London: A study has found that Asians with a normal weight were far less likely to die from any cause than individuals whose body-mass index (BMI) was too high or low.
The study of one million Asians was conducted by Wei Zheng at Vanderbilt-Ingram Cancer Center, Nashville, Tenn., Paolo Boffetta at Mount Sinai School of Medicine, and John D. Potter Fred Hutchinson Cancer Research Center, Seattle, Wash.
Zheng said that earlier studies had been conducted primarily in populations of European descent.
"The validity of these criteria in Asian populations has yet to be determined. A large proportion of Asians are very thin and the impact of a severely low BMI on the risk of death has not been well evaluated until now," he said.
The study results showed that the lowest risk of death was seen among individuals with a BMI in the range of 22.6 to 27.5, which is considered normal to slightly overweight.
Chinese, Japanese and Korean populations with a raised BMI of 35.0 or higher had a 50 percent higher risk of death.
The risk of death was increased by a factor of 2.8 among those whose BMI was very low, that is, 15.0 or less.
"The most unexpected finding was that obesity among sub-continent Indians was not associated with excess mortality,” said Potter.
"This may be because many obese people in sub-continent India have a higher socioeconomic status and so have better access to health care."
"Our findings capture two different aspects of a rapidly evolving pattern; severe underweight was highly prevalent in Asia in the past, and we can still observe its important impact on mortality," explained Boffetta.
"This confirms that most people are at a higher risk for dying early if they are obese and is a clear message not to gain weight as we age," said Potter.
The study appears in the New England Journal of Medicine.