The plight of nuns: hazards of nulliparity

Original Text

Catholic nuns are committed to leading a celibate, spiritual life in a monastery or convent. In 1713, Italian physician Bernadino Ramazzini1 noted that nuns had an extremely high incidence of that "accursed pest", breast cancer. Today, the world's 94,790 nuns still pay a terrible price for their chastity because they have a greatly increased risk of breast, ovarian, and uterine cancers: the hazards of their nulliparity.

Fraumeni and colleagues2 compiled data for cancer mortality rates in 31,658 Catholic nuns in the USA between 1900 and 1954, and showed that nuns had an increased probability of dying from breast, ovarian, and uterine cancer compared with the general population (figure). MacMahon and colleagues3 were the first investigators to make a formal link with parity, showing, in 1970, that parous women had a decreased risk of breast cancer compared with nulliparous women. Parous women receive further protection if they have their first child at a young age, bear more children, and if they breastfeed. These reproductive factors are now known also to protect against the risk of ovarian and endometrial cancer.4

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Incidence of reproductive cancers in nuns

Cancer mortality in 31,658 nuns from 41 Catholic religious orders in the USA, 1900—54.2 Nuns have an increased probability of death from breast cancer (A), ovarian cancer (B), and uterine cancer (C) compared with the female population, especially at older ages.

Nulliparous women have a higher number of ovulatory menstrual cycles than do parous women because of the absence of pregnancy and lactation, and an increased number of cycles affects cancer risk. Epidemiological studies5, 6 of breast cancer have directly linked number of menstrual cycles to cancer risk. Women experiencing menarche before age 12 years had a slightly higher risk of breast cancer than did those who were older than 15 at menarche.5 Similarly, the risk of breast cancer is increased by 17% for every 5-year delay in menopause.6 Bilateral oophorectomy before age 40 years led to a 45% reduced risk of breast cancer compared with women with a natural menopause at ages 50—54 years.5 The increased number of cycles between menarche and menopause also leads to increased risk of ovarian and uterine cancers.7, 8 This finding has been best shown by Eaton and colleagues' mathematical model,9 which used age at menarche, first pregnancy and menopause, and use of oral contraceptives to predict incidence of a woman's reproductive cancer. Findings from this model showed that the lifetime risk of reproductive cancers in modern American women was about 128 (breast), 21 (ovarian), and 287 (uterine) times that in women of similar age living in late Palaeolithic times. However, it is not known how to improve the health of breasts that do not need to lactate, ovaries that need not ovulate, and a uterus that does not need to menstruate.

Two large epidemiological studies10, 11 of the health effects of contraceptive pills have shown that the oral contraceptive pill significantly decreases overall mortality rate, does not increase breast cancer risk, and significantly reduces risk of both ovarian and uterine cancers. The overall mortality rate in ever users of the oral contraceptive pill was reduced by 12% compared with never users. In both studies, the adjusted relative risks (RR) of ovarian (RR 0.53 [95% CI 0.38—0.72]10 and 0.4 [0.3—0.6]11) and endometrial cancers (0.43 [0.21—0.88] and 0.3 [0.1—0.8]) were reduced by 50—60% compared with never users, and the protection persisted for 20 years, which shows long-term benefit. The oral contraceptive did not reduce the RR of breast cancer (0.9 [0.74—1.08] and 1.0 [0.8—1.2]).

When the oestrogen-gestagen pill was first licensed for use in 1960, it was taken for 21 days, followed by 7 days of an inactive placebo that induced menstruation as a result of the hormone withdrawal. A clinical trial12 in Edinburgh, UK, of a pill regimen every 3 months that resulted in only four menstrual periods a year was extremely popular with women. 97 (91%) of 107 women who completed the 1-year trial of the tricycle pill regimen refused to revert to monthly menstruation at the end of the trial. Contraceptive pills containing a combination of oestrogen and levonorgestrel are now available in the USA and UK to prevent all menstrual periods. Time and further research will tell whether continuous suppression of all menstrual cycles will increase the protection against breast, ovarian, and uterine cancers. The possibility of health risks, such as venous thromboembolism associated with use of the combined pill, should not be forgotten, and women's medical history should always be considered.

