Anthropometry of body fat: How anthropometric measures predict mortality and especially cardiovascular mortality

Abstract

The World Health Organization defines overweight and obesity as an abnormal or excessive fat accumulation that impairs health. However, there are no well established cut-offs to define obesity based on body fat. The NIH, WHO, the American Association of Clinical Endocrinologist, and the American College of Endocrinology define obesity as an excess of total body fat, specifically body fat that is 20-25% of total body weight in men, and 30-35% in women. But there are not enough data supporting these cut-offs as predictors of adverse outcomes. Furthermore, because direct body fat is difficult to measure, more widely available and easier to perform anthropometric measurements are used in clinical practice. Body mass index is the most commonly used and accepted anthropometric measure to define obesity. It is a well known conditional risk factor for the development of several cardiovascular risk factors, such as diabetes mellitus type 2, metabolic syndrome, systemic hypertension, dyslipidemia, obstructive sleep apnea, etc. However, recently scientists have questioned its usefulness as slightly increased body mass index (overweight and mild obesity range) has been related to improved survival and fewer cardiovascular events when compared to subjects with a normal body mass index, a phenomenon known as the "obesity paradox". Anthropometric measures of obesity that take into consideration body fat distribution, mainly truncal and/or abdominal obesity, such as waist circumference and specially waist-to-hip ratio appear to better predict cardiovascular risk than BMI alone, but this remains to be proven. Interestingly, despite body fat being the gold standard to define obesity, very little is known regarding its impact as a predictor of all-cause and cardiovascular mortality. The following chapter will analyze the different anthropometric measurements including body fat and lean mass and their impact on mortality with a focus on cardiovascular mortality, the leading cause of death worldwide.