A recent study published in Nature Aging has reframed the epidemiological transition by using global health data to classify diseases according to how their burden changes across different stages of life. The findings highlight how rising life expectancy and population aging are shifting the global disease burden toward conditions that become more common in later life.

Between 1973 and 2023, global life expectancy at birth increased from approximately 58 to more than 73 years, representing an average gain of about three years per decade. While progress varied between countries, the overall trend was widespread. By 2023, 42 countries had life expectancies above 80 years, compared with none in 1973. Declining fertility combined with longer lifespans is also rapidly changing the global age structure.

As populations age, the global burden of disease is increasingly shifting from infectious conditions toward chronic and degenerative diseases. The proportion of chronic diseases in the global disease burden rose from 42% in 1990 to 64% in 2023. However, longer lives have not necessarily translated into proportionally longer periods of good health, with people in many regions spending more years living with illness or disability.

Researchers analyzed Global Burden of Disease data covering 304 diseases and injuries across 204 countries between 1990 and 2023. Using age-specific disability-adjusted life years (DALYs), they grouped diseases according to similarities in how their burden changes across the life course. Four broad clusters emerged: infant, early-adult, late-adult, and aging-related diseases.

Aging-related conditions—including cardiovascular and kidney diseases, type 2 diabetes, certain cancers, Parkinson’s disease, and dementia—accounted for the largest current share of the global disease burden. From 1990 to 2023, the proportion of global disease burden associated with infant diseases fell from more than half to below one-third, while the share linked to aging-related diseases increased from around one-quarter to more than 40%.

This transition was particularly evident in middle- and lower-income countries, where disease patterns increasingly began to resemble those of higher-income regions. As life expectancy continues to rise and demographic differences narrow, low- and lower-middle-income countries are expected to experience some of the fastest increases in aging-related disease burden.

The study also modeled hypothetical scenarios in which the prevalence of different disease clusters was reduced by 25%, 50%, or 100%. These scenarios were intended to illustrate potential population-health effects rather than serve as realistic forecasts. In the extreme scenario of completely eliminating aging-related diseases, global life expectancy was estimated to increase by approximately 17.4 years, compared with gains of 3.3 years from eliminating infant diseases, 0.8 years from early-adult diseases, and 1.2 years from late-adult diseases.

The researchers noted that aging-related diseases are especially important because they affect a rapidly growing older population and often occur alongside multiple other health conditions. The models also suggested that reducing these diseases could produce increasingly greater benefits as prevention becomes more effective.

Overall, the findings underscore the growing importance of preventing and delaying age-related diseases throughout the life course, rather than focusing solely on treating individual conditions after they emerge. Prioritizing healthy aging could help extend healthspan, reduce years lived with disability, and address the growing global burden of disease associated with longer lifespans.

Source: https://www.news-medical.net/news/20260903/As-life-expectancy-rises-healthy-aging-is-more-important-than-ever.aspx