One in six people aged above 60 years in India has mild cognitive impairment, a condition marked by problems with memory or thinking and a potential precursor to dementia, a nationwide study has suggested.

The study, the first to use a nationally representative population sample to assess mild cognitive impairment, has estimated that about 24 million (17.6 per cent) of the country’s 138 million people aged above 60 years have this condition.

People with mild cognitive impairment can take care of themselves and engage in daily activities. The study has also estimated that 7.2 per cent of those above 60 years — or 9.9 million of the 138 million — have a major neurocognitive disorder, or dementia, marked by various levels of dependency.

“The prevalence of dementia in India is higher than previously recognised,” health researchers from India and the US who conducted the study said in a research paper on their findings published this month in the journal PLOS One.

The first-ever estimates of people living with mild cognitive impairment point to a population group that might potentially require treatment in the coming years.

The Alzheimer’s and Related Disorders Society of India, a body of medical professionals, had in 2010 estimated that 3.7 million Indians had dementia and predicted that the count would double by 2030. Other previous studies in India on dementia had estimated prevalence rates of 2.2 per cent, 10.6 per cent, and 14.4 per cent, but had relied on geographically-limited samples.

The new findings from the India-US study underline the need for health policymakers to scale up interventions to prevent or manage dementia.

The study found — as anticipated — a higher prevalence of dementia among older people.

About 3.8 per cent in the 60-64 age group and 15.2 per cent among those aged 80 years or older had dementia.

And, in line with multiple studies in the past from other countries, the study also found education had
a protective effect against dementia. The prevalence was 10.8 per cent among those with no formal education but only 3.5 per cent with those who had college-level education.

Health researchers from the Johns Hopkins Bloomberg School of Public Health, the University of Southern California, the St John’s Medical College, Bangalore, and the Venu Geriatric Institute, New Delhi, among other institutions collaborated in the study.

They relied on a sample of 4,096 people aged above 60 from 18 states, drawn from a bigger sample of over 72,000 people aged above 45 who are part of the Longitudinal Ageing Study in India, a research effort to track the health as people age.