The Catholic Church condemns all forms of contraception except abstinence, as outlined by Pope Paul VI in Humanae Vitae in 1968.13 Although Humanae Vitae never mentions nuns, they should be free to use the contraceptive pill to protect against the hazards of nulliparity since the document states that "the Church in no way regards as unlawful therapeutic means considered necessary to cure organic diseases, even though they also have a contraceptive effect". If the Catholic Church could make the oral contraceptive pill freely available to all its nuns, it would reduce the risk of those accursed pests, cancer of the ovary and uterus, and give nuns' plight the recognition it deserves.

We declare that we have no conflicts of interest.

References

1 Ramazzini B. Diseases of workers. Translation of Latin text of 1713. Chicago: University of Chicago Press, 1940.

2 Fraumeni JF, Lloyd JW, Smith EM, Wagoner JK. Cancer mortality among nuns: role of marital status in etiology of neoplastic disease in women. J Natl Cancer Inst 1969; 42: 455-468. PubMed

3 MacMahon B, Cole P, Lin TM, et al. Age at first birth and breast cancer risk. Bull World Health Organ 1970; 43: 209-221. PubMed

4 Franceschi S. Reproductive factors and cancers of the breast, ovary and endometrium. Eur J Cancer Clin Oncol 1989; 25: 1933-1943. CrossRef | PubMed

5 Brinton LA, Schairer C, Hoover RN, Fraumeni JF. Menstrual factors and risk of breast cancer. Cancer Invest 1988; 6: 245-254. CrossRef | PubMed

6 Hsieh CC, Trichopoulos D, Katsouyanni K, Yuasa S. Age at menarche, age at menopause, height and obesity as risk factors for breast cancer: associations and interactions in an international case-control study. Int J Cancer 1990; 46: 796-800. CrossRef | PubMed

7 Kvale G, Heuch I, Ursin G. Reproductive factors and risk of cancer of the uterine corpus: a prospective study. Cancer Res 1988; 48: 6217-6221. PubMed

8 Purdie DM, Bain CJ, Siskind V, Webb PM, Green AC. Ovulation and risk of epithelial ovarian cancer. Int J Cancer 2003; 104: 228-232. CrossRef | PubMed

9 Eaton SB, Pike MC, Short RV, et al. Women's reproductive cancers in evolutionary context. Q Rev Biol 1994; 69: 353-367. CrossRef | PubMed

10 Hannaford PC, Iversen L, Macfarlane TV. Mortality among contraceptive pill users: cohort evidence from Royal College of General Practitioners' Oral Contraception Study. BMJ 2010; 340: 927-935. PubMed

11 Vessey M, Yeates D, Flynn S. Factors affecting mortality in a large cohort study with special reference to oral contraceptive use. Contraception 2010; 82: 221-229. CrossRef | PubMed

12 Loudon NB, Foxwell M, Potts DM, Guild AL, Short RV. Acceptability of an oral contraceptive that reduces the frequency of menstruation: the tri-cycle pill regimen. Br Med J 1977; 2: 487-490. PubMed

13 Pope Paul VI. Humanae Vitae; on the the regulation of birth. London: Catholic Truth Society, 1968.

a Prostate and Breast Cancer Research Program, Department of Anatomy and Developmental Biology, Monash University, VIC 3800, Australia

b Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, VIC, Australia (RS)

nonsense, of course.

Nuns might have a higher rate of endometrial uterine cancer but their rate of cervical uterine cancer is almost nil.

Endometrial cancer is usually low grade and has a high cure rate in postmenopausal ladies.

There is a more aggressive type of endometrial cancer in obese women with few periods and infertility that occurs in middle age, and I often advise these women to go on the pill to regulate their periods so they lower their risk of getting cancer.

and there is an aggressive type that occurs in younger AfroAmerican women.

Cervical cancer is higher in women with more sexual partners. (it can occur in a monogamous married lady, but statistically the risk is higher in the promiscuous).

Thanks to the Pap smear, it is usually caught early and cured. without a pap smear it would be epidemic.

Yet other diseases are less common in nuns.

Nuns don’t smoke, so they don’t often die of the most common cancer that kills women: Lung cancer.

And they tend to have less diabetes due to a decent diet, so they live longer.

