In recent years, most high-income societies have experienced an increase in the overall disease burden, particularly from chronic conditions. Researchers attribute this trend to population aging and growth rather than declining individual health, as evidence suggests that people are living longer with diseases and disabilities thanks to improved medical care and disease management. Yet the findings are primarily based on data from the United States. Do they hold in Asia?

To answer this question, a new study sheds light on the drivers of disease burden, measured by total disability-adjusted life years (DALYs), across five Asian economies – China, Japan, Singapore, South Korea, and Taiwan – from 2000 to 2019. The study, published in Health Policy, confirms that, across all five economies, population-level disease burden increased due to population aging, particularly for non-communicable diseases, despite improved individual health outcomes.

“While substantial reductions were observed in the burden of communicable, maternal, and neonatal conditions, nutritional deficiencies, and injuries, these improvements were outweighed by even greater increases in the burden of non-communicable diseases,” writes the research team, which includes Stanford health economist Karen Eggleston, the director of the Asia Health Policy Program (AHPP) at APARC. Eggleston’s co-authors are Sungchul Park, an associate professor in Korea University’s Department of Health Policy and Management; Jianchao Quan, a clinical specialist in public health medicine at the University of Hong Kong; and Cynthia Chen, an associate professor at the National University of Singapore’s School of Public Health and a former visiting scholar with AHPP.

Sign up for APARC newsletters to receive our scholars' research updates >

A Demographic Change Engine

The researchers chose to study the health systems in China, Japan, Singapore, South Korea, and Taiwan because all five are classified as upper-middle or high-income economies undergoing rapid population aging. They analyzed data from these five health systems between 2000 and 2019, measuring population-level disease burden as total DALYs – a measure combining morbidity, that is, years lived with disability, and mortality, namely, years of life lost to premature death.

They found that total DALYs increased across all five economies, and that population aging, defined as changes in age-sex structure and population size, was the driver of this rise in population-level disease burden. On average, population aging accounted for 33.6% of the total increase in DALYs across the region. In South Korea, where population aging is particularly rapid, this factor was responsible for 40.5% of the increase.

Population growth also played a significant role in increases in DALYs, contributing an average of 15.3% to the rising disease burden. In Singapore, where the population has expanded over the past two decades, growth accounted for 41.7% of the increase in DALYs.

The researchers observed the most notable increases in DALYs in non-communicable diseases (NCDs), such as cardiovascular diseases and cancers. China ranked at the top, with 58.4% rise in DALYs resulting from NCDs over the two-decade period, followed by 43.3% in Singapore, and 31.6% in Taiwan.

A Victory for Modern Medicine

The encouraging finding of the study is the substantial decrease in DALYs per disease case. This is a measure of the average number of healthy years lost due to premature death or disability per incident or case of a specific illness. The metric represents the total burden of disease on an individual.

Across the five Asian economies, DALYs per case fell by an average of 29.4%. This decline suggests that, even as more people are getting sick due to old age, the healthcare systems are becoming more effective at treating them, “highlighting the critical role of advancements in disease management and health care delivery,” Eggleston and her co-authors write.

The impact was most visible in the fight against NCDs. In this category, substantial reductions in DALYs per disease case were observed, with an average decrease of 32.1% for cardiovascular diseases and reductions ranging from 37% to over 80% per case for cancers. The researchers attribute these improvements to early detection, therapeutic interventions, and improved management of chronic disease. These benefits, in turn, are made possible through expanded access to screening programs, adherence to evidence-based clinical guidelines, and technological advancements in medical care.

A Shift to Chronic Disease Care

When it comes to specific disease categories, however, the picture is heterogeneous. While all five Asian economies have made strides in reducing the burden of infectious diseases, maternal and neonatal conditions, nutritional deficiencies, and injuries, changes in disease cases per person within NCDs vary substantially.

For example, diabetes, kidney diseases, and cancers showed substantial increases in disease cases per person. This trend, the researchers explain, reflects “the growing burden of chronic and lifestyle-related conditions in aging societies, driven by factors such as sedentary behaviors, unhealthy diets, and increasing life expectancy.” The rise in cancers, which may also stem from improved screening, detection, and diagnosis, underscores “the dual challenges of managing both the increasing prevalence and the long-term care needs associated with these conditions.”

Policy Implications for Aging Societies

The study has important policy implications for addressing the health challenges associated with aging populations in Asia and elsewhere. The researchers emphasize that, while aging is irreversible, “its consequences can be mitigated through stronger health systems that emphasize prevention and management of NCDs.” They offer key policy recommendations:

• Build integrated, age-responsive care models that strengthen primary health care and promote sustainable health financing mechanisms to support the growing needs of older populations.
• Tailor health intervention policies to each country’s specific demographic and health system context.
• Expand access to disease screening, encourage adherence to clinical guidelines, and leverage technological innovations to sustain interventions that lead to efficient disease management and health gains.