Associations Between Complement Components and Vitamin D and the Physical Activities of Daily Living Among a Longevous Population in Hainan, China.

Chi Zhang,Minghao Zhao,Deping Liu,Yao Yao,Yali Zhao,Shihui Fu

doi:10.3389/fimmu.2020.01543

Abstract

Background: Vitamin D and complement components shared some common pathophysiological pathways in the musculoskeletal system, circulation, and metabolism, which were linked to physical function. It is hypothesized that serum complement components may interact with vitamin D in respect of the physical activities of daily living (PADLs).Objective: To investigate if serum complement components 3 (C3), complement components 4 (C4), and 25-hydroxyvitamin D [25(OH)D] associate with PADLs, and to examine whether the association between 25(OH)D levels and PADLs varies at different complement component levels among Chinese centenarians.Methods: This study was conducted in a group of population-based centenarians. PADLs were evaluated using the Barthel Index. Multiple regressions were used to analyze the associations among 25(OH)D, complements C3 and C4, and PADLs.Results: Among 943 participants, 672 (71.3%) had physical dependence (PD). After adjusting for potential confounders, serum 25(OH)D and C3 levels were positively correlated with PADLs, while C4 levels were negatively correlated with PADLs (Ps < 0.05). Serum 25(OH)D levels significantly interacted with both C3 (P for interaction = 0.033) and C4 (P for interaction = 0.006) levels on PADLs. At lower complement component levels, the multivariate odds ratios (ORs) of the upper tertile of vitamin D for PD were 0.32 (95% CI: 0.18–0.55) in the C3 group and 0.29 (95% CI: 0.16–0.50) in the C4 group. At higher complement component levels, the ORs in the C3 and C4 groups were not statistically significant.Conclusions: In a group of population-based Chinese centenarians, we observed that serum complement C3 and 25(OH)D levels were positively associated with PADLs, while C4 was negatively associated with PADLs. The associations between 25(OH)D levels and PADLs were more pronounced in groups with lower serum complement component levels.

Highlights

The complement system is an important constituent of the immune system, which is crucial for maintaining the health of older people [1]
As far as we are aware, this study has explored the association of serum 25(OH)D, complement components 3 (C3) and complement component 4 (C4) levels with physical activities of daily living (PADLs), as well as their interactions among a longevous population in Hainan Province, China
We observed that the associations between serum 25(OH)D and physical dependence (PD) were significantly varied at different complement component C3 and C4 levels; the associations were more pronounced in groups with lower levels of serum C3 or C4, but lost statistical significance in higher complement component groups

Summary

Introduction

The complement system is an important constituent of the immune system, which is crucial for maintaining the health of older people [1]. Complement components 3 (C3) and 4 (C4) are widely involved in three activating pathways of complements (classical pathway, alternative pathway, and mannose-binding lectin pathway) and they play vital roles in anti-infection and inflammatory response, as well as in metabolism and circulation regulation [2,3,4]. To the best of our knowledge, no human study with epidemiological or clinical designs have reported an association between the complement C3, C4, and the physical activities of daily living (PADLs). Vitamin D and complement components shared some common pathophysiological pathways in the musculoskeletal system, circulation, and metabolism, which were linked to physical function. It is hypothesized that serum complement components may interact with vitamin D in respect of the physical activities of daily living (PADLs)

Methods

Results

Conclusion