S1612 High Seroprevalence of Helicobacter pylori and CagA/VacA Virulence Factors in Northern Central America

Abstract

Introduction: Helicobacter pylori (Hp) infection is the leading cause of gastric cancer (GC). Northern Central America is the principal LMIC region in the Western Hemisphere and has among the highest GC incidence. We examined the Hp seroprevalence and active infection, and the Hp virulence factors VacA/CagA positivity of healthy individuals in the region using a novel validated Hp assay. Methods: Healthy volunteers from Western Honduras and Central Guatemala were recruited. The novel Hp Multiplex assay was used to evaluate 13 Hp antigens (CagA, VacA, GroEl, UreA, HP0231, HP0305, NapA, HpaA, HcpC, HP1564, Catalase, Cad, HyuA). Per protocol, Hp positivity was defined as positivity for ≥4 antigens, and active infection was defined as positivity to a combination of 2 out of the 4 antigens (VacA, GroEl, HcpC, HP1564). Descriptive statistics for continuous variables and frequencies for categorical variables were computed. Categorical variables were compared using Chi2. Results: Overall, 1,143 adults were tested with the multiplex assay (Guatemala n=444, Honduras=699). The mean age was 54.2±14.5 years, 46.2% were male, 60% of individuals were from rural settings and 56% lived above >1000 meters. Hp seropositivity was 87%, and 83% had active Hp infection. CagA and VacA seropositivity was 82% and 75% respectively. No significant differences were noted according to country, age group, gender, or rural/urban location. The most frequent occupations were domestic work and agriculture (40% and 19% respectively). Around half (53%) of individuals had a refrigerator, and 34% had an electric or gas stove. 44% and 16% were either current or former tobacco smokers in Guatemala and Honduras, respectively. 43% noted alcohol use (Table). Conclusion: An extremely high seroprevalence of Hp and CagA/VacA is observed in Honduras and Guatemala and is representative of Northern Central America. This correlates with the high burden of GC in the region, and has implications for regional prevention programs as well as immigrant populations in the U.S. Table 1. - General characteristics of population (N=1,143) Total Guatemala Honduras N 1143 444 699 Age, mean (SD) 54.2 (14.5) 55.4 (10.7) 53.4 (16.5) Age, categories 18-45 309 (27.0%) 90 (20.3%) 219 (31.3%) 45-54 297 (26.0%) 138 (31.1%) 159 (22.7%) 55-64 269 (23.5%) 122 (27.5%) 147 (21.0%) >65 268 (23.4%) 94 (21.2%) 174 (24.9%) Sex Female 615 (53.8%) 255 (57.4%) 360 (51.5%) Male 528 (46.2%) 189 (42.6%) 339 (48.5%) Rural setting 683 (59.8%) 272 (61.3%) 411 (58.8%) Altitude (mamsl), mean (SD) 1087.9 (453.7) 1250.8 (644.6) 983.4 (209.2) Altitude ( >1000mamsl) 641 (56.4%) 272 (61.3%) 369 (53.3%) Occupation Professional 38 (3.3%) 9 (2.0%) 29 (4.1%) Technician 39 (3.4%) 2 (0.5%) 37 (5.3%) Artisan or vendor 239 (20.9%) 182 (41.0%) 57 (8.2%) Construction 44 (3.8%) 21 (4.7%) 23 (3.3%) Agriculture 221 (19.3%) 54 (12.2%) 167 (23.9%) Household/domestic work 457 (40.0%) 144 (32.4%) 313 (44.8%) Other or not available 105 (9.2%) 32 (7.2%) 73 (10.4%) BMI, median (IQR) 25.7 (22.7, 29.7) 27.4 (23.9, 30.7) 24.8 (21.9, 28.7) BMI, categories Underweight 36 (3.2%) 5 (1.1%) 31 (4.5%) Normal 471 (41.9%) 148 (33.6%) 323 (47.3%) Overweight 352 (31.3%) 155 (35.2%) 197 (28.8%) Obese 264 (23.5%) 132 (30.0%) 132 (19.3%) Tobacco smoker 310 (27.1%) 196 (44.1%) 114 (16.3%) Recent antibiotic use 78 (6.8%) 55 (12.4%) 23 (3.3%) Refrigerator use 608 (53.2%) 200 (45.0%) 408 (58.4%) Alcohol 488 (42.7%) 321 (72.3%) 167 (23.9%) Electric or gas stove 387 (33.9%) 265 (59.7%) 122 (17.5%) H. pylori serostatus (positive) 993 (86.9%) 387 (87.2%) 606 (86.7%) H. pylori active infection 949 (83.0%) 378 (85.1%) 571 (81.7%) CagA status (positive) 941 (82.4%) 402 (90.7%) 539 (77.1%) VacA status (positive) 861 (75.4%) 368 (83.1%) 493 (70.5%)