I don't know what a "perceived identity malignancy" is.
There was a question about abortion as a risk factor for breast cancer. I don't care to get long printouts for comments on my threads, but since this came from maybe the most politically correct Department of Health in the country, headed by a woman, Antonia C. Novello, former Surgeon General of the U.S. (1990-1993) and who became Commissioner of Health for the State of New York in 1999. The title of the report is "CORAM, MT. SINAI, PORT JEFFERSON STATION (CMP) FOLLOW-UP INVESTIGATION." Its pdf link is in comment# 44. It's subject is the high rate of breast cancer in a part of Long Island. Some of you may want to bookmark this thread for the link and references for its recognition of the fact that not having a full-term pregnancy is a risk factor for breast cancer. Here's a printout from pages 25 through 29 which includes its references.
C. Breast Cancer Risk Factors
Any investigation into possible factors related to breast cancer incidence in an area needs to consider what is already known about risk factors for breast cancer. The epidemiologic literature on breast cancer is extensive. In the mid-1990s, the Collaborative Group on Hormonal Factors in Breast Cancer identified 66 epidemiologic studies from around the world that included at least 100 women with breast cancer (Collaborative Group, 1996). Several more have been completed since. This chapter is therefore not intended to be comprehensive. Current understandings of established risk factors are summarized in some recent scientific and popular reviews (Hulka 2001, Kelsey 1996, Hankinson 2002, ACS 2003, Harvard 2000).
A number of risk factors for breast cancer have been identified. The most important of these are sex and age. Breast cancer risk in females is about 100 times greater than risk in males. Risk increases sharply with age until approximately age 50, and then more gradually, leveling off at about age 70. To control for these risk factors, the mapping analysis was restricted to breast cancer in females, and expected numbers of cases in each ZIP Code were calculated taking into account the age distribution of females in that ZIP Code.
Breast cancer is known to occur more frequently in white women than in African American, Asian/Pacific Islander or Native American women. Indications are that it also is less common among women of Hispanic origin than among non-Hispanic whites. Breast cancer incidence has been found to be highest in the countries of North America and Northern Europe, and lowest in the developing countries of Asia, Africa and South America.
Other risk factors relating to genetic, reproductive, nutritional and other factors are well established. Women with a family history of breast cancer are known to be at an increased risk of the disease, particularly if the cancers occurred in first-degree relatives affected at a young age. A number of mutations have now been identified at two breast cancer genes that confer an extremely high risk of breast cancer on female carriers, although most familial cases have not been associated with identified mutations. It has been estimated that a family history of the disease in first degree relatives account for 5-10% of breast cancer cases.
Women who have had a prior breast cancer are known to be at a greater risk of developing a second cancer in the other breast, or in the remaining breast tissue. Due to the counting rules in use at the time by the Cancer Registry however, second (or later) primary breast cancers were not included in the mapping analysis. (Breast cancers that were diagnosed in persons with a history of another type of cancer, for example colon cancer, were included.) Risk is also known to be greater in women with certain types of benign breast disease and in post-menopausal women with a mammographic finding of dense breasts (Byrne 1995).
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The importance of reproductive factors in affecting breast cancer risk has been known for a long time. Women who have never given birth (or had a full-term pregnancy) are at a higher risk for breast cancer compared to women who have carried a pregnancy to term.
Among women who have given birth, the age of a woman at her first delivery is an important factor influencing breast cancer risk. Women who are under 20 years old when they have their first full-term pregnancy have the most reduced risk of breast cancer. Women who are between the ages of 20 and 29 when they have their first full-term pregnancy have a slightly greater risk than women under 20 years old who carry full-term. Women who are older than 30 when they have their first full-term pregnancy have a risk about equal to, or slightly greater than, women who had never given birth.
Women with more children also have a lower risk of breast cancer compared to women with fewer children. Researchers have considered that women who have their first full-term pregnancy at a young age are more likely to end up having more children than women who start childbearing late in life. Even among women who were the same age at first full-term pregnancy, however, those with more total births have a lower risk than those with fewer births. Breastfeeding is another reproductive factor that has received attention in relation to its effects on breast cancer risk. A recent article from the Collaborative Group on Hormonal Factors in Breast Cancer (2002a) shows that total duration of breastfeeding has an independent effect on reducing the risk of breast cancer over and above that of the reproductive factors discussed previously. Differences in the duration of breastfeeding may account for much of the observed difference in breast cancer rates between developing and developed nations. Other reproductive factors that have been shown to increase the risk of breast cancer include an early age at menarche and a late age at menopause. Both of these factors imply a longer duration of exposure to endogenous estrogens. Some recent studies have also shown a higher risk of breast cancer among women with higher levels of circulating estrogens (Thomas 1997).
