Increased BMI Linked to Increased Risk of Cancer

We know that being overweight puts you at higher risk for heart disease, diabetes, and stroke, but a recent study published in the Lancet (2008;371:569-78) makes it clear that overweight and obesity are linked to an increased risk of certain types of cancers, as well.

The researchers performed what is called a meta-analysis, which means that they looked at the results of all the published clinical studies they could find that focused on an association between body weight and twenty different types of cancers. Each study that was included had to determine the Body Mass Index of all subjects at the beginning of the study and reported all cases of cancer during the follow-up period of the study. Those studies that only included deaths from cancer, did not sufficiently specify the type of cancer, or did not report risks across at least three categories of BMI were not included.

This left 221 studies that included over 282,000 people across the globe.

After analyzing the reported cases of cancer and correlating them with Body Mass Index, gender, and ethnicity, the researchers found that for each increase of Body Mass Index by 5 points (about 33 pounds, on average), men had an increased risk of certain esophageal cancers of OVER 50%. Their risk of thyroid cancers increased by one-third, and their risk of colon cancer, renal cancer, liver cancer and malignant melanoma by almost 25%.

For women, an increase in BMI of 5 points (an average of almost 29 pounds), their risk of endometrial and gallbladder cancers increased by almost 60%, while certain esophageal cancers were more likely by just over 50%, and renal cancers' risk increased by one-third. Less significant increases in risk were seen for leukemia, thyroid cancer, and postmenopausal breast cancer (12% increase).

What this means for you

These results are sobering - and they should be. This study looked at the most conservative analyses of risk for each population - meaning that these analyses take into account such variables as smoking status, age, and level of exercise, among others. Do you know what your Body Mass Index is? If you need to reduce it to the normal range,

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