Although it is commonly believed that obesity is more of a health threat than being underweight, a recent South Korean study suggests otherwise.

The research report, published by Korea University, found that underweight Koreans had a higher chance of developing fatal health conditions than those who are obese or overweight. The report was written after analyzing government data on medical records of some 1 million Koreans aged 30 or older, from 2002-2010.

The report found that underweight Koreans, defined as those with a body mass index of 18.5 or below, had a 2.2 times higher hazard ratio for death than those overweight -- who have BMI of 23-24.9. The hazard ratio for death in underweight Koreans was in fact higher than for obese Koreans (BMI of 25 or above) as well.

Among Koreans aged 50 or older, this pattern was even more prevalent. The hazard ratio for death in underweight Koreans in the specific age group was three times higher than those overweight. 

“It is true that an obese person is at a higher risk of developing chronic health conditions, such as diabetes, high blood pressure and cardiovascular disease,” said Dr. Kim Shin-kon, who participated in the research.

“But our research findings may suggest that those who are overweight actually are more cautious about their health, as they know what their risks are and what to watch out for. They also tend to get medical check-ups more frequently.”

Dr. Kim also said malnutrition and being underweight can be a serious health threat to those aged 50 or older, as the conditions can critically affect their immune system. Those with a weakened immune system are much more vulnerable to diseases such as pneumonia and Herpes Zoster, he said.

“It is important for the elderly to remain in healthy weight ranges while trying to increase bone and muscle mass,” he said, recommending all senior citizens to invest 10 to 15 minutes daily in exercising.

By Claire Lee (dyc@heraldcorp.com)