4.1. Kidney Volume
SCHMIDT, INTRAUTERINE GROWTH RESTRICTION
In a previous study, we observed that a higher protein content in infant formula induced a larger kidney volume at 6 months compared with infants who were breastfed or those fed with a lower-protein-content formula [There are no studies assessing the effect of protein ingestion early in life on kidney volume, but there are some studies reporting the effect of breastfeeding versus formula-feeding on kidney volume. These studies report contradictory results: Schmidt et al. reported that 3-month-old infants who were formula-fed had bigger kidneys than infants who were exclusively breastfed, but this effect was found to be reversible at the age of 18 months [In the Generation R cohort, Bakker et al. [One surprising result was the positive association between maternal smoking during pregnancy and kidney volume at 11 years of age. Maternal smoking during pregnancy has been linked to intrauterine growth restriction in epidemiological studies and to low nephron endowment in animal experimental studies [Low nephron endowment is linked to worse cardiovascular and kidney outcomes, as demonstrated in animal and epidemiologic studies [