Associations Between Hiccups and Subsequent Cancer Diagnoses: A Population‐Based Cohort Study

Background Several case reports have recounted hiccups as a possible symptom of cancer, but potential associations in large study samples have not been examined. Methods This population‐based cohort study examined associations between hiccups and subsequent cancer diagnoses. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated. Results Of 8466 patients diagnosed with hiccups during the study period (1997–2018), 7531 (89.0%) were men, 4013 (47.4%) were diagnosed in primary healthcare, and 325 (3.8%) were diagnosed with cancer. In men, hiccups were associated with nervous system (SIR 1.94; 95% CI, 1.08–3.20), hematologic (1.52; 1.17–1.93), and gastrointestinal (1.61; 1.36–1.89) cancers, including esophageal (2.63; 1.47–4.43), stomach (2.27; 1.42–3.45), colon (1.61; 1.23–2.08), and liver (1.77; 1.05–2.80) cancers. In women, hiccups were associated with gastrointestinal cancer (2.23; 1.27–3.63). Particularly strong associations were observed within 12 months of follow‐up. Conclusion These findings may be useful for clinical practice and could provide foundations for detailed clinical studies on hiccups as a potential clinical cancer marker.