John Murphy, MDLinx | August 02, 2016
A study of monozygotic twins with different body-mass indices (BMI) found that BMI isn’t associated with increased risk of heart attack or death, but it is associated with increased risk of type 2 diabetes in the heavier twin, according to an article published online August 1, 2016 in JAMA Internal Medicine.
“The results suggest that lifestyle changes that reduce levels of obesity do not have an effect on the risk of death and heart attack, which contradicts conventional understandings of obesity-related health risks,” said lead researcher Peter Nordström, PhD, Professor and Chief Physician in the Department of Community Medicine and Rehabilitation at Umeå University, in Umeå, Sweden.
“What the study does show is that there’s a strong association between obesity and diabetes, which leads us to conclude that weight reduction interventions can be more effective against diabetes than when it comes to reducing the risk of heart attack and mortality,” Dr. Nordström added.
For this study, Dr. Nordström and colleagues used patient health data from a cohort of 4,046 pairs of monozygotic twins from the Swedish Twin Registry. Each pair of twins had differing levels of body fat, as measured by BMI.
During an average follow-up of 12.4 years, heavier twins had nearly the same amount of heart attacks compared with their leaner twins (5% vs 5.2%), and a comparatively similar number of deaths (13.6% vs 15.6%). Even among the 65 pairs of twins who had a difference in BMI of 7 or more, and in which the heavier twin had a BMI of 30 or higher, there were still no noticeably increased risks of heart attack or death associated with a higher BMI.
However, the heavier twins did have an increased risk (odds ratio of 2.14) of developing type 2 diabetes, the results showed. “This finding may indicate that interventions to promote weight loss are more effective in reducing the risk of diabetes than [in reducing] the risk of cardiovascular disease and mortality,” the authors concluded.