Study: Obesity is the Dominant Risk Factor for Type 2 Diabetes

Obesity increases the risk of developing type 2 diabetes (T2D) by at least 6 times, regardless of genetic predisposition, according to a study recently published in Diabetologia.¹

The researchers examined the joint association of obesity, genetic predisposition, and unfavorable lifestyle with T2D using data from a case-cohort study from the Diet, Cancer and Health cohort in Denmark. The data from the study covered 4729 individuals who developed T2D during a follow-up period at a median of 14.7 years, with a randomly selected cohort sample of 5402 individuals in the control group.¹

Participants were aged 50 to 65 years, with a mean age of 56.1 years. Of the participants, 49.6% were women and 51.4% were men. For the purposes of the study, 21.8% of participants were classified as obese, 43.0% as overweight, and 35.2% as having a normal weight.¹

Lifestyle was analyzed through a lifestyle score that assessed smoking, alcohol consumption, physical activity, and diet. Based on these scores, 40% of participants were classified as having a favorable lifestyle, 34.6% had an intermediate lifestyle, and 25.4% had an unfavorable lifestyle.¹

The genetic predisposition of participants was quantified using a genetic risk score (GRS) that comprised of 193 known T2D-associated genetic variants that were divided into 5 risk groups of 20% each (quintiles), from lowest (quintile 1) to highest (quintile 5) genetic risk. Statistical modeling then helped to assess the individual and combined associations of the GRS, obesity, and lifestyle scores with developing T2D.¹

The results of the study showed that those with obesity were almost 6 times more likely to develop T2D when compared with people of normal weight, whereas people who were overweight had an increased risk of 2.4 times.¹

In regard to genetic risk, participants with the highest GRS were found to be twice as likely to develop T2D as those with the lowest score, whereas those with an unfavorable lifestyle were 18% more likely to develop T2D than those with a favorable one.¹

Participants who were obese, with a high GRS and an unfavorable lifestyle, had a 14.5 times increased risk for developing T2D compared with those with a normal body weight, low GRS, and favorable lifestyle. Furthermore, for those participants with a low GRS and favorable lifestyle, if they were also obese, they still had an 8.4 times increased risk of T2D compared with normal weight individuals in the same GRS and lifestyle classification.¹

According to the researchers, these results demonstrated that prevention of T2D should be focused on weight management and the promotion of a healthy lifestyle, regardless of genetic risk, since the effect of obesity on T2D risk is dominant over all other risk factors.¹

REFERENCES

• Schnurr TM, Jakupović H, Carrasquilla GD, et al. Obesity, unfavourable lifestyle and genetic risk of type 2 diabetes: a case-cohort study. Diabetologia. 2020. doi: 10.1007/s00125-020-05140-5.
• Obesity is a critical risk factor for type 2 diabetes, regardless of genetics [news release]. ScienceDaily. April 15, 2020. sciencedaily.com/releases/2020/04/200415185837.htm. Accessed April 17, 2020.