Sampling and Measurements
What we measure and why?
With young people becoming more independent, or moving away from childhood homes for further education, an overview of long-term cortisol exposure – i.e., adherence to glucocorticoid regimens – might be of help.
In people who have Type 1 diabetes, Glycated haemoglobin (HbA1c) levels provide average blood glucose levels over a period of the previous three months.
This measurement is seen as a gold standard tool in monitoring, acting as an indicator of good adherence and / or disease control.
Currently, there is no non-invasive test routinely available to measure cortisol exposure over a period of time. We want to change that!
Hair sampling
It has been shown that cortisol levels in hair can be an effective biomarker for long-term exposure, and can also possibly be used in clinical practice.
This can enable the patient to undertake monitoring at home, with a one-off hair sample.
Results indicating inadequate or over-exposure of glucocorticoids can then enable initiation of further investigations if needed by the hospital.
WHEN? A sample of hair will be taken in the clinic visit, and a second sample when you come to the ward for your routine blood tests.
Saliva sampling
Salivary studies have been explored, for both androgens and cortisol levels, although these are not routinely used in clinical practice. Salivary samples can remain stable at room temperature for a week (Tonge, Keevil et al. 2022) and can work in the home environment (Valentine-Graves, Hall et al. 2020).
We want to see if saliva samples will correlate (i.e. match) the cortisol levels in your blood. This could be another method of monitoring your levels at home, so you don’t have to come into hospital so often.
WHEN? Saliva samples will be taken at the same time you will have blood tests for cortisol measurements on the ward.
Body measurements
Anthropometry is a science which explores specific body measurements. Some measurements are already done in practice, but these are usually just height, weight and body mass index calculations, alongside annual bone age (BA) x-rays.
Additional anthropometric measurements might be useful, especially as shorter CAH patients tend to have an increased body mass index (Falhammar, Frisen et al. 2015).
Body circumferences have not widely been measured in CAH, but we know that obesity is a risk factor for cardiovascular disease. Skinfold thicknesses can also be used (Falhammar, Nordenström et al. 2012) as a predictor for ‘body fatness’ (Nooyens, Koppes et al. 2007), and therefore the measurements can tell us more about cardiovascular risk.
These measurements have to be undertaken by a qualified anthropometrist for accuracy, and Kate – the PhD student – has the ISAK Level 1 anthropometry qualification. ISAK stands for the International Society for the Advancement of Kinanthropometry.
Kinanthropometry is concerned with the measurement of human body composition.
WHEN? The body measurements will be undertaken when you come to the ward for the blood tests.