Effect of birth weight on life-course blood pressure levels among children born premature: the Cardiovascular Risk in Young Finns Study

Objectives: Both fetal growth restriction and prematurity have been associated with elevated blood pressure (BP). However, their combined effects on adult BP are unclear.

Methods: Our analyses were based on 1756 participants in the population-based Cardiovascular Risk in Young Finns Study who had information on birth weight and gestational age, together with longitudinal data on cardiovascular risk markers from age 3–18 years in 1980 to age 34–49 years in 2011. Three groups were defined by birth data: those born at term (term); those born preterm (< 37 weeks) with an appropriate birth weight (> -1 SD z score according to national sex and gestational week-stratified data) for gestational age (preterm appropriate birth weight for gestational age); and those born preterm with low birth weight (≤ -1 SD z score) for gestational age [preterm small birth weight for gestational age (SGA)].

Results: There were no differences between the three groups in BP at baseline, but at the 31-year follow-up (mean age 41 years), mean SBP in the preterm SGA group was 7.2 mm Hg (95% confidence interval = 2.3–12.1 mm Hg, P = 0.004) higher than the preterm appropriate birth weight for gestational age group and 7.3 mm Hg (95% confidence interval = 5.2–9.4 mmHg, P < 0.0001) higher than the term group, adjusted for age and sex. In addition, preterm SGA individuals had a higher prevalence of adult hypertension compared with those born at term (36.9 vs. 25.4%; age, sex, and risk factors adjusted P = 0.006).

Conclusion: These longitudinal data suggest that elevated BP levels associated with prematurity are more likely to be present in those with fetal growth restriction.