Cigarette smoking, e-cigarette use, and hypertension: a population-based cross-sectional study

Cigarette smoking is an established cardiovascular risk factor, but the association between electronic cigarette (e-cigarette) use and hypertension remains unclear. We examined this association in a nationally representative adult population in Scotland using pooled cross-sectional data from 22,187 adults aged ≥16 years in the Scottish Health Survey (2017-2022). Participants were classified into five mutually exclusive groups: never users (n = 11,760), former smokers (n = 6,201), current cigarette smoking only (n = 2,747), current e-cigarette use only (n = 907), and current dual use (n = 572). Hypertension was defined as self-reported doctor-diagnosed high blood pressure, excluding pregnancy-related hypertension. Multivariable logistic regression estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Secondary analyses disaggregated current e-cigarette use only by smoking history, and propensity score matching was performed as a sensitivity analysis. Overall hypertension prevalence was 26.5%, ranging from 19.0% among current exclusive e-cigarette users to 33.5% among former smokers. Compared with never users, current e-cigarette use only was associated with lower odds of hypertension (OR 0.77, 95% CI 0.63-0.93), whereas former smokers had higher odds (OR 1.10, 95% CI 1.02-1.20). No significant associations were observed for current cigarette smoking only (OR 0.94, 95% CI 0.84-1.06) or current dual use (OR 0.95, 95% CI 0.75-1.20). The inverse association for exclusive e-cigarette use was confined to former smokers who had switched to vaping (OR 0.77, 95% CI 0.63-0.94). In propensity score-matched analyses, the inverse association for current exclusive e-cigarette use was attenuated and no longer statistically significant, suggesting that this finding may partly reflect healthy switcher bias and residual confounding rather than a protective effect.