Debunking The Myth Of Smoking To Stay Thin

In America, an estimated 28 million people smoke cigarettes, despite the unhealthy habit being well known to be the leading cause of preventable diseases and death, killing more than 480,000 people every year. Data from the CDC states that smoking shortens lifespans and causes more deaths every year than alcohol use, firearm-related incidents, motor vehicle injuries, illegal drug use, and HIV combined. Research also indicates that smokers are more likely to develop dementia, with an estimated 14% of Alzheimer’s disease cases being attributed to smoking. 

Recent research published in the journal Addiction reports that starting smoking as well as a lifetime of smoking may increase unhealthy visceral fat in the abdomen, especially the kind found deep within the abdominal cavity which is associated with an increased risk of dementia, diabetes, stroke, and heart disease. 

Researchers at the NNF Center for Basic Metabolic Research, University of Copenhagen used the Mendelian randomization (MR) statistical analysis to determine whether smoking causes an increase in abdominal fat; by combining multiple genetic results and accounting for a wide range of potential influences to ensure that any connections between smoking and body fat distribution were due to smoking and not to other factors. The study looked at 1.2 million people who started smoking and more than 450,000 lifetime smokers, and the fat distribution of over 600,000 people. 

“This study found that starting to smoke and smoking over a lifetime might cause an increase in belly fat, as seen by measurements of waist-to-hip ratio. In a further analysis, we also found that the type of fat that increases is more likely the visceral fat, rather than the fat just under the skin,” said Dr. Germán D. Carrasquilla, the lead author of the study and an assistant professor at the University of Copenhagen in Denmark.

“Previous studies have been prone to confounding, which happens when an independent variable affects the results. Because our study design uses genetic variations, it does a better job of reducing or controlling for those variables. The influence of smoking on belly fat seems to happen regardless of other factors such as socioeconomic status, alcohol use, ADHD, or how much of a risk-taker someone is.”

“From a public health point of view, these findings reinforce the importance of large-scale efforts to prevent and reduce smoking in the general population, as this may also help to reduce abdominal visceral fat and all the chronic diseases that are related to it,” he added. “Reducing one major health risk in the population will, indirectly, reduce another major health risk.”

“Our study showed that smoking initiation and lifetime smoking may causally increase abdominal adiposity, as indicated by higher waist to hip ratio… While we found no evidence of an association between smoking heaviness and abdominal fat distribution, our reverse causal analysis indicated that higher abdominal adiposity may causally increase smoking heaviness,” the study authors wrote.

“What they’ve done is sort of confirmed that, no, it’s not your genes, it’s not your family risk factors, this is actually directly attributable to smoking and the effect of tobacco and nicotine itself on the inflammatory pathways that lead to the abdominal fat,” said Dr. Jonathan Klein, a physician at Stanford University in California and a researcher in tobacco control. “From that perspective, it’s an important piece of evidence because often people say ‘oh, if you’re gonna be fat, if you have cardiac risk, that’s your lot in life.’ And there are genetic components to it, but this is very clear that regardless of that, this is still significantly because of tobacco and nicotine,” he added.