Potentially modifiable risk factors for dementia in six low-income and middle-income countries: A multinational, population-based survey

Objectives: We aimed to determine the proportion of dementia cases potentially preventable in six low-income and middle -income countries. Study design: We analyzed data from 19,278 adults aged 50 years or more from China, South Africa, Ghana, India, Russia, and Mexico included in the WHO's Study on global AGEing and adult health. Main outcome measures: We calculated the population attributable fraction for ten potentially modifiable risk factors: less education, hearing loss, hypertension, diabetes, depression, heavy drinking, obesity, smoking, physical inactivity, and social isolation. Weighted attributable fraction was calculated considering communality among risk factors. Results: We estimated that 37.6 % of the burden of dementia might be attributable to these risk factors. The highest and lowest overall weighted attributable fractions were 38.3 % and 22.9 % in China and Ghana, respectively. Less education (8.3 %), smoking (6.3 %), and physical inactivity (5.7 %) showed the highest attributable fraction for dementia. The overall attributable fraction was higher in the poorest (38.1 %) than in the richest (30.9 %) income quintile. The burden of obesity, diabetes, and hypertension was 61 % higher in the wealthiest than in the poorest population. A total of 7.2 million cases of dementia in these six low- and middleincome countries are potentially caused by these ten potentially modifiable risk factors. Conclusions: Overall, 38 % of cases of dementia in China, South Africa, Ghana, India, Russia, and Mexico can be attributable to ten potentially modifiable risk factors. Cardiometabolic risk factors account for a more significant burden of dementia in the wealthiest population. Less education had the highest population attributable fraction independent of living area and income.