Nephrolithiasis and Risk of Incident Bone Fracture

Abstract

Purpose

Higher urine calcium is a common feature of calcium nephrolithiasis and may be associated with lower bone mineral density in individuals with kidney stones (KS). However, previous population based studies of KS and risk of bone fracture report conflicting results. We examined independent associations between history of KS and incident fracture.

Materials and Methods

We conducted prospective studies in the Nurses’ Health Study (N=107,001 women; 32 years of follow-up) and the Health Professionals Follow-up Study (N=50,982 men; 26 years of follow-up). We excluded pre-menopausal women, men < 45 years old, and individuals who reported osteoporosis at baseline. The study outcomes were incident wrist (distal radius) or incident hip (proximal femur) fractures due to low or moderate trauma. Cox proportional hazards regression was used to adjust for multiple factors including age, race, BMI, thiazide use, supplemental calcium, and dietary intakes.

Results

There were 4940 wrist and 2391 hip fractures in women and 862 wrist and 747 hip fractures in men (all incident). The multivariable-adjusted relative risk (MVRR) of incident wrist fracture in participants with a history of KS compared with participants without KS was 1.18 (95% CI 1.04–1.34) in women and 1.21 (95% CI 1.00–1.47) in men. The pooled MVRR of wrist fracture was 1.20 (95% CI 1.08–1.33). The MVRR of incident hip fracture in participants with KS was 0.96 (95% CI 0.80–1.14) in women and 0.92 (95% CI 0.74–1.14) in men. The pooled MVRR of hip fracture was 0.94 (95% CI 0.82–1.08).

Conclusions

Nephrolithiasis is associated with a significantly higher risk of incident wrist but not hip fracture in women and men.