Does cigarette smoking exacerbate the effect of blood pressure on the risk of cardiovascular and all-causemortality among hypertensive patients?
- Department of Evidence Based Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
To examine the risk of cigarette smoking on cardiovascular disease (CVD) and all-cause mortality among hypertensive patients.
We conducted a prospective cohort study among 36,943 hypertensive patients aged at least 40 years. Data on smoking and other variables were obtained in 1991 and follow-up evaluation was conducted in 1999-2000.
During a median follow-up of 8.2 years, we documented 7194 deaths among 36 943 hypertensive patients. Compared with never-smokers, the multivariate-adjusted relative risks (MRRs) [95% confidence intervals (CIs)] for CVD mortality were 1.19 (1.07, 1.31) and 1.33 (1.23, 1.45) for those who smoked 0.1-19 pack-years and at least 20 pack-years (P for linear trends <0.001 for all). A similar pattern was observed for all-cause mortality. A dose-response association between pack-years smoked and risk of CVD and all-cause mortality (all P ≤ 0.01) was found among the SBP groups (140-159, 160-179, and ≥ 180 mmHg), DBP groups (<90, 90-94, and 100-109 mmHg), and pulse pressure groups (50-59, 60-69, and ≥ 70 mmHg). In addition, compared to never-smokers with stage 1 hypertension, MRRs of CVD and all-cause mortality for those who smoked at least 20 pack-years with stage 3 hypertension were remarkably increased to 3.06 (2.64, 3.54) and 2.51 (2.24, 2.80), respectively.
Smoking not only significantly increased the risk of CVD and all-cause mortality among hypertensive groups, but the synergistic effect on the risk of CVD and all-cause mortality existed between cigarette smoking and blood pressure category. Therefore, apart from hypertension management, smoking cessation should be an essential component for preventing deaths related to smoking.