Impact of dairy restriction of children with Duarte galactosemia on breastfeeding of unaffected younger siblings Open Access

McNeill, Annie Reynolds (Spring 2019)

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Background: Duarte galactosemia (DG) is a genetic condition characterized by 75% reduction in galactose-1-phosphate-uridylyltransferase (GALT) activity. While patients with complete GALT deficiency require immediate dietary galactose restriction, for decades it has been unclear whether infants with DG should be allowed to drink milk, a source of galactose. As a result, some families were advised to milk-restrict their DG infant; others were not. This research project examined whether being instructed to milk-restrict a child with DG impacted the likelihood that a younger unaffected sibling would be breastfed. 

Methods: Participants in this cross-sectional study derived from a cohort of 325 children with DG and 249 unaffected siblings initially recruited for a study of developmental outcomes in DG. After exclusions, 135 unaffected children representing 135 separate families remained; 76 were born before their sibling with DG and 59 were born after. Unaffected younger siblings were classified by the galactose-restriction status of their DG sibling. The proportion of unaffected infants who were breastfed were compared according to three exposure groups: 1) born before a DG sibling, 2) born after a galactose-restricted DG sibling, and 3) born after a non-galactose-restricted DG sibling.

Results: We found that 76% of unaffected children born before a sibling with DG were breastfed, and that 71% of unaffected children born after an unrestricted DG sibling were also breastfed. These percentages were not significantly different as judged by a z-test (p=0.7). In contrast, only 53% of unaffected children born after a milk-restricted DG sibling were breastfed. This percentage was significantly different from the 76% expected (p=0.0089). Finally, when directly comparing breastfeeding percentages between unaffected siblings born after a sibling with DG who was versus was not galactose-restricted the trend remained but the difference was no longer significant (p=.23), likely reflecting the small size of one of the cohorts.

Conclusions: The observed decrease in breastfeeding of unaffected siblings born after galactose-restricted DG children suggests that this restriction not only impacted the breastmilk exposure of affected children, but also their subsequent siblings who had no medical reason not to be breastfed. 

Table of Contents

Introduction      1

Diagnosis of galactosemia           1

Benefits of Breastfeeding            2

Project Aims      2

Potential Impact of Findings       3

Materials and Methods 4

Study Population             4

Exposure definition        5

Outcome definition        5

Covariates          6

Analyses             7

Results 9

Comparison 1-breastfeeding of unaffected siblings born before a DG sibling vs. after a DG sibling on a galactose-restricted diet   10

Comparison 2-breastfeeding of unaffected siblings born before a DG sibling vs. after a DG sibling who was not galactose-restricted       11

Comparison 3-breastfeeding of unaffected siblings born after a DG sibling who was galactose-restricted vs. after a DG sibling who was not galactose-restricted 11

Discussion          12

Strengths and Limitations            13

References        15

Tables  18

Figures 21

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