Study links waist size, U.S. diabetes rates

ARLINGTON, Va. – Americans’ larger waist size, not conventional risk factors such as obesity, appears to best explain why the United States has higher adult diabetes rates than England, according to a new study published online in the Journal of Epidemiology & Community Health.
The study, conducted at the RAND Corp., the University College London and the Institute for Fiscal Studies in London, builds on a growing body of research that accumulating fat around the waistline is particularly risky.
“Americans carry more fat around their middle sections than the English, and that was the single factor that explained most of the higher rate of diabetes seen in the United States, especially among American women,” said James P. Smith, one of the study’s authors and corporate chair of economics at RAND, a nonprofit research organization. “Waist size is the missing new risk factor we should be studying.”
The study notes that middle-aged and older Americans are far likelier to have diabetes than their English peers, despite a similar standard of living. Among adult men, the U.S. diabetes rate is 16 percent, compared with 11 percent in England; among women, it’s 14 percent, compared with 7 percent in England.
An earlier study by two of the co-authors had shown that middle-aged Americans are generally less healthy than the English, even though U.S. medical spending is more than twice as high.
For this analysis, the researchers looked at studies of the health and lifestyles of U.S. and English residents and found no association between the higher U.S. diabetes rates and conventional factors such as age, smoking, socioeconomic status or body mass index.
For the most part, people in both countries had similar risk factors; Americans were a bit older and heavier, while the English were less educated and more likely to have smoked.
American men’s waist size, however, averaged 3 centimeters more than English men’s, and The study concluded that waist size explains a substantial proportion of the higher diabetes rate in America for men and virtually all the higher rate seen among women. The difference applied not just to the overweight, but even to normal-weight women.
The researchers said Americans’ larger waists may be due to differences in physical activity, diet or other social and environmental factors such as stress that occur in the United States. More research is needed to explain how this translates into increased diabetes risk, they said. There is evidence that fat in the midsection has a different metabolism than fat carried elsewhere on the torso; waist circumference is also a better marker for visceral fat – which can lead to specific dysfunctions – than other measurements.