While body mass index (BMI) is the popular measure used by health experts for body fat content, researchers at Perelman School of Medicine said that it does not take into account critical factors, such as fat distribution, proportion of muscle to fat and racial differences, which contribute to health or mortality.
Obesity predisposes to diabetes, heart diseases, sleep apnea, cancer and other diseases. Although several studies have shown an increase in mortality in obese people, recent studies have suggested that obesity protects against death from all causes as well as death due to chronic diseases such as diabetes, heart failure, and stroke. This so-called "obesity-mortality" paradox suggesting a beneficial influence of obesity has generated a lot of controversy.
AdvertisementIn a new perspective article in the journal Science, Rexford Ahima, MD, PhD, Professor of Medicine and Director of the Obesity Unit in the Institute for Diabetes, Obesity and Metabolism, and Mitchell Lazar, MD, PhD, Professor of Medicine and Genetics and Director of the Institute of Diabetes, Obesity, and Metabolism, discuss the challenges of studying the health and mortality risks of obesity.
"There is an urgent need for accurate, practical and affordable tools to measure fat and skeletal muscle, and biomarkers that can better predict the risks of diseases and mortality," said Dr. Ahima. "Advances to improve the measurement of obesity and related factors will help determine the optimal weight for an individual, taking into account factors such as age, sex, genetics, fitness, pre-existing diseases, as well novel blood markers and metabolic parameters altered by obesity."
Obese BMI is strongly associated with substantial increases in the risk of developing diabetes, cardiovascular diseases, cancer and other chronic diseases, leading to higher mortality, However, studies have shown that some people with obese BMI have improved metabolic profile and reduced cardiovascular risk, whereas a subset of people with normal BMI are metabolically unhealthy and have increased mortality risk. The researchers note that the true impact of obesity may not be appreciated because population studies often describe associations of BMI and health and mortality risks without assessing how intentional or unintentional weight loss or weight gain affect these outcomes.
"Future research should be focused more on molecular pathways, especially how metabolic factors altered by obesity change the development of diabetes, heart diseases, cancer and other ailments, and influence the health status and mortality," noted Dr. Lazar.
Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $4.3 billion enterprise.
The Perelman School of Medicine has been ranked among the top five medical schools in the United States for the past 16 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $398 million awarded in the 2012 fiscal year.
The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania -- recognized as one of the nation's top "Honor Roll" hospitals by U.S. News & World Report; Penn Presbyterian Medical Center; and Pennsylvania Hospital - the nation's first hospital, founded in 1751. Penn Medicine also includes additional patient care facilities and services throughout the Philadelphia region.
Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2012, Penn Medicine provided $827 million to benefit our community.