PhD Dissertations: Audrey Scott, 2015

The Influence of Surgical Stress on Human Hair Fiber Dimensions

Abstract

Human scalp hair is playing an increasing role in stress research on both individual and population levels.  Hair is taphonomically robust and, through its continuous growth, creates a chronological record of biochemical history.  The production of hair fiber cells has a high demand for circulating substrates which are reallocated during the acute phase response to physical stressors.  Therefore acute physiological stress events should be registered by the hair follicle and recorded in the hair as a temporary reduction in the volume of hair fiber produced.  

Scalp hair samples were collected from male abdominal surgery patients, photomicrographed, and fiber dimensions were recorded.  Patient recruitment and sample collection were approved by relevant Ethics Review Boards.  Data were analysed to address three research goals.  First, to compare methods for examination and measurement of hair fiber dimensions.  Second, to assess the normal daily variation in hair fiber dimensions along the length of the fiber.  Third, to investigate whether hair fiber dimensions are reduced in response to surgical stress.

A new method is suggested which produces consistent results at moderate and high magnifications, and when measured digitally and manually.  The scalp hair of study participants exhibited a statistically significant narrowing of hair fiber diameter following surgery, which returned to pre-operative normal by the fourth post-operative week.  Results of this study suggest that microscopic examination and measurement of human scalp hair fibers can be used to investigate acute stress-related changes along the length of the fiber.

Keywords:     Human scalp hair; stress; surgery