Quitting smoking and new HS diagnoses: what the cohort actually found

01

What was counted—and why six groups matter

The researchers linked two health-screening questionnaires to insurance records for 6,230,189 adults without a prior HS record. From 1 January 2008 through 2021, they identified 3,761 outcomes, requiring at least three separate physician visits coded for HS. This identifies first recorded diagnoses, not the precise day disease began. HS is a chronic skin disease; identifying it is a clinical task, not something this population study can do for a reader.

HR compares diagnosis-event rates while people remain under observation and at risk; 1 means no difference from the reference. The comparison table keeps that reference visible. The quitter group contained 163,451 people but only 110 outcomes. A 0.68 estimate is not a 32-percentage-point drop in personal risk. The never-smoker HR of 0.57 is also versus continuing smokers. Dividing the two row estimates is not a direct contrast or an equivalence test reported by the paper.

[1][2][3]

02

The three-year clock did not start on each person's quit day

Follow-up began at the common study date in 2008, after the second screening. Exact quit dates were not the starting points. In the first three follow-up years, the quitter-versus-continuing contrast was not statistically clear; in years three to six, the adjusted HR was 0.58 (0.36–0.92). That later interval describes a group comparison on the study clock. It is not a switch that turns on after three smoke-free years, or proof that nothing changes earlier.

The primary groups came from two self-reports, so later changes in smoking could be missed. A secondary analysis selected 1,905,499 people whose reported category remained unchanged at subsequent biennial screenings. It was a selected subset of the same source population, not a separate replication. Its persistence requirement also does not repair uncertainty about when HS actually began, since diagnosis can be delayed.

[1]

03

A useful association, not an HS treatment forecast

This was observational research, not randomized cessation. Adjustment included age, sex, income, BMI and other measured factors, but could not remove all differences between groups, including hereditary factors. Weight changes were not considered in this analysis. The smoking groups were predominantly men in Korea, which limits automatic transfer to women and other settings. Self-report and diagnostic coding add uncertainty; nicotine replacements and electronic cigarettes were not captured.

The measured outcome was not a change in pain, drainage, scarring, flare frequency or treatment response in people already living with HS. Fewer new records cannot answer those different questions. Skin concerns or existing HS belong with a qualified clinician or dermatologist, rather than a countdown based on this study.

For help with smoking separately from skin assessment, NHS Better Health directs readers in England to local Stop Smoking Services. Outside England, ask a local health service about available cessation support. This study does not choose a nicotine product or an HS care plan.

[1][2][3][4]

04

What to keep in mind

• The outcome was first recorded HS diagnosis; the comparator was continuing smoking.
• The three-year pattern used a common study start, not a personal quit-day clock.