Introduction: Early introduction of solids (4-6 months) may be associated with a reduction in allergic outcomes; however less is known about musculoskeletal outcomes, particularly in an Australian context. Thus, we aimed to determine if age of introduction to solids was associated with childhood bone outcomes in an Australian cohort.
Methods: Participants were recruited within the Vitamin D in Pregnancy study. At birth there were 402 mother child pairs, and 209 returned at the 11 year follow-up. At age one year, mothers self-reported the age of introduction to solids. At age 11 years, children underwent total body (TBLH) and lumbar spine DXA scans. Final linear regression models were adjusted for child height, lean mass, fat mass, pubertal stage and sex.
Results: There were 177 children who had complete information. Median age of introduction to solids was 5.0 (IQR: 4.0-6.0) months. There were 161 (91.0%) who were introduced to solids at or after four months and 62 (35.0%) who were introduced at or after six months. There was no association between beginning solids at or after four months and either TBLH or spine BMD (adjusted-β: -0.002 95% CI: -0.025,0.022 & adjusted-β:-0.014 95% CI: -0.060,0.031, respectively). Nor was there an association between beginning solids at or after six months and either TBLH or spine BMD (adjusted-β: -0.000 95% CI: -0.014,0.014 & adjusted-β:0.007 95% CI: -0.020,0.034, respectively). Similarly, holding 4-5 months referent, there was no difference in BMD to those introduced to solids at six months and above compared to those introduced at 4-5 months (adjusted-β: 0.003 95% CI: -0.013,0.019 & adjusted-β:0.013 95% CI: -0.018,0.034, respectively).
Conclusion: Within this cohort, there was no evidence of an association between the age of introduction of solids and childhood bone outcomes. This association will be re-examined in an upcoming young adulthood follow-up.