title: PPARγ2 P12A polymorphism and albuminuria in patients with type 2 diabetes: a meta-analysis of case-control studies.
abstract: BACKGROUND
  Insulin resistance has a role in diabetic nephropathy. The A12 variant of the PPARγ2 P121A polymorphism has been firmly associated with reduced risk of insulin resistance, while its role on the risk of albuminuria in patients with type 2 diabetes is uncertain. This study investigated whether the PPARγ2 P12A polymorphism modulates the risk of albuminuria in these patients.
  
  
  METHODS
  We tested the association between the A12 variant and albuminuria in three new case-control studies in diabetic patients from Italy (n = 841, n = 623 and n = 714 patients, respectively) and then performed a meta-analysis of all studies available to date. The nine studies we meta-analysed (six previously published and three presented here) comprised a total of 2376 cases and 4188 controls.
  
  
  RESULTS
  In none of the three new studies was a significant association observed with odds ratio (OR) [95% confidence intervals (95% CI)] being 1.115, 0.799 and 0.849 (P = 0.603, 0.358 and 0.518, respectively). At meta-analysis, the overall OR (95% CI) for association between A12 and albuminuria was 0.694 (0.528-0.912). A significant heterogeneity of the genetic effect was observed (P = 0.026), which was totally explained by the different method of urine collection and albuminuria definition utilized across the studies. In fact, most of the effect was observed in the four studies determining albumin excretion rate rather than in those using albumin concentration in a single spot (OR, 95% CI: 0.529, 0.397-0.706, P = 0.0000164 and 0.919, 0.733-1.153, P = 0.47, respectively).
  
  
  CONCLUSIONS
  The present study shows that the PPARγ2 Ala12 variant is significantly associated with a reduced risk of albuminuria among patients with type 2 diabetes.
authors.affiliation: Department of Cardiovascular, Endocrine and Metabolic Diseases, IRCCS Casa Sollievo della Sofferenza,San Giovanni Rotondo, Italy. sdecosm@tin.it
authors.forename: Salvatore
authors.initials: S
authors.lastname: De Cosmo
authors.forename: Sabrina
authors.initials: S
authors.lastname: Prudente
authors.forename: Olga
authors.initials: O
authors.lastname: Lamacchia
authors.forename: Emanuela
authors.initials: E
authors.lastname: Lapice
authors.forename: Eleonora
authors.initials: E
authors.lastname: Morini
authors.forename: Rosa
authors.initials: R
authors.lastname: Di Paola
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Copetti
authors.forename: Piero
authors.initials: P
authors.lastname: Ruggenenti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Remuzzi
authors.forename: Olga
authors.initials: O
authors.lastname: Vaccaro
authors.forename: Mauro
authors.initials: M
authors.lastname: Cignarelli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Trischitta
mesh_terms: D000419:Albuminuria / Q000150:complications / Q000235:genetics*; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000235:genetics*; D006801:Humans; D047495:PPAR gamma / Q000235:genetics*; D011110:Polymorphism, Genetic
chemical_list: D047495:PPAR gamma