We conclude that in healthy men, changes in dietary phosphorus within the physiological range of intakes regulate serum FGF-23 concentrations and suggest that dietary phosphorus regulation of 1,25(OH)(2)D production is mediated, at least in part, by changes in circulating FGF-23.

Background: An increased rate of hip fractures has been reported in patients with end-stage renal disease, but the effect of less severe renal dysfunction on fracture risk is uncertain. Methods: We conducted a case-cohort study within a cohort of 9704 women 65 years or older to compare baseline renal function (estimated glomerular filtration rate [eGFR] using the Cockcroft-Gault equation) in 149 women who subsequently had hip fractures and 150 women who subsequently had vertebral fractures with eGRF in 396 randomly selected women. Results: In models adjusted for age, weight, and calcaneal bone density, decreasing eGFR was associated with increased risk of hip fracture. Compared with women with an eGFR 60 mL/min per 1.73 m 2 or greater, the hazard ratio (95% confidence interval [CI]) for hip fracture was 1.57 (95% CI, 0.89-2.76) in those with an eGFR 45 to 59 mL/min per 1.73 m 2 and 2.32 (95% CI, 1.15-4.68) in those with an eGFR less than 45 mL/min per 1.73 m 2 (P for trend=.02). In particular, women with a reduced eGFR were at increased risk of trochanteric hip fracture (adjusted hazard ratio, 3.93 [95% CI, 1.37-11.30] in women with an eGFR 45-59 mL/min per 1.73 m 2 and 7.17 [95% CI, 1.93-26.67] in women with an eGFR Ͻ45 mL/min per 1.73 m 2 ; P for trend=.004). Renal function was not independently associated with risk of vertebral fracture (adjusted odds ratio, 1.08 [95% CI, 0.61-1.92] in women with an eGFR 45-59 mL/min per 1.73 m 2 and 1.33 [95% CI, 0.63-2.80] in women with an eGFR Ͻ45 mL/min per 1.73 m 2 ; P for trend=.47). Conclusion: Older women with moderate renal dysfunction are at increased risk of hip fracture.

Introduction Haemophilia has been associated with low bone mineral density (BMD). However, prior clinical studies of this population have neither clearly elucidated risk factors for development of low BMD nor identified who may warrant screening for osteoporosis. Aim To evaluate the relationship between BMD and hemophilic arthropathy and other demographic and clinical variables. Methods We undertook a cross-section study of BMD in adult men with haemophilia. Measures of predictor variables were collected by radiographic studies, physical examination, patient questionnaires, and review of medical records. Results Among 88 enrolled subjects, the median age was 41 years (IQR: 20); median femoral neck BMD (n=87) was 0.90 g/cm2 (IQR 0.24); and median radiographic joint score was 7.5 (IQR 18). Among subjects <50 years (n=62), after controlling for BMI, alcohol, HIV, and White race, BMD decreased as radiographic joint score increased (est.β=−0.006 mg/cm2; 95%CI −0.009, −0.003; partial R2=0.23). Among subjects ≥ 50 years (n=26), 38% had osteoporosis (T score ≤−2.5) and there was no association between BMD and arthropathy. Conclusion Risk factors for low BMD in men with haemophilia < 50 years include hemophilic arthropathy, low or normal BMI, and HIV. Men with haemophilia over age 50 years should have routine screening for detection of osteoporosis.

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