Excess weight conferred added cancer mortality risk in Asia-Pacific region

People from the Asia-Pacific region who were overweight or obese had a significantly increased risk for cancer mortality compared with normal-weight people.

“We found that among individuals with a BMI higher than 18.5 kg/m², there was a positive and continuous association between BMI and all-cancer mortality, such that a 5 kg/m² increase in BMI was associated with a relative risk of 1.09, after excluding cases of lung and upper aerodigestive tract cancer, which had a negative association with BMI,” the researchers wrote.

Although an association between excess weight and increased cancer risk has been established among Western populations, less is known about the association when examining other ethnic populations. There has been a rapid increase in obesity in many Asian countries because of major changes in lifestyles from more traditional to more Western. This study examined the association between adult BMI and cancer mortality in populations from Asia, Australia and New Zealand.

The study looked at 424,519 adults from 39 cohorts within the Asia Pacific Studies Collaboration. They also compared cancer mortality between populations in Asia and outside of Asia (Australian and New Zealand).

Study participants were followed for a median of 4 years. The mean age of participants was 48 years.

BMI was measured as kg/m²: 18.5 was underweight, 18.5 to 24.9 was normal, 25 to 29.9 was overweight and greater than 30 was obese. During follow-up, 7,211 participants died from cancer; 57% were in Asian cohorts.

Compared with normal-weight participants, obese participants had a HR of 1.21 for all-cause cancer, 1.5 for colon cancer, 1.68 for rectal cancer, 1.63 for breast cancer in women aged 60 years or older, 2.62 for ovarian cancer, 4.21 for cervical cancer, 1.45 for prostate cancer and 1.66 for leukemia.

Researchers also found little evidence of a regional difference among Asia and Australia and New Zealand in the association between BMI and cancer.

Parr CL. Lancet Oncol. 2010:doi:10.1016/S1470-2045(10)70141-8.