Birth Weight and Systolic Blood Pressure in Adolescence and Adulthood: Meta-Regression Analysis of Sex- and Age-specific Results from 20 Nordic Studies

Abstract

The authors investigated the shape, sex- and age-dependency, and possible confounding of the association between birth weight and systolic blood pressure (SBP) in 197,954 adults from 20 Nordic cohorts (birth years 1910-1987), one of which included 166,249 Swedish male conscripts. Random-effects meta-regression analyses were performed on estimates obtained from age- and sex-stratified analyses within each of the cohorts. There was an inverse association between birth weight and SBP, irrespective of adjustment for concurrent body mass index. The association was linear for males, but for females with a birth weight greater than 4 kg, SBP increased with birth weight (p < 0.01). The association was stronger in the older age groups (p < 0.05), although this could have been a birth cohort effect. The association was stronger among females than among males (p = 0.005) when birth weight was less than or equal to 4 kg. The estimated effect of birth weight on SBP at age 50 years was -1.52 mmHg/kg (95% confidence interval: -2.27, -0.77) in men and -2.80 mmHg/kg (95% confidence interval: -3.85, -1.76) in women. Exclusion of the Swedish conscripts produced nearly identical results. This meta-analysis supports the evidence of an inverse birth weight-SBP association, regardless of adjustment for concurrent body size. It also reveals important heterogeneity in the shape and strength of the association by sex and age.

Effect of Intrauterine Growth Restriction on Kidney Function at Young Adult Age: The Nord Trøndelag Health (HUNT 2) Study

“…5 We found that systolic blood pressure increased by 0.7 to 1.3 mm Hg per 1-kg decrease in BW. This is in accordance with 2 large meta-analyses that found systolic blood pressure increased by 1 to 2 mm Hg per 1-kg decrease in BW 38,39 and strengthens the external validity of our results. Earlier studies reported much larger associations, eg, an increase in systolic blood pressure of 11 mm Hg per 1-kg lower BW in middle-aged subjects.…”

“…40 Our study shows that such adjustment clearly increased the magnitude of the association, but did not create it. Others also found similar results, 39 and noting that low BW is associated with low adult weight, which in turn is associated with lower blood pressure, it is not yet clear how to solve this problem.…”

“…39,45 Moreover, the potential effect of intervention can be different in developing countries. Mean BW is nearly 1 kg less in South Asia compared with western Europe.…”

Renal and extrarenal mechanisms of perinatal programming after intrauterine growth restriction

“…A recent metanalysis of 20 Nordic studies based on 183 026 adult males shows a drop in systolic blood pressure of approximately 1 mm Hg per kg birth weight. 2 Interestingly, the same study shows that in 14 928 females this inverse association is detected only between 2 and 4 kg of birth weight, whereas a further rise in neonatal weight is linked with an increase in systolic blood pressure later in life. Another metanalysis examined the impact of study size and investigators on the extent of hypertension.…”

“…6 The latter may explain why the risk ratio for certain adulthood diseases shows a U-or J-shaped relation to birth weight. 2 …”