ASSOCIATION OF THYROID STIMULATING HORMONES AND CORTISOL LEVELS IN YOUNG ADULTS

Abstract

Background: Thyroid stimulating hormone (TSH) plays a capacity role in regulating thyroid activity and metabolic homeostasis, and cortisol plays a major role in stress hormone, which regulates physiological reaction to physiological and psychological stress. The two hormones are closely linked with the hypothalamic-pituitary axis and any disruption in one hormone axis can affect the other. According to the recent research, changes in cortisol levels that are caused by stress have the potential to modify thyroid activity, particularly in young adults who experience academic, social, and lifestyle-related stress. Still, there is limited empirical evidence that explains the correlation between TSH and cortisol levels among this group of the population.

Purpose: This study was aimed to define the relationship between the circulating levels of TSH and cortisol amongst young people.

Methodology: all the participants of the study had their venous blood samples taken aseptically and serum obtained by centrifugation. The index of thyroid functions was measured by the levels of serum TSH, triiodothyronine (T3), and thyroxine (T4) and the index of adrenal functions was measured by the means of evening serum cortisol. All the hormonal measurements were done through standardized chemiluminescent immunoassays according to the protocols of the manufacturers. A sandwich immunoassay was used to determine serum TSH and competitive immunoassays were used to determine T3, T4 and cortisol. Strict quality-control measures were put in place in regard to each batch of the analysis to provide accuracy and precision. The level of hormones was also measured within the background of reference ranges.

Findings: 50 young adults (mean age, 24.18 +3.36 years) were recruited into the study; 72 per cent female and 28 per cent male. Thyroid dysfunction had been reported in 54% of the participants, categorized as 31% hypothyroid and 30% cases hyperthyroid. The average serum level TSH concentration was 2.6 ± 1.0 mIU/L and the average evening cortisol level was 13.9 0 -4.93 mg/dL. Afternoon cortisol (>10 mg/dl) was reported in 78 % of the participants indicating a great weight of physiological strain. There were no significant correlations found between cortisol levels and other variables obtained, i.e. gender, body mass index, anxiety, academic performance, physical activity or perceived stress (p >0.05). However, analysis with the logistic regression indicated significant correlation between TSH and high cortisol rates (p =0.02) with a Nagelkerke R² of 0.61, which implies a strong predictive value.

Correlation: The current study has revealed a high level of interdependence between TSH and cortisol levels in young adulthood, indicating a close interaction between the hypothalamic–pituitary-thyroid and the hypothalamic-pituitary-adrenal axes. Elevated cortisol levels are high, which implies that there is a significant stress load in this group. Such outcomes provide an indication of the need to be able to assess endocrinology so that it becomes an integrated approach to which it becomes easy to detect and treat thyroid and stress-pathology in a young age. It would be appropriate to conduct further large-scale, longitudinal studies to explain the causal pathways and the background mechanisms.

Key words: Thyroid stimulating hormone, cortisol, stress, thyroid functioning, young adults.