The Significance of Hair Thermal Diffusivity on Melanoma Incidence

Abstract

There is an increased risk of melanoma in adulthood when a child (pre-puberty) has been exposed to high levels of ultraviolet radiation (UVR). It has also been hypothesized that the childhood body air (vellus hair) plays a role in the increased incidence of melanoma later in life. This is attributed to the fact that the vellus hair has properties and physiology which encourage the transmission of harmful energy into the follicle of the hair and ultimately cause damage to the stem cells in residence there. Later in life these damaged stem cells become involved in the generation of melanomas in the epidermis. It has been debated whether the UVR or the heat generated by it is the main contributor to melanoma occurrence. This research is the first step in investigating this phenomenon by focusing on the contribution of changes in thermal characteristics on the incidence of melanoma. To test the hypothesis that child hair can transmit energy more easily than adult hair the transient electro-thermal technique is used to determine the thermal diffusivity of the hair. This involved subjecting platinum coated hair samples to a current pulse and measuring the subsequent voltage response in the sample. Results show that the child hair has a thermal diffusivity around two times higher than adult hair, thus supporting the hypothesis. Further research will be needed, in particular, quantifying the optical transmission characteristics of child hair compared to adult hair.