Several patients with irritable bowel syndrome (IBS) do not seek medical attention for their symptoms. When patients with IBS seek help, the majority of them are handled at primary healthcare centers, whereas research studies are performed at tertiary healthcare centers. The present study aimed to summarize findings from >4,000 participants of the general population included in the Malmö Offspring Study (inclusion rate 46.7%). The participants were clinically examined, their blood and fecal samples collected, and their questionnaires completed. The participants were divided into subjects with or without self‑reported IBS and those having functional gastrointestinal (GI) symptoms in the past 2 weeks. The presence of IBS and GI symptoms in the participants were associated with each other. Zonulin levels did not differ between participants with or without GI diseases and were not associated with the degree of GI symptoms. The parameters low body weight at birth and small for gestational age were associated with the degree of the symptoms' influence on daily life. IBS and GI symptoms were positively associated with Blautia abundance. Beta‑diversity differed between participants with or without these two conditions. Positive correlations were noted between the degree of diarrhea and the mean 24‑h measurements of systolic blood pressure, diastolic blood pressure, and heart rate. Both IBS and GI symptoms were associated with female sex, smoking, stress, poor sleeping habits, unemployment, drug use, and a family history of GI diseases, whereas younger age was inversely associated with IBS and its associated symptoms. In conclusion, only a limited number of medical findings could be identified in participants with IBS and GI symptoms, whereas sociodemographic and environmental conditions were associated with these entities.
Keywords: concomitant diseases; early life factors; gastrointestinal symptoms; irritable bowel syndrome; lifestyle habits; microbiota; population‑based; sociodemography.