Small for date preterm infants and risk of higher blood pressure in later life: A systematic review and meta‐analysis

Abstract

Background Historical reports suggest that infants born small for gestational age (SGA) are at increased risk for high blood pressure (BP) at older ages after adjustment for later age body size. Such adjustment may be inappropriate since adiposity is a known cause of cardiovascular and metabolic disease. Objectives To assess the association between SGA births and later BP among preterm births, considering potential background confounders and over‐adjustment for later body size. Methods A database search of studies up to October 2022 included MEDLINE, EMBASE and CINAHL. Studies were included if they reported BP (systolic [SBP] or diastolic [DBP]) (outcomes) for participants born preterm with SGA (exposure) or non‐SGA births. All screening, extraction steps, and risk of bias (using the Risk of Bias In Non‐randomised Studies of Interventions [ROBINS‐I] tool) were conducted in duplicate by two reviewers. Data were pooled in meta‐analysis using random‐effects models. We explored potential sources of heterogeneity. Results We found no meaningful difference in later BP between preterm infants with and without SGA status at birth. Meta‐analysis of 25 studies showed that preterm SGA, compared to preterm non‐SGA, was not associated with higher BP at age 2 and older with mean differences for SBP 0.01 mmHg (95% CI −0.10, 0.12, I2 = 59.8%, n = 20,462) and DBP 0.01 mm Hg (95% CI −0.10, 0.12), 22 studies, (I2 = 53.0%, n = 20,182). Adjustment for current weight did not alter the results, which could be due to the lack of differences in later weight status in most of the included studies. The included studies were rated to be at risk of bias due to potential residual confounding, with a low risk of bias in other domains. Conclusions Evidence indicates that preterm infants born SGA are not at increased risk of developing higher BP as children or as adults as compared to non‐SGA preterm infants.

Intrauterine growth restriction and risk for arterial hypertension in later life. Ribeirao Preto birth cohort study

“…Although these and other studies have found a reverse association between birthweight and BP throughout life, this is discreet and may have occurred due to random or selective bias, inadequate adjustment for the current weight, and other confounding factors 13 . In line, other studies do not show elevation of blood pressure in IUGR 14,15 . Part of the explanations for those findings relies on the fact that the AH phenotype observed at an adult age is due mainly to environmental factors related to sedentarism and obesity 16 and that genetic or present at-birth factors should exert a more negligible impact on the AH occurrence.…”

Small for gestational age preterm infants and later adiposity and height: A systematic review and meta‐analysis

“…[7][8][9][10][11] Recent evidence indicates that preterm infants born SGA are not at increased risk of developing higher blood pressure as children or as adults as compared to non-SGA preterm infants. 12 Individuals with short stature have smaller body components, on average. Therefore, some adiposity assessment tools (body mass index [BMI], fat mass index, per cent body fat and waist/hip ratio) take height into account, while others such as body fat mass and waist circumference do not.…”

“…This study was part of a larger review examining whether risk of higher blood pressure (BP), adiposity outcomes and height differ between individuals born preterm SGA and non-SGA 12,18 (Table S1). The protocol for this systematic review was registered in PROSPERO (CRD42020162353) 18 and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement (Table S2). 19…”

“…Healthcare providers are unsure how preterm SGA infants should be supported to optimise long‐term outcomes 7–11 . Recent evidence indicates that preterm infants born SGA are not at increased risk of developing higher blood pressure as children or as adults as compared to non‐SGA preterm infants 12 …”

Neonatal blood pressure by birth weight, gestational age, and postnatal age: a systematic review

“…Notably, there are established discrepancies between the previously established normative ranges within the neonatal period [ 3 ]. This is due to the prevalence of multiple small heterogeneous studies, whilst larger reviews have more commonly focused on longer term associations between blood pressure, neonatal parameters, and disease rather than determining normative values [ 8 – 11 ].…”