# The association between vision impairment and multi-site pain in middle-aged and older adults in China: results from the China health and retirement longitudinal study

## TL;DR

This study finds that vision impairment in older Chinese adults is linked to pain in multiple body sites, suggesting a need for integrated healthcare.

## Contribution

The study is the first to examine the relationship between vision impairment and multi-site pain in low- and middle-income countries.

## Key findings

- Vision impairment was associated with pain in eight body sites, including waist, fingers, and knees.
- Vision impairment showed a positive correlation with pain in five or more body sites.
- The association between vision impairment and multi-site pain was not influenced by age, gender, or place of residence.

## Abstract

Previous research on the association between vision impairment (VI) and multi-site pain has been sparse, and no studies have specifically examined this relationship in low- and middle-income countries (LMICs).

This study aims to investigate the relationship between VI and the coexistence of pain in 15 different body sites and multi-site pain among middle-aged and older adults in China using nationally representative survey data.

We conducted a cross-sectional study using data from the 2020 China Health and Retirement Longitudinal Study (CHARLS), which included 10,240 participants. We used the Mann–Whitney U test and chi-square test to compare the sociodemographic, economic, and health status characteristics of the participants. Two logistic regression models were constructed to analyze the relationship between VI and the coexistence of pain in different body sites and multi-site pain.

Participants with VI had a higher probability of experiencing pain across 15 body sites compared to those without VI. After adjusting for sociodemographic, economic, and health status factors, pain in eight different body sites was significantly associated with VI (p < 0.05). The most significant associations were observed for waist pain (p = 0.003), finger pain (p = 0.012), and knee pain (p = 0.009). Furthermore, VI was inversely associated with the coexistence of pain in two body sites (OR: 0.547; 95% CI: 0.354–0.810, p < 0.05) but positively associated with five or more body sites (OR: 1.550; 95% CI: 1.191–2.017, p < 0.05). Sensitivity analysis revealed that VI remained positively associated with the coexistence of five or more painful body sites after stratifying by age, gender, and place of residence (p < 0.05).

Our study revealed that Chinese middle-aged and older individuals with VI tended to experience multi-site pain, exhibiting a negative correlation with two coexisting painful sites and a positive correlation with five or more. The association between VI with the coexistence of five or more painful body sites was not influenced by age, gender, or place of residence. These findings suggest that in LMICs, VI often occurs with multi-site pain, and patients with pain could benefit from ophthalmic care and vision rehabilitation. This has major implications for improving healthcare efficiency, service planning, and clinical practice. However, VI was assessed in this study through interviewer observation rather than clinical examinations, which may have introduced misclassification bias, and future studies should validate these associations using objective visual assessments.