Relationship Between Cotinine-Verified Smoking Status and Incidence of Hypertension in 74,743 Korean Adults

BACKGROUND: The relationship between chronic smoking and hypertension (HTN) is inconclusive in previous studies, which were mainly based on self-reported smoking status. The aim of this study was to evaluate the association of cotinine-verified smoking status with incident HTN.Methods and Results:A total of 74,743 participants (43,104 men; age 38±5.4 years) were included in the study, with a mean follow-up period of 29 months. Individuals were divided into 4 groups on the basis of their cotinine-verified smoking status at baseline and at follow-up (never-smoking, new-smoking, former-smoking, and sustained-smoking). The incidence rate of HTN in the never-smoking, new-smoking, former-smoking, and sustained-smoking groups was 8.2%, 7.6%, 10.1%, and 8.7% for men and 1.8%, 2.5%, 1.5%, and 2.2% for women, respectively. In a multivariate Cox-hazard regression analysis adjusted for the variables with a univariate relationship, new-smoking and sustained-smoking had decreased relative risks (RRs) for incident HTN compared with never-smoking (RR [95% CI], 0.75 [0.58, 0.96] for new-smoking and 0.82 [0.74, 0.90] for sustained-smoking). Cotinine-verified current smoking at baseline was also inversely associated with incident HTN compared with cotinine-verified never-smoking at baseline (0.91 [0.84, 0.98]). These results remained significant only in men, although there was no sex interaction. CONCLUSIONS: This longitudinal study showed that cotinine-verified new-smoking and sustained-smoking decreased the risk for incident HTN, especially in men, compared with never-smoking.