title: Very high rates of vitamin D insufficiency in women of child-bearing age living in Beijing and Hong Kong.
abstract: We aimed to describe the vitamin D status of young women living in two Chinese cities in the spring--Beijing in the north (latitude 39 degrees north) and Hong Kong (latitude 22 degrees north) in the south. We also examined the relationship between serum 25-hydroxyvitamin D and parathyroid hormone (PTH) concentrations to determine a threshold for serum 25-hydroxyvitamin D above which there is no further suppression of PTH. Finally, we examined whether dietary Ca intake influences this relationship. Non-pregnant women aged 18-40 years (n 441) were recruited between February and June. Fasting blood was collected and dietary intakes were assessed using 5 d food records. Mean serum 25-hydroxyvitamin D concentration was lower in Beijing than Hong Kong women (29 v. 34 nmol/l; P < 0.001). Vitamin D deficiency (< or = 25 nmol/l) was indicated in 40% of Beijing and 18% of Hong Kong women, and over 90% of women in both cities were insufficient (< or = 50 nmol/l). Mean Ca and vitamin D intakes were 478 mg/d and 2.0 microg/d, respectively. The relationship between 25-hydroxyvitamin D concentration and PTH was linear throughout the range with a slope of -0.36 (different from 0; P < 0.001; R 0.26), with no apparent threshold. There was no influence of Ca intake on the relationship between 25-hydroxyvitamin D and PTH concentration. Vitamin D deficiency is common and insufficiency is very common in non-pregnant women in Hong Kong and Beijing during spring. Serum 25-hydroxyvitamin D was inversely associated with PTH with no apparent threshold. Strategies such as vitamin D fortification or supplementation may be required.
authors.affiliation: Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
authors.forename: Jean
authors.initials: J
authors.lastname: Woo
authors.forename: Christopher W K
authors.initials: CW
authors.lastname: Lam
authors.forename: Jason
authors.initials: J
authors.lastname: Leung
authors.forename: Winny Y
authors.initials: WY
authors.lastname: Lau
authors.forename: Edith
authors.initials: E
authors.lastname: Lau
authors.forename: Xu
authors.initials: X
authors.lastname: Ling
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Xing
authors.forename: Xi He
authors.initials: XH
authors.lastname: Zhao
authors.forename: C Murray
authors.initials: CM
authors.lastname: Skeaff
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Bacon
authors.forename: Jennifer E P
authors.initials: JE
authors.lastname: Rockell
authors.forename: Aaron
authors.initials: A
authors.lastname: Lambert
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Whiting
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Green
mesh_terms: D000328:Adult; D002136:Calcium, Dietary / Q000008:administration & dosage; D002681:China / Q000453:epidemiology; D015930:Diet Records; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D016014:Linear Models; D009752:Nutritional Status; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D012621:Seasons; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D