Serum cortisol level and depression severity in a sample of Brazilian elders

Dear Editor,

The recent precision medicine movement has pushed research towards the identification of biomarkers that can be used for early diagnosis. We designed a pilot study that explores the correlation between blood cortisol level (BCL) with depression, depression severity and clinical comorbidities in a sample of aged Brazilian subjects. We hypothesized that BCL will significantly correlate to depression, its severity and with clinical comorbidities in our sample.

Participants were selected from an epidemiological study of older residents of the city of Sao Paulo¹, which screened positive for depression (depression scale-D10-score ≥ 7)² and a pool of outpatients who received treatment for depression. Inclusion criteria were 60 years and older, and DSM-IV-TR³ criteria for major depressive disorder based on a diagnostic interview by geriatric psychiatrists. Controls were 10 adults who were at least 60 years old without depression. Exclusion criteria included dementia, other organic mental disorder, and DSM-IV-TR-criteria-based diagnoses of any psychiatric disorder other than depression. Diagnosis and exclusion criteria were assessed with the CAMDEX interview⁴.

We followed 11 depressed subjects. Seven patients (63.6%) began depression after age 60 (late onset depression). Both groups had more female subjects (70% of controls and 54.5% of patients). The groups were similar in terms of marital status, mini-mental score, age and education.

In the initial appointment the subjects were assessed with: Mini Mental State Examination (MMSE)⁵; the CAMCOG version validated for the Brazilian population⁶; Montgomery-Asberg Depression Rating Scale (MADRS)⁷, Cumulative Illness Rating Scale (CIRS)⁸, Bayer Activities of Daily Living Scale (B-ADL) adapted for the Brazilian population⁹, and the Hamilton Rating Scale for Depression (HAM-D)¹⁰. To ensure that no subjects with incipient dementia would be included in the group we applied MMSE, CAMCOG and the B-ADL. We were unable to standardize the blood sample collection time, but all cases had it collected between 6-10 am (controls 6:29-9:42 am, mean = 8:57:55 am, mdn = 8:57 am; depressed subjects 6:19-9:52 am, mean = 9:23:44 am, mdn = 9:10 am).

It was found that BCL was significantly higher in the depressed aged subjects (p = 0.049, U = 27, Wilcoxon-Mann-Whitney test), and correlated significantly with severity of both the depressive symptoms (HAM-D: p < 0.001, U = 0; MADRS: p < 0.001, U = 0; B-ADL: p < 0.001, U = 10; Wilcoxon-Mann-Whitney test) and the clinical comorbidities (CIRS-severity, p = 0.032, U = 25). Finally, depression could be predicted by BCL in a regression model (Table 1).

Table 1
Logistic regression results for the prediction of diagnostic status from the BCL

	B	S.E.	Wald	df	Sig.	Exp(B)	95% C.I.for EXP(B)
BCL	0338	0.162	4.333	1	0.037	1.402	1.020 - 1.926
Constant	-4.155	2.058	4.076	1	0.044	0.016

• BCL: blood cortisol levels; B: the intercept; S.E.: standard error; Wald: Wald chi-square test; df: degrees of freedom; Sig.: significance; Exp(B): odds ratio; C.I.: confidence interval.

These findings should be taken with caution, as we did not standardize the collection time for BCL. Nevertheless, they suggest that hypercortisolemic depressed elders comprise a subgroup within depressed subjects. Their clinical course may progress with more morbidity/comorbidities and functional deficits, as shown by the statistically significant relation to all four scales applied. Elevated BCL predicts depression (p = 0.037, df = 1, B = 0.34, SE = 0.162, Table 1), which suggests that BCL might be involved in the development of depression in aged patients. The odds of 1.402 means that for each raise of 1 unit (µg/dl) of cortisol level there is 40% increase in risk of depression (95% C.I. 1.020 - 1.926).

Acknowledgments

Sponsors: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes), Fundação de Amparo à Pesquisa do Estado de São Paulo (Fapesp) no. 04/09586-9 and no. 2014/05467-7.

Luís Fernando S. C. de Araújo is supported by a scholarship from Capes Foundation, Proc. no BEX 0893/14-5 Ministry of Education of Brazil, Brasília – DF 70040-20.

Salma Rose Imanari Ribeiz is supported by a postdoc scholarship from Fapesp Agency no. 2014/05467-7. She was supported by a Ph.D. scholarship from Capes Agency and by a doctorate “sandwich” scholarship from Capes Agency.

Cássio M. C. Bottino is a researcher of the “National Counsel of Technological and Scientific Development” (CNPq – Researcher Level 1C).

References

• ¹
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Publication Dates

• Publication in this collection
  Mar-Apr 2017

History

• Received
  1 Dec 2016
• Accepted
  12 Feb 2017