The impact of risk factors for dementia in China

Abstract Brief summary We evaluated the impact of seven risk factors for dementia in China. Physical inactivity, midlife hypertension and low education are proposed to be the largest fraction contributors to dementia. 55% of dementia were attributable to one or more of the seven risk factors. Background Previous studies have highlighted the impact of seven risk factors (midlife obesity, physical inactivity, smoking, low education, diabetes mellitus, midlife hypertension and depression) against dementia. However, the impact of these risk factors on dementia has not been evaluated among the Chinese population. Objective To clarify the impact of seven major risk factors on the incidence of dementia in China. Design The prevalence of risk factors was derived from the latest national surveys. Relative risks of corresponding risk factors were derived from the latest cohort or cross-sectional studies. Setting and subjects Three national surveys were included in the present study to obtain prevalence data of seven risk factors: the China Chronic Disease and Risk Factor Surveillance Survey (CCDRFSS) (2013), which covered about 170,000 adults (aged ≥18 years) from 31 provinces; (2) China National Survey of Chronic Kidney Disease (CNSCKD) (2010), which covered about 50,000 adults (aged ≥18 years) from 13 provinces; and (3) China Family Panel Studies Survey (CFPSS) (2012), which covered about 30,000 adults (aged ≥18 years) from 25 provinces. Methods Levin’s formula was used to calculate the population attributable fraction (PAF) for each risk factor for dementia. The combined PAF of the seven risk factors was calculated assuming the independence of each risk factor. Results Physical inactivity (PAF, 24.3%), midlife hypertension (PAF, 22.1%) and low education (PAF: 11.9%) were the top three factors that contributed to dementia. The total PAF of the seven risk factors was 55% in the Chinese population. Conclusions promotion of physical activity, control of hypertension and improvement of nationwide educational level may be helpful public health strategies to decrease the incidence of dementia in China.