Genetic and life-style determinants of peptic ulcer - A study of 3387 men aged 54 to 74 years: The Copenhagen Male Study

Background: In the Copenhagen Male Study men with the Lewis blood group phe notype Le(a+b-), non-secretors of ABH antigen, and men with the O or the A phenotype in the ABO blood group have been found to have a significantly hi gher lifetime prevalence of peptic ulcer than others. We investigated the i mportance of the association of these genetic markers, life-style factors, and social class with lifetime risk of peptic ulcer, testing specifically t he hypothesis that the strength of the association of risk factors with pep tic ulcer depends on genetic susceptibility. Methods: Three thousand three hundred and forty-six white men 55-74 years old were included for study. Fr om a questionnaire validated during an interview information was obtained a bout life-style factors and peptic ulcer history (gastric or duodenal). Pot ential non-genetic risk factors examined were smoking history, alcohol cons umption, physical activity level, consumption of tea and coffee, and use of sugar in tea or coffee. Results: Three hundred and eighty-four men (11.5%) had a history of peptic ulcer; 120 (3.6%) had had an operation due to pept ic ulcer. Nongenetic peptic ulcer risk factors identified were ever having been a smoker, use of sugar in tea or coffee, abstention from tea consumpti on, and low social class. On the basis of these and the genetic factors, it was possible to identify a low-risk group (n = 142) with a lifetime preval ence of 4.2 %, several intermediate-risk groups, and a high-risk group (n = 55) with a prevalence of 29 %; the odds ratio with 95 % confidence limits (OR! was 9.3 (3.4-25.3). Corresponding values with regard to operation were 1.4 % and 20.0 %; OR = 17.5 (3.7-82.0). Several significant interactions w ere found; for example, the use of sugar was associated with peptic ulcer r isk only when interacting with genetic risk groups. Conclusions: Considerin g the role of Helicobacter pylori, it is interesting that the factors ident ified in this study were able to identify groups with extremely different l ifetime risks. This finding and also the finding of strong interactions bet ween genetic and life-style factors and between genetic factors and social class for the risk of peptic ulcer may have both public-health and clinical implications.