Courtois M, Loussouarn G, Hourseau S, Grollier J F
L'Oreal, Laboratoires Recherche Appliquée et Développement, Clichy, France.
Br J Dermatol. 1996 Jan;134(1):47-54.
Ten men, with or without alopecia, were observed for a period of between 8 and 14 years using phototrichograms on a precisely located zone on the vertex of the scalp. Among the various parameters observed, we chose the percentage of hairs in telogen as the criterion for assessment of hair shedding. Mathematical analysis of the variations in this telogen percentage was carried out for each individual subject and for the whole group, as represented by the population mean (or the 'average subject'). This analysis demonstrated the existence of overall annual periodicity, manifested by a maximal proportion of telogen hairs at the end of summer and the beginning of autumn. Some subjects also exhibited a periodicity approximately corresponding to two annual peaks. In those subjects with a very low proportion of hairs in telogen, no periodicity was demonstrated. In another group of subjects, it has been shown that the variations in telogen percentage reflect those observed in hair shedding, assessed in a standardized manner. Periodicity of the telogen percentage, and hence of hair fall, is not independent of climatic factors (sunshine hours), and these must be taken into account when assessing the treatment or prevention of hair loss.
对10名男性进行了观察，他们有的有脱发问题，有的没有，在头皮顶部一个精确划定的区域使用毛发照影术进行了8至14年的观察。在观察的各种参数中，我们选择休止期毛发的百分比作为评估脱发的标准。对每个个体以及以总体均值（或“平均个体”）表示的整个群体的休止期百分比变化进行了数学分析。该分析表明存在总体年度周期性，表现为夏末和秋初休止期毛发的比例最高。一些受试者还表现出大约对应两个年度峰值的周期性。在休止期毛发比例非常低的受试者中，未显示出周期性。在另一组受试者中，已经表明休止期百分比的变化反映了以标准化方式评估的脱发情况。休止期百分比以及脱发的周期性并非独立于气候因素（日照时长），在评估脱发的治疗或预防时必须考虑这些因素。
