Dementia numbers falling in some countries and underestimated in others

New cases of dementia are diminished in developed nations, which could be a sign of the successes of preventative care and reduced risk factors. On the other hand, dementia may have been sorely underestimated in countries with lower and middle incomes, according to research presented during the current Alzheimer’s Association International Conference (AAIC) in Copenhagen, Denmark.

The research included several unique studies. One study, conducted at the University of Michigan and the VA Ann Arbor Center for Clinical Management Research, referenced patient populations in the United States, England, the Netherlands and Sweden and indicated a dip in dementia prevalence in these countries. Another study from the German Center for Neurodegenerative Diseases (DZNE) found reduced numbers of dementia sufferers in Germany between 2007 and 2009.

“The good news is that recent trends in developed countries in Europe and the U.S. suggest that reduction and possibly even prevention of Alzheimer’s disease might be possible – but, at the same time, we must acknowledge the growing worldwide epidemic,” said Maria Carrillo, PhD, Alzheimer’s Association vice president of medical and scientific relations, in a press release. “We must continue efforts to halt this terrible scourge that devastates families and economies.”

Data pointed toward the positive effects of education and stringent healthcare measures, including intensive treatment for cardiovascular disease. This was based on new information from the Framingham Heart Study and Boston University, which showed progressively declining numbers of new dementia cases over three decades. A 22 percent reduction was found in the second phase of research after baseline, 38 percent in the subsequent phase and 44 percent in the fourth phase. Risk dropped the most in women and patients who finished a high-school level of education.

Researchers found less smoking, improved blood pressure, higher HDL cholesterol, and fewer incidence of heart disease and stroke during the course of the 30-year study. However a red flag was a growing trend toward obesity and diabetes.

“These reductions in age-specific rates of new cases of dementia in the Framingham Study participants might be partly explained by the beneficial trends we observed in educational attainment and heart health risk factors,” said co-author Claudia L. Satizabal, PhD. “This leads us to cautious optimism that some cases of dementia may be preventable. However, one of the limitations of this work is that the Framingham sample is largely of European descent. Additional studies are needed in populations of different racial and ethnic backgrounds.”

Still other research noted that developing countries may be underrepresented in dementia data. This was especially the case for Colombia, where it may be underestimated up to 50 percent, as well as areas across Asia and Africa. Risk factors such as obesity and diabetes were implicated in rising numbers.

“According to new data reported at AAIC 2014, Alzheimer’s and dementia incidence and prevalence in developing countries may be much higher than previously thought, and rising rates of obesity and diabetes pose an unknown but potentially serious threat to cognitive health throughout the world. Many questions remain, and the only way we can get the answers is through more research,” added Carrillo.

Alzheimer’s Disease International (ADI) published data in 2009 regarding United Nations population projections and worldwide prevalence of dementia based on 154 studies. An update of that data for last year’s G8 Dementia Summit in London revealed much greater numbers in Asia and Sub-Saharan Africa. The results of a meta-analysis of research across China and Sub-Saharan Africa presented at the AAIC shows that approximately 44.35 million had dementia across the world in 2013 compared to earlier estimates of about 36 million in 2010.

Prevalence of dementia increased from five percent to about 7 percent in East Asia and from two percent to 4 percent in Sub-Saharan Africa. By 2030 the number of people with dementia worldwide is expected to rise to more than 75 million and more than 135 million in 2050.

“Dementia, including Alzheimer’s disease, is one of the biggest global health challenges facing our generation,” said Marc Wortmann, executive director of Alzheimer’s Disease International. “As more and better data becomes available, the effect we’ve seen is a reduction in the variation of prevalence between world regions.”