Lower incidences of dementia are indicated from countries with low or middle incomes then in high-income countries, according to a new study in The Lancet, which was led by researchers at King’s College London’s Institute of Psychiatry.

A few population-based cohort studies were performed in various countries with people aged 65 year and older living in Cuba, the Dominican Republic, and Venezuela. The studies were also conducted in Peru, Mexico and China.

The study said that questionnaires were given to people in these areas to ascertain information about age, sex, educational level, literacy and number of household assets. Information was obtained about mortality from all the countries.

A new cross-cultural approach to diagnosing dementia that is sensitive to more mild to moderate cases (the 10/66 Dementia Diagnosis) was performed, according to King’s College London’s Institute of Psychiatry.

Over 12,000 participants were interviewed and 11,718 were found to be free of dementia. This has been one of the largest studies to date.

Professor Martin Prince led the research and coordinated the 10/66 Dementia Research Group.

"Our studies provide supportive evidence for the cognitive reserve hypothesis- that better brain development can mitigate the effects of neurodegeneration in later life," Prince said. "We need to understand more about cognitive reserve, how to measure it, and how it is simulated across cultures."

During the research phase, the professor pointed out that a high incidence of dementia in less developed countries reminds us that we are facing a global epidemic and there needs to be a focus on prevention.

Findings from the research support the assumption that cognitive reserve might counter the effects of neurodegeneration later in life. The conclusion of the study suggests that dementia incidence in middle-income countries might be much the same as in higher-income countries.

It was also determined at the start of the study that people with dementia had a nearly three-fold greater risk of dying compared with those that were dementia-free. The findings were also associated with increased age, being female and low education.

It is estimated that over 24 million people live with dementia worldwide; with 4.6 million cases added every year. Dementia leads to memory impairment, quality of life and depression. It also places a high level of burden on the caregiver.

Dementia is basically a loss of brain function. Alzheimer’s disease is the most common type of dementia. It is generally nonreversible, which means it cannot be stopped or turned back. Dementia can also occur from many small strokes.