are associated with increases in serum parathyroid hormone in otherwise healthy adults. Amongst 2589 community-dwelling, postmenopausal women with osteoporosis from 18 countries, recruited to determine risk factors for vitamin D inadequacy, 64% had vitamin D inadequacy. General health, education, ethnicity, sun exposure, skin reactivity, diet, recent travel to sunny climates, vitamin D supplementation, body mass index (BMI), season and latitude were assessed using logistic regression models. Asian ethnicity, BMI ≥30 kg/m2, living in non-equatorial countries, inadequate vitamin D supplementation, poor/fair health, no education about vitamin D, skin reactivity and no recent travel to sunny areas were significant predictors. Several modifiable risk factors are associated with vitamin D inadequacy worldwide, suggesting potentially simple ways to increase vitamin D and improve bone health in postmenopausal women.