SUMMARYAim: To measure the prevalence of gastro-oesophageal reflux symptoms and to identify associated factors in a representative sample of the Spanish population. Methods: A telephone survey of 2500 subjects was performed using a validated questionnaire. The association of gastro-oesophageal reflux symptoms (defined as the presence of heartburn or acid regurgitation) and their clinical characteristics with potential risk factors was summarized using the odds ratios (OR) obtained by multiple logistic regression. Results: The response rate was 71.2%. The annual prevalence of gastro-oesophageal reflux symptoms was 31.6% [95% confidence interval (CI), 29.8-33.4] and the weekly prevalence was 9.8% (95% CI, 8.6-10.9) 2 . Gastro-oesophageal reflux symptoms were associated with excess weight (OR, 1.53; 95% CI, 1.23-1.92), obesity (OR, 1.74; 95% CI, 1.30-2.32), the psychosomatic symptom score (OR, 2.98; 95% CI, 2.41-3.67) and the presence of gastro-oesophageal reflux symptoms in a direct family member (OR, 1.61; 95% CI, 1.17-2.23). Gastro-oesophageal reflux symptoms of ‡ 10 years' duration were more frequent in obese subjects (OR, 1.92; 95% CI, 1.14-3.22) and those with a direct family member with gastro-oesophageal reflux symptoms (OR, 2.42; 95% CI, 1.44-4.06). Factors associated with gastro-oesophageal reflux symptoms of £ 1 year duration were a spouse with gastro-oesophageal reflux symptoms (OR, 2.33; 95% CI, 1.39-3.9) and the consumption of 1-5 aspirins/week (OR, 1.70; 95% CI, 1.01-2.86). Conclusions:The prevalence of frequent gastrooesophageal reflux symptoms in Spain is lower than that observed in other Western populations. The psychosomatic symptom score is the factor most strongly associated with gastro-oesophageal reflux symptoms. Long-term gastro-oesophageal reflux symptoms are associated with certain genetic factors (obesity, family history of gastro-oesophageal reflux symptoms), whereas shortterm gastro-oesophageal reflux symptoms are associated with factors of probable environmental nature.

Impaired drug metabolism is a major cause of adverse drug reactions, and it is often caused by mutations at genes coding for drug-metabolising enzymes. Two amino-acid polymorphisms of cytochrome P4502C9 (CYP2C9), an enzyme involved in the metabolism of several nonsteroidal antiinflammatory drugs (NSAIDs), were studied in 94 individuals with acute bleeding after NSAIDs use and 124 individuals receiving NSAIDs with no adverse effects. The frequency of CYP2C9 variant alleles was increased in overall bleeding patients, with a significant trend to higher risk with increasing number of variant alleles (P ¼ 0.02). The odds ratio for bleeding patients receiving CYP2C9 substrates (n ¼ 33) was 2.5 for heterozygous and 3.7 for homozygous carriers of mutations (Po0.015), suggesting that the inherited impairment of CYP2C9 activity increases the risk for severe adverse drug reactions after NSAIDs use.

The hypothesis postulating that Mycobacterium avium paratuberculosis (MAP) is the cause of Crohn's disease (CD) has been circulating for many years. Advances in molecular techniques, such as polymerase chain reaction and culture methods, have enabled researchers to demonstrate that there is an association between MAP and CD. Recently, genome-wide association studies have identified novel susceptibility genes for CD, which are critical for generation of an adaptive immune response that is protective against intracellular pathogens, including M. tuberculosis infection. However, the role of MAP as a cause of CD suffered a setback with the report that administration of antimycobacterial therapy failed to lead to a sustained response in CD patients. Accordingly, this review sought neither to confirm nor refute this, but instead to survey recent literature on the role of MAP in CD.

The prevalence of atypical GER symptoms is extremely high. There is an association between typical and atypical GER symptoms, particularly chest pain, dysphagia, dyspepsia, belching and globus.

SUMMARY BackgroundSeveral studies showed high prevalence of ineffective oesophageal motility (IOM) in gastro-oesophageal reflux disease (GERD) and suggested an important role for ineffective oesophageal motility in increased acid exposure. However, impedance-manometric studies proposed that only severe ineffective oesophageal motility might affect oesophageal clearance.