Negative associations of morning serum cortisol levels with obesity: the Henan rural cohort study

The association of cortisol, testosterone, and cortisol/testosterone ratio with stroke: A cross-sectional study

AIMS

We aimed to investigate the association between serum cortisol, testosterone, and cortisol/testosterone (C/T) ratio and stroke.

MATERIALS AND METHODS

A total of 6157 subjects were included in this study. The serum levels of cortisol and testosterone were determined by liquid chromatography-tandem mass spectrometry method. The relationships of serum cortisol, testosterone, and C/T ratio levels with the odds ratios (ORs) of stroke were calculated using logistic regression analysis. The dose-response associations between serum cortisol, testosterone, and C/T ratio levels with stroke estimated by restricted cubic splines.

RESULTS

After adjusting for multiple variables, serum testosterone levels were negactively associated with stroke in males (per 1 unit, odds ratio (OR) = 0.83, 95 % confidence interval (CI): 0.70, 0.97). The serum C/T ratio is positively associated with stroke in both males and females (OR = 1.16, 95 % CI:1.04,1.34 in males and OR = 1.15, 95 % CI:1.02,1.31 in females). Restricted cubic splines showed a significant linear dose-response relationship between testosterone and C/T ratio and stroke in males (P for overall association <0.05, P for nonlinearity >0.05).

CONCLUSION

Our study findings show that serum testosterone levels are negatively correlated with stroke in males; meanwhile, serum C/T ratio is positively correlated with stroke in both males and females.

The Role of Morning Plasma Cortisol in Obesity: A Bidirectional Mendelian Randomization Study

CONTEXT

Cortisol, an important hormone regulated by the hypothalamic-pituitary-adrenal axis, is associated with obesity. However, it is unclear whether the relationship between cortisol and obesity is causal or could be explained by reverse causality.

OBJECTIVE

This work aims to assess the role of morning plasma cortisol in clinical classes of obesity.

METHODS

In this bidirectional, 2-sample mendelian randomization (MR) study, cortisol-associated genetic variants were obtained from the CORtisol NETwork consortium (n = 12 597). The primary outcomes were obesity class I (body mass index [BMI] ≥ 30), class II (BMI ≥ 35), and class III (BMI ≥ 40). The inverse variance weighting method was used as the main analysis, with weighted median, MR-Egger, and MR pleiotropy residual sum and outlier (MR-PRESSO) as sensitivity analyses. Conversely, genetic variants predicting clinical classes of obesity were applied to the cortisol genome-wide association study.

RESULTS

Genetically predicted cortisol was associated with reduced risk of obesity class I (OR = 0.905; 95% CI, 0.865-0.946; P < .001). Evidence from bidirectional MR showed that obesity class II and class III were associated with lower cortisol levels ([class II-cortisol OR = 0.953; 95% CI, 0.923-0.983; P = .002]; [class III-cortisol OR = 0.955; 95% CI, 0.942-0.967; P < .001]), indicating reverse causality between cortisol and obesity.

CONCLUSION

This study demonstrates that cortisol is negatively associated with obesity and vice versa. Together, these findings suggest that blunted morning plasma cortisol secretion may be responsible for severe obesity. Regulating morning plasma cortisol secretion might be a prevention measure for obese people.

Circadian Rhythm of Salivary Cortisol in Obese Adolescents With and Without Apnea: A Pilot Study

BACKGROUND AND OBJECTIVE

Obstructive sleep apnea (OSA) and obesity are associated with stress system activation involving the hypothalamic-pituitary-adrenal (HPA) axis in adults, but these effects in childhood and adolescence remain unclear. We examined diurnal salivary cortisol as a measurement of the HPA axis function in obese adolescents with and without OSA and the relationships between cortisol levels, body weight, and parameters of polysomnography (PSG).

METHODS

After PSG, saliva samples were collected from obese participants (with and without OSA) and lean participants four times over a 24-h period, namely, at 7:00 h (m-sCort), 13:00 h (a-sCort), 19:00 h (e-sCort), and 23:00 h (n-sCort). An enzyme-linked immunosorbent assay (ELISA) was used to measure salivary cortisol levels. The mean values of cortisol levels and fixed-time point diurnal cortisol slope (DCS) were calculated and compared among the three study groups. Correlations between parameters were analyzed using Spearman's correlation coefficients.

RESULTS

Obese OSA participants had significantly higher e-sCort and n-sCort levels than both obese non-OSA participants and lean controls. However, m-sCort and a-sCort in these patients had a pronounced upward trend. M-sCort was significantly correlated with both the lowest oxygen saturation (SpO₂) and time with SpO₂ <90%. Moreover, in the obese OSA group, DCS was significantly flatter than in the other two groups. The a-sCort in obese non-OSA participants was significantly higher than that in the lean control group and, surprisingly, was positively correlated with the apnea/hypopnea index. Additionally, m-sCort was related to body weight.

CONCLUSION

This study provided further evidence for alterations in diurnal cortisol production in obese adolescents, which may indicate a chronically stressed HPA axis. However, there were significant differences in salivary cortisol parameters between participants with and without OSA. Furthermore, patients with OSA had more associations between time-point cortisol levels and OSA-related indices. Nonetheless, this research is a pilot study, and further investigations are necessary.