title: The energy intake modulates the association of the -55CT polymorphism of UCP3 with body weight in type 2 diabetic patients.
abstract: BACKGROUND
  Previous association studies of the -55CT polymorphism of the uncoupling protein 3 (UCP3) gene with body mass index (BMI) have provided inconsistent results. The study aim is twofold: (1) to evaluate the association of the -55CT polymorphism of UCP3 with BMI in two independent populations to verify the reproducibility of the finding; (2) to evaluate whether this association is modulated by energy intake.
  
  
  METHODS
  Study participants are 736 males and females with type 2 diabetes belonging to independent populations (N=394 population 1; N=342 population 2). Anthropometry and laboratory parameters were measured; in population 2, energy intake and physical exercise were also assessed.
  
  
  RESULTS
  The -55CT polymorphism was associated with a significantly lower BMI in population 1 (27.8±3.9 vs 28.9±4.6 kg m(-2); P<0.02), the finding was confirmed in population 2 (that is, 30.3±6.0 vs 32.1±5.9 kg m(-2); P<0.01) independent of gender, age, HbA1c, use of drugs and energy intake. To evaluate the role of diet in population 2, the study participants were stratified by genotype and tertiles of energy intake. In both genotype groups, BMI increased with increasing caloric intake with a significant trend (P<0.001), the BMI difference between the two genotype groups was large and statistically significant in the lower tertile (27.6 vs 31.2 kg m(-2); P<0.001), intermediate in the second tertile and negligible in the upper tertile (32.8 vs 32.9; kg m(-2); nonsignificant). The multivariate regression analysis confirmed a significant interaction between genotype and energy intake as correlates of BMI independent of age, gender, glucose control, physical activity and medications for diabetes (P=0.004).
  
  
  CONCLUSIONS
  The study replicates in two independent populations the association between the -55CT polymorphism of UCP3 and a lower BMI. This association was modulated by energy intake, thus suggesting that the unmeasured effect of diet may partly account for inconsistencies of prior association studies.
authors.affiliation: Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Lapice
authors.affiliation: 1] Department of Cellular and Molecular Biology and Pathology A Califano DBPCM, University of Naples Federico II, Naples, Italy [2] IEOS CNR, Naples, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Monticelli
authors.affiliation: Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Cocozza
authors.affiliation: Department of Cellular and Molecular Biology and Pathology A Califano DBPCM, University of Naples Federico II, Naples, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Pinelli
authors.affiliation: Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Giacco
authors.affiliation: Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy.
authors.forename: A A
authors.initials: AA
authors.lastname: Rivellese
authors.affiliation: Department of Cellular and Molecular Biology and Pathology A Califano DBPCM, University of Naples Federico II, Naples, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Cocozza
authors.affiliation: Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Riccardi
authors.affiliation: Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy.
authors.forename: O
authors.initials: O
authors.lastname: Vaccaro
mesh_terms: D000328:Adult; D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism*; D004032:Diet; D002149:Energy Intake / Q000235:genetics; D015444:Exercise; D005260:Female; D005838:Genotype; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D024101:Mitochondrial Proteins / Q000378:metabolism*; D011110:Polymorphism, Genetic; D015203:Reproducibility of Results; D000071247:Uncoupling Protein 3; D015431:Weight Loss
chemical_list: D007473:Ion Channels; D024101:Mitochondrial Proteins; C000604392:UCP3 protein, human; D000071247:Uncoupling Protein 3
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