This study strengthens the case for a causal relationship between smoking and coeliac disease by demonstrating a strong, temporally appropriate and dose-dependent effect, thus meeting the Bradford Hill criteria. This suggests that cigarette smoking truly protects against the development of adult coeliac disease.

The submerged component of the 'coeliac iceberg' may be diminishing due to increasing case ascertainment, with a projected ratio of undiagnosed to diagnosed cases as low as 1.5:1. Our identification of clustering must be interpreted with caution, but suggests that an additional environmental factor may influence the pathogenesis of CD.

ObjectiveTo report our cumulative experience from a dedicated iron deficiency anaemia (IDA) clinic over the last 15 years—with particular emphasis on referral rate, uptake of investigation, impact on endoscopy services, diagnostic yield of gastrointestinal (GI) investigation and the issue of recurrent IDA.MethodA series of analyses of a register of 2808 referrals to the Poole IDA clinic between 2004 and 2018.ResultsThe study population of 2808 had a sex ratio of 1.9 (female/male ratio) and a median age of 72 years (IQR: 60–79). A rising referral rate over the study period appears to be plateauing at around 2 cases per 1000 population per annum. On the basis of a snapshot audit, investigation of IDA may now account for over 20% of all diagnostic endoscopies.Overall, 86% of cases underwent examination of the upper and lower GI tract. Significant GI pathology was identified in 27% of the investigated cohort. Adenocarcinoma of the upper or lower GI tract was found in 8.3%, the majority in the right colon. The prevalence of recurrent IDA was estimated at 12.4%, and the results of investigation of this subgroup are reported.ConclusionUnexplained IDA is common, particularly in those over 60 years, and may be the first indication of underlying GI malignancy in over 8% of cases. Unresolved challenges include accommodating the resulting endoscopy workload, establishing a risk/benefit ratio for investigating those with major comorbidities and the management of recurrent IDA.