A poor diet and excess weight are some of the main reasons people develop cancer, according to a major new review. Out of seven million worldwide cancer deaths in 2001, more than one-third were the result of common environmental and lifestyle factors that can be readily avoided, such as giving up smoking or cutting out alcohol. The findings, published in the Lancet, are among the latest to suggest that good habits can counter bad genes.
"Every cancer has a genetic route," says Dr. Majid Ezzati, a researcher at the Harvard School of Public Health who lead the study. "But those genetic changes are the result of environment and behavior."
The researchers attributed 35 percent of all cancer deaths to nine major risk factors, based on reports collected from various countries involved with the World Bank. The main cancer dangers include obesity, lack of physical activity, diets low in fruits and vegetables, smoking, alcohol, urban and indoor air pollution, unsafe sex and contaminated needles.
Overall, smoking, alcohol use and eating too few fruits and vegetables proved to be the leading-controllable risks for 12 types of cancers that were studied. In wealthier countries, the most important causes were smoking, alcohol and obesity.
Despite having a smaller portion of the worlds' population, developed countries had a disproportionately higher rate of cancer deaths. Ezzati blames men.
"Smoking and alcohol are still mostly male issues," says Ezzati, adding that with more and more women taking up these habits in wealthier regions, the cancer rates have risen there as well. "Females in developing countries haven't caught up."
Women in poorer areas, however, are at a greater risk for cervical cancer, which is spread by the sexually-transmitted human papilloma virus. Such cancers are kept under control in wealthier countries due to widespread use of pap smears and other screening methods.
Health
Most of the steps that are needed to prevent cancer are relatively cheap, and getting more exercise and losing weight can help against other diseases as well. The one sticking point is alcohol. In moderate amounts, beer and wine seems to protect the heart, but there is no noticeable benefit against cancer.
"Binging is bad, regardless," Ezzati says. Although he is encouraged by the latest treatments and breakthroughs for cancer, Ezzati adds that the surest way to a cure is prevention.
"The risks come well before the full-blown disease," says Ezzati.
