Association between cotinine-verified smoking status and hypertension in 167,868 Korean adults.

PURPOSE

Previous studies showed inconsistent results concerning the relationship between chronic smoking and blood pressure. Most of the studies involved self-reported smoking status. This study was performed to evaluate the association of urinary cotinine or self-reported smoking status with hypertension and blood pressure in Korean adults.

MATERIALS AND METHODS

Among individuals enrolled in the Kangbuk Samsung Health Study and Kangbuk Samsung Cohort Study, 167,868 participants (men, 55.7%; age, 37.5 ± 6.9 years) between 2011 and 2013 who had urinary cotinine measurements were included. Individuals with urinary cotinine levels ≥50 ng/mL were defined as cotinine-verified current smokers.

RESULTS

The prevalence of hypertension and cotinine-verified current smokers in the overall population was 6.8% and 22.7%, respectively (10.0% in men and 2.8% in women for hypertension: 37.7% in men and 3.9% in women for cotinine-verified current smokers). In a multivariate regression analysis adjusted for age, sex, body mass index, waist circumference, alcohol drinking, vigorous exercise, and diabetes, cotinine-verified current smoking was associated with lower prevalence of hypertension compared with cotinine-verified never smoking (OR[95% CI], 0.79 [0.75, 0.84]). Log-transformed cotinine levels and unobserved smoking were negatively associated with hypertension, respectively (0.96 [0.96, 0.97] and 0.55 [0.39, 0.79]). In a multivariate linear regression analysis, the cotinine-verified current smoking was inversely associated with systolic and diastolic blood pressure (BP) (regression coefficient[95% CI], -1.23[-1.39, -1.07] for systolic BP and -0.71 [-0.84, -0.58] for diastolic BP). In subgroup analyses according to sex, the inverse associations between cotinine-verified current smoking and hypertension were observed only in men.

CONCLUSIONS

This large observational study showed that cotinine-verified current smoking and unobserved smoking were inversely associated with hypertension in Korean adults, especially only in men.