Effects of rapid growth on fasting insulin and insulin resistance: a system review and meta-analysis

Infants with congenital deficiency have high risk of glucose metabolism disorder, and often experience rapid growth in early childhood. However, the role of rapid growth on glucose metabolism is controversial. We conducted a systematic review and meta-analysis to examine the association of rapid growth with fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR). We searched EMBASE and Medline for English articles, and CNKI and WANFANG database for Chinese articles. Studies measuring the associations between rapid growth and insulin or HOMA-IR were included. Relevant information was extracted independently by two reviewers. Random effects model was adopted for combined and stratified analyses. At last, twenty-two relevant studies for insulin and 20 for HOMA-IR were identified. Rapid growth was associated with high insulin (weighted mean differences [WMD] 5.544, 95% confidence interval [CI] [1.436, 9.653], P = 0.008) and high HOMA-IR (WMD 0.194, 95% CI [0.098, 0.290], P < 0.001). This elevated association was statistically significant in rapid growth subjects that were >6 years old, full-term, and from developed countries. However, rapid growth among low birth weight subjects did not lead to high insulin and HOMA-IR, but decreased HOMA-IR among preterm children (WMD -0.305, 95% CI [-0.607, -0.004], P = 0.047). Follow-up age was positively correlated with HOMA-IR (r = 0.095, P < 0.001). This meta-analysis suggested that rapid growth would result in high insulin and HOMA-IR, especially for full-term infants. However, rapid growth is relatively harmless for subjects who are <6 years old, low birth weight or SGA, and is even protective for preterm subjects.