OBJECTIVETo estimate the dose response relationship between cigarette smoking and hypertension in men based on restricted cubic spline method.

METHODSUnder the proportion to the population size, 38 520 subjects were randomly selected from May to August 2012 with cluster sampling method in urban and rural areas of Kunshan, China.Each participant received face-to-face interview with the standardized questionnaire, and physical examination.Restricted cubic spline was employed to estimate the dose response relation of cigarette smoking on the risk of hypertension.

RESULTSThe overall prevalence of cigarette smoking was 22.6% (8 691/38 520), prevalence of cigarette smoking in men was 46.1% (8 499/18 454). Multiple logistic regression analysis showed that current smoking (OR = 1.16, 95%CI:1.05-1.28) and previous cigarette smoking (OR = 1.32, 95%CI:1.07-1.63) were associated with hypertension after adjusted confounding factors (age, sex, body mass index, education, family income per month, urban or rural areas, physical activity and physical exercise) in men. After further adjusting drinking status, only previous cigarette smoking was associated with hypertension (OR = 1.28, 95%CI:1.04-1.58). The restricted cubic spline model indicated a linear dose-response relation between hypertension and cigarette smoking per day in men (non-linearity test P = 0.604 1).However, a non-linear dose response relation was found between duration of smoking (non-linearity test P < 0.000 1), smoking index (non-linearity test P = 0.009 9) and hypertension.

CONCLUSIONLong-term and heavy cigarette smoking is associated with hypertension in men.