Do Factors Related to Endogenous and Exogenous Estrogens Modify the Relationship between Obesity and Risk of Colorectal Adenomas in Women?

Abstract

Obesity has consistently been associated with increased colorectal cancer risk in men, but not in women. In the absence of postmenopausal hormone use (PMH), adiposederived estrogen is the primary determinant of circulating estrogen levels in postmenopausal women, perhaps ameliorating the mitogenic effects of obesity in this group. Using data from a case-control study in the United States, we examined associations among obesity, potential modifying effects of factors related to endogenous and exogenous estrogen levels, and risk of colorectal adenoma. Cases (n = 219) were women of ages 30 to 74 years with colonoscopy proven, incident, sporadic, pathologyconfirmed, adenomatous polyps of the colon and rectum. Two control groups were recruited: colonoscopy-confirmed polyp-free women (n = 438) and age-and zip code frequency -matched women randomly selected from the community (n = 247). Multivariate odds ratios and 95% confidence intervals (95% CI) for obese [body mass index (BMI) z30.0; compared with nonobese, BMI <25.0] premenopausal women were 2.09 (95% CI, 0.81-5.41) versus colonoscopy controls, and 5.18 (95% CI, 1.40-19.32) versus population controls. For PMH users, the corresponding odds ratios were 0.29 (95% CI, 0.12-0.70) versus colonoscopy controls and 0.64 (95% CI, 0.23-1.83) versus population controls. There was no significant association of BMI with adenoma risk for PMH nonusers. Findings for waist-to-hip ratio were similar to those for BMI. These data support the hypothesis that risk for colorectal adenoma may be increased with obesity among premenopausal women but decreased among postmenopausal women, especially if they also take PMH. (Cancer Epidemiol Biomarkers Prev 2007;16(4):676 -83)

Glycosylated Hemoglobin and Risk of Colorectal Cancer in Men and Women, the European Prospective Investigation into Cancer and Nutrition

“…The difference in cancer association by gender cannot be explained by a different prevalence of diabetes in women compared with men, because in our study 11.9% of men and only 8.3% of women were defined as diabetics. This difference in association may be due to the interaction of some other female hormones influencing cancer risk (4,49,50). The results of our study confirm the relatively strong association of diabetes with colorectal cancer risk, which seems stronger for colon than for rectum cancer.…”

Comparison of Associations of Body Mass Index, Abdominal Adiposity, and Risk of Colorectal Cancer in a Large Prospective Cohort Study

“…Four previous studies have reported on the association between parameters of adiposity and colon cancer risk in postmenopausal women stratified by HRT use-two prospective studies observing positive associations between adiposity and colon cancer among postmenopausal women without HRT use, but not among HRT users (2,27); one case-control study observing an inverse association between BMI and colorectal adenoma in HRT users (28); and by contrast, one case-control study showing a positive association between BMI and colorectal cancer risk among HRT users (29). Several reasons may explain these inconsistencies, including different criteria to define HRT use and different types of HRT between study populations.…”

Lifestyle factors, obesity and the risk of colorectal adenomas in EPIC-Heidelberg

“…It has been recommended to analyse data of women stratified by menopausal status and use of HRT. A casecontrol study has shown that obesity was associated with a strong increase in adenoma risk among premenopausal women, whereas only a weak association was detected among women after menopause [40]. Taking, additionally, HRT use into account, a cohort study observed that for postmenopausal women with abdominal obesity, and using HRT, the risk of colon cancer was not influenced, whereas women with the same characteristics, but not using HRT had an elevated risk of colon cancer [41].…”