Multivariable-adjusted hazard ratio (HR) and 95% CI of fracture by baseline cross-linked N-telopeptide of type I collagen (NTX) and lumbar spine bone mineral density (BMD; P interaction = 0.32). fx, fracture.
Normal BMD = Quartile 2, 3 or 4 (> 0.98 g/cm2); Low BMD = Quartile 1 (≤0.98g/cm2); Normal NTX = Quartile 1, 2 or 3 (≤ 41.5 nM BCE/nMCr); High NTX = Quartile 4(> 41.5nM BCE/nMCr). Models adjusted for baseline age, race, site, fracture history, education, smoking, diabetes, menopausal status, height and weight.