8.8 million Indians have dementia: Why early diagnosis matters

For years, forgetting a name, misplacing the keys or repeating a question was often dismissed as simply “getting older”. But doctors say there is an important line between occasional forgetfulness and persistent changes that begin to interfere with everyday life — and recognising that line could become increasingly important as India’s population ages.

India is already home to a large and growing population of older adults. According to the Government’s Technical Group on Population Projections, the number of people aged 60 years and above is projected to increase from about 10 crore in 2011 to 23 crore by 2036, raising their share of the population from 8.4 per cent to 14.9 per cent.

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That demographic transition is bringing dementia and Alzheimer’s disease into sharper focus, while advances in blood biomarkers, brain imaging and artificial intelligence are beginning to change how doctors investigate cognitive decline.

Nearly 8.8 million Indians with dementia

A landmark nationwide study published in Alzheimer’s and Dementia, titled Prevalence of dementia in India: National and state estimates from a nationwide study, estimated that 7.4 per cent of Indians aged 60 and above were living with dementia.

The study, led by Jinkook Lee and colleagues and based on the Longitudinal Aging Study in India (LASI), used nationally representative data collected between 2017 and 2020. Researchers estimated that this translated to approximately 8.8 million people aged over 60 living with dementia.

The study also found important variations. Dementia prevalence was estimated at 9 per cent among women compared with 5.8 per cent among men, while prevalence was higher in rural areas than urban areas. The researchers projected that if the prevalence rate remained unchanged, the number of Indians aged 60 and above living with dementia could reach 16.9 million by 2036, largely because of population ageing.

Alzheimer’s and dementia

Importantly, 8.8 million is an estimate of people with dementia, not a direct count of Alzheimer’s patients in India. Dementia has several causes, with Alzheimer’s disease being the most common.

The World Health Organization (WHO) says Alzheimer’s disease may contribute to 60–70 per cent of dementia cases globally. It also notes that dementia is not an inevitable consequence of ageing and can result from several diseases and injuries affecting the brain.

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A 2026 review in Alzheimer’s & Dementia, titled The landscape of dementia in India: Prevalence, risk factors, and opportunities ahead, similarly highlights India’s growing dementia challenge and identifies higher prevalence among women, rural populations and people with certain cardiovascular and metabolic risk factors.

The awareness gap

The numbers, however, tell only part of the story.

The WHO says a lack of awareness and understanding of dementia can contribute to stigma and create barriers to diagnosis and care. Risk is also influenced by factors such as hypertension, diabetes, physical inactivity, smoking, harmful alcohol use, hearing and vision loss, social isolation and air pollution.

This makes awareness an important first step. Progressive memory loss, difficulty performing familiar tasks, getting lost in familiar surroundings or changes that begin affecting independence warrant medical evaluation rather than being automatically attributed to age.

As neurologists point out, the question is not simply whether someone is forgetful. It is whether the changes are persistent, progressive and affecting day-to-day functioning.

Blood test enters Alzheimer’s diagnosis

One of the most significant developments in recent years has been the emergence of blood-based biomarkers for Alzheimer’s disease.

The US Food and Drug Administration (FDA) in May 2025 cleared the Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio, describing it as the first FDA-cleared blood test used to aid in diagnosing Alzheimer’s disease. The test is intended for adults aged 55 and older with signs and symptoms of cognitive decline and measures the ratio of phosphorylated tau 217 and beta-amyloid 1-42 in blood.

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In the FDA-reviewed multicentre study of 499 cognitively impaired individuals, 91.7 per cent of people with a positive test had amyloid pathology confirmed by PET or CSF testing, while 97.3 per cent of those with a negative result had a negative amyloid assessment. The FDA nevertheless makes clear that the test is not intended as a stand-alone screening or diagnostic test and that results need to be interpreted alongside other clinical information.

That distinction is critical. A blood biomarker can provide biological evidence, but it does not replace the neurologist, cognitive assessment or appropriate imaging.

From MRI to AI-enabled brain analysis

Brain imaging is undergoing a similar transformation.

MRI remains an important tool because it can reveal structural changes and help doctors identify other causes of cognitive symptoms, including stroke and other brain abnormalities. Increasingly, artificial intelligence is being explored to quantify subtle patterns in brain structure and potentially support clinicians in interpreting complex imaging data.

Functional imaging can add another layer. FDG PET, which measures glucose metabolism in the brain, can reveal patterns of altered metabolism associated with neurodegenerative disease. Its role is particularly relevant in selected patients where the diagnosis remains uncertain.

This combination of laboratory biomarkers and imaging was the focus of a recent expert webinar hosted by Mahajan Imaging & Labs on the occasion of World Alzheimer’s Day.

Blood biomarkers

The webinar, titled Alzheimer’s Disease: From Early Signs to Early Diagnosis – The Role of Advanced Diagnostics in Timely Intervention, brought together neurologist Dr Vinit Suri, Founder and Chairperson of Mahajan Imaging & Labs Dr Harsh Mahajan, Lab Director Dr Shelly Mahajan, and Director – PET CT & Nuclear Medicine Dr Ritu Verma.

Dr Suri emphasised the importance of recognising when memory changes warrant neurological evaluation, while Dr Verma noted that FDG PET can provide a functional perspective that structural imaging alone cannot offer. The central message was that imaging and biomarkers work best when interpreted alongside the patient's clinical picture.

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Dr Shelly Mahajan described blood-based biomarkers as an important step towards making biological assessment simpler and more accessible, while Dr Harsh Mahajan said the convergence of clinical expertise, biomarkers and imaging could strengthen how Alzheimer’s disease is identified and followed.

Mahajan Imaging & Labs says its dementia diagnostic offering includes pTAU217/βAmyloid1-42 blood biomarker testing, along with cognitive health and genetic-risk assessments, with MRI and FDG PET available where clinically indicated.

Why timing matters

The push towards earlier diagnosis is taking place alongside a changing treatment landscape.

Established medicines such as donepezil, rivastigmine, galantamine and memantine remain part of symptomatic management. At the same time, newer disease-modifying treatments targeting amyloid pathology have introduced additional options for appropriately selected people with early Alzheimer’s disease.

That makes determining the underlying biology increasingly relevant.

For India, the challenge is therefore two-fold: improving awareness so that concerning symptoms are recognised earlier, and ensuring that diagnostic technologies are used appropriately once someone enters the healthcare system.

The next phase of Alzheimer’s care may not be defined by a single breakthrough test. Instead, it is likely to involve a combination of clinical assessment, cognitive testing, blood biomarkers, MRI, PET imaging and increasingly sophisticated computational tools.

For millions of ageing Indians and their families, that convergence could change an important question from “Is this just old age?” to a more useful one: “What is causing these changes, and can we identify it early enough to act?”