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Lessons Learned

Learn about the significance of cortisol measurement in various disease conditions such as Cushing's Disease and Addison's Disease. Explore the different mediums like urine, blood, saliva, and hair for cortisol measurement, along with their pros and cons. Discover the importance of accurate measurement and analysis for assessing cortisol levels over different time periods.

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Lessons Learned

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  1. Lessons Learned Cortisol

  2. Why Measure Cortisol? • Hyper-cortisolism or hypo-cortisolism associated with several disease conditions • Cushing’s Disease • Addison’s Disease • Congenital Adrenal Hyperplasia • Depression • Thyroid Disease • Cortisol is an objective marker of the stress response

  3. What Medium to Use? • Urine • Blood (serum or plasma) • Saliva • Hair • Pros and Cons for each

  4. Urine Cortisol (Normal range 10-100 mcg/24hours) • Pros: • Non-invasive • 24-hr urine cortisol/creatinine ratio excellent diagnostic for disease states. Not influenced by diurnal rhythm. • Cons • Need a timed urine sample, so difficult to collect diurnal samples • Labor intensive for patients; can’t be used in patients with renal failure or dialysis • High rate of cross-reactivity (numerous excreted steroid metabolites in urine) • Most urine assays pick up cortisol metabolites (95%); only 2-3 % free cortisol

  5. Blood Cortisol • Pros • Can collect diurnal data or after stress exposure • Best measure for diagnosing certain hyper-cortisol states (e.g., Cushing’s via dex suppression test) • Cons • Blood draw expectation may increase cortisol release • Provide measurement of cortisol at a single point in time • Major fraction bound to corticosteroid binding globulin (CBG) and albumin (only 2-3% free). • CBG influenced by pregnancy, oral contraceptives, hyperthyroidism – so levels measured may be high, but not reflective of bioactive cortisol • Methods for assaying serum free cortisol are time consuming, expensive and require advanced techniques (ultrafiltration, gel filtration, gold standard: equilibrium dialysis)

  6. Salivary Cortisol • Pros • Non-invasive – can collect from infants, children, patients with poor veins • Avoids stress-induced rise in secretion (like with a blood draw) • Can collect at home or in the wild: Do not need to freeze or keep refrigerated • Can collect one time or diurnal data • Provides measure of free cortisol – best indicator of active hormone • Correlates well with serum levels across a 24-hour period • r=.67 in healthy people; r= .73 in patients with Addison’s disease; and r= .61 in patients with Cushing’s) • Cons • Provides measurement of cortisol concentration at a single point in time • Periodontal disease, eating, tooth brushing can affect levels • Sample quantity may be low (e.g., dry mouth, impatient) • Messy

  7. Hair Cortisol • Pros • Biomarker of chronic stress • Relatively non-invasive • Only free cortisol represented • Easily transported and stored - put in an envelope or vial & store at room temp for months to years • Reflects cortisol levels over past months (Hair grows predictably about 1 cm/month) – • 1 cm closest to skull reflects last month; 2nd cm out reflects preceding month • So may not need to take multiple samples to evaluate chronic stress and perhaps compare months with and without a stressor • Not affected by hair color – but maybe by dying of hair • Significantly correlated with self-reports of stress (Kalra, 2007; Van Uum, 2008) • Cons • No clinically relevant reference range established to date • Exposure to exogenous steroids in lotions or creams may cause sample contamination • Mechanism of incorporation of cortisol into hair not known– is it from blood? Exocrine or sebaceous sources?

  8. Cortisol Assays • Radioimmunoassay • Immunoassay - most common but may be at risk of cross reactivity with steroids other than cortisol (problematic in critically ill patients and in urine samples) • High pressure liquid chromatography (HPLC)/mass spectrometry

  9. Measurement and Analysis • A single sample • unreliable unless: • Collected accurately at a specific time of day for all subjects or • Collected accurately at a specific time of day related to known time of awakening • Diurnal Rhythm • Unreliable unless collected accurately at correct times of day

  10. Measurement and Analysis • Diurnal Rhythm • Usually collect between 3-6 samples over the course of 1-3 days to evaluate: • Awakening level – considered a measure of allostatic load • Awakening response (15-45 mins after awakening) – considered a measure of acute stress response. • Then one or more collections across the day • High in morning, then falls over the day, lowest late in the evening (Kudielka& Kirschbaum, 2003) • If an individual or group deviate from that rhythm, indicates dysregulation

  11. Diurnal Rhythm

  12. Awakening Response • Awakening Response (Pruessner, 1997) [30 min post awakening] – [awakening] [awakening]

  13. Area Under the Curve • Mathematically transforms multivariate data into a summary of the information (Fekedulegn et al., 2007). • Reflects the total cortisol released during the day • Provides information on the magnitude of the response

  14. Measurement and Analysis • Must validate correct collection times • Self-report • Phone calls • MEMs Caps (electronic monitoring)

  15. Special Populations • Pregnant women • Levels very high but maintain a diurnal rhythm • Blood levels very high unless measure only free because CBG increases significantly blood = bound + free • Infants and toddlers

  16. Thank you! • Questions?

  17. References • Fekedulegn, D.B., Andrew, M.E., Burchfiel, C.M, et al. (2007). Area under the curve and other summary indicators of repeated waking cortisol measurements. Psychosomatic Medicine, 69, 651-659. • Kalra, S., Einarson, A., Karaskov, T., Van Uums, S., & Koren, G., (2007). The relationship between stress and hair cortisol in healthy pregnant women. Clinical and Investigative Medicine, 30, E103-107. • Kudielka, B.M., Kirschbaum, C. (2003). Awakening cortisol response are influenced by health status and awakening time but not by menstrual cycle phase. Psychoneuroendocrinology, 28, 35-47. • Pruessner, J., C., Wolf, O.T., Hellhammer, D. H., et al. (1997). Free cortisol levels after awakening: a reliable biological marker for the assessment of adrenocortical activity. Life Science, 61, 2539-2549. • Russell, E., Koren, G., Rieder, M., & Van Uum. (2012). Hair cortisol as a biological marker of chronic stress: current status, future directions and unanswered questions. Psychoneuroendocrinology, 37, 589-601.

  18. Thyroid Stimulating Hormone and Cortisol Concentration • Serum cortisol levels among individuals with TSH levels >2.0 uIU/L (N=31) were significantly higher than among those individuals with TSH levels ≤ 2.0 uIU/L (N=20) [13.83 ± 0.93 ug/dL vs. 8.66 ± 0.59 ug/dL, respectively, F(1,48)=14.24, p<0.0001]. • Walter, Corwin, Ulbrecht, Demers, Bennett, Whetzel, & Klein (2012). Thyroid Research.

  19. Conversion Factor • To change cortisol from • Microgram to nanomolar ; • Microgram x 2.76

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