Hair mineralogram analysis for health assessment: Statistical bias from gender and aesthetic treatments

Abstract

The hair mineralogram is a complementary multielement analysis that provides information to aid in the diagnosis of a patient’s health status; however, aesthetic treatments can affect the analysis results. This research aimed to identify standard patterns among mineralogram results and some variables, such as gender and the use of aesthetical treatments that can point out differences and causes of variation in elemental concentrations in hair. For this purpose, 151 hair samples were obtained from volunteers and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). This work is pilot research, part of a project to encourage girls to the STEM area, called “Girls in Science”, with financial support from the Brazilian Government. Mineralogram results were compared through statistical analysis. The results of natural hair indicate significant differences (p<0.05) between genders in the concentrations of Ca, Mg, Sr, and Mo, being higher in women. This behavior was related to the remodeling of minerals in bones, which is different between men and women. The metal concentration in natural hair from women was also compared among different skin colors and no significant differences were observed. Hair treatment, in contrast, has affected significantly the concentrations of many elements. Concentrations increased in hair submitted to dyeing only or with straightening, when compared to natural hair, especially for Ca, Mg, Sr, Ba, and Ni. These results confirm the recommendation of physicians to let the hair grow free of aesthetic treatments for at least 3 months before performing the mineralogram.