Department of Epidemiology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China.
Shandong University Climate Change and Health Center, Jinan, China.
JMIR Public Health Surveill. 2024 Aug 13;10:e55822. doi: 10.2196/55822.
Studies have reported the adverse effects of cold events on influenza. However, the role of critical factors, such as characteristics of cold spells, and regional variations remain unresolved.
We aimed to systematically evaluate the association between cold spells and influenza incidence in mainland China.
This time series analysis used surveillance data of daily influenza from 325 sites in China in the 2014-2019 period. A total of 15 definitions of cold spells were adopted based on combinations of temperature thresholds and days of duration. A distributed lag linear model was used to estimate the short-term effects of cold spells on influenza incidence during the cool seasons (November to March), and we further explored the potential impact of cold spell characteristics (ie, intensity, duration, and timing during the season) on the estimated associations. Meta-regressions were used to evaluate the modification effect of city-level socioeconomic indicators.
The overall effect of cold spells on influenza incidence increased with the temperature threshold used to define cold spells, whereas the added effects were generally small and not statistically significant. The relative risk of influenza-associated with cold spells was 3.35 (95% CI 2.89-3.88), and the estimated effects were stronger during the middle period of cool seasons. The health effects of cold spells varied geographically and residents in Jiangnan region were vulnerable groups (relative risk 7.36, 95% CI 5.44-9.95). The overall effects of cold spells were positively correlated with the urban population density, population size, gross domestic product per capita, and urbanization rate, indicating a sterner response to cold spells in metropolises.
Cold spells create a substantial health burden on seasonal influenza in China. Findings on regional and socioeconomic differences in the health effects of cold spells on seasonal influenza may be useful in formulating region-specific public health policies to address the hazardous effects of cold spells.
已有研究报道了寒冷天气事件对流感的不良影响。然而，有关寒冷期特征和地域差异等关键因素的作用仍未得到解决。
本系统评价旨在评估中国内地寒冷天气事件与流感发病率之间的关系。
本时间序列分析使用了 2014-2019 年期间中国 325 个监测点的每日流感监测数据。共采用了 15 种寒冷天气定义，基于温度阈值和持续时间天数的组合。采用分布式滞后线性模型来估计寒冷天气对凉爽季节（11 月至 3 月）流感发病率的短期影响，我们还进一步探讨了寒冷天气特征（即强度、持续时间和季节内时间）对估计关联的潜在影响。Meta 回归用于评估城市级别社会经济指标的修饰效应。
寒冷天气对流感发病率的总体影响随着定义寒冷天气的温度阈值而增加，而附加效应通常较小且无统计学意义。寒冷天气与流感相关的相对风险为 3.35（95%CI 2.89-3.88），且在凉爽季节的中期估计效应更强。寒冷天气的健康影响具有地域差异，江南地区的居民是脆弱人群（相对风险 7.36，95%CI 5.44-9.95）。寒冷天气的总体影响与城市人口密度、人口规模、人均国内生产总值和城市化率呈正相关，表明大城市对寒冷天气的反应更为强烈。
寒冷天气给中国季节性流感带来了巨大的健康负担。有关寒冷天气对季节性流感的健康影响在地域和社会经济方面存在差异的发现，可能有助于制定针对特定地区的公共卫生政策，以应对寒冷天气的危险影响。
