28 Gut and Liver, Vol. 6, No. 1, January 2012 59. Kersulyte D, Kalia A, Gilman RH, et al. Helicobacter pylori from Peruvian amerindians: traces of human migrations in strains from remote Amazon, and genome sequence of an Amerind strain. PLoS One 2010;5:e15076. 60. Mane SP, Dominguez-Bello MG, Blaser MJ, et al. Host-interactive genes in Amerindian Helicobacter pylori diverge from their Old World homologs and mediate inflammatory responses. J Bacteriol 2010;192:3078-3092. 61. Suzuki M, Kiga K, Kersulyte D, et al. Attenuated CagA oncoprotein in Helicobacter pylori from Amerindians in Peruvian Amazon. J Biol Chem 2011;286:29964-29972. 62. Bravo LE, van Doom LJ, Realpe JL, Correa P. Virulence-associated genotypes of Helicobacter pylori : do they explain the African enigma? Am J Gastroenterol 2002;97:2839-2842. 63. de Sablet T, Piazuelo MB, Shaffer CL, et al. Phylogeographic origin of Helicobacter pylori is a determinant of gastric cancer risk. Gut 2011;60:1189-1195. 64. Howlader N, Noone AM, Krapcho M, et al. Surveillasnce Epidemi- ology and End Results (SEER) Cancer Statistics Review, 1975-2008 [Internet]. Bethesda: National Cancer Institute; 2011 [cited 2011 Nov 22]. Available from: http://seer.cancer.gov/csr/1975_2008/. 65. Epplein M, Signorello LB, Zheng W, et al. Race, African ancestry, and Helicobacter pylori infection in a low-income United States population. Cancer Epidemiol Biomarkers Prev 2011;20:826-834. 66. Sonnenberg A. Differences in the birth-cohort patterns of gastric cancer and peptic ulcer. Gut 2010;59:736-743. 67. Sonnenberg A. Time trends of mortality from gastric cancer in Europe. Dig Dis Sci 2011;56:1112-1118. 68. Aragonés N, Pollán M, López-Abente G, et al. Time trend and age- period-cohort effects on gastric cancer incidence in Zaragoza and Navarre, Spain. J Epidemiol Community Health 1997;51:412-417. 69. Anderson WF, Camargo MC, Fraumeni JF Jr, Correa P, Rosenberg PS, Rabkin CS. Age-specific trends in incidence of noncardia gas- tric cancer in US adults. Jama 2010;303:1723-1728. 70. Strachan DP. Hay fever, hygiene, and household size. BMJ 1989;299:1259-1260. 71. Arnold IC, Dehzad N, Reuter S, et al. Helicobacter pylori infection prevents allergic asthma in mouse models through the induction of regulatory T cells. J Clin Invest 2011;121:3088-3093.