First-trimester maternal protein intake and childhood kidney outcomes: the Generation R Study.

backgroundNutritional exposures during in utero development may have long-lasting consequences for postnatal renal health. Animal studies suggest that specifically maternal dietary protein intake during pregnancy influences childhood kidney function.

objectiveWe examined the associations of total, animal, and vegetable maternal protein intake during pregnancy with kidney volume and function in school-aged children.

designThis study was conducted in 3650 pregnant women and their children who were participating in a population-based cohort study from early life onward. First-trimester energy-adjusted maternal protein intake was assessed with a food-frequency questionnaire. At the child's age of 6 y, we assessed kidney volume, estimated glomerular filtration rate (eGFR) using serum creatinine and cystatin C concentrations, and microalbuminuria using urine albumin:creatinine ratios.

resultsFirst-trimester maternal total protein intake was associated with a higher childhood creatinine-based eGFR (difference: 0.06 mL × min(-1) × 1.73 m(-2); 95% CI: 0.01, 0.12 mL · min(-1) · 1.73 m(-2) per gram of protein intake). This association was mainly driven by vegetable protein intake (0.22 mL × min(-1) × 1.73 m(-2); 95% CI: 0.10, 0.35 mL · min(-1) · 1.73 m(-2) per gram of vegetable protein intake). These associations were not explained by protein intake in early childhood. First-trimester maternal protein intake was not significantly associated with childhood kidney volume, cystatin C-based eGFR, or the risk of microalbuminuria.

conclusionsOur findings suggest that higher total and vegetable, but not animal, maternal protein intake during the first trimester of pregnancy is associated with a higher eGFR in childhood. Further follow-up studies are needed to investigate whether maternal protein intake in early pregnancy also affects the risk of kidney diseases in later life.