Having a big belly may be a risk factor for death even among people with normal weight. The Body Mass Index (BMI) is the standard measurement used to measure obesity; but the distribution of fat in the body, especially at the waistline, maybe even more important than the extra weight a person has. Being over-weight and obese is in itself a poor indicator of one's bad health. But to judge whether a person's fatness puts them at risk is controversial. To investigate the relationship between belly fat, BMI and mortality, American researchers followed 245,533 men and women in the age range of 51 to 72 years for nine years. It was found that among men, those in the top fifth based on their waist circumference were about 22 percent more likely to die during the study period than men with trimmer waistlines, independent of BMI. A similar risk was seen among women. In addition, people considered to be abdominally obese based on World Health Organization (WHO) guidelines - a waistline of 35 inches or more for women, or 40 inches or more for men - were 20 percent more likely to die over the nine-year study than their peers with slimmer waists. The findings were true for smokers and non-smokers, healthy people and those with chronic illness, and across all ethnic groups. In fact, there was evidence that mortality risk climbed more quickly with waist circumference among Asian men. While the dangers of abdominal fat (in particular visceral fat, which collects around the internal organs in the abdomen) is becoming clear, the reason why a fat belly is bad for health is still not well understood and more research is needed to explain this relationship.
American Journal of Epidemiology
June 2008