Hypovitaminosis D is common in general medical inpatients, including those with vitamin D intakes exceeding the recommended daily allowance and those without apparent risk factors for vitamin D deficiency.

BACKGROUND Current approaches to diagnosing testosterone deficiency do not consider the physiological consequences of various testosterone levels or whether deficiencies of testosterone, estradiol, or both account for clinical manifestations. METHODS We provided 198 healthy men 20 to 50 years of age with goserelin acetate (to suppress endogenous testosterone and estradiol) and randomly assigned them to receive a placebo gel or 1.25 g, 2.5 g, 5 g, or 10 g of testosterone gel daily for 16 weeks. Another 202 healthy men received goserelin acetate, placebo gel or testosterone gel, and anastrozole (to suppress the conversion of testosterone to estradiol). Changes in the percentage of body fat and in lean mass were the primary outcomes. Subcutaneous- and intraabdominal-fat areas, thigh-muscle area and strength, and sexual function were also assessed. RESULTS The percentage of body fat increased in groups receiving placebo or 1.25 g or 2.5 g of testosterone daily without anastrozole (mean testosterone level, 44±13 ng per deciliter, 191±78 ng per deciliter, and 337±173 ng per deciliter, respectively). Lean mass and thigh-muscle area decreased in men receiving placebo and in those receiving 1.25 g of testosterone daily without anastrozole. Leg-press strength fell only with placebo administration. In general, sexual desire declined as the testosterone dose was reduced. CONCLUSIONS The amount of testosterone required to maintain lean mass, fat mass, strength, and sexual function varied widely in men. Androgen deficiency accounted for decreases in lean mass, muscle size, and strength; estrogen deficiency primarily accounted for increases in body fat; and both contributed to the decline in sexual function. Our findings support changes in the approach to evaluation and management of hypogonadism in men.

Alendronate impairs the ability of parathyroid hormone to increase the bone mineral density at the lumbar spine and the femoral neck in men. This effect may be attributable to an attenuation of parathyroid hormone-induced stimulation of bone formation by alendronate.

Osteoporosis in men causes significant morbidity and mortality. We recommend testing higher risk men [aged ≥70 and men aged 50-69 who have risk factors (e.g. low body weight, prior fracture as an adult, smoking, etc.)] using central dual-energy x-ray absorptiometry. Laboratory testing should be done to detect contributing causes. Adequate calcium and vitamin D and weight-bearing exercise should be encouraged; smoking and excessive alcohol should be avoided. Pharmacological treatment is recommended for men aged 50 or older who have had spine or hip fractures, those with T-scores of -2.5 or below, and men at high risk of fracture based on low bone mineral density and/or clinical risk factors. Treatment should be monitored with serial dual-energy x-ray absorptiometry testing.

The aim of this study was to determine the effects of initial treatment with a GnRH agonist on body composition in asymptomatic men with nonmetastatic prostate cancer. Forty men with locally advanced, node-positive or biochemically recurrent prostate cancer, no radiographic evidence of metastases, and no prior androgen deprivation therapy were treated with leuprolide 3-month depot 22.5 mg im every 12 wk for 48 wk. The main outcome measures were percentage changes in weight, percentage fat body mass, percentage lean body mass, fat distribution, and muscle size after 48 wk. Thirty-two subjects were evaluable. Serum T concentrations decreased by 96.3% plus or minus 0.4% (P < 0.001). Weight increased by 2.4% plus or minus 0.8% (P = 0.005). Percentage fat body mass increased by 9.4% plus or minus 1.7% (P < 0.001), and percentage lean body mass decreased by 2.7% plus or minus 0.5% (P < 0.001). Cross-sectional areas of the abdomen and abdominal sc fat increased by 3.9% plus or minus 1.2% (P = 0.003) and 11.1% plus or minus 3.4% (P = 0.003), respectively. In contrast, the cross-sectional area of intraabdominal fat did not change significantly (P = 0.94). Cross-sectional paraspinal muscle area decreased by 3.2% plus or minus 1.3% (P = 0.02). GnRH agonists increase weight and percentage fat body mass and decrease percentage lean body mass and muscle size in men with nonmetastatic prostate cancer. Increased fatness resulted primarily from accumulation of sc rather than intraabdominal adipose tissue.

Pamidronate prevents bone loss in the hip and lumbar spine in men receiving treatment for prostate cancer with a gonadotropin-releasing hormone agonist.

Bone loss accelerates substantially in the late perimenopause and continues at a similar pace in the first postmenopausal years. Body weight is a major determinant of the rate of menopausal BMD loss, whereas ethnicity, per se, is not. Healthcare providers should consider this information when deciding when to screen women for osteoporosis.

FGF-23 is a novel regulator of phosphate metabolism. We studied the regulation of FGF-23 by dietary phosphate in 66 men and women using two assays. Dietary phosphate restriction decreased FGF-23 and loading increased FGF-23 significantly. An assay that measured intact FGF-23 showed the effects of dietary phosphate much more clearly than an assay that also measures presumed biologically inactive fragments. Dietary phosphate is a key regulator of circulating FGF-23; choice of assay is critical when studying FGF-23 physiology.Introduction: Fibroblast growth factor 23 (FGF-23) is a novel phosphaturic factor discovered through genetic studies of patients with renal phosphate wasting disorders. Ablation of the FGF-23 gene in mice reduces renal phosphate excretion and increases serum phosphate, suggesting that FGF-23 is critical for normal phosphate homeostasis. We examined the role of dietary phosphate in the regulation of FGF-23 in humans. Materials and Methods: Sixty-six healthy males and females were randomized to either phosphate-depleted or -loaded diets for 5 days, after a 4-day run-in diet. FGF-23 was measured using an "intact" assay that only detects intact FGF-23 peptide and with a "C-terminal" assay that measures both intact FGF-23 peptide and presumed biologically inactive carboxyl terminal fragments. The main outcome was the within group change in FGF-23 with either phosphate depletion or loading. Results: Using the intact FGF-23 assay, mean FGF-23 area under the curve (AUC) decreased by 9 ± 16% with phosphate depletion (p ‫ס‬ 0.0041) and increased by 35 ± 29% with loading (p < 0.0001). Using the C-terminal FGF-23 assay, mean FGF-23 AUC decreased by 8 ± 12% with phosphate depletion (p ‫ס‬ 0.0003) and increased by 13 ± 20% with loading (p ‫ס‬ 0.0016). Increases in FGF-23 with phosphate loading were greater with the intact assay than with the C-terminal assay (p ‫ס‬ 0.0003). Using the intact assay only, FGF-23 was significantly associated with serum phosphate (r ‫ס‬ 0.39, p < 0.01), 24-h urinary phosphate (r ‫ס‬ 0.47, p < 0.01), fractional excretion of phosphate (r ‫ס‬ 0.29, p < 0.01), and 1,25-dihydroxyvitamin D (r ‫ס‬ −0.30, p < 0.01). The association between the assays was weak (r ‫ס‬ 0.26, p < 0.01). Conclusions: Dietary phosphate is a key regulator of circulating FGF-23 levels in humans. Additionally, choice of assay is critical when performing physiologic investigations of FGF-23.