Passive smoking raises risk of type 2 diabetes

Back to news
22 Sep 2015

Non-smokers who breathe in other people’s cigarette smoke are at significantly higher risk of developing type 2 diabetes, research published on Friday shows.

“Passive smoking” increases a non-smoker’s chances of becoming a diabetic by 22% compared with the chances for those who have never inhaled tobacco smoke, the study says.

It is well known that active smokers are more likely to develop diabetes, and these latest findings assess that risk as being 37%. Former smokers are also at an increased risk – put at 14% more than for those who have never lit up – of type 2 diabetes, which itself increases the risk of stroke, heart attack and blindness.

The NHS has warned that 80% of “secondhand” smoke is invisible and that it can raise the risk of meningitis, cancer, bronchitis and pneumonia.

The findings are contained in a meta-analysis of 88 previous studies, covering almost six million participants. It looked at the link between active and passive smoking, and was published in The Lancet Diabetes & Endocrinology medical journal. Both smoking and inhalation of secondhand smoke were “associated with significantly increased risks of type 2 diabetes”, the authors concluded.

Deborah Arnott, chief executive of the anti-smoking charity Ash, said: “We already know that smoking increases the risk of type 2 diabetes but it now appears that people exposed to secondhand smoke and former smokers are also at risk.

“We advise smokers with diabetes who want to stop smoking to use licensed nicotine products or electronic cigarettes which will deal with any cravings and will help them manage their diet to avoid putting on excess weight.”

The authors said that accumulating evidence suggested that secondhand smoke could also be a concern for diabetes risk, as was smoking. “Reduction of active smoking should automatically reduce the prevalence of secondhand smoke exposure.”

Their findings further emphasised the importance of adoption and enforcement of smoke-free legislation to reduce the number of people exposed to secondhand smoke, they said.

Richard Elliott, research communications manager at Diabetes UK, said: “We know that both smoking and passive smoking are extremely harmful to health for many reasons and that a huge proportion of people who smoke die as a result of it.”

The study added to evidence of a link between smoking and type 2 diabetes but it did not prove that smoking directly caused it, Elliott warned. The study, however, states that its findings “suggest that smoking might be a causal risk factor for type 2 diabetes”.

Smoking is particularly ill advised for diagnosed diabetics because it increases their already heightened risk of suffering a heart attack or stroke, and people should give up the habit if they could, Elliott added.

From 1 October it will be illegal for an adult in England to smoke in a car containing anyone under the age of 18, and both the driver and passenger could be fined £50, in a further attempt to tackle passive smoking.

The new study calculates that light, moderate, and heavy smokers are at respectively a 21%, 34% and 57% higher risk, relative to lifetime non-smokers, of developing diabetes due to the habit.

It also estimates that 27.8m cases of diabetes worldwide – amounting to 11.7% of the male incidents and 2.4% of the female incidents – could be due to smoking.

In a linked opinion piece in the journal five authors say that doctors should tell patients who smoke that lighting up puts them at extra risk of developing diabetes as well as cancer, stroke and heart attack.


Stressed, worried, or low?  Are you feeling stressed, worried or low? Buckinghamshire Healthy Minds is your local NHS service for anyone experiencing such feelings.

Stressed, worried, or low?

At risk of Type 2 Diabetes

Diabetes Education and Support

Bexley Carers

Bexley - Memory Issues

Bexley Type 2 Diabetes Risk Reduction

Long Term Conditions Support Buckinghamshire

Get Healthy Coaches

Increase Exercise

Healthy Eating

Weight Management

Smoking Cessation

Alcohol Reduction