Oral Contraceptive Used More than 5 Years is Associated with Increased Risk of Breast Cancer: A Meta-Analysis of 28,776 South East Asian Women

Abstract

Background: Breast cancer associated with variety of hormonal inter-ethnic and reproductive factors. Duration of oral contraceptives use with breast cancer risk is not well understood in Southeast Asian women. Methods: A comprehensive literature search of published articles from January 2001 to June 2019 (PubMed, ProQuest, and EBSCO online article databases) and meta-analysis were performed to link the duration of oral contraceptive application with risk of breast cancer among women in Southeast Asia. We identified the reference category, being ≤5 years' duration and >5 years' duration of oral contraceptive application. We use the Fixed and random-effect models to rely pooled odds ratios (OR). Egger's and Begg's test used for publication bias was presented with funnel plots. All analyzed data in Review Manager 5.3 (RevMan 5.3) and Stata version 14.2. Results: A total of 385 studies were reviewed and 10 studies involving a total of 28,776 women were included in a meta-analysis. This study found a slight increase in breast cancer risk in Southeast Asian women with oral contraceptives application ≤5 years with OR = 1.21 (95% CI 0.96-1.52, p>0.05). A higher risk of breast cancer was found in women with oral contraceptive application >5 years with OR = 2.66 (95% CI 1.79-3.94, p<0.00001). Publication bias and heterogeneity were not found particularly in a group of Southeast Asian women with oral contraceptive application for more than 5 years. Conclusion: Oral contraceptives use more than 5 years are at a higher risk in breast cancer among women in Southeast Asia. Although other reproductive factors including age at first childbirth, menarche, menopause, and lactation might influence the risk of breast cancer. Keywords: breast cancer, five years, oral contraceptive, Southeast Asia

Association of Hormonal Contraceptive Use With Adverse Health Outcomes

“…Of those, 102 articles (32.8%) were eligible for preliminary data extraction (eFigure 1 in the Supplement ). After the selection criteria for the overlapping meta-analyses were applied ( Table 2 ), 58 articles 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , …”

“…Forty-five eligible meta-analyses 25 , 28 , 29 , 30 , 31 , 33 , 34 , 38 , 40 , 41 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 75 , 76 , 77 , 78 , 79 described 96 potential associations, including 171 individual study estimates of adverse health outcomes associated with hormonal contraceptive exposure. The median number of studies per meta-analysis was 3 (IQR, 2-5), and the follow-up duration ranged from 3 months to 42 years.…”

“…Analysis of the methodological quality of 45 meta-analyses 25 , 28 , 29 , 30 , 31 , 33 , 34 , 38 , 40 , 41 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 75 , 76 , 77 , 78 , 79 using the AMSTAR-2 tool revealed that 6 meta-analyses 41 , 57 , 62 , 66 , 68 , 77 (13.3%) were of high quality, 14 meta-analyses 40 , 44 , 46 , 49 , 50 , 52 ...…”

“…Forty 25 , 28 , 31 , 33 , 38 , 40 , 43 , 44 , 45 , 46 , 47 , 49 , 50 , 52 , 54 , 59 , 61 , 62 , 64 , 65 , 66 , 69 , 70 , 71 , 76 , 78 of the 96 examined associations (41.7%) were nominally statistically significant ( P ≤ .05), and only 4 associations 44 , 46 , 65 , 78 (4.2%) reached high significance with a P value of 1.00 × 10 −6 or less ( Table 3 ). Thirty-eight associations 25 , 28 , 29 , 31 , 33 , 38 , 40 , 41 , 44 , 47 , 48 , 49 , 51 , 52 , 53 , 57 , 59 , 60 , 62 , 64 , 65 , 67 , 69 , 72 ,…”

“…We also assessed 96 associations from 45 meta-analyses of cohort studies. 25 , 28 , 29 , 30 , 31 , 33 , 34 , 38 , 40 , 41 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 75 , 76 , 77 , 78 , 79 We found that none of the 40 statistically significant associations 25 , 28 , 31 , 33 , 38 , 40 , 43 , 44 , 45 , 46 , 47 , 49 , 50 , 52 , 54 , 59 ...…”