title: Strong evidence of sexual dimorphic effect of adiposity excess on insulin sensitivity.
abstract: OBJECTIVE
  Our aims were to investigate in several large samples, with a wide range of adiposity, whether: (1) the effect of BMI on insulin sensitivity is different between sexes; (2) also waist circumference plays a sex-specific role on insulin sensitivity; and (3) serum adiponectin and resistin are mediators of such sex-dimorphic effect.
  
  
  METHODS
  Samples used were: Gargano study 1 (GS1), GS2 and Catania study (CS) comprising 3274 individuals. Adiponectin and resistin were measured by ELISA. Associations between variables were tested by linear models.
  
  
  RESULTS
  In all samples, relationship between BMI and HOMAIR was steeper in males than in females (BMI-by-sex interaction p = 0.04-0.0007). No interaction was observed on serum adiponectin and resistin (p = 0.40-059), which are therefore unlikely to mediate the sex-dimorphic effect of BMI on insulin resistance. Relationship between waist circumference and HOMAIR was similar between sexes in GS1 and GS2 but not in CS (waist-by-sex interaction p = 0.01), comprising much heavier individuals. This suggests that a sex-dimorphic effect of abdominal adiposity on insulin resistance is observable only in the context of high BMI.
  
  
  CONCLUSIONS
  Our findings represent a proof of concept that BMI and insulin sensitivity are associated in a sex-specific manner. This may explain why females are protected from diabetes and cardiovascular disease, compared to males of similar BMI.
authors: Research Unit of Diabetes and Endocrine Diseases, Poliambulatorio Giovanni Paolo II, IRCCS "Casa Sollievo della Sofferenza", Viale Padre Pio, 71013, San Giovanni Rotondo, Italy. a.marucci@operapadrepio.it.
authors: Antonella
authors: A
authors: Marucci
authors: Research Unit of Diabetes and Endocrine Diseases, Poliambulatorio Giovanni Paolo II, IRCCS "Casa Sollievo della Sofferenza", Viale Padre Pio, 71013, San Giovanni Rotondo, Italy.
authors: Claudia
authors: C
authors: Menzaghi
authors: Unit of Biostatistics, IRCCS "Casa Sollievo della Sofferenza", San Giovanni Rotondo, Italy.
authors: Massimilano
authors: M
authors: Copetti
authors: Endocrine Unit, Department of Clinical and Molecular Biomedicine, University of Catania, Catania, Italy.
authors: Federica
authors: F
authors: Vinciguerra
authors: Endocrine Unit, Department of Clinical and Molecular Biomedicine, University of Catania, Catania, Italy.
authors: Roberto
authors: R
authors: Baratta
authors: Research Unit of Diabetes and Endocrine Diseases, Poliambulatorio Giovanni Paolo II, IRCCS "Casa Sollievo della Sofferenza", Viale Padre Pio, 71013, San Giovanni Rotondo, Italy.
authors: Lucia
authors: L
authors: Salvemini
authors: Research Unit of Diabetes and Endocrine Diseases, Poliambulatorio Giovanni Paolo II, IRCCS "Casa Sollievo della Sofferenza", Viale Padre Pio, 71013, San Giovanni Rotondo, Italy.
authors: Eleonora
authors: E
authors: Morini
authors: Endocrine Unit, Department of Clinical and Molecular Biomedicine, University of Catania, Catania, Italy.
authors: Lucia
authors: L
authors: Frittitta
authors: Research Unit of Diabetes and Endocrine Diseases, Poliambulatorio Giovanni Paolo II, IRCCS "Casa Sollievo della Sofferenza", Viale Padre Pio, 71013, San Giovanni Rotondo, Italy. r.dipaola@operapadrepio.it.
authors: Rosa
authors: R
authors: Di Paola
authors: Research Unit of Diabetes and Endocrine Diseases, Poliambulatorio Giovanni Paolo II, IRCCS "Casa Sollievo della Sofferenza", Viale Padre Pio, 71013, San Giovanni Rotondo, Italy. v.trischitta@operapadrepio.it.|Department of Experimental Medicine, "Sapienza" University, Rome, Italy. v.trischitta@operapadrepio.it.
authors: Vincenzo
authors: V
authors: Trischitta
mesh_terms: D050153:Abdominal Fat; D052242:Adiponectin / Q000097:blood; D050154:Adiposity; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D007558:Italy; D008297:Male; D008875:Middle Aged; D050177:Overweight / Q000503:physiopathology*; D052243:Resistin / Q000097:blood; D012727:Sex Characteristics; D055105:Waist Circumference
chemical_list: C499918:ADIPOQ protein, human; D052242:Adiponectin; C499624:RETN protein, human; D052243:Resistin
keywords: BMI; Insulin resistance; Sexual dimorphism