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Potential for dementia prevention greater in low-, middle-income countries

Dementia may be more preventable in in Asia and Latin America than in high-income countries, according to cross-sectional survey data published in Lancet Global Health.

"After our previous research finding that one in three cases of dementia could be preventable, we realized that the evidence was skewed towards higher-income countries," Naaheed Mukadam, PhD, division of psychiatry, University College London, said in a press release. “If life-course risk factors such as low levels of education in early life and hearing loss, obesity and low physical activity in mid-life to old age are addressed, these countries could see large improvements in their dementia rates."

Using data obtained from the 10/66 Dementia Research surveys, the researchers calculated population attributable fractions (PAFs) for dementia in certain low-income and middle-income countries — India, China, Cuba, Dominican Republic, Mexico, Peru, Puerto Rico and Venezuela — and identified possible dementia prevention targets in these countries. Residents aged 65 years and older living in predefined catchment areas participated in the survey between 2004 and 2006, and between 2007 and 2010 in Puerto Rico.

Dementia risk factors included less education, hearing loss, hypertension, obesity, smoking, depression, physical inactivity, social isolation and diabetes. To calculate PAFs for each risk factor, the investigators used risk factor prevalence estimated from the survey data as well as relative risk estimates from prior meta-analyses. They adjusted PAF to account for individuals having overlapping risk factors, then used these values to calculate overall weighted PAFs for India, China and the Latin American sample.

Analysis included data from 2,162 respondents in China, 2,004 in India and 12,865 in the Latin America sample. Mukadam and colleagues found that after eliminating the nine risk factors, the proportion of potentially preventable dementia cases (ie, overall weighted PAF) was 55.8% (95% CI, 54.9-56.7) in Latin America, 39.5% (95% CI, 37.5-41.6) in China and 41.2% (95 % CI, 39.1-43.4) in India.

The investigators found that five dementia risk factors were more prevalent in China, India and Latin America than worldwide estimates, leading to higher weighted PAFs for dementia; these included:

• less childhood education (10.8% in China, 13.6% in India, and 10.9% in Latin America vs. 7.5% worldwide);
• smoking (14.7%, 6.4% and 5.7% vs. 5.5%);
• hypertension (6.4%, 4% and 9.3% vs. 2%);
• obesity (5.6%, 2.9% and 7.9% vs. 0.8%); and
• diabetes (1.6%, 1.7% and 3.2%, vs .1.2%).

“Reducing the prevalence of all of these risk factors clearly has numerous health benefits, so here we've identified an added incentive to support public health interventions that could also reduce dementia rates,” Mukadam said in the release. “The growing global health burden of dementia is an urgent priority, so anything that could reduce dementia risk could have immense social and economic benefit.” – by Savannah Demko

Disclosure: The researchers report no relevant financial disclosures.