Table 3. Relationship between physical activity and incident hypertension in rural areas of China.

Items	Volume of physical activity
	1st quartile	2nd quartile	3rd quartile	4th quartile
Cox proportional hazard model was used with the 1st quartile of physical activity as the reference category and adjustment for the confounders at baseline, including age, sex, BMI, southern and northern regions, education, alcohol drinking, smoking, fast plasma glucose, total cholesterol and SBP. BMI: body mass index; SBP: systolic blood pressure.
Numbers of incident cases	1,813	1,748	1,591	1,628
Duration of follow-up/(person-year)	58,102	59,116	62,601	61,962
Annual incidence /%	3.12	2.96	2.54	2.63
HR (95% CI )	1.00	0.92 (0.86–0.99)	0.72 (0.67–0.77)	0.70 (0.65–0.75)