Interaction between plant-based dietary pattern and air pollution on cognitive function: a prospective cohort analysis of Chinese older adults

Anna Zhu; Hui Chen; Jie Shen; Xiaoxi Wang; Zhihui Li; Ai Zhao; Xiaoming Shi; Lijing Yan; Yi Zeng; Changzheng Yuan; John S Ji

doi:10.1016/j.lanwpc.2021.100372

Interaction between plant-based dietary pattern and air pollution on cognitive function: a prospective cohort analysis of Chinese older adults

Lancet Reg Health West Pac. 2022 Jan 5:20:100372. doi: 10.1016/j.lanwpc.2021.100372. eCollection 2022 Mar.

Authors

Anna Zhu^{1

2}, Hui Chen³, Jie Shen³, Xiaoxi Wang⁴, Zhihui Li⁵, Ai Zhao⁵, Xiaoming Shi⁶, Lijing Yan⁷, Yi Zeng^{8

9}, Changzheng Yuan^{3

10}, John S Ji⁵

Affiliations

¹ Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.
² Medical Faculty Heidelberg, Heidelberg University, Heidelberg, Germany.
³ School of Public Health, Zhejiang University School of Medicine, Zhejiang, China.
⁴ China Academy for Rural Development, Zhejiang University, Hangzhou, China.
⁵ Vanke School of Public Health, Tsinghua University, Beijing, China.
⁶ National Institute of Environmental Health, Chinese Center for Disease Control and Prevention, Beijing, China.
⁷ Global Health Research Center, Duke Kunshan University, Kunshan, China.
⁸ Center for the Study of Aging and Human Development, Duke Medical School, Durham, NC, USA.
⁹ Center for Healthy Aging and Development Studies, National School of Development, Peking University, Beijing, China.
¹⁰ Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, US.

Abstract

Background: Air pollution is a risk factor for poor cognitive function, while a plant-based dietary pattern is associated with better cognitive function. We aimed to explore their interaction with cognitive function among older adults.

Methods: We used a prospective cohort of old individuals, including 6525 participants of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), aged 65-110 years and with normal cognition at baseline. Air pollution measurement was derived using satellite-derived annual average fine particulate matter (PM_2.5) concentrations based on residential locations. Plant-based diet index (PDI) was calculated using survey responses to assess the dietary pattern. Repeated measures of the Mini-Mental State Examination (MMSE) were utilized to assess cognitive function. We applied the Cox proportional hazard regression to explore the associations and further stratified the analysis by PDI.

Findings: During a median of 5·6-year follow-up, 1537 (23·6%) out of 6525 participants with normal cognition at baseline developed poor cognitive function (MMSE <18). Living in areas with the highest quintile of cumulative PM_2.5 was associated with a 46% increase in the risk of developing poor cognitive function (hazard ratio (HR): 1·46, 95% confidence interval (CI): 1·20, 1·77), compared to those living in areas with the lowest quintile. We observed a significant interaction between cumulative PM_2.5 and PDI (p-interaction: 0·04), with the corresponding associations of cumulative PM_2.5 being more pronounced among participants with lower PDI (HR: 1·68, 95% CI: 1·26, 2·24) than those with higher PDI (HR: 1·28, 95% CI: 0·98, 1·68).

Interpretation: Plant-based dietary pattern may attenuate detrimental impacts of PM_2.5 on cognitive function among older adults. Adherence to the plant-based dietary pattern could be used to prevent adverse neurological effects caused by air pollution, especially in developing regions.

Keywords: Air pollution; Cognitive function; Healthy longevity; Plant-based dietary pattern.