Trends in gastro-oesophageal reflux in a Norwegian general population: the Tromsø Study 1979-2016.

Background: The prevalence of overweight and smoking has changed over time. However, whether the changes in the risk factors are reflected in the prevalence of gastro-oesophageal reflux disease (GORD) is unknown. The aims of this study were to assess the changes in prevalence of GORD and the associated risk factors over time in a general population.

Methods: This was a population-based study using repeated surveys of the Tromsø Study: Tromsø2 (1979-1980,  = 14,279), Tromsø6 (2007-2008,  = 11,460) and Tromsø7 (2015-2016,  = 20,664). Complaints of heartburn and acid regurgitation and common risk factors were reported, and height and weight were measured. The prevalence of GORD was calculated and the association with risk factors was assessed at each time point by odds ratios (OR) and 95% confidence intervals (CI) using multivariable logistic regression.

Results: The prevalence of GORD was 13% in 1979-1980, 6% in 2007-2008 and 11% in 2015-2016. In all three surveys, the risk of GORD was consistently increased with overweight and smoking. However, overweight was a weaker risk factor in the first (OR 1.58, 95% CI 1.42-1.76) compared to the last (OR 2.16, 95% CI 1.94-2.41) survey. Smoking was a stronger risk factor in the first (OR 1.45, 95% CI 1.31-1.60) than at the last (OR 1.14, 95% CI 1.01-2.29) survey.

Conclusion: During four decades of follow-up of the same population, no clear change in prevalence of GORD was found. GORD was clearly and consistently associated with overweight and smoking. However, overweight has become a more important risk factor than smoking over time.