The study, published in the Lancet Journal, reaffirms that a high body-mass index of 25 kg/m2 or greater is associated with increased risk of cancer. Researchers believe that in 2012 nearly 500,000 cases of cancer were attributable to high BMI around the world. The vast majority of these obesity related cancers occur in the United States and Europe, because of the higher levels of obesity found in those locations.
Women were more likely to be affected by cancer relating to obesity, particularly breast cancer. The most common forms of cancer caused by obesity were corpus uteri, postmenopausal breast, and colon cancers. These forms accounted for 63·6% of cancers and are attributable to high BMI.
The research looked at cancer rates in over 184 countries and found that obesity was associated with 5.4 percent of cancer in women and 1.9 percent in men during 2012. Those percentages are higher in developed countries with excess weight causing 8 percent of cancers in women and 3 percent in men.
The cancer rates were lowest in parts of Africa, due to lower calorie intake.
According to the researchers:
These findings emphasise the need for a global effort to abate the increasing numbers of people with high BMI. Assuming that the association between high BMI and cancer is causal, the continuation of current patterns of population weight gain will lead to continuing increases in the future burden of cancer.