Among middle-aged adults, researchers found that every extra body mass index (BMI) point - equal to about six or seven pounds - was tied to a four-percent higher chance of being admitted to the hospital over a two-year period.

"There is considerable evidence that severe obesity is bad for your health, resulting in higher rates of disease and consequently higher use of health services and higher death rates," lead author Rosemary Korda, from the Australian National University in Canberra, told Reuters Health in an email.

"What this study shows is that there is a gradual increase in risk of hospitalization as BMI increases, starting with people in the overweight range," she added. "In other words, even being overweight (but not obese) still increases your risk."

Korda and her colleagues recruited close to 250,000 people age 45 and above from New South Wales. After surveying them about their height, weight and other health and lifestyle issues, the researchers tracked participants through hospital data.

Over the next two years, they had more than 61,000 total hospitalizations lasting at least one night.

Korda's team found that among people considered in the normal range for BMI, there were 120 hospitalizations for every 1,000 men and 102 per 1,000 women each year. For those considered severely obese, on the other hand, there were 203 hospitalizations for every 1,000 men and 183 per 1,000 women, on average.

Overweight and moderately obese people had hospitalization rates somewhere in between.

That pattern held up even after taking into account whether participants smoked, how physically active they were and their general health at the start of the study.

Extra weight seemed especially to play a role in people's chances of being hospitalized for diabetes, heart disease, chest pain, arthritis and asthma, the researchers reported in the International Journal of Obesity.

The new study "gives the public one more reason to try to lose weight," said Robert Klesges, a preventive medicine researcher from the University of Tennessee Health Science Center in Memphis.

"Extending this research to overweight individuals… is a unique contribution. Basically it tells to tens of millions of Americans that, ‘You are now at risk,'" Klesges, who wasn't involved in the study, told Reuters Health.

According to the Centers for Disease Control and Prevention, just under 36 percent of American adults are obese. Another 33 percent are overweight but not obese.

Those people are more likely than leaner adults to develop lifestyle-related conditions such as diabetes, high blood pressure and high cholesterol - all of which are tied to heart problems. Extra pounds are also linked to respiratory problems like asthma, among other ailments.

"Even people who are overweight but not obese are more likely to experience these health problems than people who are of healthy weight," Korda said.

"While increasing weight leads to increasing risk, this also means that a gradual decrease in weight is likely to gradually decrease your risk - i.e. if you are overweight or obese, even small decreases in weight may make a positive difference to your health."

SOURCE: bit.ly/TBTyZQ International Journal of Obesity, online September 18, 2012.

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