Endocrine Abstracts

Introduction: Some studies have reported associations between five uncoupling protein (UCP) 1–3 polymorphisms and obesity. This paper describes a case–control study and a meta-analysis conducted to determine if the following polymorphisms are associated with obesity: −3826A/G (UCP1); −866G/A, Ala55Val and Ins/Del (UCP2) and −55C/T (UCP3).

Methods: The case–control study enrolled 282 obese and 483 non-obese patients with type two diabetes mellitus. A literature search was conducted in order to identify all studies that investigated associations between UCP1–3 polymorphisms and obesity. Pooled odds ratios (OR) were calculated for allele contrast, recessive, dominant and additive inheritance models.

Results: In the case–control study the frequencies of the UCP polymorphisms did not differ between obese and non-obese groups (P>0.05). Forty-seven studies were eligible for inclusion in the meta-analyses. Meta-analysis results showed that the UCP2 −866G/A and UCP3 −55C/T polymorphisms were associated with protection for obesity in Europeans (−866G/A: OR=0.89 (95% CI 0.82-0.97); −55C/T: OR=0.88 (95% CI 0.80-0.97)) assuming dominant and co-dominant inheritance models respectively. In contrast, the UCP2 Ala55val polymorphism was associated with risk for obesity in Asians (OR=1.61 (95% CI 1.13-2.30)) in the recessive model, whereas the UCP2 Ins/Del polymorphism was associated with risk for obesity mainly in Europeans under an allele contrast model (OR=1.19 (95% CI 1.00-1.42)). No significant association was observed between the UCP1 −3826A/G polymorphism and obesity.

Conclusions: In our case–control study we were not able to demonstrate any association between UCP polymorphisms and obesity; however, in the meta-analysis we detected a significant association of UCP2 −866G/A, Ins/Del, Ala55Val and UCP3 −55C/T polymorphisms with obesity.