These reproductive factors are all associated with variations in the levels, types and timing of endogenous estrogen a woman is exposed to. It might be expected that exogenous estrogens such as those found in various hormone preparations may also play a role. In many studies, oral contraceptives (birth control pills) have been found to increase risk of breast cancer. The greatest increased risk has been observed in current users, and former users within five years of discontinuing use; little increased risk is observed ten or more years after discontinuing use. Hormone replacement therapy is used to counteract the effects of the cessation of estrogen production during menopause. Replacement therapy has been found to increase breast cancer risk to the same extent as not going through menopause.
Dietary factors are believed to play a role in breast cancer. Obesity is an established risk factor for breast cancer in post-menopausal women. International comparisons show higher rates of breast cancer in countries where dietary fat consumption is high, but dietary intervention studies have not been able to reduce breast cancer risk in women by restricting fat consumption. Several recent studies have suggested that physical activity may decrease the risk of breast cancer, possibly by leading to anovulatory cycles and hence, lower total estrogen exposure in some women. Some studies have shown the risk of breast cancer to be greater in taller women, which might be related to
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high caloric intake or to a faster growth rate during childhood and adolescence (Tretli 1989, Kelsey 1996, Harvard 2000). It has often been observed that breast cancer rates are higher in more affluent areas (see, for example, Rimpela 1987). This is usually attributed to childbearing patterns, as more affluent women are more likely to attend college and thereby delay childbearing. Certain occupations have been observed to be associated with characteristically high breast cancer rates, including teaching and health care occupations (see, for example, NYS DOH 1986, Bernstein, et al., 2002). These associations as well might be attributable, at least in part, to childbearing patterns. Breast cancer studies in the past 20 years have produced fairly consistent results showing elevated breast cancer risk associated with heavy alcoholic beverage consumption, defined in most studies as more than three drinks per day. An important study published in 2002 (Collaborative Group 2002b) reanalyzed individual data from 53 epidemiological studies, which included 58,515 women with breast cancer and 95,067 without the disease. This meta-analysis concluded that breast cancer risk was elevated by approximately 30% for individuals consuming between three and four drinks per day and by approximately 40% for those consuming more than four drinks per day. If the observed relationship is causal, the authors estimate that about 4% of breast cancers in developed countries are attributable to alcohol. Studies of cigarette smoking and breast cancer conducted in the 1960s and 1970s usually compared women who have ever smoked to women who have never smoked. They showed no consistent association between smoking and breast cancer risk (Collaborative Group, 2000b). However, these studies did not take into account the possible effects of exposure to secondhand tobacco smoke or “passive smoking.” Because study questionnaires did not ask about passive smoking, women with this type of exposure were grouped together with non-smokers in these analyses. In some more recent studies, passive smoking was taken into account. These more recent studies show associations with both passive and active smoking and breast cancer risk. In a Canadian study of 2,317 breast cancer cases and 2,438 controls for whom full risk factor histories, including lifetime residential and occupational histories of exposure to passive smoking, were gathered by questionnaire, active and passive smoking were each associated with more than a doubling of premenopausal risk of breast cancer. Postmenopausal risk estimates were not as high, but were also elevated (Johnson, 2000). Five other studies have assessed passive as well as active smoking, and these studies consistently show an approximate doubling of breast cancer risk associated with passive and with active smoking (Lash, 1999; Morabia, 1996; Smith, 1994; Hirayama, 1990; Sandler, 1985). Studies of tobacco exposures are complicated by the fact that individuals with tobacco exposures are also more likely to be consumers of alcoholic beverages. Since heavy alcohol use is associated with increased breast cancer risk, alcohol use needs to be carefully addressed in these studies. An additional complication in studying the effect of tobacco use is that active smoking is known to have an antiestrogenic effect resulting in, for example, some women having an earlier natural menopause, which would reduce their potential risk for breast cancer. Studies of tobacco exposure and breast cancer have also suggested that individual genetic variations that affect the body’s metabolism of compounds from cigarette smoke alter breast cancer risk associated with tobacco exposures (Morabia, 2000; Ishibe, 1998).
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It has been estimated that known risk factors account for only 30% of breast cancer cases. A more recent study, however, concluded that almost half of breast cancer cases in the United States population could be accounted for by these risk factors: later age at first birth, never having given birth, higher family income and family history of breast cancer. Inclusion of additional risk factors, including earlier age at menarche, history of benign breast disease, and alcohol consumption, would increase the proportion even further (Madigan and Ziegler, 1995). 1. References
Collaborative Group on Hormonal Factors in Breast Cancer, Breast cancer and hormonal contraceptives: Collaborative reanalysis of individual data on 53297 women with breast cancer and 100239 women without breast cancer from 54 epidemiological studies, Lancet 347:1713-1727 (1996). Hulka BS and Moorman PG, Breast cancer: hormones and other risk factors, Maturitas 38: 103-116, 2001.
