Breast cancer is the most common cancer in women both in the developed and less developed world. It is estimated that worldwide over 508 000 women died in 2011 due to breast cancer (Global Health Estimates, WHO 2013). Incidence rates vary greatly worldwide from 19.3 per 100,000 women in Eastern Africa to 89.7 per 100,000 women in Western Europe. In most of the developing regions the incidence rates are below 40 per 100,000 (GLOBOCAN 2008).
Risk factors are being understood for such a widespread disease that is turning into a chronic condition for the survivors. It is hard to pinpoint specific risk factors for cancer due to its long incubation period. Some feel powerless to prevent it as many of the risk factors seem to be decided before birth. Genetic factors do have a huge impact on people’s risk of a breast cancer prognosis, and it has long been thought that these factors are almost always outside of one’s control. Recent research though has renewed hope with contradicting results and that is what this paper is going to talk about. The risk of breast cancer and in turn its incidence can be brought down by modifying lifestyle choices. In this paper I will discuss the research conducted on the effect of lifestyle choices on the risk of breast cancer.
The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) has estimated that over 40% of post-menopausal breast cancer could be prevented by reductions in alcohol, excess body weight, and inactivity (Howell 7). Smoking, exposure to toxins dietary nutrient adequacy and fertility treatments in women also contribute to increased risk.
· Excess body weight
Positive energy balance, as a consequence of excess caloric intake and/or insufficient energy expenditure, results in overweight and/or obesity. Strong observational data indicate that weight gain in the premenopausal period and being overweight or obese after menopause increase breast cancer risk (Howell 7). There is a well-established relationship between the two diseases, with most epidemiological studies demonstrating an increased risk of developing post-menopausal breast cancer in overweight or obese women.
· Physical Inactivity
Physical inactivity is a common risk factor for multitude of diseases. Reduced energy expenditure is linked with obesity which is another identified risk factor for breast cancer.
A recent review of 73 observational studies indicated that moderate to vigorous PA reduces breast cancer risk by an average of 25% in pre- and post-menopausal women compared with inactive women (Howell 8). Both obesity and physical inactivity increase the risk of breast cancer development in women. Increased risks for overall mortality and breast cancer-specific mortality associated with increasing body mass index
In recent decades a lot of research has unearthed the connection between smoking and cancer, recognizing the negative effects on health.
Martin Sollie and his colleagues in their research found a 28% increase in breast cancer-associated mortality in those who were current smokers compared to never smokers (Sollie 8). They concluded that mortality in former smokers was equal to the one found in never smokers. This indicates that people diagnosed with breast cancer can reduce their risk of mortality dramatically if they ceasing smoking.
· Alcohol intake
Alcohol consumption is a casual risk factor for more than 200 disease and injury conditions(WHO). The positive association between alcohol intake and increased risk of developing cancer has been supported with large amount of evidence gathered by the scientific community.
Alcohol Women with the highest alcohol intake (of at least 27 units per week) were 51% more likely to develop breast cancer compared with non-drinkers. These studies suggest that to minimize the risk of women should not be drinking more than one unit daily and probably have at least two alcohol-free days weekly. (Howell 8)
· Toxicant Exposure
Our interactions with our environment greatly affect the health status we enjoy. Over the past several decades our interactions with toxicants have increased significantly along with exponential increase in the use of pesticides, herbicides, plastics, cosmetics and other personal care products. These have increased the risk of breast cancer. There was a significant rise in the incidence of breast cancer in the decades following World War II, the same decades that saw exponential increases in the use of chemicals for production. (Gray 1)
Medicine can also have a negative impact due to incomplete research or lack of understanding of the chemical structure and its interaction with the biological environment. Between 1938 and 1971 millions of fetuses were exposed to the synthetic estrogen, diethylstilbestrol (DES), when their pregnant mothers were prescribed the drug to prevent miscarriages and other complications (Gray 7). DES exposure was associated with an increased risk of breast cancer in the mothers. In this case the timing of the exposure also plays an important role as it was during fetal development which is a sensitive time for development. In a follow-up study of daughters who were exposed prenatally to DES, a nearly twofold increase in breast cancer risk was observed in women older than age 40.(Gray 7)
After the industrial revolution and due to high pressure from the growing population there has been an increase in use of pesticides to maximize yield. Janet M. Gray in her research found that higher maternal dichlorodiphenyl-trichloroethane (DDT) levels were associated with an almost 4-fold increase in occurrence of breast cancer in their daughters by age 5 (7).
· Reproductive Factors
It has long been clear the positive association of estrogen with breast cancer development. More Recent research is showing similar trends with long term exposure to progesterone. Numerous studies have demonstrated an increased risk of breast cancer in women using oral contraceptives. The risk for breast cancer is greatest among current and recent users of oral contraceptives, particularly those who have used them for more than 5 years and initiated use at a young age. (Gray 10)
· Fertility Treatment
Women facing fertility issues and undergoing treatments are also at increased risk for breast cancer. Two studies found increased risk of breast cancer for women who have been treated for ovarian infertility with drugs including gonadotropins or clomiphene citrate. However, the results were significant only when the incidence of breast cancer was compared with the general population of women, but not with the more appropriate control of women with ovarian infertility who have not been treated with fertility drugs. (Gray 11)
· Personal Care Products
Cosmetics with placental extracts, probably with high concentrations of progesterone and estrogenic chemicals and recently it has become clear that long-term exposures to progesterone can also influence the possible development of breast cancer.
· Folate Levels
Folate is a naturally occurring, water-soluble vitamin B High folate intake may increase breast cancer risk by promoting the progression of existing (pre-)neoplastic lesions, by expanding the breast stem cell population or by preventing terminal differentiation in ductal cells.
· Plant Based Food
An increase in consumption of plant based food has been associated with a reduction in breast cancer risk. A review performed by Albuquerque and colleagues concluded that a diet rich in vegetables, fruit, fish and soy are associated with decreased risk (Howell 8). Soy products have been found to be rich in isoflavones and studies indicate significant association between decreased risk for breast cancer and intake of isoflavones (Li 3).
Certain fruits help reduce risk of cancer more so than others. Pomegranate, mangosteen, apple, citrus fruits, grapes (including wine), and