Breast Cancer Risk Factors in a Defined Population: Weighted Logistic Regression Approach for Rare Events

Abstract

PurposeThis study aimed to determine out risk factors for female breast cancer in a low socioeconomic population in Iran.MethodsBetween 2007 and 2009, a total of 25,592 women who were ensured by the Imam Khomeini Relief Foundation participated in this screening program. The characteristics of patients diagnosed with breast cancer (n=111) were compared with those of control cases (n=25,481). In this study, we used relogit analysis (rare event logistic regression) with a weighting method using program Zelig.ResultsOf 25,592 women, 3.9/1,000 had breast cancer, from which 38 were diagnosed during screening and 73 had already been diagnosed. The mean and standard deviation of age in breast cancer patients and in healthy controls were 49.18±8.86 years and 46.65±9.40 years, respectively. The findings based on the multivariate model revealed that the past history of ovarian cancer, hormone therapy, and first relatives with breast cancer were associated with increased risk for breast cancer. However, the use of oral contraceptive pills was found to be associated with reduced risk for breast cancer.ConclusionDue to the rarity of the event in the population, relogit with a weighting method was used to investigate the major risk factors for breast cancer. These factors include oral contraceptive pill use, a history of ovarian cancer of the person under study, first relatives with breast cancer and hormone therapy.

Breast Cancer Risk Factors in Women Participating in a Breast Screening Program: a Study on 11,850 Iranian Females

“…Some studies (Naieni et al, 2007) have come to the same conclusions as the present study, while some others have reported a significant association (Ghiasvand et al, 2011). Consistent with other epidemiological researches (Naieni et al, 2007;Ghiasvand et al, 2011;Ghiasvand et al, 2012;Zare et al, 2013), the results of the current study in consistent with other studies (Ren, 2012;Ronco et al, 2012b;Toleutay et al, 2013) indicated a significant relationship between family history of breast cancer and increased risk of breast cancer. This finding suggests the existence of genetic and environmental factors that are common among families.…”

The Role of Oral Contraceptive Pills on Increased Risk of Breast Cancer in Iranian Populations: A Meta-analysis

“…Some have shown that using the pills only trivially increased breast cancer risk and this was limited to those who used the pills for a long time 18,19. The other studies that have reported inconsistent results are not negligible 14,20–22. Bethea et al20 examined the relationship between using contraceptive pills and emergence of breast cancer and found that using contraceptive pills and the term of using the pills were significantly related to development of breast cancer in African American women.…”

“…Marchbanks et al14 studied women ranged from 35 to 64 years old and found no significant relationship between breast cancer risk and using contraceptive pills. Veisy et al21 found a significant relationship between the term of using contraceptive pills and breast cancer, while Zare et al22 found a that using the pills significantly decreased risk of breast cancer.…”

Body Mass Index and Risk of Breast Cancer: A Systematic Review and Meta-Analysis in Iran

“…Therefore, the results of the present study were heterogeneous and the difference among studies or Tau 2 = 0.18. From 7 analyzed studies, 3 studies showed no significant relation between obesity and breast cancer (8,17,18). Out of 7 analyzed studies, 5 studies reported no significant relation between overweightness and breast cancer in women (8,17,18,21,23).…”

“…In one article (8), overweightness was the protecting factor and 4 studies showed no significant relation between overweightness and breast cancer (17,18,21,23).…”