Obesity as a standalone disease puts patients at increased risk of adverse cardiovascular outcomes, researchers have discovered.
For the study, researchers reviewed previous reports that used mendelian randomization methods to find a correlation between obesity and cardiovascular events with 95% CIs. The primary outcome was a correlation between obesity and type 2 diabetes, coronary artery disease, or stroke.
Obesity alone has been linked to diabetes & coronary artery disease: https://t.co/bU1zSdTkhe
— Cleveland Clinic (@ClevelandClinic) November 16, 2018
Researchers found 4,660 potential studies for inclusion, screened 2,511 titles, and ultimately included seven studies in the systematic review and five in the meta-analysis. The five studies chosen for analysis included 881,692 total participants. The authors identified a significant correlation between obesity and risk of type 2 diabetes (odds ratio [OR], 1.67; 95% CI, 1.30-2.14; P < .001; I2 = 93%) and coronary artery disease (OR, 1.20; 95% CI, 1.02-1.41; P = .03; I2 = 87%), but they did not find a link between obesity and stroke (OR, 1.02; 95% CI, 0.95-1.09; P = .65; I2 = 0%).
For every 1-SD increase in body mass index, the risk of type 2 diabetes and coronary artery disease increased by 67% and 20%, respectively. If current trends continue, about one-fifth of the world’s adult population—roughly 1.2 billion people—will be obese by 2030, the researchers wrote, “with the prevalence of metabolic syndromes such as diabetes and [cardiovascular disease] to increase by 54% and 22%, respectively.”
— CDC DNPAO (@CDC_DNPAO) November 16, 2018
The study shows that adverse effects that come along with obesity are not the only risk factors for disease, said lead study author Haitham Ahmed, MD, of the Cleveland Clinic.
“This study is important because we can conclude that it is not solely factors like high blood pressure, high cholesterol, or lack of exercise that tend to come with obesity that are harmful—the excess fat itself is harmful,” Ahmed said. “Patients may think their cardiovascular risk is mitigated if their other risk factors are normal or being treated, but this study suggests you cannot ignore the extra weight. Physicians should take heed and make sure they are counseling their patients about weight loss in a comprehensive and collaborative manner.”
— James McCarter (@JPMcCarter) November 13, 2018
The researchers noted that while their findings indicated a causal association, they could not determine causality.
“Mendelian randomization assumptions were often not verified in individual studies, and this could have contributed bias to the present meta-analysis,” they wrote.