Response: Preterm Birth – Another Risk Factor for Renal and Cardiovascular Diseases in Later Life ?

Today perinatal events are established risk factors for diseases in later life. Overthe last 2 decades research in this field has predominantly focused on the outcome after small for gestational age (SGA) birth. The reason is that birth weight and gestational age can be easily accessed, even in retrospective studies.

Due to the fact that the number of surviving preterm babies is growing, scientific interest shifts toward the lifelong clinical outcome of this population. Beside the well known behavioral and cognitive consequences, several studies suggest blood pressure elevation in young adults after preterm birth [5] [6] [8] [9] [10] [13]. A recent Australian study examined the outcome after preterm birth in children at the age of 13–14 years [2]. Interestingly, there was no statistically significant difference in the blood pressure between former preterm SGA, preterm appropriate for gestational age (AGA), term SGA and term AGA children. However, the study showed an influence of SGA birth in preterm and term babies on the later systolic blood pressure. The authors concluded that intrauterine growth restriction (IUGR) is the more relevant risk factor for later systolic blood pressure than prematurity. Low nephron number and kidney mass is often accessed as an important reason for later renal disease and arterial hypertension in former SGA and IUGR children [4]. As a surrogate for reduced nephron number Keijzer-Veen et al. showed reduced kidney length and volume at least in former female preterm infants [7].

As a consequence of these data in former IUGR and SGA individuals [3], the suggestion by Dahlem [3] in his letter to the editor to look for an aggravation of secondary renal disease in former preterm infants seems reasonable. Nevertheless, there are some obstacles and confounders to be addressed in such projects. Neonatological morbidity and nephrotoxic treatment such as amino glycosides and diuretics must be considered as confounders in this setting [12]. As shown in the paper of our group on the course of Henoch-Schönlein Nephritis [11], weight gain and growth during infancy must be considered as isolated risk factors for the later course of kidney disease in preterms, too.

Nonetheless, elevated blood pressure, renal damage and the possibility of a higher risk for an aggravated course of renal disease should be kept in mind after IUGR and preterm delivery.

C. Plank, J. Dötsch

References

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