Kelsey JL and Bernstein L, Epidemiology and prevention of breast cancer, Annual Reviews of Public Health 17:47-67, 1996.
Hankinson S and Hunter D, Breast Cancer, in Adami H, Hunter D, Trichopoulos D, Textbook of Cancer Epidemiology, Oxford 2002; 301-339.
American Cancer Society, Breast Cancer Facts and Figures 2003-2004, Atlanta: American Cancer Society, 2003. Harvard Center for Cancer Prevention, Your Cancer Risk: Breast Cancer Risk List, at http://www.yourcancerrisk.harvard.edu/hccpquiz.pl?func=show&quiz=breast&page=risk list, 2000, accessed April 2004.
Byrne C, Schairer, C, Wolfe J et al., Mammographic features and breast cancer risk: effects with time, age and menopause status, J Natl Cancer Inst 87:1622-9, 1995.
Collaborative Group on Hormonal Factors in Breast Cancer, Breast cancer and breastfeeding: collaborative reanalysis of individual data from 47 epidemiological studies in 30 countries, including 51302 women with breast cancer and 96973 women without the disease, Lancet 360: 187-195, 2002(a). Thomas HV, Reeves GK, Key TJ, Endogenous estrogen and postmenopausal breast cancer: a quantitative review, Cancer Causes Control 8:922-8, 1997.
Tretli, Height and weight in relation to breast cancer morbidity and mortality. A prospective study of 570,000 women in Norway, Int J Cancer 44:23-30, 1989.
Rimpela AH, Pukkala EI, Cancers of affluence: positive social class gradient and rising incidence trend in some cancer forms, Soc Sci Med 24:601-606, 1987.
New York State Department of Health, Mortality in New York State* (*Exclusive of New York City), 1980-1982. A Report by Occupation and Industry, Albany NY: New York State Department of Health, Monograph No. 21, 1986.
Bernstein L et al., High breast cancer incidence rates among California teachers: results from the California Teachers Study (United States), Cancer Causes and Control 13: 625-635, 2002.
Collaborative Group on Hormonal Factors in Breast Cancer “Alcohol, tobacco and breast cancer- collaborative reanalysis of individual data from 53 epidemiological studies, including 58 575 women with breast cancer and 95 067 without the disease,” Br. J. Cancer 87: 1234-1245, 2002(b).
Johnson KC, Hu J, Mao Y and the Canadian Cancer Registries Epidemiology Research Group, Passive and active smoking and breast cancer risk in Canada, 1994-97, Cancer Causes and Control, 2000, 11: 211-221.
Lash TL, Aschengrau A, Active and passive Cigarette smoking and the occurrence of breast cancer, Amer J of Epid, 1999, 149:1, 5-12.
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Morabia A, Bernstein M, Heritier S, Khatchatrian N, Relation of breast cancer with passive and active exposure to tobacco smoke, Amer J of Epid, 1996, 143:9, 918-928. Sandler DP, Wilcox AJ, Everson RB, Cumulative effects of lifetime passive smoking on cancer risk. Lancet, 1985, 1, 312-315.
Hirayama T, Cancer de mama: avances in diagnostico y tratamiento. In: Diaz-Faes J, (ed.) Epidemiologia y factores desriesgo del cancer de mama. 1990, Leon, Spain: Santiago Garcia, pp. 21-38 (described in Johnson, 2000).
Smith SJ, Deacon JM, Chilvers CE, Alcohol, smoking, passive smoking and caffeine in relation to breast cancer risk in young women. UK National case-control study group, British J of Cancer 1994, 70, 112-119.
Morabia A, Bernstein MS, Bouchardy I, Kurtz J, Morris MA, “Breast cancer and active and passive smoking: the role of the NAcetyltransferase 2 genotype, Am J of Epid, 2000, 152:3, 226-232. Ishibe N, Hankinson SE, Colditz GA, Spiegelman D, Willet WC, Speizer FE, Kelsey KT, Hunter DJ, Cigarette smoking, cytochrome P450 1A1 Polymorphisms, and breast cancer risk in the nurses’ health study, Cancer Research, 1998, 58, 667-671.
Madigan MP, Ziegler RG et al., Proportion of breast cancer cases in the United States explained by well-established risk factors, J Natl Cancer Institute 87(22): 1681-1685.
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I thought that I might as well share this with everyone, IMHO.
Thanks for the ping. Very interesting topic. My cousin was taking anti-depressants when he committed suicide. I thought that they were not good for him and often told him so. A couple of months after his death they came out with warning labels (not that it would have stopped him from taking them). I am still undecided as to the direct link, but in my cousin’s case at times he seemed detached from himself.
Thanks to all contributors to this thread.
Thanks for the ping!