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Weight loss recommended to decrease CV risk in metabolically healthy obesity
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Obesity typically associates with metabolic abnormalities and increased risks for developing CVD and diabetes. However, some individuals have a BMI in the obesity range — at least 30 kg/m2 — without accompanying hypertension, hypercholesterolemia and insulin resistance. Researchers are assessing the long-term health risks that obesity may present for these metabolically healthy people. Cardiology Today spoke with cardiologist Carl J. Lavie, MD, FACC, and endocrinologist Ivania M. Rizo, MD, about how they manage CV risks for patients with metabolically healthy obesity.
How do you address CV risks for people with metabolically healthy obesity?
A cardiologist weighs in.
Some studies years ago suggested that metabolically healthy obesity was benign, but more recent studies indicate that there is still an increased risk for developing metabolic unhealthiness — basically, increases in blood glucose, triglycerides and BP — over time, mainly due to additional weight gain. Also, most recent studies show that there still is at least a small increased risk for CVD among people with metabolically healthy obesity compared with those who are lean and metabolically healthy.
The risk for HF, however, is more increased with obesity regardless of metabolic health, as the weight itself places a “heavy” toll on the CV system, especially the heart.
For other CVDs, there is only a small increase in risk, and lean patients who are metabolically unhealthy actually have a higher risk than those with metabolically healthy obesity, as the metabolic healthiness is more important than the weight for most CVDs.
We have published data recently showing that what is missing in most of these studies is assessment of physical activity and cardiorespiratory fitness. Our data show that those with metabolically healthy obesity who have good physical activity and cardiorespiratory fitness really do have a good prognosis.
The most important things, therefore, are to perform daily physical activity and exercise to maintain a good level of cardiorespiratory fitness and prevent additional weight gain. Even better would be to lose 5 lb to 10 lb. Physical activity also helps to keep dietary sugars and carbohydrates low and maintain metabolic health. Metabolic abnormalities can be treated with now very effective pharmacologic agents if elevations in sugar, lipids or BP occur.
Most studies show that people who are lean but metabolically unhealthy assessed at one point in time have a higher overall CVD risk, with the exception of HF, than those with metabolically healthy obesity, also assessed at one point in time and then followed long-term. Although it is known that many patients with metabolically healthy obesity develop metabolic unhealthiness over time, mainly from weight gain and/or more insulin resistance with aging and sedentary lifestyle, I am not aware of studies showing this impact on CVD, but one would expect that it would be negative. Although efforts at weight loss would be desirable, the main thing for those with metabolically healthy obesity would be to prevent additional weight gain over time and to increase physical activity and fitness, which really makes the prognosis better.
- References:
- Fletcher GF, et al. J Am Coll Cardiol. 2018;doi:10.1016/j.jacc.2018.08.2141.
- Lavie CJ, et al. Circ Res. 2019;doi:10.1161/CIRCRESAHA.118.312669.
- Lavie CJ, et al. J Am Coll Cardiol. 2018;doi:10.1016/j.jacc.2018.08.1037.
- For more information:
- Carl J. Lavie, MD, FACC, medical director and cardiac rehabilitation and prevention director of exercise laboratories at John Ochsner Heart and Vascular Institute, Ochsner Clinical School, at The University of Queensland School of Medicine in New Orleans.
Disclosure: Lavie reports no relevant financial disclosures.
An endocrinologist weighs in.
Not all individuals who have obesity experience metabolic abnormalities. The prevalence of metabolically healthy obesity varies widely, depending on the criteria used to define it, from as low as 6% to 44% of the population. The most important criterion used to define the condition is the absence of type 2 diabetes.
Overweight and obesity are currently defined by BMI, which does not distinguish between fat and lean tissue and cannot differentiate body fatness, health status and associated risks. The limitations of BMI may explain the phenomenon of metabolically healthy obesity. For instance, subcutaneous adipose tissue does not confer the same metabolic risk as visceral adipose tissue and ectopic fat accumulation. Individuals with metabolically healthy obesity have been characterized by more subcutaneous and less visceral adipose tissue compared with individuals with metabolically unhealthy obesity.
Metabolically healthy obesity is not a fixed status. In a prospective longitudinal study evaluating 1,051 individuals with the metabolically healthy obesity phenotype, a significantly increased risk for developing diabetes was noted over 6 to 11 years. In another prospective study, researchers noted a 49% increase in risk for CHD, a 7% increased risk for cerebrovascular disease and a 96% increased risk for HF in adults who were defined to have metabolically healthy obesity vs. those with metabolically healthy normal weight.
A weight loss of 5% to 10% with comprehensive lifestyle interventions consisting of a moderate reduction in calories, physical activity and behavioral health support can significantly decrease metabolic risk factors. For example, in patients with overweight or obesity, a weight loss of 2.5 kg to 5.5 kg at 2 years or more had a 30% to 60% reduction in diabetes risk. There also is a dose-response relationship between weight loss and reduction in lipid profile and hypertension.
A single, specific dietary recommendation is not available, but overall the American College of Cardiology/American Heart Association Guideline on the Primary Prevention of Cardiovascular Disease advises a healthy diet consisting predominantly of vegetables, fruits, nuts, lean vegetable or animal protein, whole grains and fish with minimal intake of trans fats, red meat, processed meats, refined carbohydrates and sweetened beverages.
Obesity is associated with an increased risk for all-cause and CVD mortality. Metabolically healthy obesity is not a fixed status, and over time these individuals are at higher risk for becoming metabolically unhealthy. It is critical to have a patient-focused approach to assist patients in achieving a minimum of 5% weight loss to reduce CV risks.
- References:
- Caleyachetty, et al. J Am Coll Cardiol. 2017;doi:10.1016/j.jacc.2017.07.763.
- Soriguer F, et al. J Clin Endocrinol Metab. 2013;doi:10.1210/jc.2012-4253.
- For more information:
- Ivania M. Rizo, MD, assistant professor at Boston University School of Medicine. She is board certified in endocrinology and obesity medicine.
Disclosure: Rizo reports no relevant financial disclosures.