Serum 25-Hydroxyvitamin D and Risk of Disability in Activities of Daily Living among the Oldest-Old: An Observational and Mendelian Randomization Study

Xinwei Li; Chen Chen; Yue Zhang; Jun Wang; Xingyao Cui; Lanjing Xu; Jinhui Zhou; Luojia Deng; Min Zhang; Yuebin Lv; Qiong Yu; Xiaoming Shi

doi:10.1016/j.tjnut.2024.01.016

Serum 25-Hydroxyvitamin D and Risk of Disability in Activities of Daily Living among the Oldest-Old: An Observational and Mendelian Randomization Study

J Nutr. 2024 Mar;154(3):1004-1013. doi: 10.1016/j.tjnut.2024.01.016. Epub 2024 Jan 19.

Authors

Xinwei Li¹, Chen Chen², Yue Zhang³, Jun Wang², Xingyao Cui¹, Lanjing Xu⁴, Jinhui Zhou², Luojia Deng³, Min Zhang¹, Yuebin Lv², Qiong Yu⁵, Xiaoming Shi⁶

Affiliations

¹ Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, Jilin, China; China Centers for Disease Control and Prevention (CDC) Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese CDC, Beijing, China.
² China Centers for Disease Control and Prevention (CDC) Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese CDC, Beijing, China.
³ Department of Bioinformatics and Biostatistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
⁴ China Centers for Disease Control and Prevention (CDC) Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese CDC, Beijing, China; Department of Big Data in Health Science, School of Public Health, Zhejiang University, Hangzhou, Zhejiang, China.
⁵ Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, Jilin, China. Electronic address: yuqiong@jlu.edu.cn.
⁶ China Centers for Disease Control and Prevention (CDC) Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese CDC, Beijing, China. Electronic address: shixm@chinacdc.cn.

PMID: 38246357
DOI: 10.1016/j.tjnut.2024.01.016

Abstract

Background: Vitamin D deficiency and disability are both prevalent among older adults. However, the association between them has rarely been investigated in the oldest-old subjects (aged ≥80 y), and the causality remains unclear.

Objective: This study aimed to elucidate the causal effect of vitamin D on the incident risk of disability in activities of daily living (ADL) among Chinese oldest-old based on the 2012-2018 Chinese Healthy Ageing and Biomarkers Cohort Study.

Methods: Serum 25-hydroxyvitamin D [25(OH)D] concentrations and ADL status at baseline and follow-up interviews were documented. Cox regression models were applied among 1427 oldest-old (mean age, 91.2 y) with normal baseline ADL status. One sample Mendelian randomization (MR) analyses were performed on a subset of 941 participants with qualified genetic data, using a 25(OH)D-associated genetic risk score as the genetic instrument.

Results: During a median follow-up of 3.4 y, 231 participants developed disability in ADL. Serum 25(OH)D concentration was inversely associated with the risk of disability in ADL [per 10 nmol/L increase hazard ratio (HR) 0.85; 95% CI: 0.75, 0.96]. Consistent results from MR analyses showed that a 10 nmol/L increment in genetically predicted 25(OH)D concentration corresponded to a 20% reduced risk of ADL disability (HR 0.80; 95% CI: 0.68, 0.94). Nonlinear MR demonstrated a monotonic declining curve, with the HRs exhibiting a more pronounced reduction among individuals with 25(OH)D concentrations below 50 nmol/L. Subgroup analyses showed that the associations were more distinct among females and those with poorer health conditions.

Conclusions: Our study supports an inverse causal relationship between serum 25(OH)D concentration and the risk of disability in ADL among Chinese oldest-old. This protective effect was more distinct, especially for participants with vitamin D deficiency. Appropriate measures for improving vitamin D might help reduce the incidence of physical disability in this specific age group.

Keywords: Mendelian randomization; genetic risk score; healthy aging; physical disability; vitamin D deficiency.

Publication types

Observational Study
Research Support, Non-U.S. Gov't

MeSH terms

Activities of Daily Living*
Aged
Aged, 80 and over
Calcifediol
Cohort Studies
Female
Humans
Mendelian Randomization Analysis
Vitamin D / analogs & derivatives*
Vitamin D Deficiency* / complications
Vitamin D Deficiency* / genetics
Vitamins

Substances

25-hydroxyvitamin D
Vitamin D
Calcifediol
Vitamins