Self-reported smoking, urine cotinine, and risk of incident hypertension: findings from the PREVEND prospective cohort study.

Abstract

This study compared the associations of smoking status assessed by self-report versus urine cotinine with incident hypertension risk. Using the PREVEND study, a prospective cohort conducted in the Netherlands, smoking status was assessed at baseline by self-reports and urine cotinine in participants without a history of hypertension. Participants were classified as never, former, light current (≤10 cigarettes/day), and heavy current smokers (>10 cigarettes/day) by self-report, and analogously by urine cotinine: <100 ng/mL (never), 100-500 ng/mL (former), 501-1456 ng/mL (light current), and >1456 ng/mL (heavy current). Incident hypertension was defined as systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or the initiation of antihypertensive medications. Hazard ratios (HRs) with 95% CIs were estimated. The cohort comprised of 3296 participants (mean age 49 years, 46.0% male). The distribution of participants by self-reported smoking category was: never (n = 1045), former (n = 1271), light current (n = 379), and heavy current (n = 601). Based on urine cotinine, the distribution was: never (n = 2288), former (n = 161), light current (n = 404), and heavy current (n = 443). During a median follow-up of 7.2 years, 832 participants developed hypertension. Compared with self-reported never smokers, the multivariable adjusted HRs (95% CI) for hypertension were 1.03 (0.87-1.23) for former, 1.55 (1.22-1.97) for light current, and 1.43 (1.17-1.76) for heavy current smokers. Using urine cotinine (never smokers as referent), the corresponding adjusted HRs (95% CI) were 1.04 (0.74-1.45), 1.32 (1.06-1.64), and 1.62 (1.34-1.95). Light and heavy current smoking, as assessed by self-reports and urine cotinine, are each associated with an increased risk of hypertension.