Original Article

Osteoporosis International

, Volume 23, Issue 7, pp 1939-1945

Lactation is associated with greater maternal bone size and bone strength later in life

  • P. K. WiklundAffiliated withDepartment of Health Sciences, University of Jyväskylä
  • , L. XuAffiliated withDepartment of Health Sciences, University of Jyväskylä
  • , Q. WangAffiliated withEndocrine Centre, Austin Health, University of Melbourne
  • , T. MikkolaAffiliated withDepartment of Health Sciences, University of Jyväskylä
  • , A. LyytikäinenAffiliated withDepartment of Health Sciences, University of JyväskyläCentral Hospital, Central Finland
  • , E. VölgyiAffiliated withHealth Science Center, Preventive Medicine, University of Tennessee
  • , E. MunukkaAffiliated withDepartment of Health Sciences, University of Jyväskylä
  • , S. M. ChengAffiliated withDepartment of Health Sciences, University of Jyväskylä
  • , M. AlenAffiliated withDepartment of Medical Rehabilitation, Oulu University Hospital
    • , S. Keinänen-KiukaanniemiAffiliated withInstitute of Health Sciences, University of Oulu
    • , S. ChengAffiliated withDepartment of Health Sciences, University of JyväskyläDepartment of Orthopaedics and Traumatology, Kuopio University Hospital Email author 

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Summary

The association between lactation and bone size and strength was studied in 145 women 16 to 20 years after their last parturition. Longer cumulative duration of lactation was associated with larger bone size and strength later in life.

Introduction

Pregnancy and lactation have no permanent negative effect on maternal bone mineral density but may positively affect bone structure in the long term. We hypothesized that long lactation promotes periosteal bone apposition and hence increasing maternal bone strength.

Methods

Body composition, bone area, bone mineral content, and areal bone mineral density of whole body and left proximal femur were assessed using DXA, and cross-sectional area and volumetric bone mineral density of the left tibia shaft were measured by pQCT in 145 women (mean age 48 years, range 36–60 years) 16 to 20 years after their last parturition. Hip (HSI) and tibia strength indexes (TBSI) were calculated. Medical history and lifestyle factors including breastfeeding patterns and durations were collected via a self-administered questionnaire. Weight change during each pregnancy was collected from personal maternity tracking records.

Results

Sixteen to 20 years after the last parturition, women who had breastfed in total more than 33 months in their life, regardless of the number of children, had greater bone strength estimates of the hip (HSI = 1.92 vs. 1.61) and the tibia (TBSI = 5,507 vs. 4,705) owing to their greater bone size than mothers who had breastfed less than 12 months (p < 0.05 for all). The differences in bone strength estimates were independent of body height and weight, menopause status, use of hormone replacement therapy, and present leisure time physical activity level.

Conclusion

Breastfeeding is beneficial to maternal bone strength in the long run.

Keywords

Bone size Bone strength index Breastfeeding Lactation Women