Johnston Neil W, Johnston Sebastian L, Norman Geoff R, Dai Jennifer, Sears Malcolm R
Firestone Institute for Respiratory Health, St Joseph's Healthcare and McMaster University, Hamilton, Ontario, Canada.
J Allergy Clin Immunol. 2006 Mar;117(3):557-62. doi: 10.1016/j.jaci.2005.11.034. Epub 2006 Jan 27.
Viral infections are associated with the majority of asthma exacerbations in children and adults. Increased asthma hospitalization rates of children and adults, particularly in the early fall, have been observed to follow school vacations.
We sought to determine the sequence of timing of September asthma hospitalization epidemics in children and adults and to determine whether school-age children are the primary source of transmission of agents that cause them.
By using Canadian asthma hospital admission data from 1990 to 2002, we examined geographic variation in the timing of fall asthma epidemics and applied mathematical modeling to estimate their exact timing and magnitude in school-age children, preschool children, and adults, and relation to school return.
The September asthma hospitalization epidemic peak occurred in school-age children each year on average 17.7 (95% CI, 16.8-18.5) days after Labor Day. Similar epidemics of lesser magnitude were observed in preschool children peaking 1.7 (95% CI, 0.9-2.5; P<.001) days later, and in adults 6.3 (95% CI, 4.7-7.9; P<.001) days later than in school-age children. The epidemics peaked 4.2 (95% CI, 1.2-7.1; P<.001) days earlier in school-age children in northernmost compared with southernmost latitudes.
September epidemics of asthma hospitalizations in Canada have a precise relationship to school return after the summer vacation. It may be speculated that school-age children transmit the agents responsible for the epidemic to adults. Measures to improve asthma control and reduce transmission of infections should be directed at children with asthma before school return.
病毒感染与儿童和成人的大多数哮喘发作有关。观察到儿童和成人哮喘住院率增加，尤其是在初秋，且发生在学校假期之后。
我们试图确定儿童和成人9月哮喘住院流行的时间顺序，并确定学龄儿童是否是导致这些流行的病原体的主要传播源。
利用1990年至2002年加拿大哮喘住院数据，我们研究了秋季哮喘流行时间的地理差异，并应用数学模型估计其在学龄儿童、学龄前儿童和成人中的准确时间和规模，以及与开学的关系。
9月哮喘住院流行高峰平均每年在劳动节后17.7（95%可信区间，16.8 - 18.5）天出现在学龄儿童中。在学龄前儿童中观察到类似但规模较小的流行，高峰比学龄儿童晚1.7（95%可信区间，0.9 - 2.5；P <.001）天，在成人中则比学龄儿童晚6.3（95%可信区间，4.7 - 7.9；P <.001）天。与最南端纬度相比，最北端纬度的学龄儿童流行高峰提前4.2（95%可信区间，1.2 - 7.1；P <.001）天出现。
加拿大9月哮喘住院流行与暑假后开学有确切关系。可以推测学龄儿童将导致流行的病原体传播给成人。在开学前，应针对哮喘儿童采取措施改善哮喘控制并减少感染传播。
