While nonskeletal benefits of vitamin D remain a matter o debate, its importance in bone health is known for decades. Secondary hyperparathyroidism is considered to play a significant role in the pathogenesis of age-related bone loss. In the present study we investigate the association between serum PTH, 25-hydroxyvitamin (25(OH)D) and other clinically related variables in a cross sectional sample of patients followed in an Endocrine consultation during the year 2016. Patients with diseases or medications known to affect calcium metabolism were excluded. 509 participants, 365 female and 145 male, were selected for analysis. Mean age±S.D. was 52±16 yrs (286); 47% were diabetics; 31% suffered of thyroid disorders and 7% were obese. The mean±S.D. serum level of 25(OH) D was 20.4±10.2 ng/ml; 17.8±8.7 ng/ml in measurements during winter months and 23.4±10.04 during summer. In 61 patients (12% of the sample) with more than one determination, there was a 51.9% increase in 25(OH) D from a mean level of 16.81±9.3 ng/ml during winter to 24.94±11.2 ng/ml during summer months (P<0.02). Patients treated with statins presented significantly lower levels of 25(OH)D than non-treated patients, 15.9±6.7 ng/ml and 26±10.1 ng/ml, respectively (P<0.01).This difference remained statistically significant after adjusting for age, sex and disease.
We found an inverse relationship between 25(OH)D and PTH. The best fitted line was obtained as a logarithmic expression of 25(OH)D (r=0.65; P<0.001). There was no further significant decrease in PTH for serum levels of 25(OH)D of more than 25 ng/ml. In conclusion, more than half of our patients were Vit D deficient (<20 ng/ml) particularly elderly people treated with statins, but serum levels of 25(OH)D above 25 ng/ml are needed in order to prevent secondary hyperparathyroidism. This value can be considered as the lower limit of Vitamin D sufficiency in the sample studied.
20 - 23 May 2017
European Society of Endocrinology