Historically, obesity has been a problem of western countries. For instance, nearly 1 in 3 Americans is obese (defined as having a body mass index that tops 30), as are about 1 in 4 members of the United Kingdom. According to this ranking compiled with data from the Organization for Economic Cooperation and Development, the most obese countries in Asia are Japan and South Korea, where a mere 3.2% of the population has a BMI over 30.
But with obesity rates rising in China, South Korea, Thailand, Singapore and other Asian countries, an international group of researchers wondered how those extra pounds might be raising the risk of death from cancer. After all, adding 5 points to one’s BMI is known to increase the risk of cancer among Caucasians by 10% to 60%. Was the same true for Asians?
To find out, they analyzed data from 424,519 people who were part of the Asia-Pacific Cohort Studies Collaboration. The researchers found that for every 5 points added to BMI, the risk of death rose 9%. (That calculation excluded two types of cancer – of the lung and the upper aerodigestive tract – whose risk is linked to a lower BMI.) Compared with people who have a healthy weight (BMI between 18.5 and 24.9), those who were obese were 21% more likely to die of cancer.
The increased risk was traced primarily across six types of cancer – ovarian, cervical, prostate, breast (among women older than 60), leukemia and cancer of the large intestine. The results were published online Tuesday by the journal Lancet Oncology.
Even though obesity is still a comparatively small problem in Asia, the large number of cancer patients there (6.2 million, compared with 1.6 million in North America and 3.4 million in Europe) means that a great many cases might be traced to excess body weight, according to an editorial accompanying the study.
— Karen Kaplan
Photo: These patients at a weight loss center in northeastern China have an increased risk of cancer. Credit: Sheng Li / Reuters.