An analysis of peroxisome proliferator-activated receptor gamma (PPAR-g2) Pro12Ala polymorphism distribution and prevalence of type 2 diabetes mellitus (T2DM) in world populations in relation to dietary habits R. Scacchi a, *, A. Pinto b , O. Rickards c , A. Pacella b , G.F. De Stefano c , C. Cannella b , R.M. Corbo a,d a CNR Institute of Molecular Biology and Pathology, Rome, Italy b Institute of Food Science and Nutrition, University ‘‘La Sapienza’’, Rome, Italy c Department of Biology, University ‘‘Tor Vergata’’, Rome, Italy d Department of Genetics and Molecular Biology, University ‘‘La Sapienza’’, Rome, Italy Received 12 September 2006; received in revised form 23 November 2006; accepted 11 December 2006 KEYWORDS DNA polymorphisms; Peroxisome proliferator-activated receptor gamma; PPAR-g; Ethiopia; Benin; Ecuador; Sardinia Abstract Background and aim: The human peroxisome proliferator-activated receptor gamma (PPAR-g) is involved in lipid storage, glucose homeostasis and adipocyte differentiation. The Ala allele of the Pro12Ala polymorphism has been associated with a protective effect against T2DM. Ala allele frequencies are known for many populations, but data are absent for other interesting human groups. Methods and results: We examined samples from Ethiopia, Benin, Ecuador and Italy. In addition, we performed an analysis of the Pro12Ala polymorphism distribu- tion in world populations, also in relation to T2DM prevalence and the diet lipid content. In the European populations, the Ala allele frequencies are distributed according to a latitudinal trend, with the highest in the northern and central Euro- pean populations and the lowest in the Mediterranean populations. Considering the world populations, a significant inverse relationship between Ala frequency and T2DM prevalence was observed mainly in populations where energy from lipids exceeded 30% of the total energy intake. * Corresponding author. CNR Institute of Molecular Biology and Pathology, C/o Department of Genetics and Molecular Biology, University ‘‘La Sapienza’’, P.le Aldo Moro 5, 00185, Rome, Italy. Fax: þ39 6 4456866. E-mail address: renato.scacchi@uniroma1.it (R. Scacchi). 0939-4753/$ - see front matter ª 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.numecd.2006.12.007 Nutrition, Metabolism & Cardiovascular Diseases (2007) 17, 632e641 www.elsevier.com/locate/nmcd