Low birthweight or rapid catch-up growth: which is more associated with cardiovascular disease and its risk factors in later life? A systematic review and cryptanalysis

Background: The effects of birthweight (the Barker hypothesis) and growth trajectory in early life on the incidence of cardiovascular disease (CVD) and its risk factors in later life have been investigated in a number of studies. Objective: To undertake a systematic review and cryptanalysis of the association of low birthweight (LBW) and the postnatal growth trajectory with CVD and its risk factors. Methods: English-language publications in PubMed, ISI Web of Science and Scopus were searched. Initially, two independent reviewers identified relevant papers in several steps and the quality of papers was then determined by a validated quality-appraisal checklist. Results: By applying maximum sensitivity, 7259 paper were identified, 382 of which were duplicates and 1273 were considered to be relevant to the topic. Then, after title and abstract review, 628 irrelevant papers were excluded; 26 papers were added after reference-checking. Then, 250 other papers were deleted after full text review. Finally, 39 relevant papers remained and were entered into the systematic review. Overall, 79.6% of all CVD risk factors reported in primary studies of the rapid catch-up growth hypothesis were statistically significant, whereas the corresponding figure was 58.5% for the effects of LBW (Barker hypothesis). Conclusions: This systematic review highlights the importance of low birthweight in increasing the risk of CVD and its risk factors in later life. The results support rapid postnatal catch-up growth of LBW neonates as a more important factor than LBW alone in CVD and its risk factors.