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Experts say tobacco exposure before birth can raise type 2 diabetes risk later in life. enigma_images/Getty Images
  • A new analysis shows a strong correlation between tobacco exposure early in life and the development of type 2 diabetes later in life.
  • Researchers report that people with preexisting genetic risk factors for type 2 diabetes face an even higher risk if they smoke.
  • They say that adopting a healthy lifestyle later in life helped lower the risk.

New research shows that early exposure to tobacco – whether in the womb or during childhood and adolescence – has a strong correlation with the development of type 2 diabetes later in life.

The large-scale observational analysis pulled records of about 476,000 adults in the UK Biobank.

The findings, which have not been published yet in a peer-reviewed journal, were presented this week at the annual American Heart Association’s Epidemiology and Prevention/Lifestyle and Cardiometabolic Scientific Sessions in Chicago.

While the data only shows correlation and not causation, it adds to the body of evidence that correlates tobacco exposure with poor health – particularly for those who are exposed early in life.

“This emphasizes the importance of preventing tobacco exposures in early life stages including during pregnancy, especially for people with high genetic risk for type 2 diabetes,” Victor Wenze Zhong, a senior study author and a professor and chair of the department of epidemiology and biostatistics at Shanghai Jiao Tong University School of Medicine in China, told Medical News Today.

“Adopting a healthy lifestyle later in adulthood could lower the risk of type 2 diabetes among people who have had tobacco exposure in utero, childhood, or adolescence,” he added.

It’s already been established that smoking and tobacco exposure are associated with a host of negative health outcomes such as cancer, heart disease, stroke, and diabetes.

The study authors reported that people who started smoking in childhood had double the risk of type 2 diabetes. In addition, those who started smoking as adolescents had a 57% higher risk while those who started smoking as adults had a 33% higher risk of developing type 2 diabetes compared to those who never smoked.

The study categorized childhood as ages 5 to 14 and adolescence as ages 15 to 17. Those with a genetic predisposition for type 2 diabetes faced a higher risk.

Dr. Robert Eckel, an endocrinologist and past president of the American Heart Association who was not involved in the study, told Medical News Today that while the research carries some caveats in terms of being observational, it could help physicians better understand the association between tobacco and type 2 diabetes.

“I think we’ve known for some time that tobacco utilization is associated with all kinds of adverse effects – type 2 diabetes, cancer, hypertension, and many others that affect the cardio metabolic space,” he explained. “So the idea that tobacco is potentially insightful for the diagnosis of type 2 diabetes is really important.”

While the correlation is established, proving causation is more elusive. Eckel said that a clue could lie in the fact that tobacco exposure is associated with insulin resistance – but there are many factors, genetic and otherwise, at play.

The analysis also found that adopting a healthy lifestyle later in adulthood could lower the risk of developing type 2 diabetes, even for those who were exposed to tobacco early in life.

Smoking is still commonplace, but its prevalence has been on a downward trajectory for decades.

About 42% of U.S. adults were smokers in 1965, while under 14% were smokers in 2018. The U.S. Centers for Disease Control and Prevention (CDC) estimates that the number fell to less than 12% in 2021.

“There’s been a concerted effort made to curb smoking, from labeling products that contain tobacco to public education and public regulations,” Eckel explained.

While numbers are lower, they’re still nowhere near zero. The number of U.S. adults who smoke still amounts to 28 million people and cigarette smoking is still the leading cause of preventable disease and death in the United States.

Eckel said that for those who might need one more reason to quit smoking, it’s worth considering that their polygenic risk for type 2 diabetes could make them even more susceptible to developing the condition if they smoke – adding that many people have no idea what their risk factor may be.

“I think type 2 diabetes is something we don’t want in addition to all the other risks that relate to tobacco utilization,” he said. “So the take-home message is that if you’ve been exposed to tobacco when you were young, it’s time to get your lifestyle activated in a way that would prevent excess body weight gain and understand what your risk factors may be.”