Duration of Poverty and Subsequent Cognitive Function and Decline Among Older Adults in China, 2005-2018.

Abstract

To investigate the relationship between late-life duration of poverty exposure and cognitive function and decline among older adults in China. Data were from 3,209 participants ≥64 years of age in the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Duration of poverty, defined according to urban and rural regional standards from the China Statistical Yearbook, was assessed according to annual household income from 2005 to 2011 (never in poverty; one-third of the period in poverty; two-thirds or more of the period in poverty). Cognitive function was measured by the Chinese Mini-Mental State Examination (CMMSE) from 2011 to 2018. We used attrition-weighted, multivariable mixed-effects Tobit regression to examine the association of duration of poverty with cognitive function and rate of decline. A total of 1,162 individuals (36.21%) were never in poverty over the period from 2005 to 2011; 1,172 (36.52%) were in poverty one-third of the period; and 875 (27.27%) were in poverty two-thirds or more of the period. A longer poverty duration was associated with lower subsequent CMMSE scores with a dose-response relationship (one-third vs never in poverty: β = -0.98; 95% confidence interval -1.61 to -0.35; two-thirds or more vs never in poverty: β = -1.55; 95% confidence interval -2.29 to -0.81). However, a longer duration of poverty was associated with a slower rate of CMMSE score decline over time from 2011 to 2018. These findings provide valuable evidence for the role of cumulative late-life poverty in relation to cognitive health among older adults in a rapidly urbanizing and aging middle-income country. Our findings may support a compensation hypothesis for cognitive reserve in this setting.