Nine out of 10 US men aged over 60 years are now overweight, according to the first study to assess the long-term risk of piling on the pounds. The study ran from 1971 to 2001 and involved people aged between 30 and 59 at the beginning.
Furthermore, seven out of 10 women in the study were also overweight and at the end of the study one in three of both sexes was clinically obese. The study involved 4000 adults enrolled in an ongoing landmark study in Framingham, Massachusetts.
“National surveys and other studies have told us that the US has a major weight problem, but this study suggests that we could have an even more serious degree of overweight and obesity over the next few decades,” says Elizabeth Nabel, director of the US National Heart, Lung and Blood Institute, which funded the work, and co-chair of the NIH obesity research task force.
A 1999 to 2002 survey by the US Centers of Disease Control and Prevention (CDC), suggested that 65% of US adults aged over 20 were either overweight or obese, with 30% being clinically obese.
“Our results, although not surprising, are worrisome,” says Ramachandran Vasan of Boston University School of Medicine, who led the new Framingham study. “If the trend continues, our country will continue to face substantial health problems related to excess weight.”
“It’s not terribly surprising,” agrees Andrew Prentice, professor of international nutrition at the London School of Tropical Hygiene and Medicine, UK. “Americans have been gaining weight as a nation inexorably for the last 30 years. We know also that weight gain is a gradual phenomenon going into middle age.”
As people age, they tend to put on weight. The study notes that even if people remained svelte till middle age, this was no guarantee for staying at a healthy weight. One in four men, and one in five women who made it to middle age slim, were overweight four years later.
Nabel adds: “In addition, these results may underestimate the risk for some ethnic groups.” This is because the Framingham study includes only white Americans, and other studies have indicated that Hispanic and black individuals, particularly women, may be more likely to be overweight or obese than white counterparts.
Being overweight is defined as having a body mass index (BMI) above 25, while a BMI of over 30 is classed as obese. Prentice points out that in some population groups in the US, the average BMI among women is over 30.
Being overweight or obese carries with it the risk of chronic illnesses such as heart disease and diabetes. Prentice notes that a controversial study in the US, published by Katherine Flegal at CDC in the Journal of the American Medical Association in April 2005 suggested that being overweight or obese might not carry an increased mortality risk compared with being a healthy weight.
However, he believes this may be because health care for managing related chronic diseases has improved over time. “It is keeping people healthy, but at a huge cost to the medical services,” he says. “That could be massively reduced by weight loss.”
“Overweight and obesity increase the risk of poor health. We hope these results will serve as a wake-up call to Americans of all ages,” urges Nabel.
Journal reference: Annals of Internal Medicine (vol 143, p 473)