Text

theses

Endometrial and ovarian cancers are hormone related cancers with the most significant risk factors being those related to high estrogen exposure, such as late age at menopause and hormone therapy use. Diet and obesity, two modifiable risk factors, have been implicated in the risk for both cancers. Early life exposures including diet, as well as early onset of puberty, may play a role in the lifetime risk of endometrial and ovarian cancers. Dairy foods, vitamin D and calcium have been implicated in endometrial and ovarian cancer risk, playing either a direct role or an indirect role through their association with body size. A major source of dietary vitamin D and calcium, dairy foods are also sources of animal derived hormones and growth factors which may have physiologic activity in humans. Obesity is a known risk factor for early sexual development in girls, possibly due to estrogen synthesis in adipose tissue. In this study, data from two population based case-control studies and baseline data from a prospective cohort study were used to examine the association between dairy foods, vitamin D and calcium with risk of endometrial cancer, ovarian cancer, and early breast development and body size in pre-pubertal girls, respectively. Endometrial cancer risk was significantly inversely associated with dietary calcium intake in our study. Among post menopausal women, high versus low intake of total calcium was associated with significantly lower risk of endometrial cancer. Less frequent consumption of low-fat cheese was associated with significantly greater risk of endometrial cancer compared to frequent consumption of low-fat type. Effect modification was found by hormone therapy use for total calcium and risk of endometrial cancer, with ‘ever’ users having greater risk compared to ‘never’ users. Milk intake was significantly associated with ovarian cancer risk; significant effect modification by hormone therapy use was found for the association between ovarian cancer risk and total vitamin D intake, with ‘ever’ users having lower risk estimates versus ‘never’ users. Higher dietary calcium intake was associated with lower mean BMI, fat mass and percent body fat among young girls, while higher total milk and dairy intake were associated with higher adiposity measures. Girls in the highest tertile of total milk were significantly more likely to be overweight and above, as were those in the middle tertile of dietary calcium. In conclusion, our results suggest a possible protective role for calcium with risk of endometrial cancer and reduced adiposity in young girls, and an increased risk for ovarian cancer risk with milk intake. Future research should build on these findings by further elucidating calcium’s role in endometrial and ovarian cancer risk and body size in young girls through larger studies focused on high risk populations (i.e., obese and post-menopausal women, young girls) as well as associations with epithelial ovarian cancer tumor sub-types.

ETD_8652

Ph.D.

Includes bibliographical references

by Susan Gabriel

doi:10.7282/T31N84B4

ETD doctoral

The author owns the copyright to this work.