Table 2.

Association between outdoor walking and risk of osteoporosis

	Duration of daily outdoor walking (minutes/day)				p trend
	None	≤ 30	> 30 and ≤ 60	> 60
No. of incident osteoporosis/No. of subjects	3244/16491	716/3840	570/3814	56/555
Incident rate per 100 persons	19.67	18.65	14.94	10.09
Model 1	1.00 (reference)	0.95 (0.87, 1.03)	0.80 (0.73, 0.88)	0.54 (0.41, 0.70)	< 0.001
Model 2	1.00 (reference)	1.03 (0.95, 1.12)	0.89 (0.81, 0.98)	0.62 (0.47, 0.82)	< 0.001
Model 3	1.00 (reference)	1.03 (0.91, 1.16)	0.83 (0.72, 0.95)	0.60 (0.39, 0.92)	0.001

Model 1: no adjustment

Model 2: adjusted for age, sex, body mass index, waist, educational attainment, smoking status, drinking status, hypertension, diabetes mellitus, dyslipidemia, stroke, coronary artery disease, cancer, and depression, calcium supplementation use, vitamin D supplementation use, and hormone medication use

Model 3: adjusted for Model 2 plus genetic risk score, the first 10 primary components of ancestry, and genotype measurements batches. In model 3, only 13,426 subjects were included in the analysis, because 11,274 subjects were lack of osteoporosis-genetic risk score

95%CI = 95% confidence interval