A Cleveland Clinic genetic analysis has found that obesity itself – not just the adverse health effects associated with it – significantly increases the risk of Type 2 diabetes and coronary artery disease. The paper was published in the Journal of the American Medical Association Network Open.
Coronary artery disease – and complications that arise from it, such as heart attacks and heart failure – is the leading cause of death in the United States and across the world. While other factors such as high cholesterol have been tied to coronary artery disease, the association between obesity and cardiovascular disease has not been clearly established.
For the study, researchers performed a meta-analysis of five studies with more than 880,000 participants. They examined participants’ genetic variations using a method called Mendelian randomization, which offers insight into the relationships between health risks and health outcomes. By relying on genetic data, this method removes confounding, or outside, variables that can extraneously influence outcomes, such as smoking, high blood pressure, or elevated cholesterol. Mendelian randomization cannot prove causality, but it can be suggestive of a causal association – as was the case in this study.
“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,” said Haitham Ahmed, M.D., the senior author of the study and a preventive cardiologist at Cleveland Clinic. “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.”
According to the Centers for Disease Control and Prevention, 39.8 percent of U.S. adults are obese. Meanwhile, World Health Organization reports 13 percent of the world’s adult population is obese and that the prevalence of obesity has tripled between 1975 and 2016. Obesity rates, along with rates of cardiovascular disease and diabetes, are expected to continue to rise, if current trends continue.
Obesity Facts
Obesity is common, serious and costly
- The prevalence of obesity was 39.8 percent and affected about 93.3 million of U.S. adults in 2015-2016.
- Obesity-related conditions include heart disease, stroke, type 2 diabetes and certain types of cancer, which are some of the leading causes of preventable, premature death.
- The estimated annual medical cost of obesity in the United States was $147 billion in 2008 U.S. dollars; the medical cost for people who have obesity was $1,429 higher than those of normal weight.
Obesity affects some groups more than others
- Hispanics (47.0 percent) and non-Hispanic blacks (46.8 percent) had the highest age-adjusted prevalence of obesity, followed by non-Hispanic whites (37.9 percent) and non-Hispanic Asians (12.7 percent).
- The prevalence of obesity was 35.7 percent among young adults aged 20 to 39 years, 42.8 percent among middle-aged adults aged 40 to 59 years, and 41.0 percent among older adults aged 60 and older.
Obesity and socioeconomic status
The association between obesity and income or educational level is complex and differs by sex and race/ethnicity, reports CDC.
- Overall, men and women with college degrees had lower obesity prevalence compared with those with less education.
- By race/ethnicity, the same obesity and education pattern was seen among non-Hispanic white, non-Hispanic black, and Hispanic women, and also among non-Hispanic white men, although the differences were not all statistically significant. Although the difference was not statistically significant among non-Hispanic black men, obesity prevalence increased with educational attainment. Among non-Hispanic Asian women and men and Hispanic men there were no differences in obesity prevalence by education level.
- Among men, obesity prevalence was lower in the lowest and highest income groups compared with the middle income group. This pattern was seen among non-Hispanic white and Hispanic men. Obesity prevalence was higher in the highest income group than in the lowest income group among non-Hispanic black men.
- Among women, obesity prevalence was lower in the highest income group than in the middle and lowest income groups. This pattern was observed among non-Hispanic white, non-Hispanic Asian, and Hispanic women. Among non-Hispanic black women, there was no difference in obesity prevalence by income.
Source: Centers for Disease Control and Prevention, Division of Nutrition, Physical Activity and Obesity, https://stateofobesity.org/obesity-rate-youth-1017/