Gastrointestinal symptoms and bowel habits in 53 046 healthy Danish blood donors: a nationwide cross-sectional study.

Abstract

Objective: To characterise gastrointestinal symptoms and bowel habits in healthy blood donors and explore symptom phenotypes and their associated factors.

Methods: Between November 2020 and March 2023, 53 046 participants in the nationwide Danish Blood Donor Study completed a questionnaire including 13 gastrointestinal symptoms, defaecation pattern regularity, stool frequency, and stool consistency. We used a data-driven approach to explore symptom phenotypes and investigated associated factors by multinomial logistic regression.

Results: Among the 53 046 participants (52% women), 68% (95% CI 67.5% to 68.3%) reported at least one of 13 gastrointestinal symptoms. The most frequent symptoms were bloating (40%), abdominal rumbling (40%), abdominal pain (17%), acid regurgitation (13%), heartburn (12%), diarrhoea (12%), nausea (12%), and constipation (10%). Half of the participants (50%) had a regular defaecation pattern (defined as generally the same stool consistency and stool frequency) consisting of Bristol Stool Form Scale 4 stools 1-3 times per day. Symptom phenotypes and their prevalence among 51 820 near-complete case participants were as follows: (1) no gastrointestinal symptoms (32%); (2) bloating and/or rumbling only (21%); (3) acid regurgitation and/or heartburn only (4%); (4) any other one or two symptoms (14%); (5) any three or four symptoms (18%); (6) any five or six symptoms (7%); (7) at least seven symptoms (3%). The acid regurgitation and/or heartburn only phenotype associated with obesity, and the remaining symptomatic phenotypes were associated with female sex, decreasing age, and an irregular defaecation pattern, even after excluding individuals with self-reported irritable bowel syndrome, lactose intolerance, or gluten intolerance.

Conclusion: Most healthy adults, especially women younger than 50 years, experience gastrointestinal symptoms. Symptom phenotypes strongly correlate with sex, age, and bowel habits.