Breastfeeding and maternal bone health 10 years postpartum: findings from the ROLO longitudinal cohort study

Brief rationale: To investigate associations between breastfeeding behaviours and maternal bone health at 10-year follow-up.

Breastfeeding durations were not associated with DXA measurements. Significance of the paper: These findings add to the evidence that breastfeeding is not associated with adverse long-term maternal bone health.

To investigate associations between breastfeeding behaviours and dual-energy X-ray absorptiometry (DXA) measurements of maternal bone health at 10-year follow-up. Associations with bone turnover markers (BTMs) were examined as exploratory secondary outcomes.

This was an analysis of 196 women from the ROLO (Randomised cOntrol trial of a LOw glycaemic index diet in pregnancy to prevent macrosomia) longitudinal cohort study at 10-year follow-up. Data on demographics, lifestyle and breastfeeding were collected by questionnaire. DXA measurements were available for 171 participants and BTM measurements for 60. Exclusive breastfeeding duration, any breastfeeding duration and three mutually exclusive cumulative breastfeeding groups (never breastfed, breastfed for <12 months, and breastfed for ≥12 months) were each examined in relation to bone health outcomes.

The mean (SD) age of participants was 42.8 (3.87) years and 97.9% were premenopausal. Ever breastfeeding rates were 70.9% (n = 139/196) and 40.3% (n = 79/196) had a cumulative breastfeeding duration of ≥12 months. Breastfeeding durations were not associated with DXA measurements at 10-year follow-up. An unadjusted difference in β-CTX-I was observed between the ≥12-month and never-breastfed groups (p = 0.038) however, given the small group size an adjusted analysis was underpowered.

These findings reassure women that breastfeeding does not have a lasting negative impact on skeletal health. The exploratory BTM finding should be interpreted cautiously.