BACKGROUND For the past decade, hand, foot and mouth disease (HFMD), caused by entero and coxsackie viruses, has been spreading in Asia, particularly among children, overloading healthcare settings and creating economic hardships for parents. Recent studies have found meteorological factors, such as temperature, are associated with HFMD in Asia. However, few studies have explored the relationship in the United States, although HFMD cases have steadily increased recently. As concerns of climate change grow, we explored the association between temperature and HFMD admissions to the Emergency Department (ED) in California. METHODS Weekly counts of HFMD for 16 California climate zones were collected from 2005 to 2013. We calculated weekly temperature for each climate zone using an inverse distance-weighting method. For each climate zone stratified by season, we conducted a time-series using Poisson regression models. We adjusted models for weekly averaged relative humidity, average number of HFMD cases in previous weeks and long-term temporal trends. Climate zone estimates were combined to obtain an overall seasonal estimate. We attempted stratified analyses by region, race/ethnicity, and sex to identify sensitive subpopulations. RESULTS Risk of ED visits for HFMD per 1 °F increase in mean temperature during the same week increased 2.00% (95% confidence intervals 1.15, 2.86%) and 2.35% (1.38, 3.33%) during the warm and cold seasons, respectively. The coastal region showed a higher, though not statistically different, association during the cold season [3.18% (1.99, 4.39)] than the warm season [1.64% (0.47, 2.82)]. CONCLUSIONS Our findings indicated an association between temperature and ED visits for HFMD, with variation by season and region. Thus, the causative pathogen's ability to persist in the atmosphere may vary by season. Furthermore, the mild and wet winter in the coastal region of California may contribute to different results than studies in Asia. With the onset of climate change, HFMD cases will likely grow in California, warranting further investigation on this relationship, including new populations at-risk.

中文翻译：

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加利福尼亚州的温度和手足口病：2005-2013 年按季节急诊就诊的探索性分析。

背景 在过去十年中，由肠道病毒和柯萨奇病毒引起的手足口病 (HFMD) 一直在亚洲蔓延，尤其是在儿童中，导致医疗机构不堪重负，并给父母带来经济困难。最近的研究发现气象因素，如温度，与亚洲的手足口病有关。然而，尽管最近手足口病病例稳步增加，但很少有研究探讨美国的这种关系。随着人们对气候变化的担忧加剧，我们探索了温度与加州急诊室 (ED) 的手足口病入院人数之间的关联。方法 从 2005 年到 2013 年，每周收集 16 个加利福尼亚气候区的手足口病计数。我们使用反距离加权法计算每个气候区的每周温度。对于按季节分层的每个气候带，我们使用泊松回归模型进行了时间序列分析。我们根据每周平均相对湿度、前几周手足口病平均病例数和长期时间趋势调整了模型。气候区估计被合并以获得一个整体的季节估计。我们尝试按地区、种族/民族和性别进行分层分析，以确定敏感的亚群。结果 在同一周平均温度每升高 1°F，因手足口病而就诊的风险在暖季和冷季分别增加 2.00%（95% 置信区间 1.15，2.86%）和 2.35%（1.38，3.33%）。沿海地区在寒冷季节 [3.18% (1.99, 4.39)] 比暖季 [1.64% (0.47, 2.82)] 表现出更高的关联，但没有统计学差异。结论 我们的研究结果表明，温度与手足口病急诊就诊之间存在关联，且随季节和地区而异。因此，致病病原体在大气中持续存在的能力可能因季节而异。此外，加利福尼亚沿海地区温和潮湿的冬季可能导致与亚洲研究不同的结果。随着气候变化的开始，加利福尼亚州的手足口病病例可能会增加，需要进一步调查这种关系，包括新的风险人群。