TOPLINE:

Exclusive use of heated tobacco products was associated with a higher risk for type 2 diabetes (T2D) than never smoking. Individuals who exclusively used heated tobacco products — most of whom had previously smoked cigarettes — did not have a lower risk for T2D than exclusive cigarette smokers.

METHODOLOGY:

• Researchers conducted a prospective cohort study to assess the association between heated tobacco product use and T2D.
• They analyzed data from 29,584 adult participants (mean age, 45.9 years; 82.5% male) who did not have diabetes at baseline from a large company in Japan (April 2018-March 2019).
• Participants completed self-administered questionnaires assessing their tobacco product use and were categorized into five groups on the basis of usage: never smokers, former smokers, exclusive cigarette smokers, exclusive heated tobacco product users, and dual users of cigarettes and heated tobacco products.
• Incident T2D was identified through annual health checkups and defined as fasting plasma glucose levels ≥ 126 mg/dL, casual plasma glucose levels ≥ 200 mg/dL, A1c levels ≥ 6.5%, or receipt of antidiabetic treatment.

TAKEAWAY:

• Over the mean follow-up duration of 4.8 years, 2141 incident cases of T2D were identified (overall incidence rate, 15.2 per 1000 person-years).
• Exclusive heated tobacco product users had a higher risk for T2D than never smokers (adjusted hazard ratio [aHR], 1.61; 95% CI, 1.39-1.86), as did exclusive cigarette smokers (aHR, 1.53; 95% CI, 1.34-1.74) and dual users (aHR, 1.76; 95% CI, 1.48-2.09).
• Among ever smokers, exclusive heated tobacco product users and exclusive cigarette smokers showed comparable risk for T2D; risk was also comparable between dual users and exclusive cigarette smokers.
• A dose-response association was observed, with higher daily consumption linked to an increased risk for T2D (aHR, 1.43; 95% CI, 1.11-1.85 for 1-10 heated tobacco products per day, and aHR, 1.72; 95% CI, 1.46-2.03 for ≥ 11 heated tobacco products per day; P for trend < .001).

IN PRACTICE:

“[The study] findings suggest that dual use may not confer a reduction in diabetes risk, which has important implications for those who smoke cigarettes and may perceive partial switching to HTPs [heated tobacco products] as a health benefit,” the authors of the study wrote, further adding that “if HTPs also increase the risk of diabetes, as the present findings suggest, their growing popularity could hinder the progress in reducing the global diabetes burden and other tobacco-related diseases.”

SOURCE:

The study was led by Huan Hu, PhD, Research Center for Prevention from Radiation Hazards of Workers, National Institute of Occupational Safety and Health, Kawasaki, Japan. It was published online on April 07, 2026, in the American Journal of Preventive Medicine.

LIMITATIONS:

Participants reported their own tobacco use, which could result in incorrect classification of their exposure. The questionnaire did not differentiate between heated tobacco products and e-cigarettes. Other factors, such as exposure to secondhand smoke and smoking history before the study began, might have affected the findings. The study mostly included male employees from one large company, which may make it hard to apply the results to a broader population.

DISCLOSURES:

The study received support from the Industrial Health Foundation, Industrial Disease Clinical Research Grants, JSPS KAKENHI Grants, the NCGM Intramural Research Fund, the JIHS Intramural Research Fund, and grants from the Japan Association for Diabetes Education and Care. The authors reported having no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.