A recent meta-analysis of 72 prospective studies confirms the correlation between central fatness and all cause premature mortality.
Obesity, global scourge of the 21st century
Obesity is a veritable 21st century scourge that is now reaching epidemic proportions on a worldwide scale. According to the WHO (World Health Organization), in 2016 there were almost 1.9 billion overweight adults on the planet, i.e. three times more than there were in 1975, and more than 650 million of them were obese.1 Excess abdominal fat is one of the very characteristic symptoms of metabolic syndrome. In reality, this syndrome is a combination of abnormalities, including a high waist circumference and high blood sugar and triglycerides.2 Excessive fat around the internal organs can sometimes lead to the development of type 2 diabetes in the long term, due to marked insulin resistance.
A meta-analysis suggests that abdominal fat is a stronger risk factor for premature death than general adiposity
Iranian and Canadian researchers studied 72 prospective cohort studies including almost 2.5 million people. Of these studies, 30 came from Europe, 22 from the USA and 2 from Canada, 16 from Asia, 1 from Brazil and 1 from Tobago. 48 studies included both men and women, 12 only men, and another 12 only women. Depending on the studies, the follow-up duration was 3 to 24 years.
The Iranian and Canadian scientists compared various measurements (waist circumference, waist-to-hip ratio, waist-to-height ratio and waist-to-thigh ratio) along with the body adiposity index and the body shape index. It was observed that these two indices were significantly associated with a higher all cause mortality risk, irrespective of general adiposity. The researchers also observed that, conversely, a higher hip circumference and thigh circumference were associated with a lower risk of premature mortality.
In view of the results, the researchers believe that central adiposity measurements should be used alongside body mass index as an additional approach to determine the risk of premature death. However, certain limitations of this study need to be taken into consideration, in particular potentially undiagnosed pre-existing diseases in some patients. The authors therefore consider that an additional meta-analysis with multiple markers, including body mass index, is required.3 These studies should further support the need to prevent overweight and obesity - and especially excess abdominal fat - in Western populations.
Central fatness and risk of all cause mortality: systematic review and dose-response meta-analysis of 72 prospective cohort studies; BMJ 2020; 370 doi: https://doi.org/10.1136/bmj.m3324, 23 September 2020