Retinol binding protein 4 and risk of type 2 diabetes in Singapore Chinese men and women: a nested case-control study.

Background: Although retinol binding protein 4 (RBP4) has been implicated in insulin resistance in experimental studies, the association between RBP4 and risk of type 2 diabetes remains unclear. We assessed this association in a Chinese population, and pooled our results with those from two prior studies.
Methods: Plasma RBP4 levels were measured among 571 incident type 2 diabetes cases and 571 controls nested within the Singapore Chinese Health Study. All participants were free of diabetes, cancer and cardiovascular disease at blood collection (1999-2004). Incident cases of physician-diagnosed diabetes were self-reported at subsequent interviews (2006-2010).
Results: Plasma RBP4 levels were significantly higher in men than women, and the respective median values were 30 (interquartile range: 24-35) μg/mL and 25 (interquartile range: 21-31) μg/mL, respectively. With adjustment for diabetes risk factors, compared to the lowest quartile, the odds ratio (OR) and confidence interval (CI) for risk of type 2 diabetes associated with the highest quartile of RBP4 levels were 1.23 (0.73-2.07; P -trend = 0.14) in all subjects, 0.63 (0.27-1.45; P -trend = 0.65) in men, and 2.29 (1.05-5.00; P -trend = 0.018) in women. The difference in the risk estimates between men and women was statistically significant ( P -interaction = 0.032). When we pooled our results with two prior studies, ORs (95% CIs) comparing high versus low category of RBP4 was 1.01 (0.70-1.46; I ²  = 8.2%; P -heterogeneity = 0.34) in men, and 1.73 (1.28-2.33; I ²  = 0%; P -heterogeneity = 0.80) in women.
Conclusions: Increased plasma RBP4 levels were associated with higher risk of type 2 diabetes in women but not in men.
Competing Interests: The study protocol was approved by the Institutional Review Boards at the National University of Singapore and the University of Pittsburgh. Informed consent was provided and completed by participants at the baseline interview.Not applicable.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.