Cohort study of corticosteroid use and risk of hospital admission for diverticular disease.

Medication has been suggested as a potential risk factor for diverticular disease. The objective of this study was to investigate the association between the intake of corticosteroids, indometacin or aspirin and diverticular disease. This was a prospective population-based cohort study of middle-aged women in the Swedish Mammography Cohort. Use of corticosteroids (oral or inhaled), indometacin or aspirin in 1997 was determined from questionnaires. Cases of diverticular disease were identified from the Swedish national registers until the end of 2010. The relative risk (RR) of diverticular disease requiring hospital admission according to the use of medication was estimated using Cox proportional hazards models, adjusted for age, body mass index, physical activity, fibre intake, diabetes, hypertension, alcohol, smoking and education. A total of 36 586 middle-aged women in the Swedish Mammography Cohort were included, of whom 674 (1.8 per cent) were hospitalized with diverticular disease at least once. Some 7.2 per cent of women reported intake of oral corticosteroids and 8.5 per cent use of inhaled corticosteroids. In multivariable analysis, women who reported oral corticosteroid intake had a 37 per cent (RR 1.37, 95 per cent c.i. 1.06 to 1.78; P = 0.012) increased risk of diverticular disease compared with those who reported no intake at all. Use of inhaled corticosteroids was associated with an even more pronounced increase in risk of 71 per cent (RR 1.71, 1.36 to 2.14; P < 0.001). There was a significant dose-response relationship, with the risk increasing with longer duration of inhaled corticosteroids (P for trend < 0.001). Use of indometacin (2.5 per cent of women) or aspirin (44.2 per cent) did not influence the risk. There was a significant relationship between corticosteroids (especially inhaled) and diverticular disease requiring hospital admission.