LAUSR

Dear Editor, Age-related hair changes are becoming a major concern in daily dermatological practice due to an ageing world population and growing concerns about hair appearance. Ageing affects hair colour, production and structure. Thinning of the hair follicles has also been observed, but the occurrence of miniaturization remains controversial. It is difficult to discriminate the effects of hair ageing from those of pre-existing alopecic phenomena. Microarray analysis has revealed differences in gene expression profiles between men with senescent alopecia and those with androgenetic alopecia (AGA). However, studies involving women without hair loss are scarce and mainly restricted to Asian populations. Our comparative, observational study aimed to objectively characterize hair ageing – independently of any form of alopecia – in healthy White European women. Sixty women, all with hair ≥5 cm in length and without any clinical signs of alopecia or scalp disorders, were recruited in Germany in 2014 and 2015. To exclude potential disturbances linked to perimenopausal hormonal changes, women aged 36– 59 years were not eligible. Hair growth patterns on the top of the head (TH) and the occiput (Oc) were assessed using phototrichograms (Trichoscan , Tricholog GmbH, Freiburg, Germany). Hair samples from the TH and Oc phototrichogram zones were used to measure hair diameter and porosity (swelling) using a laser micrometre (Laser Scan Micrometer, Mitutoyo, Kawasaki, Japan) and to assess breakage under stress using an extensometer (Miniature Tensile Tester, Dia-Stron Limited, Andover, UK). Data were grouped and analysed according to age: 25–35 years, 60–70 years and 71+ years. Total hair density (Fig. 1a) and thin hair (<40 μm) density (Fig. 1b) decreased significantly with age for both the TH and Oc areas. Significantly less hair regrowth on the TH was observed in the 71+ group compared to the 25–35 group (Fig. 1c). Break stress decreased with age for hair from both areas (Fig. 1d), whereas hair porosity in the 71+ group was only significantly higher than that in the 25–35 group for the TH area (Fig. 1e). Standardized photographs of both the TH and Oc areas are presented in Fig. 2.