Dementia may be much more prevalent in developing countries than what was thought until now, researchers report.
The new findings suggest that policymakers in low-income and middle-income countries may need to re-examine the impact of dementia on their health services.
As the average age of the global population increases, dementia and other age-related illnesses are increasing in prevalence. Recent estimates have suggested that over 24 million people live with dementia worldwide, with 4.6 million new cases every year.
A number of studies have suggested that the prevalence of dementia in the developing world is between a quarter and a fifth of that typically recorded in developed countries.
Shocking new figures
Now, research announced at the International Conference on Alzheimer's Disease and published online in the medical journal The Lancet suggests that this figure has been underestimated and that levels of dementia in the developing world may be much closer to those in the developed world.
Professor Martin Prince from the Institute of Psychiatry, King's College London, who led the research, believes that a number of factors may have led to researchers failing to identify a significant proportion of cases of dementia.
"It's likely that cultural differences may be partly responsible for researchers missing cases of dementia," he said. "Our evidence suggests that relatives in developing world countries are less likely to perceive or report that their elders are experiencing difficulties, even in the presence of clear evidence of disability and memory impairment."
How the study was conducted
The research group assessed almost 15 000 people over the age of 65 in eleven countries, including India, China, Cuba and Peru.
The assessment consisted of interviews with the participant and, typically, a family member, as well as a physical examination and a blood test. The criteria used by the researchers were developed and validated cross-culturally across Latin America, Africa, South and South East Asia in an attempt to enable valid comparisons to be made between different countries and cultures even when a high proportion of older people had had little or no education.
According to the study, prevalence of dementia in urban settings in Latin America is comparable with rates in Europe and the US, though the prevalence in China and India is lower.
High burden on carers
Pilot studies carried out by the group suggest that, apart from the patient, dementia places a high burden on the carer and that this is exacerbated by lack of knowledge of the disease and its likely progression.
"You could question the point of labeling someone as having dementia if their relatives do not acknowledge it as a problem," says Professor Prince. "Our data suggest that even if it is not recognised as dementia, the illness places a heavy burden on both the elderly patient and their relatives. Being able to estimate accurately the true population of people living with the burden is the first important step towards putting into place appropriate health and social care systems."
The investigators are now analysing their data to examine the impact of dementia in different countries relative to that of other chronic diseases. This will include the effect of dementia on disability, dependency, strain on the carer, and the economic cost of dementia and other diseases. These data, in conjunction with the prevalence estimates now published, will enable policymakers in low-income and middle-income countries to prioritise more effectively, as they begin to invest more heavily in the prevention and control of chronic non-communicable diseases.
The research was welcomed by Marc Wortmann, Executive Director of Alzheimer's Disease International, who supported the research.
"Behind every case of dementia, there are relatives who are also affected, and both patients and carers need support," Wortmann said. – (EurekAlert)
July , 2008