Vitamin D status is currently considered among the relevant determinants of skeletal integrity. Since vitamin D levels present seasonal variations, we longitudinally studied young healthy men and women in order to investigate the related physiologic modifications of both calcium homeostasis and bone remodeling. Thirty-two men (mean age 39.4 +/- 7.8 years) and 58 premenopausal women (aged 36.9 +/- 6.4 years) from southern Italy were studied. In all subjects the following parameters were measured both in winter and in summer: serum calcium, phosphorus, creatinine, total alkaline phosphatase activity, 25-hydroxyvitamin D (25OHD), parathyroid hormone (PTH), osteocalcin (BGP), together with urinary calcium (Ca/Cr), total pyridinoline (Pyr/Cr) and deoxypyridinoline (d-Pyr/Cr), corrected for creatinine excretion. In both sexes 25OHD levels were significantly higher in summer, while PTH values were lower, than in winter. The prevalence of hypovitaminosis D, defined by concentrations of 25OHD lower than 30 nmol/l, was 17.8% in winter and 2.2% in summer in the whole sample, while it was 27.8% and 3.4%, respectively, among female subjects. Indeed male subjects did not display hypovitaminosis D, having throughout the year significantly higher calcium and 25OHD levels together with lower PTH values, than the women. Moreover, alkaline phosphatase total activity was more elevated in men both in winter and in summer. In women, during winter, bone remodeling markers levels were higher while urinary calcium levels were lower than in summer. In the whole sample serum 25OHD correlated positively with serum calcium and inversely with PTH. The seasonal percentage variations in PTH were inversely correlated with those of Ca/Cr. Our results show a relatively high prevalence of subclinical vitamin D deficiency among young healthy women from southern Italy. Significant gender-specific differences have been demonstrated in both calcium homeostasis and skeletal remodeling indexes; the seasonal fluctuations in the vitamin D-PTH axis are accompanied by cyclical variations of bone turnover rate, which were more pronounced in women.

The strategy of treatment for patients with adrenal incidentalomas (AI) may depend upon the presence of hormonal hypersecretion. Although alterations of bone turnover have been recently reported, data on bone mineral density (BMD) are not available in AI patients. We evaluated bone turnover and BMD in 32 female AI patients and 64 matched controls. Spinal and femoral BMD were similar in patients and controls. Serum bone GLA protein (6.8+/-3.5 vs. 8.8+/-3.2 ng/mL; P<0.005) and PTH (48.8+/-15.1 vs. 37.2+/-10.9 pg/mL; P<0.0001) were different in patients and controls. Patients were then subdivided into 2 groups: with (n = 8; group A) or without (n = 24; group B) subclinical hypercortisolism. PTH was higher (P<0.05) in group A than in group B and in both groups than in controls (57.1+/-13.6, 46.0+/-14.8, and 37.2+/-10.9 pg/mL, respectively), and bone GLA protein was lower in group A than in group B and controls (3.8+/-2.3, 7.5+/-3.1, and 8.8+/-3.2 ng/mL, respectively; P<0.05). Serum type I cross-linked C telopeptide and fasting urinary deoxypyridinoline/ creatinine were not different in the three groups. BMD at each site was lower (P<0.05) in group A than in group B and controls. Bone mass and metabolism are altered in AI patients with subclinical hypercortisolism and should be taken into account, therefore, when addressing the treatment of choice for these patients.

A single oral dose of 600,000 IU of cholecalciferol rapidly enhances 25(OH)D and reduces PTH in young people with vitamin D deficiency.

Bone involvement is a common clinical feature in acromegalic patients, though previous studies gave divergent results possibly because of the different gonadal status of the patients studied. To study the influence of estrogen milieu in these patients, we evaluated 23 acromegalic patients with active disease, subdivided into two groups: menstruating and amenorrheal patients, comparable for duration and activity of disease. Forty-two matched women served as controls. Skeletal involvement was studied by measuring: (a) the main biomarkers of bone turnover: serum alkaline phosphatase total activity (AP), bone GLA protein (BGP), serum carboxy-terminal propeptide of type I collagen (PICP), serum type I cross-linked N-telopeptide (ICTP), and urinary pyridinoline and deoxypyridinoline corrected for creatinine (Pyr/Cr, D-Pyr/Cr) and urinary calcium/creatinine ratio (Ca/Cr); (b) bone mineral density (BMD), as measured by quantitative computed tomography both at lumbar spine and distal radius, and by dual X-ray absorptiometry both at lumbar spine and at three femoral sites (Ward's triangle, femoral neck, and great trochanter). AP, BGP, ICTP, Pyr/Cr, D-Pyr/Cr were significantly higher in patients than in controls, independent of the menstrual pattern. Higher PICP levels were found in the whole group and in menstruating acromegalics when compared with control women; no difference was found in amenorrheal patients, who in turn showed higher urinary Ca/Cr values. When patients were considered all together, BMD at spine, femoral neck, and trochanter was higher than in controls. In contrast, when the gonadal status was taking into account and, menstruating and amenorrheal subjects were considered separately, BMD at spine, but not in other sites, was significantly higher in menstruating patients than in controls. In contrast, no difference of BMD values at any site was observed between amenorrheal patients and controls. The mean BMD Z scores allowed us to detect an unequal involvement of different skeletal sites. Our results show that bone turnover is increased in acromegalic women and suggest that GH anabolic effect on bone is more evident in the presence of estrogens and that different skeletal sites may be affected differently by hormone