With population aging, cognitive function among the elderly has been growing public health concern in China. This study aimed to investigate the trend of income-related inequality in cognitive function, and to track the health-related income mobility among the Chinese elderly.
The data were drawn from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2005, 2008, 2011, 2014 and 2018, with a sample of 10203 Chinese aged 65 and older. The cognitive function was evaluated by the Mini-Mental State Examination (MMSE). The cross-sectional and longitudinal concentration indices were used to measure the magnitudes of inequalities at different length of time. The mobility index was used to capture the discrepancy between the short-term and long-term measures. The contribution of determinants to mobility was estimated by decomposition analysis.
The results showed that, the cognitive function among the Chinese elderly scored 21.13 at the baseline. Men, activities, daily living ability, education, marriage status, income, community service, vision and hearing condition were positively associated with cognitive function, whereas age, negative well-being and drinking were negatively associated with cognitive function. The cross-sectional concentration index was positive and significant only at the baseline. In the long run, however, the concentration indices were all positive and became larger over time. After five waves, the mobility reached -4.84. The largest negative contributor to the mobility index was daily living ability, followed by relaxing activity, domestic activity and hearing condition. The two largest positive contributors were negative well-being and income.
Our study found that, as a whole, the cognitive function was not performed well among the Chinese elderly. In the long term, the weighted cross-sectional concentration indices underestimated the inequality in cognitive function and good cognitive performance was concentrated more among the rich. When formulating intervention measures, the Chinese government could give priority to vulnerable groups, especially the elderly who are poor or downwardly income mobile.