Obesity has again been linked to an increased risk of cancer, findings that constitute yet another building block in the wall of pressure being built around the food industry.
The latest study found that the fatter women become in their adult lives, the higher their risk of developing breast cancer.
Published in the July 1 2006 issue of Cancer, a peer-reviewed journal of the American Cancer Society, the study confirms previous findings that obesity increases the risk of breast cancer, while also examining the risk specific to certain types of breast cancer.
Researchers led by Dr Heather Spencer Feigelson examined the connection between weight gain and type of invasive breast cancer among 44,161 postmenopausal women.
Their findings revealed that the greater the weight gain, the greater the risk for all types, stages and grades of breast cancer, particularly advanced malignancies.
Breast cancer risk is linked to increased levels of circulating estrogen hormones. And because fat tissue increases the levels of estrogen, obesity has been shown to play a significant role in increasing the risk for this disease.
The latest study revealed that compared to women who gained 20 pounds or less during adulthood, women who gained over 60 pounds were almost twice as likely to develop certain types of tumors.
And the most extremely obese women were up to three times more likely to develop regional or distant metastases than women with less weight gain.
"These data further illustrate the relationship between adult weight gain and breast cancer, and the importance of maintaining a healthy body weight throughout adulthood," said Dr Feigelson.
The findings add to the growing evidence that suggests that overall cancer incidence and mortality resulting from overweight and obesity is increasing, potentially thwarting other prevention and treatment efforts aimed at reducing these dire statistics.
Other cancers that have been linked to obesity include cancers of the colon, stomach, kidney and esophagus.
Last year, a number of academic studies presented at the AACR International Conference on Frontiers in Cancer Prevention Researchprovided further worrying reading for the food industry, while presenting regulators with yet another headache.
And a report published in The Lancet in November (vol 366, no 9499), estimated that 35 per cent of the 7 million deaths from cancer in 2001 were caused by a lifestyle that could have been changed, and drew attention to nine modifiable risk factors.
In this instance, the researchers from Harvard University based their findings on a comprehensive review of scientific studies and other sources such as government reports.