The impact of birth weight on blood pressure and arterial stiffness in later life: The Enigma Study

BACKGROUND: Accumulating evidence suggests that low birth weight is associated with increased cardiovascular risk. However, the relationship between birth weight, blood pressure, arterial stiffness and wave reflections as putative mechanisms is controversial. 

METHOD: Data from 882 participants (mean age 21 years) were analysed. Participants underwent a detailed physiological assessment, including anthropometric measurement, blood pressure, aortic pulse wave velocity, augmentation index (AIx) and cardiac output (CO). Analyses were conducted in men and women separately, according to birth weight quartiles and categories referenced to UK birth weight percentiles. 

RESULTS: In men, those in the lowest birth weight quartile had higher brachial SBP (P=0.04), central pulse pressure (PP; P=0.03) and AIx (P=0.02). Further analysis of the low birth weight spectrum revealed that central PP (P=0.03), AIx (P=0.03) and peripheral vascular resistance index (P=0.01) were higher in those in the lowest birth weight percentile, although the association with AIx disappeared after adjustment for adult height. In women, analysis by birth weight quartiles and categories referenced to UK birth weight percentiles revealed a significant positive association between birth weight and CO (P=0.04, P=0.02) and stroke volume (P=0.03, P=0.002); although these associations disappeared when body size was taken into account. There was no association between birth weight and aortic pulse wave velocity in either men or women.

CONCLUSION: These data suggest that although lower birth weight is associated with altered haemodynamics in young adulthood, the associations are predominantly driven by other factors such as adult body size, rather than intrinsic structural changes within the large elastic arteries.