EPIDEMIOLOGY OF HELICOBACTER-PYLORI INFECTION AMONG 4742 RANDOMLY SELECTED SUBJECTS FROM NORTHERN-IRELAND

Background. Despite the widespread prevalence and serious clinical seq uelae of infection with Helicobacter pylori, there have been few large population-based studies, using randomly selected subjects, examining the epidemiology of this infection. Aim. To examine the distribution and determinants of H. pylon infection in a developed country. Subject s and Setting. Overall 4742 subjects, aged 12-64, from Northern irelan d were randomly selected. Methods. Helicobacter pylori specific IgG an tibodies were measured by enzyme linked immunosorbent assay, using an acid-glycine extract antigen, in stored serum from subjects who had pa rticipated in three linked population-based surveys of cardiovascular risk factors performed in 1986 and 1987. Results. The overall prevalen ce of H. pylori infection was 50.5%. Prevalence increased with age fro m 23.4% in 12-14 year olds to 72.7% in 60-64 year olds: chi(2) for tre nd 518, P < 10(-4). In subjects aged greater than or equal to 25, infe ction was more common in males (60.9%) than females (55.2%):;chi(2) = 9.53, P < 0.01. This relation remained significant after adjusting for age, and measures of socioeconomic class: odds ratio (OR) for infecti on, male versus female was 1.19 (95% confidence interval [CI] : 1.02-1 .40). infection was associated with social class: the adjusted OR of i nfection in subjects from manual social classes relative to those from non-manual classes was 1.7 (95% Ci : 1.47-1.98). Infection was signif icantly more common in current smokers and ex-smokers than in subjects who had never smoked: adjusted OR for infection, ex-smokers versus ne ver smoked was 1.22 (95% CI : 1.01-1.49); for smokers of greater than or equal to 20/day versus never smoked OR = 1.33 (95% CI:1.05-1.67). I nfection was not associated with height in adult males but mean height in infected women was lower than in uninfected women after adjusting for age and socioeconomic status: difference in mean height (SE), -0.8 5 cm (0.32), P < 0.01. There was no demonstrable relationship between H. pylori infection and current alcohol intake. Conclusions. This stud y demonstrated a high prevalence of infection in a population from a d eveloped country. Previously reported associations between H. pylori i nfection, age, sex, social class, and reduced height in females were c onfirmed and smoking was identified asa possible risk factor for H. py lori infection.