Physical multimorbidity and incident urinary incontinence among community-dwelling adults aged ≥50 years: findings from a prospective analysis of the Irish Longitudinal Study on Ageing

Background: There are no prospective studies on the association between multimorbidity and urinary incontinence (UI), while mediators in this association are unknown. Thus, we aimed to (i) investigate the longitudinal association between multimorbidity and UI in a large sample of Irish adults aged ≥50 years and (ii) investigate to what extent physical activity, polypharmacy, cognitive function, sleep problems, handgrip strength and disability mediate the association. Methods: Data on 5,946 adults aged ≥50 years old from the Irish Longitudinal Study on Aging were analysed. The baseline survey was conducted between 2009 and 2011 and follow-up after 2 years was conducted. Information on self-reported occurrence of UI in the past 12 months and lifetime diagnosis of 14 chronic conditions were obtained. Multivariable logistic regression and mediation analysis were conducted. Results: After adjustment for potential confounders, compared to having no chronic conditions at baseline, having three (odds ratio [OR] = 1.79; 95% confidence interval [CI] = 1.30–2.48) and four or more (OR = 1.86; 95% CI = 1.32–2.60), chronic conditions were significantly associated with incident UI. Mediation analysis showed that polypharmacy, sleep problems and disability explained 22.7, 17.8 and 14.7% of the association between multimorbidity (i.e. two or more chronic conditions) and incident UI, respectively. Conclusion: A greater number of chronic conditions at baseline were associated with a higher risk for incident UI at 2-year follow-up among adults aged ≥50 years in Ireland. Considering the effects of different medications on UI and improving sleep quality and disability among people aged ≥50 years with multimorbidity may reduce the incidence of UI.