Heatstroke characteristics and meteorological conditions in Hefei, China: thresholds and driving factors.

BACKGROUND

Due to climate change and rapid urbanization, the frequency of heatwave events in East China has increased considerably since the 21st century, which has a considerable influence on human health, such as heatstroke. However, few studies have been conducted in this region on the relationship between heatstroke and meteorological conditions. To address this point, this study aimed to analyze the characteristics of heatstroke and their relationship with meteorological conditions in Hefei, China.

METHODS

The 2008-2022 heatstroke data from Hefei Center for Disease Control and Prevention was used. The relationship between heatstroke and meteorological conditions was discussed by statistical methods, such as correlation analysis, cluster analysis and linear regression analysis.

RESULTS

The number of heatstroke cases fluctuated upward from 36 cases in 2008 to 1051 cases in 2022, with 71.5% of all cases for males and females accounting for 28.5%. The highest frequency of heatstroke occurrence was found to be concentrated in the middle age group (40-59 years old). According to the statistical analysis, air temperature and relative humidity were the most important meteorological factors that influenced the occurrence of heatstroke. Then a threshold system of meteorological factors for heatstroke was established by utilizing the relationship: daily average temperature (T) ≥ 30 °C & daily average relative humidity (RH) ≤ 80% and daily maximum temperature (Tmax) ≥ 35 °C & daily minimum relative humidity (RHmin) ≤ 65%. The threshold in group outbreak areas was stricter than it in high incidence areas. Furthermore, the Pacific Subtropical High (PSH) was found to be the primary climatic factor that determined the occurrence of heatstroke occurrence on a seasonal scale. In addition, significant differences in heatstroke risk were found among different groups of people. Heatstroke risk was substantially higher in males than in females due to larger opportunities for outdoor labor. The reduced physical fitness of elderly people raised the risk of heatstroke more than other age groups in extremely high temperatures.

CONCLUSIONS

A meteorological threshold system had been established to forecast heatstroke occurrence in a short-term time, and a key climate driving factor of heatstroke was found for long-term heatstroke prediction in Hefei. These findings could facilitate the disease control department to take preventive and control measures to reduce the impact of heatstroke on human health and society.