A finding from an analysis of 30 long-term studies of colon cancer, reinforces the link between obesity and colon cancer in men and, to a lesser extent, in women. Obesity, the study shows, boosts the risk of rectal cancer in men but not in women.

The study suggests that belly fat is more relevant to colon cancer risk than fat in other places. For every 4 inches gained around the waist, the risk of colon cancer goes up 33% in men and 16% in women. It's not clear why obesity is more likely to cause colon and rectal cancer in men than in women.

"Abdominal obesity was more strongly related to increased colon cancer risk than was overall obesity,"