Endocrine Abstracts

Aims: Some studies have reported associations between uncoupling protein (UCP) 1–3 polymorphisms and obesity or related-features. However, other studies have failed to confirm these associations. Thus, this study describes a cross-sectional study and a meta-analysis conducted to attempt to determine whether the -3826A/G (UCP1), -866G/A, Ala55Val and Ins/Del (UCP2) and -55C/T (UCP3) polymorphisms are associated with body mass index (BMI) in patients with type 2 diabetes mellitus (T2DM).

Methods: The cross-sectional study enrolled 767 T2DM patients, all of European ancestry. A literature search was conducted in order to identify all studies that investigated associations between UCP1–3 polymorphisms and BMI. Weighted mean differences (WMD) were calculated for additive, recessive, dominant and co-dominant inheritance models.

Results: In the cross-sectional study, mean of BMI did not differ significantly according to the different genotypes of UCP1–3 polymorphisms (P>0.05). Fifty-five studies were eligible for the meta-analysis. Meta-analysis results showed that the UCP2 -866 and Ala55Val polymorphisms were associated with increased BMI in Asian and European population, respectively (866: WMD=0.10 (95% CI 0.04–0.16) for the co-dominant model; Ala55Val: WMD=0.39 (95% CI 0.02–0.75) for the dominant model]. Moreover, the UCP2 Ins/Del polymorphism was associated with increased BMI in Asians (WMD=0.46 (95% CI 0.14–0.77), dominant model). In contrast, the UCP2 -866 polymorphism was associated with decreased BMI in Europeans (WMD=−0.17 (95% CI −0.33–−0.01), for the dominant model). There was no significant association of the UCP1 -3826A/G polymorphism with BMI mean differences.

Conclusions: In our cross-sectional study we were not able to demonstrate any association between the UCP polymorphisms and BMI. However, our meta-analysis detected a significant association between the UCP2 -866G/A, Ins/Del, Ala55Val and UCP3 -55C/T polymorphisms and BMI mean differences.