Table 2.

Linear regression coefficients for ultrasound attenuation (dB/MHz) in men and women aged 45-74 for models based on covariates and time in high impact activity

	Men			Women
	Regression coefficient (95% CI)	P value		Regression coefficient (95% CI)	P value
Model 1—confounding factors:
Age (years)	−0.09 (−0.17 to 0.01)	0.07		−0.59 (−0.67 to −0.50)	<0.001
Weight (kg)	0.20 (0.13 to 0.27)	<0.001		0.38 (0.33 to 0.43)	<0.001
Height (m)	0.08 (−0.04 to 0.20)	0.2		0.11 (0.02 to 0.20)	0.01
Never smoker	2.46 (−0.05 to 4.97)	0.05		2.52 (0.60 to 4.44)	0.01
Stopped menstruating	—	—		−4.40 (−5.99 to −2.82)	<0.001
Never used hormone replacement therapy	—	—		−3.84 (−5.06 to −2.63)	<0.001
Constant	63.04 (41.54 to 84.53)	<0.001		76.25 (60.63 to 91.88)	<0.001
Model 2—Time in high impact recreational activity (hours/week)*:
0.1-0.9	3.27 (0.33 to 6.20)	0.03		3.07 (0.37 to 5.78)	0.03
1-1.9	6.72 (2.26 to 11.19)	0.003		2.14 (−1.51 to 5.79)	0.3
⩾2	8.40 (4.49 to 12.32)	<0.001		1.33 (−2.20 to 4.86)	0.5
Model 3—Time in high impact recreational activity (hours/week)†	2.97 (1.85 to 4.08)	<0.001		0.87 (−0.10 to 1.84)	0.08
Model 4—Participated in high impact recreational activity (yes v no)	5.39 (3.15 to 7.63)	<0.001		2.36 (0.42 to 4.31)	0.02

Coefficients in models 2-4 were calculated including the confounding variables in model 1. All models include adjustment for machine. 

^*Reference category 0 hours. 

^†Linear trend for ordered categories of model 2.