Leptin levels in cord blood and anthropometric measures at birth: a systematic review and meta‐analysis

<jats:title>Summary</jats:title><jats:p>Karakosta P, Chatzi L, Plana E, Margioris A, Castanas E, Kogevinas M. Leptin levels in cord blood and anthropometric measures at birth: a systematic review and meta‐analysis. <jats:italic>Paediatric and Perinatal Epidemiology</jats:italic> 2010.</jats:p><jats:p>The role of intrauterine environment in the development of obesity is increasingly recognised. Adipokines and specifically leptin have been examined as potential biomarkers predicting early development of obesity. We conducted a systematic review and meta‐analysis of the epidemiological evidence for the association between leptin levels in cord blood and anthropometric measurements at birth in healthy mother‐newborn pairs. A PubMed search was performed between 1994 and 2009 and manual search of reference lists of retrieved articles. Forty‐four studies met the inclusion criteria set. All studies reported a positive correlation between leptin levels and birthweight. The combined correlation coefficient (<jats:italic>r</jats:italic>) was 0.46 [95%CI 0.43, 0.50]. Leptin levels explained 21% of variation in birthweight. Results were similar in males (<jats:italic>r</jats:italic> = 0.55; 0.40, 0.68) and females (<jats:italic>r</jats:italic> = 0.60; 0.50, 0.69), and between Caucasians (<jats:italic>r</jats:italic> = 0.45; 0.39, 0.51) and eastern Asian populations (<jats:italic>r</jats:italic> = 0.47; 0.37, 0.55). Statistically significant positive correlations were also found for birth length (<jats:italic>r</jats:italic> = 0.29; 0.23, 0.34) and ponderal index (<jats:italic>r</jats:italic> = 0.36; 0.31, 0.41). There was no indication of publication bias (Egger's test <jats:italic>P</jats:italic>‐value = 0.23). This meta‐analysis shows a clear but moderate correlation between leptin levels in cord blood and birthweight that is observed in different population groups.</jats:p>