1514-P: Is Low Birthweight Associated with Lower Adiponectin Levels? A Systematic Review and Meta-analysis

Background: Compared to people with normal birth weight (NBW), individuals born with low and high birth weights (LBW and HBW) are at increased risk of developing type 2 diabetes. Studies have suggested that this could be due to lower levels of the insulin-sensitizing adipokine adiponectin. We performed a systematic review and meta-analysis of studies that have reported circulating levels of adiponectin in relation to birthweight across all age groups to determine the extent to which levels of adiponectin are lower in LBW and/or HBW subjects, respectively.

Methods: Searching MEDLINE, Embase and Web of Science yielded a total of 1486 studies. Two independent reviewers screened studies against inclusion criteria and among these were 67 included in the meta-analysis. Using a random-effect model, two meta-analyses were carried out to calculate the pooled effect size and corresponding 95% confidence interval. Heterogeneity was assessed using the I²-test, and subgroup and meta-regression analyses performed to identify potential sources of variation.

Results: The first meta-analysis included 24 studies comparing adiponectin levels in LBW to NBW individuals. Pooled effect size revealed a statistically significant lower level of adiponectin in LBW compared to NBW individuals (SMD= -0.55 μg/ml [95% CI: -2.75; 1.65], P=0.02). The heterogeneity of results was significant (I²=92%, P<0.01), but meta-regressions failed to identify sources of heterogeneity. The second meta-analysis included 15 studies comparing adiponectin levels between HBW and NBW subjects but failed to establish firm evidence of any significant difference in the overall effect size (SMD= -0.33 μg/ml [95% CI: -2.84; 2.17], P=0.28). Similar to the LBW analysis, significant heterogeneity was observed (I²=94%, P<0.01).

Conclusion: Despite considerable heterogeneity between studies, there is firm evidence that LBW, but not HBW, subjects exhibit lower adiponectin levels compared to individuals born with NBW.