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Secondhand Smoke May Have an Impact on Diabetes Risk

Oct 2, 2015

Findings suggest further study regarding increased risk for type 2…

A research report was published in The Lancet as a meta-analysis of prospective studies to investigate the associations between smoking associations and risk of diabetes. Smoking has already been linked to lung cancer, strokes, heart disease, birth defects and more. Little research has linked smoking to diabetes, however.


The researchers looked at patients from studies who were active smokers, exposed to secondhand smoke or past smokers. The research was pooled as 88 prospective studies with over 5,898,795 patients and 295,446 incidences of type 2 diabetes.

The study found significant relative risks for diabetes associated with current smokers (RR=1.37), former smokers (RR=1.14) and those exposed to secondhand smoke (RR=1.22). The association of smoke exposure and diabetes incidence persisted in all subgroups and the researchers identified the relationship as being dose-response related to light, moderate or heavy exposure.

The findings are more suggestive than causal due to the nature of the research. However, such links prove important for suggesting future research be done to evaluate these risks further.

It was surprising to see a link between secondhand smoke exposure and an increased risk for diabetes. Nonetheless, the study did little to evaluate if the people with exposure to smoke may have been prone to other lifestyle choices such as poor diet.

One thing is for certain, nearly 80% of secondhand smoke is invisible to the naked eye. Perhaps, the issue of smoke exposure and diabetes risk is also invisible to us. More research will need to be conducted to evaluate this risk.

Practice Pearls:

  • A recent meta-analysis evaluated nearly 6 million patients from 88 studies for exposure to cigarette smoke and risk of diabetes.
  • To some surprise, patients who were active smokers, past smokers and even those exposed to secondhand smoke had significant elevated risk for diabetes incidence.
  • While this research is not causal in nature, it is suggestive of an increased need to further evaluate the risk of smoking and diabetes. It remains important to continue to encourage patients to quit smoking.

Pan A, Y Wang, M Talaei et al. “Relation of active, passive, and quitting smoking with incident type 2 diabetes: a systematic review and meta-analysis.” Lancet. Web. 25 Sept. 2015. <http://www.thelancet.com/journals/landia/article/PIIS2213-8587%2815%2900316-2/fulltext>.