Extreme temperature potentially triggers eye disease in children: a multicity hospital-based study in China.

BACKGROUND

Extreme temperature is a major health threat worldwide and multiple organs including eyes are particularly vulnerable. However, knowledge is limited regarding the association between extreme temperature and eye disease. We aimed to investigate the association between extreme temperature and childhood eye disease, and to explore differences in the effects of daytime and nighttime extreme temperature.

METHODS

We collected daily data on 572,970 eye disease outpatient visits for children under 18 years old from hospitals of nine cities across China from 2010 to 2023. Daily temperature data were obtained from the ERA5-land database. A space-time-stratified case-crossover design was employed to examine the short-term associations of eye disease with temperature exposure of whole-day, during the daytime and nighttime periods.

RESULTS

There was a U-shaped association between temperature and childhood eye disease over lag 0-7 days, suggesting an increased risk of eye disease on hot and cold days. Using the minimum morbidity temperature as the reference, extremely high temperature (95th percentile of daily temperature distribution) was associated with 15 % (95 %CI: 12 %-18 %) risk increase in childhood eye disease, which was significantly greater than extremely low temperature (5th percentile of daily temperature distribution) with the risk increase of 10 % (95 %CI: 7 %-14 %). In addition, the association of eye disease with daytime and nighttime temperature was obviously different, with a significantly stronger association with high and low temperatures at night than during the day. Under high humidity, the effect of extremely high temperature was significantly higher than extremely low temperature, while no difference was observed for low humidity.

CONCLUSIONS

This multi-city study suggests that high and low temperatures could increase the risk of eye disease in children, with differences in the effects of daytime and nighttime temperature. Our findings may have public and medical implications in safeguarding children's eye health in the context of climate change.