Casale R, Natali G, Colantonio D, Pasqualetti P
Department of Internal Medicine and Public Health, School of Medicine and Surgery, University of L'Aquila, Italy.
Thorax. 1992 Oct;47(10):801-3. doi: 10.1136/thx.47.10.801.
Because airway calibre shows a circadian rhythm and since exposure to passive smoking reduced lung function this study was undertaken to investigate whether passive smoking affects the circadian rhythm of peak expiratory flow (PEF) in schoolchildren.
Twenty schoolchildren (12 boys and 8 girls, aged 10-11 years) exposed to passive smoking were matched for sex, age, and height with 20 children who had not been exposed to cigarette smoke. Exposure to passive smoking was assessed by questionnaire and by urinary cotinine concentrations. A portable spirometer was used to measure PEF at 16:00, 20:00, 22:00, 06:00, 08:00, and 12:00 hours on a consecutive Saturday and Sunday. The circadian changes in PEF were measured by the cosinor method.
Both groups showed diurnal fluctuation in PEF values with a noticeable circadian rhythm. PEF peaks were the same in the two groups and occurred around 15:00 hours. The cosinor mean was approximately 10% lower in children exposed to passive smoking and the amplitude was approximately 60% higher than in the unexposed children.
Passive smoking in children is associated with a reduction in the cosinor mean and an increase in the amplitude of the normal circadian rhythm of airway calibre. This increased PEF rhythm amplitude may be considered as an early indication of airway obstruction.
由于气道口径呈现昼夜节律，且被动吸烟会降低肺功能，因此开展本研究以调查被动吸烟是否会影响学童的呼气峰值流速（PEF）昼夜节律。
20名暴露于被动吸烟环境的学童（12名男孩和8名女孩，年龄10 - 11岁），在性别、年龄和身高方面与20名未接触香烟烟雾的儿童进行匹配。通过问卷调查和尿可替宁浓度评估被动吸烟暴露情况。使用便携式肺活量计在连续的周六和周日的16:00、20:00、22:00、06:00、08:00和12:00测量PEF。采用余弦分析法测量PEF的昼夜变化。
两组的PEF值均呈现昼夜波动，且有明显的昼夜节律。两组的PEF峰值相同，均出现在15:00左右。暴露于被动吸烟环境的儿童的余弦分析均值比未暴露儿童低约10%，振幅比未暴露儿童高约60%。
儿童被动吸烟与气道口径正常昼夜节律的余弦分析均值降低和振幅增加有关。这种增加的PEF节律振幅可能被视为气道阻塞的早期迹象。
