Is there a link between the variation in gastric cancer mortality and differences in Helicobacter pylori prevalence in different regions of France?

An ecological study was performed to correlate the cumulative gastric cancer mortality rate to the prevalence of Helicobacter pylori infection in France. National data on mortality, standardized for age and gender, and the results of a nationwide prevalence study on Helicobacter pylori infection among 1,586 patients consulting for symptoms other than upper digestive tract symptoms, in seven defined French regions were used. The correlation was described by linear regression with the standardized data and then evaluated in a linear regression model including age and gender as co-variables. The Southwest region was the least affected by the infection (15.2%) while prevalence varied from 20.5 to 25.3% for the other regions. The cumulative gastric cancer mortality rate varied from 34.4 to 51.8/100,000. The prevalence of Helicobacter pylori infection in the model explained 5% of the variability in the gastric cancer mortality. A number of biases which were difficult to control could explain the lack of association between these variables.