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Hair analysis may identify Cushing’s syndrome
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The use of a hair analysis to measure cortisol levels may be an effective initial or supportive test for signaling Cushing’s syndrome, according to recent findings published in Endocrine.
“It can be difficult and time-consuming to diagnose Cushing’s syndrome,” Mihail Zilbermint, MD, an endocrinologist at NIH’s Eunice Kennedy Shriver National Institute of Human Health and Development, told Endocrine Today. “Diagnosis could require any of a combination of these tests — 24-hour free urine cortisol monitoring, an overnight dexamethasone-suppression test and measurement of late-night salivary cortisol. Cortisol levels may change daily, so tests may need to be repeated. Moreover, if Cushing’s syndrome is not diagnosed and treated, the patient’s risk for morbidity and mortality increases. Having an easy-to-use, accurate means to diagnose cortisol levels from hair samples — as an initial or supportive tests — could ease the burden of a complex diagnostic process, and perhaps increase diagnostic speed and accuracy.”
Zilbermint and colleagues evaluated 36 adults (mean age, 26.5 years; 75% women; 75% white) to determine the effectiveness of a hair analysis over 16 months for evaluation of Cushing’s syndrome.
Researchers collected 3-cm hair samples closest to the scalp that were cut into 1-cm segments (proximal, medial and distal) to assess cortisol levels. The hair samples were compared with testing done within the previous 2 months of the evaluation.
Overall, 30 participants had Cushing’s syndrome, and the remaining served as controls.
Midnight serum cortisol (P < .001), early morning cortisol (P = .02), urinary free cortisol corrected for body surface area (P < .001) and 17-hydroxysteroids corrected for creatinine (P < .001) were greater in participants with Cushing’s syndrome compared with controls.
Participants with Cushing’s syndrome had higher proximal hair cortisol values compared with the control group (P = .003), whereas the differences for medial, distal and average segments did not reach statistical significance. The proximal 1-cm hair had the highest cortisol level in 69.4% of all participants and 73.3% of participants with Cushing’s syndrome.
There were positive associations between proximal hair cortisol levels and urinary free cortisol corrected for body surface area (P = .005), midnight serum cortisol (P = .03) and 17-hydroxysteroids corrected for creatinine (P = .06) in the whole study population. Similarly, positive associations were found between proximal hair cortisol levels and urinary free cortisol corrected for body surface area (P = .009), midnight serum cortisol (P = .03) and 17-hydroxysteroids corrected for creatinine (P = .07) in participants with Cushing’s syndrome.
“Cortisol levels of hair samples taken from within 1 cm of the scalp corresponded closely with levels of cortisol detected in a standard test of urinary cortisol and late night serum cortisol,” Zilbermint told Endocrine Today. “Our results need to be confirmed, but they support further investigations into using the most proximal 1 cm of hair as an initial or supportive diagnostic test for Cushing’s syndrome.”
Zilbermint added that replication of the findings using a larger population would be a “good first step for future research.”
“Also, many factors are known to degrade hair cortisol levels — among them shampoo and ultraviolet light,” he said. “So we also need more work looking at how to consistently obtain accurate cortisol data from hair samples.” – by Amber Cox
For more information:
Mihail Zilbermint, MD, can be reached at mihail.zilbermint@nih.gov.
Disclosure: The researchers report no relevant financial disclosures.
Perspective
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The diagnosis of Cushing's syndrome consists typically of a three-step process. Based on a true index of suspicion, after ruling out use of exogenous glucocorticoids, specific screening tests should be done. Some patients will require additional confirmatory tests, but it is essential to avoid performing localization tests before having a confirmed diagnosis. The screening tests clinically available now include 24-h urinary free cortisol (24 UFC), salivary cortisol and dexamethasone suppression test, each with its own pitfalls that need to be taken into account for a particular patient.
The role of cortisol measurement in the hair has been previously entertained as an easier way of detecting integrated cortisol secretion. The paper by Hodes and colleagues, from the well-known Stratakis group at NIH, attempted to further elucidate this in a larger group (30 Cushing's syndrome participants and 6 controls) by comparing hair cortisol with other known Cushing’s tests.
The main findings of this study are that proximal hair cortisol was higher in Cushing's syndrome patients than in controls (P = 0.003) and also that proximal hair cortisol (rather than distal or medium segments) was highest of all segments in a majority (69%) of patients. Furthermore, proximal hair cortisol had a strong correlation with UFC (r = 0.5, P = 0.005) and midnight cortisol (r = 0.4, P = 0.03). Interestingly, the authors did not see a direct linear relationship between ACTH and hair cortisol, and there was no significant correlation of hair with any non-hair tests in patients with Cushing’s disease. Measuring hair cortisol has its own limitations, too, well described by the authors, but further, both sensitive and specific tests that can help in diagnosing Cushing's syndrome earlier and in a more convenient way, are clearly needed.
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