Prolonged breast-feeding is an independent risk factor for postmenopausal osteoporosis

Objectives: This study investigated the effects of parity and age at first pregnancy and breast-feeding, as well as duration of BF for total and per child on postmenopausal osteoporosis. Study design: The study was conducted among 542 cases who were divided based on the presence or absence of osteoporosis. Patients were separated according to their first pregnancy and breast-feeding age as before or after 27 years. Osteoporosis was defined as a T score of -2.5 or lower. Main outcome measures: Parity, age at first pregnancy and breast-feeding, breast-feeding period for total and average duration per child according to a questionnaire were assessed. Results: Osteoporosis group had significantly lower parity compared to non-osteoporosis group. The age at first pregnancy and breast-feeding <27 age were significantly more frequent in osteoporosis group. They also had prolonged breast-feeding period. Women who had a breast-feeding period per child >1 year under age 27 was higher in osteoporosis group. In multivariate analysis, women who breast-fed >1 year per child had the highest risk for osteoporosis (odds ratio: 12.92; 95% confidence interval, 3.1-52.6) and osteoporosis risk for women who breast-fed >1 year per child under age 27 was 7.1. Increased parity was associated with a significant protective effect for osteoporosis. Conclusions: Extended breast-feeding period per child >1 year is the highest risk factor for osteoporosis independent of first breast-feeding age. However, high parity has a protective effect. (C) 2013 Elsevier Ireland Ltd. All rights reserved.