The Hair-to-Belly Cortisol Connection: Hair Analysis As Reliable Tool for Longterm Cortisol Analyses

Figure 1: 3D model of molecular
structure of cortisol (Wikipedia)

Although cortisol is probably one of the most important hormones, and a lack of cortisol will provoke symptoms which can range from simple fatigue to death, chronically elevated levels of this essential corticosteroid are associated with increases in visceral obesity and its entailing metabolic pathologies, which are commonly described as "the metabolic syndrome". The results of a very recent study (Manenschijn: 2011), that was published in the medical journal Steroids, may thus turn out to be a valuable tool in the a:nalysis of the underlying causes of pathological obesity and its consequences.

Manenschijn et al. collected hair samples of 195 healthy individuals, 9 hypercortisolemic and one hypocortisolemic patient and measured the cortisol levels in the hais and saliva of their subjects. They then correlated the data with waist and hip circumferences, as well as blood pressure values of 46 of the healthy subjects and found:

[...] a positive correlation between hair cortisol and both waist circumference (r = 0.392, p = 0.007) and waist-to-hip ratio (WHR) (r = 0.425, p = 0.003). No correlations were found between hair cortisol levels and BMI, blood pressure or age. There was no decline in cortisol levels in six consecutive hair segments. Hair cortisol levels were elevated in patients with known hypercortisolism (p < 0.0001).

This is an interesting result. On the one hand, it does show that hair analysis may serve as a valuable tool in the assessment of longterm cortisol levels (as long as confounding factors, as washout effects due to certain shampoos and other hair care products are taken into consideration), on the other hand, however, it raises the question whether the well accepted association between stress, high cortisol and elevated blood pressure is practically relevant, if longterm cortisol levels remain within certain "healthy" limits.