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

Objective To determine the association of age, lifestyle habits and the self-perception of hair condition with the objectively measured physical properties of hair in Caucasian females with brown hair. Methods Hair biophysical properties, lifestyle 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 fibres (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. Lifestyle habits and practices and self-perceived hair condition were obtained via a standardized self-assessment questionnaire. Results Hair fibre diameter and break extension decreased significantly with age. Hair fibre elastic modulus and Savin hair loss scores increased significantly with age. No age-related change in hair fibre break stress was observed. A history of smoking or being overweight was significantly associated with having lower hair fibre cross-sectional area but was 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. Conclusion The biophysical properties of hair change significantly with age. A history of smoking or being overweight was significantly associated with having smaller hair cross-sectional area but was 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.Abstrait