title: The effect of breast-feeding duration on bone mineral density in postmenopausal Turkish women: a population-based study.
abstract: BACKGROUND
  In the present study, we investigated the effects of breast-feeding time on bone mineral density (BMD) later in life.
  
  
  METHODS
  The current study was based on a retrospective analysis of 586 postmenopausal women with a mean age of 60.8 years, who were screened for osteoporosis by dual energy X-ray absorptiometry (DXA).They were classified into 4 groups with respect to the duration of their breast-feeding as never (group 1), 1-24 months (group 2), 25-60 months (group 3), or > 60 months (group 4). Bone mineral density results for the femur neck and lumbar spine were classified into 3 groups according to WHO criteria as normal (T score > -1.0 SD), osteopenia (T score -1.0 to -2.5 SD), and osteoporosis (T score < -2.5 SD). Patients with osteopenia or osteoporosis (T score < -1.0 SD) were considered as having low bone mass (LBM).
  
  
  RESULTS
  We found a correlation between duration of lactation and femur BMD or spine BMD in the study population (r = 0.116, p < 0.005; r = -0.151, p = 0.001, respectively). Significant differences were found between femur BMD and spine BMD of groups in one-way ANOVA analysis (p = 0.025, p = 0.005, respectively). Additionally, when compared with the other three groups, group 4 was older and had longer duration of menopause (p < 0.01). In logistic regression analysis, age and body mass index were found as independent risk factors of LBM [odds ratio: 1.084 (95% CI 1.031-1.141); odds ratio: 0.896 (95% CI 0.859-0.935)], while duration of lactation was not found as an independent predictor of LBM.
  
  
  CONCLUSIONS
  In this study, we have found that changes of bone metabolism during lactation had no effect on postmenopausal BMD measured by DXA. Consequently, it can be suggested that long breast-feeding duration is not a risk factor for low bone mass later in life.
authors.affiliation: Physical Therapy Rehabilitation Clinic, Düzce Medical Faculty, Düzce, Turkey.
authors.forename: Selma
authors.initials: S
authors.lastname: Yazici
authors.forename: Ugur
authors.initials: U
authors.lastname: Korkmaz
authors.forename: Melih
authors.initials: M
authors.lastname: Erkan
authors.forename: Nurdan
authors.initials: N
authors.lastname: Korkmaz
authors.forename: Ali
authors.initials: A
authors.lastname: Erdem Baki
authors.forename: Aytekin
authors.initials: A
authors.lastname: Alçelik
authors.forename: Elif
authors.initials: E
authors.lastname: Onder
authors.forename: Safinaz
authors.initials: S
authors.lastname: Ataoğlu