Prevalence and prevention of chronic conditions in different populations and settings

Life expectancy has been rising globally. Disease patterns and risk factors are converging between world regions. The most prevalent non-communicable diseases in the world are chronic conditions. In addition, globally common infectious diseases can be chronic or have chronic forms. The three studies in this dissertation assessed the prevalence and prevention of chronic conditions in different populations and settings. Study 1 assessed a broad range of chronic conditions and estimated a high prevalence of multimorbidity among middle-aged and elderly people living in Dar es Salaam, Tanzania. We estimated the prevalence of multimorbidity and underlying chronic conditions by sex and age and show varying causes of multimorbidity. Study 2 assessed the usage and cost of a web portal for prevention and health promotion in the Berlin-Brandenburg region of Germany. Web portal usage peaked before the middle of its 6.5-year life cycle. The web portal would have had to cause a health improvement of approximately one quality-adjusted life year among its users to be considered a cost-effective health intervention. Study 3 synthesized the available evidence on the additional benefits of using motivational interviewing in brief interventions aiming to reduce risky alcohol consumption in young people. We studied randomized controlled trials of brief interventions targeting young people after admission to emergency care. In a meta-analysis, motivational interviewing was at least as effective as or more effective than other brief interventions in reducing the drinking frequency and quantity. The studies in this dissertation provide new insights into local care needs for chronic conditions, the usage and cost of digital prevention and health promotion, and the effectiveness of motivational interviewing in alcohol prevention among young people.