Those Who Are Obese May Also Be More Likely To Smoke: New Study

New European research has found that those who are obese may be more likely to take up smoking and smoke more per day. Carried out by researchers at the International Agency for Research on Cancer, France, and the University of Bristol, UK, the new study set out to establish whether genetic variants associated with obesity play a direct role in influencing smoking behavior.

Using data from nearly 450,000 participants taken from two different databases, the UK Biobank and the TAG consortium, the team analyzed the genetic variants that are known to have an effect on body mass index (BMI), body fat percentage and waist circumference.

Three measures of smoking behavior were also assessed, including current and past smoking, smoking frequency (the number of cigarettes smoked per day), and age of smoking initiation. The team used a technique called Mendelian randomization for the analysis as it gives more reliable results; therefore if an association is found it is more likely to suggest a direct relationship.

They found that being obese is associated with an increased risk of taking up smoking and smoking frequency. More specifically, for each 4.6 kg/m2 increase in BMI the team also found an 18% increased risk of being a smoker in UK Biobank participants and a 19% increased risk for those in the TAG consortium. Each increase in BMI was also estimated to increase smoking frequency by around one cigarette per day -- 0.88 in the UK Biobank group and 1.27 in the TAG consortium.

The researchers also found that body fat percentage and waist circumference had a similar effect on smoking, with the results also consistent in both men and women. The team noted that socio-demographic factors may have also influenced the results. However, with the strengths of the study including the comprehensive genetic data and large sample size they also added that, "our study provides evidence that differences in body mass index and body fat distribution causally influence different aspects of smoking behavior, including the risk of individuals taking up smoking, smoking intensity, and smoking cessation.

"These results highlight the role of obesity in influencing smoking initiation and cessation, which could have implications for public health interventions aiming to reduce the prevalence of these important risk factors," they conclude.