Almost 1 in 5 Indian adults aged 60+ show signs of mild neurocognitive disorder, according to a study.

Given an estimated 138 million adults over 60 years of age in India, these estimates suggest approximately 24 million and 9.9 million older adults in India are living with mild and major neurocognitive disorders, respectively, revealed the study published in the journal PLOS One.

The findings showed that the prevalence of major neurocognitive disorder was greater with older ages - from about 4 per cent among those aged 60-64 years to 15.2 per cent among those aged over 80 years.

"India, with its rapidly ageing population, faces an alarming burden of dementia," said the team including from St. John’s Medical College in Bengaluru and Johns Hopkins University in the US.

For the study, the team recruited almost 4,100 participants residing in 18 geographically and linguistically diverse states such as Jammu & Kashmir, Punjab, Delhi, West Bengal, Maharashtra, Karnataka, and Tamil Nadu, among others. The majority of the group was aged 60-79 years.

They found that the prevalence is higher with older age, less educational attainment, and among illiterate and rural-living older adults. These findings highlight the growing importance of dementia in India.

"The prevalence of dementia in India is higher than previously recognised. These findings, coupled with a growing number of older adults in the coming decades in India, have important implications for society, public health, and families," the researchers said in the paper.

The team analysed the participants using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) -- a widely recognised clinical diagnostic authority.

The results showed that the population prevalence of DSM-5 mild and major neurocognitive disorders was 17.6 per cent and 7.2 per cent, respectively.

Further, 12 per cent reported severe loss in at least one ADL (activities of daily living) and 8.5 per cent reported impairment in any IADL (instrumental activities of daily living).

Major neurocognitive disorder was more prevalent among illiterate (9.3 per cent) than literate (5 per cent) and rural (10.3 per cent) than urban (4.9 per cent)