Table 2.

Linear regression analysis with the effect of impact group on total hip and femoral neck

	Group	Crude			Model 1			Model 2
		Coef.	95% conf.	p	Coef.	95% conf.	p	Coef.	95% conf.	p
Mean total hip BMD (g/cm2)	Low impact	0.124	0.077–0.171	< 0.001	0.077	0.029–0.126	0.002	0.066	0.020–0.112	0.005
	High impact	0.192	0.143–0.240	< 0.001	0.144	0.094–0.195	< 0.001	0.110	0.061–0.159	< 0.001
Mean total hip Z-score	Low impact	0.7	0.4–1.1	< 0.001	0.6	0.2–1.0	0.001	0.5	0.2–0.9	0.004
	High impact	1.2	0.9–1.6	< 0.001	1.1	0.7–1.5	< 0.001	0.8	0.4–1.2	< 0.001
Mean total hip BMC (g)	Low impact	7.7	5.1–10.4	< 0.001	5.4	3.2–7.7	< 0.001	4.8	2.7–6.9	< 0.001
	High impact	8.8	6.1–11.5	< 0.001	6.6	4.3–8.9	< 0.001	4.8	2.6–7.1	< 0.001
Mean total hip area (cm2)	Low impact	3.2	1.9–4.5	< 0.001	2.6	1.6–3.5	< 0.001	2.4	1.4–3.4	< 0.001
	High impact	2.0	0.6–3.3	< 0.001	1.4	0.4–2.5	0.006	1.0	− 0.1–2.0	0.066
Mean femoral neck BMD (g/cm2)	Low impact	0.142	0.091–0.192	< 0.001	0.097	0.044–0.149	< 0.001	0.085	0.036–0.135	0.001
	High impact	0.208	0.156–0.259	< 0.001	0.163	0.109–0.217	< 0.001	0.127	0.074–0.179	< 0.001
Mean femoral neck Z-score	Low impact	0.9	0.5–1.2	< 0.001	0.7	0.3–1.1	0.001	0.6	0.2–1.0	0.002
	High impact	1.3	1.0–1.7	< 0.001	1.2	0.8–1.6	< 0.001	0.9	0.5–1.3	< 0.001
Mean femoral neck BMC (g)	Low impact	0.8	0.2–1.4	0.011	0.3	− 0.3–0.9	0.388	0.2	− 0.4–0.8	0.529
	High impact	0.7	0.1–1.3	0.028	0.2	− 0.4–0.8	0.564	0.0	− 0.7–0.6	0.887
Mean femoral neck area (cm2)	Low impact	− 0.1	− 0.5–0.4	0.797	− 0.3	− 0.8–0.2	0.219	− 0.3	− 0.7–0.2	0.219
	High impact	− 0.5	− 0.9	0.042	− 0.7	− 1.2 to − 0.2	0.005	− 0.7	− 1.2 to − 0.2	0.006

Model 1—impact group + age + sex adjusted; Model 2—impact group + age + sex + BMI adjusted. Control group as the reference category