To explore the distribution characteristics and influencing factors of spring immune conjunctivitis patients in Beijing.

13 086 patients with spring immune conjunctivitis who visited the emergency department of Chongwenmen Branch of Beijing Tongren Hospital in March each year from 2021 to 2025 were selected as the research subjects. Among them, there were 6223 males and 6863 females with a median age of 34 (14, 43) years old (ranging from 2 to 90 years old). Patients were divided into three groups based on their age: underage group, young group, middle-aged group, and elderly group. The daily number, age, gender, diagnosis, and medication treatment information of patients with this disease in the Donghua Digital Hospital Information Management System were retrieve and recorded. The pollen concentration, maximum temperature, wind force level, and rainfall or sleet weather monitoring data of the Beijing Meteorological Bureau for the day were reviewed and recorded. The number of patients did not follow a normal distribution according to the Kolmogorov Smirnov test, and was represented by median and interquartile range, and 90% percentile M (Q1, Q3, 90%). The pollen concentration and maximum temperature follow a normal distribution, was represented by ±s. The correlation between the number of patients and pollen concentration, maximum temperature, wind intensity, and rainfall or sleet weather, and draw a logarithmic line graph was evaluated by Spearman correlation coefficient. Single factor generalized linear regression was used to analyze the correlation between the number of patients and climate factors such as pollen concentration, maximum temperature, wind intensity, and rainfall or sleet weather. Further, the variables selected from single factor screening were included in the multi factor generalized linear regression analysis to control for confounding factors and explore the correlation between each factor and the number of patients in depth.

Among all 13 086 patients with spring immune conjunctivitis, there were 3951, 6463, 2187, and 485 patients in the underage group, young group, middle-aged group, and elderly group, respectively, accounting for 30.2%, 49.4%, 16.7%, and 3.7%, respectively. There were 6223 males and 6863 females, accounting for 47.6% and 52.4%, respectively. The number of patients in March 2021, March 2022, March 2023, March 2024, and March 2025 were 2551, 1886, 2180, 2901, and 3568, respectively, accounting for 19.5%, 14.4%, 16.6%, 22.2%, and 27.3%. The range of patient numbers was 3 to 449, 7 to 321, 4 to 208, 5 to 560, and 3 to 521, respectively. The number of patients in the 90^th percentile was 53 (20, 81 206), 35 (21, 60 212), 59 (41, 108 131), 46 (24, 128 173), and 79 (43, 140 308), respectively. The average pollen concentrations were (549.4±611.7) grains/1000 mm^2, (735.7±1175.7) grains/1000 mm^2, (818.7±847.6) grains/1000 mm^2, (835.7±1618.5) grains/1000 mm^2, and (1234.1±2202.6) grains/1000 mm^2, respectively. The average maximum temperatures are (13.9±5.2) ℃, (13.3±4.2) ℃, (16.7±4.5) ℃, (15.3±5.2) ℃, and (15.4±5.9) ℃, respectively. The daily wind speeds were 0 to 4, 1 to 3, 1 to 4, 0 to 4, and 1 to 4, respectively. The types of precipitation are light rain, light rain or sleet, light rain, light rain or sleet, and light rain or sleet. The Spearman correlation analysis results showed that the number of patients was significantly correlated, moderately correlated, moderately correlated, and weakly correlated with pollen concentration, maximum temperature, rainfall or sleet weather, and wind intensity, respectively, with statistical significance (r=0.734, 0.460, 0.452, 0.232; P<0.05). The results of single factor generalized linear regression analysis showed that the number of patients was affected by pollen concentration, maximum temperature, and rainfall or sleet weather, and the correlation analysis had statistical significance (β=0.047, 7.856, 94.316; 95%CI: 0.039 to 0.056, 5.021 to 10.691, 56.621 to 132.012; P<0.05). The number of patients was not affected by wind intensity, and the correlation was not statistically significant (β=14.440, P>0.05). The results of multiple generalized linear regression analysis showed that there was a statistically significant correlation between the number of patients and pollen concentration, maximum temperature, and rainfall or sleet weather (β=0.038, 3.564, 69.460; 95%CI: 0.029 to 0.047, 1.175 to 5.954, 40.754 to 98.166; P<0.05).

The epidemiological characteristics of spring immune conjunctivitis patients in Beijing are slightly higher in females than males. Mainly targeting minors and young people, with a small proportion occurring in middle-aged people, and occasional cases in the elderly population. The number of patients is affected by pollen concentration, maximum temperature, and rainfall or sleet weather, while the effect of wind is not significant.