In a recent study, researchers followed almost 100,000 individuals to study if obesity is a risk factor for heart disease in those who are metabolically healthy.
Metabolic syndrome describes several different medical conditions that occur together: abdominal obesity, high blood pressure, high blood sugar, abnormal cholesterol levels, and abnormal triglyceride levels. Metabolic syndrome is a major risk factor for cardiovascular disease and diabetes. As such, physicians closely watch these indicators in many patients to actively prevent the onset of more serious health conditions.
What is the link between metabolic health and obesity?
There is a large amount of evidence showing that obesity increases the likelihood of cardiovascular disease. Obesity is defined based on weight, but scientists have identified certain obese individuals who do not have conditions associated with metabolic syndrome. This observation has raised questions about whether obese individuals who are in good metabolic health are still at risk for cardiovascular disease.
Due to the ongoing debates, a group from Germany aimed to address this question by examining the health data of almost 100,000 women over a period of 30 years. This group recently published their findings in Lancet Diabetes & Endocrinology, showing that obesity is, in fact, a risk factor for cardiovascular disease, even for individuals who maintain good metabolic health.
The Nurses’ Health Study
A total of 90,257 women from the Nurses’ Health Study were recruited into this study in 1976 and then followed up every other year from 1980 to 2010. In this study, they considered participants to be metabolically healthy if they did not have diabetes, hypertension, or high cholesterol levels. The researchers calculated body mass index (BMI) at each visit and any new cases of cardiovascular diseases were recorded. In addition, a number of other sociodemographic and health indicators were documented.
Metabolically healthy obesity is a risk factor for cardiovascular disease
Researchers found that most women who were healthy at the beginning of the study eventually fall into the definition of “metabolically unhealthy” as defined by the study (i.e., having diabetes, hypertension, or high cholesterol), regardless of their weight.
The authors of the study also observed that these negative metabolic indicators increased the risk of cardiovascular disease, which aligns with previous research. The study also demonstrates that obesity is a risk factor for cardiovascular disease, irrespective of metabolic disorders.
Overall, this study highlights that under different degrees of metabolic health, obesity is still associated with the risk of cardiovascular disease. Even though there is a higher likelihood of getting cardiovascular disease in individuals with worse metabolic health, obese individuals with good metabolic health are still at risk of cardiovascular disease.
This study serves as a reminder that it is important for the population to maintain good metabolic health to prevent cardiovascular disease since many healthy participants succumbed to metabolic disorders over time. Finally, the findings presented here help physicians better understand the factors that influence cardiovascular disease risk, which may affect future recommendations and guidelines.
Written by Branson Chen, BHSc
Reference: Eckel N, Li Y, Kuxhaus O, Stefan N, Hu FB, Schulze MB. Transition from metabolic healthy to unhealthy phenotypes and association with cardiovascular disease risk across BMI categories in 90 257 women (the Nurses’ Health Study): 30 year follow-up from a prospective cohort study. Lancet Diabetes Endocrinol [Internet]. 2018 May 31; Available from: http://www.sciencedirect.com/science/article/pii/S2213858718301372