An Integrative Approach for Deciphering the Causal Associations of Physical Activity and Cancer Risk: The Role of Adiposity

Recent theories propose that a Western lifestyle may increase cancer risk through alterations in the metabolism of insulin and insulin-like growth factors (IGF; McKeown-Eyssen, 1994; Giovannucci, 1995; Kaaks, 1996; Werner & LeRoith, 1996). Insulin regulates energy metabolism, and increases the bioactivity of IGF-I, by enhancing its synthesis, and by decreasing several of its binding proteins (IGFBP; IGFBP-1 and -2). Insulin and IGF-I both stimulate anabolic processes as a function of available energy and elementary substrates (e.g. amino acids). The anabolic signals by insulin or IGF-I can promote tumour development by inhibiting apoptosis, and by stimulating cell proliferation. Furthermore, both insulin and IGF-I stimulate the synthesis of sex steroids, and inhibit the synthesis of sex hormone-binding globulin (SHBG), a binding protein that regulates the bioavailability of circulating sex steroids to tissues. The present paper reviews epidemiological findings relating the risk of cancers of the colo-rectum, pancreas, breast, endometrium and prostate to body size (obesity, height) and physical activity, and discusses the relationships between obesity and physical activity and plasma levels of insulin, IGF-I and IGFBP. Subsequent sections review epidemiological findings relating cancer risk to indices of chronic hyperinsulinaemia, and to plasma levels of IGF-I and IGFBP. Conclusions are that chronic hyperinsulinaemia may be a cause of cancers of the colon, pancreas and endometrium, and also possibly of the breast. On the other hand, elevated plasma IGF-I, as total concentrations or relative to levels of IGFBP-3, appears to be related to an increased risk of prostate cancer, breast cancer in young women, and possibly colo-rectal cancer. For cancers of the endometrium, breast and prostate, these findings are discussed in the context of relationships between insulin and IGF-I and levels of bioavailable sex steroids.

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Implication of oestrogen in the development of breast cancer: a brief narrative review

International Journal of Research in Medical Sciences ◽

10.18203/2320-6012.ijrms20175076 ◽

2017 ◽

Vol 5 (12) ◽

pp. 5088

Author(s):

Princess Nweze ◽

Ezekiel U. Nwose ◽

Eunice O. Igumbor

Keyword(s):

Breast Cancer ◽

Physical Activity ◽

Breast Cancer Risk ◽

Cancer Risk ◽

Human Health ◽

Negative Impact ◽

Cow Milk ◽

Dairy Foods ◽

Exogenous Oestrogen

The presence of hormones in milk and dairy foods was discussed decades ago but more concerns were with respect to finding hormones as biomarkers in milk for diseases and pregnancy diagnosis. Considerable amount of studies demonstrated that milk is essential for infants growing and immunity, while increasing body of evidence are indicating possible negative impact on human health including the role of some estrogens in the initiation and provoking of breast cancer. In this brief narrative, we reviewed recent data on oestrogens and breast cancer risk including comparative levels of hormones in cow milk, risk of breast cancer attributable to intake of different foods and lifestyle factors. Empirical findings indicate that consumption of cow milk is probably being over-emphasized as source of exogenous oestrogen, whereas control of alcohol as well as obesity and physical activity are under-emphasized in discourses on preventive protocols.

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The role of anthropometric and nutritional factors on breast cancer risk in African-American women

Public Health Nutrition ◽

10.1017/s136898001100303x ◽

2011 ◽

Vol 15 (4) ◽

pp. 738-748 ◽

Cited By ~ 12

Author(s):

Urmila Chandran ◽

Kim M Hirshfield ◽

Elisa V Bandera

Keyword(s):

Breast Cancer ◽

Physical Activity ◽

African American ◽

Black Women ◽

Breast Cancer Risk ◽

Cancer Risk ◽

African American Women ◽

Dietary Factors ◽

American Women

AbstractObjectiveWhile the role of nutrition, physical activity and body size on breast cancer risk has been extensively investigated, most of these studies were conducted in Caucasian populations. However, there are well-known differences in tumour biology and the prevalence of these factors between African-American and Caucasian women. The objective of the present paper was to conduct a review of the role of dietary factors, anthropometry and physical activity on breast cancer risk in African-American women.DesignTwenty-six research articles that presented risk estimates on these factors in African-American women and five articles involving non-US black women were included in the current review.SettingRacial disparities in the impact of anthropometric and nutritional factors on breast cancer risk.SubjectsAfrican-American and non-US black women.ResultsBased on the few studies that presented findings in African-American women, an inverse association with physical activity was found for pre- and postmenopausal African-American women, while the association for anthropometric and other dietary factors, such as alcohol, was unclear. Studies assessing the effect by molecular subtypes in African-American women were too few and based on sample sizes too small to provide definitive conclusions.ConclusionsThe effect of certain nutrition and lifestyle factors on breast cancer in African-American women is not starkly distinct from those observed in white women. However, there is an enormous need for further research on this minority group to obtain more confirmatory findings.

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