P. Aguado et al., Low vitamin D levels in outpatient postmenopausal women from a rheumatology clinic in Madrid, Spain: Their relationship with bone mineral density, OSTEOPOR IN, 11(9), 2000, pp. 739-744
To evaluate a possible relationship between vitamin D levels and bone miner
al density (BMD) and the prevalence of hypovitaminosis in a population of p
ostmenopausal women from a rheumatologic outpatient clinic in Madrid, Spain
, 171 postmenopausal women (aged 47-66 years) divided into two groups (oste
oporotic and nonosteoporotic, according to WHO criteria) were studied betwe
en November and June. Liver and kidney function were normal in all subjects
. Serum parathyroid hormone (PTH) and calcidiol levels were determined and
bone densitometry carried out at the lumbar spine and hip level. PTH and ca
lcidiol serum levels did not show any correlation. Serum PTH was inversely
related to BMD at both hip and lumbar spine in the total group, and at the
hip with calcidiol levels lower than 37 nmol/l. Calcidiol was directly rela
ted to hip BMD only when levels were lower than 37 nmol/l. Results of a ste
pwise multiple regression analysis showed that the single factor which affe
cted BMD at the hip was calcidiol in the subgroup with serum calcidiol leve
ls below 37 nmol/l, while in the subgroup with serum calcidiol levels above
37 nmol/l, the main factor affecting hip BMD was serum PTH. The prevalence
of vitamin D deficiency at a cutoff of 37 nmol/l was 64%. In summary, calc
idiol serum levels below 37 nmol/l seem to affect bone mass, regardless of
the effect of PTH. Vitamin D deficiency is a frequent finding in the postme
nopausal women who attend a rheumatology outpatient clinic in Madrid. Vitam
in D supplementation should therefore be considered in this population duri
ng the winter season.