Age, life-style, and self-perceptions of hair: Is there an association with hair diameter and tensile properties?

To determine the association of age, life-style habits and the self-perception of hair condition with the objectively measured physical properties of hair in Caucasian females with brown hair.Hair biophysical properties, life-style habits data and self-perceptions of hair condition were collected on 110 Caucasian females with brown hair ranging in age from 17 to 78. Hair diameter (cross-sectional area), and tensile properties (elastic modulus, break strength and break extension) were measured at the root end of individual fibers (n=100/subject) from the crown and frontal regions using objective instrumental methods. Other measures included body mass index (BMI) and Savin female-pattern hair loss grades based on judging of standardized front, top and side view head images. Life-style habits and practices and self-perceived hair condition were obtained via a standardized self-assessment questionnaire.Hair fiber diameter and break extension decreased significantly with age. Hair fiber elastic modulus and Savin hair loss scores increased significantly with age. No age-related change in hair fiber break stress was observed. A history of smoking or being overweight were significantly associated with having lower hair fiber cross-sectional area but were not associated with any of the measured tensile properties. Subjects who perceived their hair as fine, thinning, or weak had significantly lower cross-sectional areas than subjects who did not. Subjects who perceived their hair to be healthy or strong had significantly higher cross-sectional areas than subjects who did not.The biophysical properties of hair change significantly with age. A history of smoking or being overweight were significantly associated with having smaller hair cross-sectional area but were not associated with differences in hair tensile properties. The self-perception of having strong or healthy hair seems more associated with having a larger cross-sectional area than any real differences in hair strength. This article is protected by copyright. All rights reserved.