# The exposure-lag-response association between solar radiation components and meibomian gland dysfunction in Shanghai, China

## TL;DR

This study explores how solar radiation components are linked to meibomian gland dysfunction in Shanghai, China, finding increased risk with exposure.

## Contribution

The study introduces a novel analysis of solar radiation's lagged effects on meibomian gland dysfunction using distributed lag nonlinear models.

## Key findings

- Global horizontal irradiance increases MGD risk within 0–3 days.
- Diffuse horizontal irradiance increases MGD risk within 7–14 days.
- Direct normal irradiance increases MGD risk within 0–15 days.

## Abstract

Meibomian gland dysfunction (MGD) is a prevalent cause of evaporative dry eye disease with significant public health implications. This study investigated the potential impact of solar radiation (SR) on the incidence of MGD in Shanghai, China.

Daily information was collected in Shanghai, China, from January 1, 2017, to December 31, 2023, including air pollution, outpatient visits for MGD, meteorological data, and SR data. A distributed lag nonlinear model was used to explore the relationships between SR and MGD, taking into account potential nonlinear exposure-response relationships and lag effects. Additionally, the study used weighted quantile sum and quantile-based g-computation models to examine whether SR components independently affected MGD.

The present study identified 64,038 records of outpatient visits for MGD. Exposure to global horizontal irradiance, diffuse horizontal irradiance, and direct normal irradiance was associated with an increased risk of MGD outpatient visits at the lags of 0–3 days, 7–14 days, and 0–15 days, respectively. Furthermore, the study identified subgroup-specific effects of SR, which differed by age, gender, and season.

These results underscore the importance of considering environmental factors in understanding the prevalence of MGD. The study was conducted in Shanghai, China, and provides valuable insights into the potential risk factors for MGD in this region.