Reproductive risk factors of breast cancer

Background: Reproductive risk factors are important factors that have an effect on breast cancer risk, and incidence. This study aimed to study the effect of reproductive factors such as breast cancer risk factor. Methods: Retrospective case control study, with a randomly selected 147 breast cancer cases compared with 161 non-breast cancer cases. Results: Age at 1st delivery >= 30 years was significantly associated with increased risk of breast cancer OR 2.7. Nulliparity parity, had >= 3 full term pregnancies had no-significant association with increased risk of breast cancer1.28, and 1.97 respectively. Among those aged <= 45years having >= 3 children significantly had 2.7(1.02-7.3) risk than those who had 1-2 children, while among those aged > 45 years multiparty showed a non significantly protective effect with OR, 0.8(0.3-2.3). Age stratification show that age at first delivery >= 30 years had significant increased risk among those aged <= or > 45 years; OR 4.1, and 1.2, respectively. The Odds ratio for lactation for >12 month was 1.03(0.5-2.1), among those aged <= 45 years, with higher protective effect among those aged > 45 years, 0.6 (0.3-1.3). Conclusion: Age at 1st full term pregnancy was an important factor affecting breast cancer risk. Parity has a dual effect in breast cancer risk.