Breast cancer is higher in women who don’t breast feed and who have their children later in life. Yet other things such as obesity and hormones and genetics influence breast cancer, I’m not sure if taking the pill would make a difference.

and of course breast cancer is higher in older women, and most nuns live to a ripe old age due to their healthy life style.

It is beyond ludicrous to attempt to say that by virtue of their contemplative lifestyle, nuns are more prone to cancer than others. The sheer rankness of the contention compares favorably, with anthropomorphic global warming. This article smells of agenda. And feces.

An increased cancer risk, especially breast cancer, among nuns is not "by virtue" of a "contemplative lifestyle." It's just a matter of biology.

It's been known for some time that women who go through more fertile cycles throughout their lifetime are at greater risk of developing breast cancer. The factors (aside from surgery or drugs) that determine the total number of fertile cycles are these: age of menarche, pregnancy, and age of menopause.

There is also the matter of breast feeding. Women who breast feed for longer periods of time over a greater range of time from an earlier time in their lives have a correspondingly lower risk of developing breast cancer than those who do not.

From this, two things are evident:

A. the group of women with the lowest risk of developing breast cancer would be those who had a later onset of menarche, early and multiple pregnancies followed by lengthy breast feeding, and an earlier, rather than later, menopause.

B. the group of women with the highest risk of breast cancer (aside from those who carry the BRCA mutations) would be those with an earlier onset of menarche, no pregnancies or breast feeding, and a later menopause.

Which group of women do most nuns belong to? A or B?

Unfortunately, your unexamined prejudices are causing you to look for motives for this study rather than at the biological and epidemiological basis for the study itself. Furthermore, unlike "anthropomorphic" (you really mean "anthropogenic") global warming, no one stands to make trillions of dollars carbon-trading with no added benefit to society off a relatively smaller number of women (those who have never had a child or been pregnant) having an increased risk of breast cancer.

All women should be thankful to nuns whose lifestyle more clearly isolates certain variables and has made it possible for researchers to get better epidemiological insight into factors determining the risks of breast cancer.

Noticing the difference in the rates of disease through epidemiology led to investigation of the biological basis for pregnancy and lactation reducing the risk of breast cancer. See the abstract of a review article posted below (emphasis added).

J Mammary Gland Biol Neoplasia. 2011 Sep;16(3):221-33.

Pregnancy-induced changes in breast cancer risk.

Russo IH, Russo J.

Molecular Endocrinology Section, Breast Cancer Research Laboratory, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA. Irma.Russo@fccc.edu

Abstract

Breast cancer is the malignant disease most frequently diagnosed in women of all races and nationalities. Since the 1970s the worldwide incidence of this disease has increased 30-40% in postmenopausal women, in whom, paradoxically, the risk of developing breast cancer is significantly reduced by an early first full term pregnancy (FTP) as compared to nulliparous and late parous women. Although the cause of breast cancer is not known, the mechanisms mediating the protection conferred by an early FTP have been identified to reside in the breast itself, and to be modulated by endogenous and environmental exposures that might negatively affect this organ during specific windows in its development that extend from prenatal life until the first pregnancy. Soon after conception the embryo initiates the production of human chorionic gonadotropin (hCG), the glycoprotein hormone that is diagnostic of pregnancy. HCG in conjunction with ovarian steroid hormones primes the hypothalamic neuroendocrine system for maintaining the pregnancy. Higher levels of hCG during the first trimester of pregnancy have been associated with a reduction in maternal breast cancer incidence after age 50. In preclinical studies it has been demonstrated that both FTP and hCG treatment of virgin rats prevent the development of chemically-induced mammary tumors, a phenomenon mediated by the differentiation of the mammary gland epithelial cells prior to carcinogen exposure. Complete differentiation proceeds through complex morphological, physiological and molecular changes that occur during pregnancy and lactation, that ultimately result in increased DNA repair capabilities of the mammary epithelium, activation of genes controlling differentiation and programmed cell death and imprinting in the breast epithelium a specific and permanent genomic signature of pregnancy. This signature is indicative of a reduced breast cancer and serves as a molecular biomarker of differentiation for evaluating the potential use of chemopreventive agents.

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