Hidradenitis suppurativa (HS) is a chronic skin condition characterised by painful, inflamed nodules, primarily affecting areas rich in apocrine glands. Established as a risk factor, tobacco smoking has been closely linked with the development of HS. Yet, the influence of smoking cessation on HS risk remains underexplored. A comprehensive nationwide cohort study involving over 6 million Korean participants provides new insights into how changes in smoking habits affect HS onset.

Study Methodology

This population-based cohort study leverages data from the Korean National Health Insurance Service database, focusing on participants who underwent biennial health examinations in 2004-2005 and again in 2006-2007. The primary cohort included individuals who participated in these checkups, while the secondary cohort consisted of those who maintained the same smoking status throughout the follow-up period. The study analysed data from July to December 2023, employing a Cox proportional hazards model to estimate HS risk based on changes in smoking status.

Key Findings

The study analysed a total of 6,230,189 participants, with a mean age of 47.2 years, and 55.6% of whom were male. Over an extensive follow-up period amounting to 84,457,025 person-years, 3,761 HS events were recorded. The findings reveal significant differences in HS risk related to smoking habits:

• Sustained Smokers vs. Quitters: Participants who continued smoking across both health checkups (sustained smokers) exhibited a higher risk of HS development. In contrast, those who quit smoking by the second checkup (smoking quitters) demonstrated a significantly lower risk, with an adjusted hazard ratio (AHR) of 0.68 (95% CI, 0.56-0.83). Those who maintained a smoke-free status throughout the study period showed an AHR of 0.67 (95% CI, 0.57-0.77).
• Never Smokers: Individuals who reported never smoking at either checkup had the lowest risk of HS onset, with an AHR of 0.57 (95% CI, 0.52-0.63), highlighting the protective effect of never engaging in smoking.
• Quitters Who Resumed Smoking: Participants who initially quit smoking but resumed by the second checkup, as well as those who started smoking after the first checkup (new smokers), exhibited HS risks similar to sustained smokers, indicating that resuming or initiating smoking can negate the benefits of cessation.
• Time-Smoking Interaction: The study further explored how the duration since smoking cessation affects HS risk. A rapid reduction in HS risk was noted approximately three years after quitting smoking, with levels resembling those of never smokers. This significant risk reduction persisted, with an AHR of 0.58 (95% CI, 0.36-0.92) observed between three to six years post-cessation, and an AHR of 0.70 (95% CI, 0.50-0.97) after twelve years.

Implications

The study underscores the importance of smoking cessation in reducing the risk of HS development. By maintaining a smoke-free status, individuals can substantially lower their risk of developing HS, emphasising the need for public health strategies focused on smoking cessation and prevention of smoking initiation or resumption.

Source: JAMA Network