FRIDAY, Dec. 21 (HealthDay News) --The morbidly obese may not be the only people who should be eligible for bariatric surgery to lose weight, U.S. researchers report.

People with a body-mass index (BMI) less than the required 40 could still reap heart health benefits from the surgery, they say.

BMI is calculated based on height and weight. A healthy BMI ranges between 18.5 and 25. A person with a BMI of 40 -- for example, someone 5 feet 9 inches tall and 270 pounds -- is considered morbidly obese. According to the Centers for Disease Control and Prevention, one in three adults is obese.

Bariatric surgery options include gastric bypass and lap band surgeries. Typically, a person must have a BMI of 40, or be at least 100 pounds over their healthy weight, to qualify for these surgeries. People who have a BMI greater than 35 and suffer from a life-threatening illness, such as non-insulin dependent diabetes, sleep apnea or heart disease, can also qualify.

However, researchers at University of Texas Southwestern Medical Center at Dallas published data in the December issue of Surgery for Obesity and Related Diseases suggesting that some otherwise healthy overweight people with a BMI lower than 40 may benefit. And they may benefit more from the surgery than people who are morbidly obese, the team added.

The study is among the first to evaluate the risk-factor relationship between BMI and cardiovascular disease as it relates to bariatric surgery criteria, said study author Dr. Edward Livingston, chairman of GI/endocrine surgery at UT Southwestern.

"Our results show that cardiovascular risk factors do not necessarily worsen with increasing obesity," Livingston said in a prepared statement. "They also support the concept that obesity, by itself, doesn't trigger an adverse cardiovascular risk profile or increased risk of death."

The research team analyzed health data from more than 17,200 adults who had a BMI greater than 20 and had participated in the Third National Health and Nutrition Examination. The researchers assessed their heart disease risk factors with respect to their BMI. They found a subgroup of people whose BMIs were lower than 40 but who had significant heart disease risk factors.

This suggests that some patients who are obese but not morbidly obese could benefit from bariatric surgery, which can help reduce cardiovascular disease, said Livingston.

The research team theorized that some morbidly obese people may be more efficient than moderately overweight people at storing fat in their cells, so it does not have as great an effect on the cardiovascular system.

More information

To learn more about body-mass index and calculate your own, visit the U.S. Centers for Disease Control and Prevention.

-- Madeline Vann

SOURCE: University of Texas Southwestern Medical Center at Dallas, news release, Dec. 18, 2007

Copyright © 2007 ScoutNews, LLC. All rights reserved.