Those following daily are beginning to get confortable with the jargon (I hope). For ease of newcomers following along , please consult the glossary of terms that I’ve written to make the terminology very understandable. Also, consult the post that explains the essential background.
Title: Prolonged breastfeeding reduces risk of breast cancer in Sri Lankan women: A case–control study
Authors: Malintha De Silva , Upul Senarath, Mangala Gunatilake , Dilani Lokuhetty
Journal: Cancer Epidemiology 34 (2010) 267–273
Goal: To assess the association between duration of breastfeeding and the risk of breast cancer in Sri Lankan women.
The method in the author’s own words. It’s very clear and worth the read:
We conducted a case–control study in selected health care
facilities in the Western province of Sri Lanka from January to
December 2007. The cases were selected from three tertiary care
hospitals: the Cancer Institute Maharagama, the National Hospital
of Sri Lanka and the Colombo North Teaching Hospital. The Cancer
Institute Maharagama is the only referral hospital for cancer in Sri
Lanka, and provides care for the majority of cancer patients in the
country. The National Hospital of Sri Lanka and the Colombo North
Teaching Hospital also provide diagnostic facilities and initial
treatment for selected cancers, i.e., surgery for breast cancer.
A ‘case’ of breast cancer was deﬁned as a woman who was
newly diagnosed to have invasive breast cancer either by ﬁne
needle aspiration (cytological) or core/excision biopsy (patholo-
gical), with or without a positive mammogram (radiological),
together with clinical diagnosis. The sample was restricted to
women aged 30–64 years and admitted to the surgical units of the
above mentioned hospitals. Among the excluded were those
having more than a 3-year delay between diagnosis and admission
for surgery, secondary deposits in the breast where the primary
malignancy was at another site and critically ill patients. All the
women who satisﬁed the above mentioned criteria were enrolled
in the study as ‘cases’ until the required sample size was fulﬁlled.
The control group was selected from Well Women Clinics
conducted in ﬁve Medical Ofﬁcer of Health divisions in the
Western province, namely Pitakotte, Nugegoda, Wattala, Ragama
and Ja-ela. The Well Women Clinics offer screening services
including clinical examination of breasts and PAP smear test for
cervical cytology for apparently healthy women in the community.
However, these clinics do not provide mammographic screening
facilities for breast cancer. The controls were matched to the cases
by the respondent’s age group (5-year age groups) and parity, since
these 2 variables were well recognized risk factors, which would
otherwise confound the hypothesized association between breast
cancer and breastfeeding. Once a case was identiﬁed, two controls
comparable to the index case were selected from the immediate
Well Women Clinic out of the 5 clinic centers.
The data were collected by interviewing women by the trained
interviewers using a pre-tested, structured questionnaire.
The questions were focused to collect details of
breastfeeding and other potential confounding factors for breast
cancer. The lactation history was obtained for each live birth
separately, including details regarding duration of breastfeeding,
period of amenorrhea during breastfeeding, age at ﬁrst lactation
and at most recent lactation. The total duration of breastfeeding
was calculated by summing up the number of months of
breastfeeding per each child. In addition, information was
collected on level of education, employment, family history of
breast cancer, menstrual and reproductive history, exposure to
passive smoking, use of alcohol and daily activity level.
Results: Data are reported with a 95% Confidence Interval
Among women with past history of abortion, the OR is 3.42 (More than triple the risk of developing BC).
Paasive smoking raised the risk three-fold (OR=2.96)
Breastfeeding 24 months or more compared to no breastfeeding OR=0.40 (60% reduction in breast cancer among breastfeeding women)
The results validate well-known data indicating an increase in BC among women exposed to cigarette smoke.
The data validate what is known about the protective effect of a full term pregnancy and prolonged exposure to lactogen and the general maturational effects of lactation hormones on the lobule cells during breastfeeding.
And the data support all the aforementioned risk associated with breast cancer in women who have not had the protective effect of a first full term pregnancy because of abortion.
Note to those who continue to assert that I am ideologically driven in my presentation of the data and rejection of the fantasy called recall bias, or reporting bias:
Ideology is manifest when researchers claim the presence or activity of a phenomenon for which they have absolutely no data. All that these folks have is a hunch. But there needs to be a way to test for this phenomenon. In paper #3 yesterday, we saw even stronger association between abortion and breast cancer in Greece where there are no cultural constraints on abortion, and a diminished likelihood of reporting error. Thus, the Greek study tells us that if anything, the underreporting is not in the control groups, but in the experimental groups here in America.
The Sri Lankan study shows an overwhelmingly high incidence of BC associated with abortion. This is a nation that is 70% Buddhist, 15% Hindu, 7.5% Muslim, and 7.5% Christian. Thus, there doesn’t appear to be the grounds for Palmer and Rosenberg’s contention of Catholic scruples as the source of reporting bias.
I am reporting the science. The ideologues are those who invent phenomena to attenuate data that challenge their most cherished beliefs and practices.
This study was entirely funded by Sri Lankan sources.
This October, please consider $upporting the following who desperately need our $upport to get the truth out*:
*I have no institutional affiliation or membership with either group. Karen Malec and BCPI have been great resources for me, utterly generous with their time and resources.