We read with interest the article by Hummel et al. (1) regarding predictors of childhood overweight risk in offspring of type 1 diabetic parents. Beyond the reevaluation of large-for-gestational-age (LGA) status as a long-term risk factor for later overweight, it is important and became clear that in this study breast-feeding significantly decreased childhood overweight risk. Thus, the study provides new data supporting the promotion of breast-feeding, which is undoubtedly worth targeting. Moreover, the authors also confirmed that, of course, maternal type 1 diabetes is not a risk factor as such, but that tight metabolic control during pregnancy may optimize the short- and long-term outcomes in the offspring of diabetic mothers (ODM), as already evaluated and recommended in a variety of earlier studies. Optimal metabolic control, however, may not only improve the perinatal outcome, e.g., birth size, but also maternal milk composition, which appears to be crucial for beneficial breast-feeding effects (2).
From the presented data it seems, however, that no clear dose-response relationship existed between duration of breast-feeding and outcome in this large ODM cohort. For instance, as shown in Table A1 of the online appendix (1), while full breast-feeding in ODM had beneficial effects only after a duration of 4 months, any breast-feeding was observed to significantly decrease overweight risk already when performed for only 1–3 months and then, again, at least after 6 months. This is in contrast to the general population where a clear dose-response exists with any breast-feeding up to 9 months leading to a childhood overweight risk reduction of 4% per month (3).
These discrepancies might indicate a relatively reduced protective effect of breast-feeding in ODM. Interestingly, this is in line with data not only from our group (2), but also with those by Mayer-Davis et al. (4). Also confirming earlier studies(5), Hummel et al. (1) found LGA offspring of diabetic mothers as being particularly prone to later obesity, potentially resulting from less tight metabolic control in the mothers, which, on the other hand, may affect their breast-feeding performance. Furthermore, LGA was not a significant risk factor in ODM at a greater childhood age of 8 years, i.e., not for the long term, which is also contrary to other populations and cohorts, respectively.
Therefore, it might be worthwhile to know whether LGA babies of type 1 diabetic mothers did particularly benefit from breast-feeding in terms of a secondary prevention, at best. This would be particularly interesting with information on the overweight prevalence in the subcohort of ODM in this large cohort in order to get a better estimate on the preventive potential of breast-feeding in these cases. According to the authors and others, this group can particularly benefit from tight metabolic control during pregnancy and beyond. Irrespective of these points, the study (1) once again underlines that mothers with diabetes should be supported to breast-feed and, most of all, that tight metabolic control during pregnancy and beyond is essentially necessary to improve the outcome (2,5).
Acknowledgments
No potential conflicts of interest relevant to this article were reported.
