- A new review of randomised controlled trials found some health risk markers improved when smokers switched to heated tobacco products (HTPs).
- One cancer biomarker and two cardiovascular biomarkers showed statistically significant signs of harm reduction.
- For many other biomarkers, results pointed in a positive direction but were limited by small study sizes.
- Researchers emphasise that larger, more robust studies would help strengthen the evidence of the benefits of switching.
Heated tobacco products (HTPs) – devices that warm tobacco instead of burning it – may offer health benefits to smokers who cannot quit entirely, according to new research.
Published in the Pakistan Journal of Medical Sciences, the review analysed six randomised controlled trials (RCTs) involving 1,362 participants.
The study found evidence that some key health risk markers improved when smokers switched to heated tobacco compared with continuing conventional cigarettes. It examined 40 biomarkers linked to cancer, cardiovascular disease, lung health, inflammation, metabolism, and kidney function. Out of these, three stood out.
The authors reported that “one cancer biomarker (nitrosamine) and two cardiovascular biomarkers (eosinophils and total bilirubin) showed statistically significant harm reduction.”
Cancer and heart risk markers dropped
The findings suggest that switching to heated tobacco could reduce some of the health risks caused by smoking. The biomarker nitrosamine, linked to cancer risk, dropped significantly in smokers who changed to HTPs. Similarly, two cardiovascular markers – eosinophils (a type of white blood cell) and total bilirubin – also showed measurable improvements.
For many other biomarkers, the results pointed in a positive direction but were limited by the small size of the studies. According to the authors, “the remaining biomarkers of harm in cardiovascular, inflammatory, metabolic, pulmonary, and renal categories showed imprecise findings.”
The researchers noted that most of the included studies were relatively small and all were conducted in high-income countries such as the United States, Poland, and Japan. As they put it: “The majority of the findings are imprecise due to the small sample sizes of the included studies.”
Building on evidence base
Smoking remains one of the world’s leading causes of preventable death, killing more than eight million people annually, according to the World Health Organization. Conventional cigarettes expose users to thousands of harmful chemicals created by combustion. HTPs, by contrast, use lower temperatures to release nicotine without burning tobacco leaves, reducing exposure to toxic substances.
The authors stressed that “harm reduction associated with the tobacco consumption is a key public health concern.” While quitting entirely is always best, the findings add to growing evidence that less harmful alternatives can play a vital role for smokers who struggle to quit.
Earlier reviews had shown that heated tobacco lowers exposure to harmful chemicals, but this study goes further by linking switching to measurable improvements in health risk markers.
Looking ahead
While the results are promising, the authors highlighted the importance of continued research to confirm and expand on these findings. They explained that “sufficiently powered, robust RCTs targeting key harm reduction biomarkers within both upper and low-middle income country settings are required in the future.”
The analysis also noted that all six RCTs compared smokers who continued with conventional cigarettes against those who switched fully to HTPs. The devices studied included a range of models, from the Tobacco Heating System (THS) IQOS to carbon-heated and electrically heated products, but all worked on the same principle of heating rather than burning tobacco. Despite differences between devices, the pooled results consistently showed significant reductions in nitrosamine and improvements in the two cardiovascular biomarkers.
The review underlined that five of the six trials had a low risk of bias across most domains, adding weight to the findings. Only one study showed a high risk of bias in a single area.
Reducing health risks
The study suggests that switching from conventional cigarettes to HTPs may reduce certain health risks, particularly in relation to cancer and cardiovascular disease.
The authors concluded: “In human RCTs of moderate quality among smokers unable to quit and switching to HTPs within high-income country settings some biomarkers demonstrated harm reduction while the rest demonstrated imprecise findings due to small sample sizes.”
