Body weight is directly associated with mortality from cancer, according to a study carried out in the US.
The researchers at the American Cancer Society in Atlanta found that increased body weight is not only related to specific cancers but also to death rates for all cancers combined.
The team examined a population of more than 900,000 US adults (around half men and half women) who were free of cancer at enrollment in 1982, and looked at the relation between body mass index at baseline and the risk of death from all cancers and from cancers at individual sites, while controlling for other risk factors.
In the 16 years of follow-up, there were 57,145 deaths from cancer. The heaviest members of the cohort (those with a body-mass index of at least 40) had death rates from all cancers combined that were 52 per cent higher for men and 62 per cent higher for women when compared to people of normal weight.
For men, the relative risk of death was 1.52, and even higher for women at 1.62. In both men and women, body-mass index was also significantly associated with higher rates of death due to cancer of the oesophagus, colon and rectum, liver, gallbladder, pancreas, and kidney. The results held true for death due to non-Hodgkin's lymphoma and multiple myeloma, and significant trends of increasing risk with higher body-mass-index values were observed for death from cancers of the stomach and prostate in men and for death from cancers of the breast, uterus, cervix, and ovary in women.
Using both the study findings and national estimates of the prevalence of overweight and obesity in the US adult population, the researchers concluded: "On the basis of associations observed in this study, we estimate that current patterns of overweight and obesity in the United States could account for 14 per cent of all deaths from cancer in men and 20 per cent of those in women."
The findings are reported in this month's New England Journal of Medicine.