Higher blood cadmium level is associated with greater cognitive decline in rural Chinese adults aged 65 or older

Hang Liu; Liqin Su; Xi Chen; Sisi Wang; Yibin Cheng; Shaobin Lin; Liang Ding; Jingyi Liu; Chen Chen; Frederick W Unverzagt; Ann M Hake; Yinlong Jin; Sujuan Gao

doi:10.1016/j.scitotenv.2020.144072

Higher blood cadmium level is associated with greater cognitive decline in rural Chinese adults aged 65 or older

Sci Total Environ. 2021 Feb 20:756:144072. doi: 10.1016/j.scitotenv.2020.144072. Epub 2020 Nov 26.

Authors

Hang Liu¹, Liqin Su², Xi Chen¹, Sisi Wang³, Yibin Cheng¹, Shaobin Lin¹, Liang Ding¹, Jingyi Liu¹, Chen Chen¹, Frederick W Unverzagt⁴, Ann M Hake⁵, Yinlong Jin¹, Sujuan Gao⁶

Affiliations

¹ China CDC Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
² China CDC Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese Center for Disease Control and Prevention, Beijing 100050, China. Electronic address: suliqin@nieh.chinacdc.cn.
³ Center for Biostatistics, Bioinformatics and Big Data, School of Public Health, Zhejiang University School of Medicine, Hangzhou 310058, China.
⁴ Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
⁵ Department of Neurology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
⁶ Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN 46202-2872, USA.

Abstract

Cadmium (Cd) exposure has been reported to have neurotoxic effects in animal studies and associated with increased Alzheimer's Disease mortality and lower cognitive function in cross-sectional and case-control studies. However, no results from longitudinal studies on Cd and cognitive decline are available. In this prospective cohort study, we recruited 1867 participants aged 65 years or older from rural areas in China, blood Cd and cognitive function were measured at baseline (2010-2012), and 1554 participants completed cognitive function tests during a 3-year follow-up (2013-2015). Cognitive function was evaluated using nine standardized cognitive tests: The Community Screening Instrument for Dementia, the CERAD Word List Learning, Word list recall, IU Story Recall, Animal Fluency Test, Boston Naming Test, Stick Design, Delayed Stick Design and the IU Token Test. Analysis of covariance models and logistic regression models were used to determine the association between Cd and standardized cognitive decline adjusting for covariates. The median blood Cd concentration of this study population was 2.12 μg/L, and the interquartile range was 1.42-4.64 μg/L. Significant association of higher Cd levels with lower cognitive scores were observed in five individual cognitive tests (Delayed Stick Design Test, Boston Naming Test, CERAD Word List Learning Test, Word List Recall Test and IU Story Recall Test) and the composite cognitive score adjusting for multi-covariates at baseline. Higher Cd levels were significantly associated with greater 3-year cognitive decline in Delayed Stick Design Test, Boston Naming Test, IU Token Test, Word List Recall Test and Composite cognitive score. For these cognitive tests, participants in the top two Cd quartile groups had significantly greater decline than those in the lowest Cd quartile group, while the two lowest Cd quartile groups were not significantly different. Our findings suggest that higher Cd exposure is associated with greater cognitive decline in older Chinese adults.

Keywords: Cadmium; Cognitive decline; Cognitive function; Older adults; Prospective cohort study.

MeSH terms

Adult
Aged
Asian People
Cadmium*
China / epidemiology
Cognitive Dysfunction* / chemically induced
Cognitive Dysfunction* / epidemiology
Cross-Sectional Studies
Humans
Middle Aged
Neuropsychological Tests
Prospective Studies

Substances

Cadmium

Grants and funding

R01 AG019181/AG/NIA NIH HHS/United States