Hypovitaminosis D and parathyroid hormone response in the elderly: effects on bone turnover and mortality.
OBJECTIVE
To investigate whether absence of secondary hyperparathyroidism in the presence of hypovitaminosis D has altered bone turnover, fracture risk and mortality.


METHODS
A prospective cohort study.


METHODS
A total of 1280 older men and women living in residential care facilities.


METHODS
We measured baseline serum 25-hydroxyvitamin D (25OHD), serum intact PTH, serum amino-terminal propeptide of type I collagen (PINP) and serum carboxy-terminal telopeptide of type I collagen (CTX-I). Deaths and fractures were recorded prospectively.


RESULTS
Hypovitaminosis D (25OHD < 39 nmol/l) and absence of secondary hyperparathyroidism (PTH > 7.0 pmol/l) in the presence of hypovitaminosis D were common in this sample with a prevalence of 77.5% and 53.3%, respectively. In the presence of hypovitaminosis D, residents showing a hyperparathyroid response (n = 406) had significantly higher serum bone turnover markers than individuals with serum PTH levels < or = 7.0 pmol/l (termed 'low vitamin D, normal PTH', n = 463). After adjusting for risk factors, mortality was significantly higher in the secondary hyperparathyroidism group than in the 'low vitamin D, normal PTH' group [hazard ratio (HR) = 1.35, 95% confidence interval (CI) 1.12-1.64; P = 0.002]. All residents with serum PTH levels < or = 7.0 pmol/l (n = 603) were similar with regard to both bone turnover and mortality, independent of their actual vitamin D status.


CONCLUSIONS
Absence of secondary hyperparathyroidism in the presence of hypovitaminosis D appears to be common in the frail elderly and is associated with longer survival, similar to that observed in vitamin D-replete elderly subjects.
Chen
Jian Sheng
JS
Institute of Bone and Joint Research, Royal North Shore hospital, St Leonards, Sydney, New South Wales, Australia.
Sambrook
Philip N
PN
March
Lyn
L
Cameron
Ian D
ID
Cumming
Robert G
RG
Simpson
Judy M
JM
Seibel
Markus J
MJ
D000368:Aged; D000369:Aged, 80 and over; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology; D005260:Female; D050723:Fractures, Bone / Q000097:blood / Q000378:metabolism; D006801:Humans; D006961:Hyperparathyroidism / Q000150:complications; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000378:metabolism / Q000401:mortality*; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D011446:Prospective Studies; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000378:metabolism* / Q000401:mortality*
D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D