Dementia, Diabetes and Data Gaps: South Asia’s Next Health Test

South Asia is ageing into a public-health challenge that remains largely absent from national planning. Dementia is already imposing substantial health and social costs across the region, yet governments still lack the surveillance systems, trained workforce, caregiver support and country-specific evidence needed to respond.

A new study, "Burden and Risk Factors of All-Cause Dementia in South Asia: An Analysis of Global Health Data and a Framework for Future Dementia Longitudinal Studies in Low-Resource Settings," published in the Journal of Dementia and Alzheimer's Disease, examines the burden across Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. The authors are Dushani L. Palliyaguru, Nipuni Palliyaguru, Camila Vieira Ligo Teixeira, Nicole M. Armstrong, Sanka Liyanage, Upul Senarath, Carukshi Arambepola, Saroj Jayasinghe and Chamila Dalpatadu.

Using demographic data, World Health Organization reporting and Global Burden of Disease 2019 estimates, the researchers compare dementia deaths, incidence and disability-adjusted life years, or DALYs. They also assess the regional distribution of established risk factors and propose a framework for longitudinal studies in resource-constrained settings.

South Asia is confronting the disease through a combination of rapid population ageing, poorly controlled metabolic conditions, weak diagnosis and major data gaps. Unless governments act early, much of the burden will fall on families and health systems that are already under pressure.

An Ageing Region Is Entering a Policy Vacuum

South Asia contains more than a quarter of the world's population and is undergoing a demographic transition alongside rising rates of diabetes, hypertension, heart disease and other chronic conditions. The study notes that one in five adults in the region could be older than 65 by 2050.

Age remains the strongest dementia risk factor. But ageing is not occurring in isolation. Many countries must still manage infectious diseases, maternal health needs, malnutrition and weak primary-care systems while preparing for a growing population requiring long-term management of complex, noncommunicable conditions.

Despite this trajectory, the policy response remains strikingly limited. According to the study, none of the eight South Asian countries examined had a national dementia plan. Only Bangladesh, India, Maldives and Pakistan participated in the WHO Global Dementia Observatory, and none had compiled dementia data in a national report during 2017–2019.

This policy vacuum has consequences beyond diagnosis. Dementia gradually increases dependency, reduces quality of life and places substantial demands on unpaid caregivers. South Asia's strong tradition of multigenerational households can offer support, but it can also conceal the true economic cost. Families frequently absorb caregiving responsibilities without formal training, income protection, respite services or community support.

The region also has limited formal infrastructure such as specialized nursing facilities, trained social workers and community dementia teams. Younger family members may leave employment or reduce working hours to provide care, creating an invisible transfer of costs from the health system to households.

Treating dementia as a family matter rather than a public-health priority may therefore delay action while increasing inequality. Better-off households can purchase private care, while poorer families face greater financial and emotional strain.

Sri Lanka and Afghanistan Reveal Two Different Crises

The study shows why regional averages can be misleading. Sri Lanka recorded the highest crude dementia death rate in South Asia, at 18.95 per 100,000 people. It also had the highest crude incidence rate, at 84.32 per 100,000, and the highest crude DALY rate, at 321.52 per 100,000. The country also has the region's largest share of people aged 65 and above, at 12.4%, making population ageing a major driver of its burden.

Afghanistan presents a different pattern. Its population is considerably younger, but it recorded the highest age-standardized dementia death, incidence and DALY rates. The age-standardized DALY rate reached 432.72 per 100,000, above the global estimate reported in the study.

Age standardization adjusts for differences in population structure. Afghanistan's result therefore suggests that factors beyond the size of the older population may be influencing the estimated burden. The paper discusses multidimensional poverty, disrupted health services, conflict and trauma as possible areas requiring investigation, but it does not establish them as direct causes.

The comparison is strategically important. Sri Lanka needs to prepare for the predictable demands of an older society, while Afghanistan requires stronger epidemiological evidence capable of explaining why its age-adjusted estimates are so high.

Women also carry a higher dementia burden across the region. Longer life expectancy is one explanation, but the authors note that life-course exposures and metabolic changes may also contribute. The available dataset did not permit a detailed sex-specific analysis of risk factors, leaving a major evidence gap.

Metabolic Disease Creates a Prevention Window

The study's most actionable finding concerns metabolic health. High fasting blood glucose and high blood pressure were prominent across South Asian countries, while diabetes was especially significant in Sri Lanka. Air pollution also represented a substantial share of the broader risk profile in India, Bangladesh and Nepal.

In the initial correlation analysis, crude dementia DALYs were strongly associated with hearing loss, diabetes and high fasting glucose. Age-standardized dementia DALYs showed notable relationships with physical inactivity, high body mass index and high glucose. After adjustments for multiple comparisons, hearing loss and diabetes remained significant in the crude analysis.

Because many of these risks overlap, the researchers used principal component analysis to group them. A metabolic-health cluster combining high blood glucose, high blood pressure and high BMI emerged as the strongest risk grouping.

These findings do not prove that metabolic disease caused dementia in the populations examined. The analysis relies on national-level estimates rather than individual patient data. Nevertheless, it points toward a practical prevention strategy.

Dementia policy should not be isolated inside specialist neurological services. It should be integrated into diabetes control, cardiovascular care, obesity prevention, hearing services, physical-activity programmes and healthy-ageing strategies.

This creates an opportunity for resource-constrained countries. Investments in blood-pressure control, healthier diets, diabetes screening and community exercise can potentially improve outcomes across several diseases at once. Such measures are more immediately scalable than expensive imaging or specialist-led diagnostic systems.

The result also connects dementia prevention with wider development challenges. Urban design affects physical activity. Food systems shape diabetes and obesity. Air-quality regulation influences neurological as well as respiratory and cardiovascular health. Brain health must therefore become part of economic, environmental and social policy, not only clinical medicine.

Better Data Must Become Health Infrastructure

The study's estimates come with major uncertainty. Dementia remains widely underdiagnosed in South Asia because of low awareness, limited specialist services, stigma and the belief that cognitive decline is a normal part of ageing.

Global Burden of Disease estimates are valuable where national evidence is missing, but they depend partly on statistical modelling and information borrowed from settings with better data. Differences in diagnostic methods, health-system capacity and surveillance quality can affect country comparisons.

The risk-factor analysis also uses country-level DALYs that are not specific population-attributable measures for dementia. Correlations across only eight countries cannot establish individual-level relationships and are vulnerable to ecological fallacy. The findings should therefore guide research priorities rather than be treated as precise causal estimates.

The authors propose a framework for longitudinal studies organized around four areas: planning, study design, data and expansion. The model includes sustainable financing, culturally appropriate recruitment, local-language assessments, biomarkers, data infrastructure, workforce training, public engagement and policy translation.

Better dementia evidence is not created by a single survey. It requires durable research institutions capable of following people over time, distinguishing dementia subtypes and tracking how metabolic, environmental and social risks interact.

India and Nepal already participate in the Harmonized Cognitive Assessment Protocol network. Expanding comparable studies throughout South Asia could improve regional learning while preserving country-level detail.

Governments should not wait for perfect data before acting. National dementia plans, primary-care screening, caregiver support and metabolic-risk reduction can begin now. At the same time, investment in longitudinal research, portable diagnostics and harmonized data systems is essential to prevent policy from being driven indefinitely by uncertain estimates.

South Asia still has time to prepare. But dementia must be recognized for what it is: not an inevitable private consequence of ageing, but an emerging development challenge that will test public health, social protection and the capacity of families to absorb long-term care.