Factors for the Primary Prevention of Breast Cancer: A Meta-Analysis of Prospective Cohort Studies

Abstract

Background: This report provided the effect of 15 preventable factors on the risk of breast cancer incidence. Study design: A systematic review and meta-analysis. Methods: A detailed research was conducted on PubMed, Web of Science, and Scopus databases in January 2020. Reference lists were also screened. Prospective cohort studies addressing the associations between breast cancer and 15 factors were analyzed. Between-study heterogeneity was investigated using the χ2 , τ2 , and I2 statistics. The probability of publication bias was explored using the Begg and Egger tests and trim-and-fill analysis. Effect sizes were expressed as risk ratios (RRs) with 95% confidence intervals (CIs) using a random-effects model. Results: Based on the results, out of 147,083 identified studies, 197 were eligible, including 19,413,702 participants. The RRs (95% CI) of factors associated with breast cancer were as follows: cigarette smoking 1.07 (1.05, 1.09); alcohol drinking 1.10 (1.07, 1.12); sufficient physical activity 0.90 (0.86, 0.95); overweight/obesity in premenopausal 0.92 (0.82, 1.03) and postmenopausal 1.18 (1.13, 1.24); nulliparity 1.16 (1.03, 1.31); late pregnancy 1.37 (1.25, 1.50); breastfeeding 0.87 (0.81, 0.93); ever using oral contraceptive 1.00 (0.96, 1.05); ever using estrogen 1.13 (1.04, 1.23); ever using progesterone 1.02 (0.84, 1.24); ever using estrogen/progesterone 1.60 (1.42, 1.80); ever taking hormone replacement therapy 1.26 (1.20, 1.32); red meat consumption 1.05 (1.00, 1.11); fruit/vegetable consumption 0.87 (0.83, 0.90); and history of radiation therapy, based on single study 1.31 (0.87, 1.98). Conclusions: This meta-analysis provided a clear picture of several factors associated with the development of breast cancer. Moreover, the useful information in this study may be utilized for ranking and prioritizing preventable risk factors to implement effective prevention programs.

Determinants of breast cancer in Ethiopia: a systematic review and meta-analysis

“…It was identified that a history of ever breastfeeding decreased the odds of developing BC by 72% (AOR = 0.28, 95% CI: 0.15–0.42) which is supported by findings of previous meta-analyses done in other countries [ 25 , 26 ]. Breastfeeding reduces BC risk biologically through lower levels of systemic estrogen and progesterone levels during breastfeeding and the excretion of estrogen and carcinogens from the breast ducts [ 21 ].…”

Role of Secreted Frizzled-Related Protein 1 in Early Breast Carcinogenesis and Breast Cancer Aggressiveness

“…We also observed that the decrease in both Sfrp1 and Esr1 expression following E2 treatment was associated with a lobulo-alveolar phenotype in organoids obtained from nulliparous mice only. Interestingly, nulliparous women have a majority of type 1 lobules (>12 acini), which are more positive to ERα and PR than type 3 lobules (>80 acini), while parous women have more type 3 lobules, expressing less ERα and PR than type 1 lobules, which is concordant with the fact that organoids obtained from nulliparous mice expressed more Esr1 than those obtained from multiparous mice [ 12 , 13 , 14 , 15 , 49 , 50 ]. In addition, virgin mice depleted of Sfrp1 developed branched mammary glands, similar to pregnant mice in vivo, corroborating that the decrease in Sfrp1 expression by E2 treatment in organoids obtained from nulliparous mice increased organoid luminal organization ex vivo [ 22 ].…”

AGO Recommendations for the Diagnosis and Treatment of Patients with Early Breast Cancer: Update 2022

“…A balanced diet including extra virgin olive oil (LoE2b/B/AGO+), nuts (LoE 2b/B/AGO+) (>10 g/die), reduced consumption of fat (LoE2a/B/AGO+), and reduced consumption of red meat (LoE2b/C/AGO+) may decrease the incidence of breast cancer. For other factors such as supplementation of vitamin D3 (LoE1b/B/AGO+/−), vegetarian or vegan diet (LoE2b/C/AGO+/−), vegetables and fruits (LoE2a/B/AGO+/−), dairy products or phytoestrogens (LoE2a/B/AGO+/−), the data are contradictory regarding the reduction of breast cancer incidence [4, 5]. However, it should be considered that prospective randomized trials to investigate the impact of nutrition aspects on breast cancer risk are almost impossible to conduct.…”