Researchers from the University of Copenhagen in Denmark have found that smoking is linked to a rise in visceral belly fat, the kind that surrounds internal organs. The study, published in Addiction, adds a crucial piece to the puzzle of how tobacco use affects body composition and health risks. It underscores that the distribution of fat inside the abdomen matters for disease risk, not just total body weight. [Citation: University of Copenhagen study, Addiction journal]
To explore this relationship, the team used Mendelian randomization, a method that leverages natural genetic variation to infer causality between smoking behavior and fat distribution. The study analyzed data from about 600,000 adults, tracking genetics alongside measurements such as height, weight, and waist circumference. By examining genetic variants linked to smoking, the researchers could infer how tobacco exposure might influence where fat is stored in the body. This approach helps distinguish direct effects from correlations that could arise from other factors common in observational research. [Citation: University of Copenhagen study, Addiction journal]
The findings revealed an interesting paradox: smokers typically weighed less on average than non-smokers but tended to have a larger waistline due to greater visceral fat deposition. In other words, smoking may reduce overall body mass while simultaneously shifting fat toward the abdominal cavity, where it can encroach on vital organs including the heart, liver, and kidneys. This pattern helps explain why some smokers maintain a leaner appearance while still carrying a higher risk for certain health problems. [Citation: University of Copenhagen study, Addiction journal]
Excess visceral fat is associated with a range of serious health issues, affecting both people who are lean and those who are overweight. The abdominal buildup contributes to hypertension, atherosclerosis, type 2 diabetes, and an elevated risk of heart attack and stroke. These relationships highlight why fat distribution often matters more for disease risk than total body weight alone, and they emphasize the importance of monitoring waist circumference as part of routine health assessments for smokers and former smokers alike. [Citation: University of Copenhagen study, Addiction journal]
According to the researchers, the accumulation of visceral fat appears to be linked to specific genetic variants. These genetic factors appear to influence visceral fat more strongly than subcutaneous fat, suggesting that biology plays a distinct role in how tobacco exposure reshapes fat distribution. The study adds to a growing body of evidence that smoking interacts with inherited traits to influence where the body stores fat, which can have long-term implications for metabolic health. [Citation: University of Copenhagen study, Addiction journal]
Past investigations have explored various molecules and proteins involved in weight regulation, and some researchers have identified proteins that promote weight loss under certain conditions. This study contributes to that broader conversation by focusing on how smoking interacts with genetics to alter fat distribution, potentially informing future interventions for reducing visceral fat and related health risks in populations with high smoking prevalence. [Citation: University of Copenhagen study, Addiction journal]