Table 6.

Effect of age on the associations between serum copper levels (Per 10 ug/dL increased in serum copper) and BMDs and fracture.

	<50 y		50 to 65 y		≥65 y		P for interaction
	β/OR (95% CI)	p	β/OR (95% CI)	p	β/OR (95% CI)	p
Total femur BMD (g/cm2)
Unadjusted model	0.005 (−0.002, 0.012)	0.1550	−0.001 (−0.007, 0.006)	0.8528	−0.010 (−0.022, 0.001)	0.0875	0.0584
Adjusted model	0.005 (−0.005, 0.016)	0.3141	0.002 (−0.007, 0.011)	0.7039	−0.011 (−0.027, 0.005)	0.1944	0.1139
Femoral neck BMD (g/cm2)
Unadjusted model	0.008 (0.002, 0.015)	0.0149	0.002 (−0.004, 0.009)	0.4695	−0.007 (−0.017, 0.004)	0.2182	0.0426
Adjusted model	−0.001 (−0.012, 0.010)	0.8804	−0.001 (−0.010, 0.008)	0.7660	−0.013 (−0.029, 0.002)	0.0997	0.2206
Total spine BMD (g/cm2)
Unadjusted model	0.008 (0.002, 0.015)	0.0171	0.002 (−0.007, 0.011)	0.6848	−0.008 (−0.027, 0.011)	0.4046	0.1264
Adjusted model	0.001 (−0.012, 0.014)	0.8410	−0.003 (−0.018, 0.012)	0.7299	−0.021 (−0.060, 0.017)	0.2966	0.2312
Total fracture
Unadjusted model	0.970 (0.865, 1.089)	0.6107	0.890 (0.801, 0.989)	0.0300	1.168 (1.015, 1.344)	0.0298	0.0085
Adjusted model	1.012 (0.767, 1.334)	0.9343	0.855 (0.679, 1.078)	0.1851	1.35a (0.996, 1.838)	0.0527	0.0005
Adjusted model plus BMDa	0.989 (0.725, 1.347)	0.9420	0.881 (0.604, 1.284)	0.5097	NA	NA	NA

BMD = bone mineral density; CI = confidence interval; HDL = high-density lipoprotein; LDL = low-density lipoprotein; OR = odds ratio.

β regression coefficient. Adjust for: sex; race; body mass index (kg/m²); smoking status; alcohol drinking; moderate physical activity; cardiovascular diseases; dyslipidaemia; triglyceride (mg/dL), total cholesterol(mg/dL); HDL-cholesterol (mg/dL); LDL-cholesterol (mg/dL); serum selenium (ug/L); serum zinc (ug/dL).

^aAdjusted model plus total spine BMD; total femur BMD