Women who are metabolically healthy but obese have higher risk of cardiovascular diseases compared to normal weight metabolically healthy women
Obesity alone can increase the risk of cardiovascular diseases in women – including those who are otherwise fit.
A new study published in The Lancet Diabetes and Endocrinology has revealed that women who are obese but have been metabolically healthy for decades are still at higher risk of developing cardiovascular disease compared to metabolically healthy women of normal weight. Researchers came to this conclusion through an observational study that followed over 90000 American women for up to 30 years.
The findings indicate that obesity is a risk factor for cardiovascular disease, regardless of whether or not women develop any of the common metabolic diseases such as high blood pressure or type 2 diabetes. The study also found that the majority of metabolically healthy women are likely to become metabolically unhealthy over time, even if they were normal weight. India has an estimated 20 million obese women, the third largest in the world.
“Our large cohort study confirms that metabolically healthy obesity is not a harmless condition, and even women who remain free of metabolic diseases for decades face an increased risk of cardiovascular events. What’s more, we observed that most healthy women are likely to develop type 2 diabetes, high blood pressure, or high cholesterol over time, irrespective of their BMI, putting them at much higher risk for cardiovascular disease,” explains Professor Matthias Schulze from the German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany, who led the research.
Women who maintained metabolically healthy obesity over 20 years still had a 57% higher risk of developing cardiovascular disease compared with normal weight metabolically healthy women
Obesity (BMI of more than 30kg/m²) affects almost all of the cardiovascular disease risk factors, particularly those related to metabolic syndrome including high blood pressure, poor blood sugar control or diabetes, and abnormal blood fats. These double the risk of cardiovascular disease such as heart attacks and stroke. However, some people with obesity seem to be free of these metabolic abnormalities – estimates suggest as many as a third of obese people might be metabolically healthy.
Whether this so called ‘metabolically health obesity’ is associated with a higher risk of cardiovascular disease has been hotly debated for many years. It remains unclear how changes or maintenance of metabolic status affect the development of cardiovascular disease in both normal weight and overweight/obese individuals.
To investigate this further, Schulze and colleagues examined the association between obesity and cardiovascular disease incidence in 90257 women (initially free from cardiovascular disease) from the Nurses’ Health Study – a study tracking the health of female nurses (aged 30-55 years) in the USA since 1976.
Cardiovascular disease risk was especially high in all metabolically unhealthy women, regardless of their BMI. Metabolically unhealthy normal weight women were around 2.5 times more likely to develop cardiovascular disease compared to normal weight women with no metabolic abnormalities, whilst those with ‘metabolically healthy obesity’ were also at higher risk of cardiovascular disease (39% higher risk).
Importantly, the majority of women who were initially metabolically healthy obese (84%), and around two-thirds (68%) of normal weight metabolically healthy women, converted to unhealthy phenotypes over 20 years.
Furthermore, even women who maintained metabolically healthy obesity over 20 years still had a 57% higher risk of developing cardiovascular disease compared with normal weight metabolically healthy women.
“Long-term maintenance of metabolic health is a challenge for overweight/obese, but also for normal-weight women,” says Professor Schulze. “Our findings highlight the importance of preventing the development of metabolic diseases, and suggest that even individuals in good metabolic health may benefit from early behavioural management to improve their diet and increase physical activity in order to guard against progression to poor metabolic health.”
