Clinical and biochemical aspects between “stress” and “non-stress” induced Graves’ disease

1Young Researchers and Elite Club, Ardabil Branch, Islamic Azad University, Ardabil, Iran 2Faculty of Medicine, Azad Ardabil University of Medical Sciences, Ardabil, Iran 3Endocrine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran 4Department of Internal Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Immunopathologia Persa http www.immunopathol.com


Introduction
The first people reporting goiter and ophthalmopathy were Iranian philosophers, Avicenna and Al-Jorjani. These manuscripts were written in 1000 and 1100 AD (1). Graves' disease is an autoimmune disorder, in which the body produces autoantibody-stimulatory receptor on the thyroid (2). The reason of generation of these antibodies is unknown and it is unclear why some people develop, thyroidstimulating immunoglobulin antibody (TSI Ab) (3). The most important features of this disease are goiter and ophthalmopathy (4). For this reason, in patients with thyrotoxicosis who have ophthalmopathy, Graves' disease is confirmed. Various factors contribute to the development of this disease such as gender, genetic and environmental factors (4,5). One of these environmental factors is stress. Stress is known as a flam or causative

Key point
Several factors contribute to flare up in Graves' disease, one of which is stress. We evaluated stress induced and non-stress induced Graves' disease. Severity of disease in stress induced Graves' group was more severe, but duration of disease was shorter than that of non-stress induced Graves' group.
agent. Emotional or physical stress or severe illness may be a factor for the onset of Graves' disease among people who are genetic susceptibility to the disease (6). Stress stimulates the immune system by mechanism of activity of Th17, Th1 and Th2. Increasing these cells stimulates B cells since these cells secrete TSI antibodies (7). Psychological and physical stress can stimulate this mechanism (6), while during the Second World War, the incidence of Graves' disease increased sharply DOI:10.34172/ipp.2021.06 in Nazi prisons (8). Paunkovic et al in a prospective study showed while the incidence of Graves' disease had been stable since 1971, it significant increased in eastern Serbia during the civil war in the former Yugoslavia between 1992 and 1995 (9).
Other stresses include; divorce, death of relatives, emigration, change jobs, bankruptcy, torture, accident, falling and thunderbolt (4,7,10). The perceived stress scale is a classic stress assessment instrument. The perceived stress questionnaire was developed by Cohen et al in 1983 and contains 14 questions that measure how much stress a person experienced during his last month (11). Numerous studies have focused on the role of genetics in Graves' disease. Genetics plays an important role in the development of Graves' disease. The study of Brix et al, on monozygot twins, strongly supports the idea that genetic factors play a major role in the etiology of Graves' disease (12). Winsa et al on 208 Graves' patients showed that negative events in life and genetic susceptibility play an important role in the development of Graves' disease (13). However, in addition to genetics, stress also plays a major role in the development and severity of Graves' disease. We therefore decided to do this study on stress induced and non-stress induced Graves' patients.

Objectives
The aim of this study was to evaluate the association between stress and onset or worsening of Graves' disease and differences between "stress induced" and "non-stress induced" Graves' group.

Study design
This prospective study was conducted in 2017. This study evaluated 148 patients with Graves' disease in Endocrine Research Center, Tabriz University of Medical Sciences in Iran. The perceived stress scale (PSS) questioner (11) form was filled up for patients and laboratory information was extracted based on information in the records. According to PSS all patients were divided into two groups; stress and non-stress induced Graves' group. Individual scores on the PSS can range from 0 to 56 with higher scores indicating higher perceived stress. PSS score questionnaire was filled after the onset of the disease or long afterwards. Hence the questionnaire was originally a reminder of the past.
Scores ranging from 0-14 are considered low-stress. Scores ranging from 15-28 are considered moderate stress. Scores ranging from 29-56 are considered high perceived stress. All of the patients were divided into two groups: stress induced and non-stress induced Graves' group. In this study, specific stress was considered, thereby score more than the 28 was entry criteria in stress induced Graves' group. Thus patients with scores "between" 0 to 28 were in non-stress induced" Graves' group and those with scores of more than 28 were in stress induced" Graves' group. Mean ± standard deviation of PSS score in stress induced Graves's group and in non-stress induced Graves's group was 40.24 ± 6.53 and 18.47± 3.90 respectively. Graves' disease was diagnosed by assessment of serum TSH, free thyroxin (FT4), diffused goiter and ophthalmopathy. Antithyroid peroxidase (anti-TPO) was measured in all of them. To estimate thyroid volume, a clinical examination by an endocrinologist was conducted; since thyroid ultrasound was not used due to reducing the cost. The degree of goiter and ophthalmopathy and rate of relapse or no response to methimazole were determined from available information for all patients. In both groups, the dose and duration of treatment were determined. Patients who did not respond to anti-thyroid drugs were treated with ablative therapy such as radioactive iodine and thyroidectomy.

Ethical issues
The research followed the tenets of the Declaration of Helsinki. The Ethics Committee of Tabriz University of Medical Sciences approved this study (IR.TBZMED. REC.1397.067). Accordingly, written informed consent taken from all participants before any intervention.

Statistical analysis
Statistical analysis was done by SPSS 21. The data are shown as mean ± SD and 95% confidence interval. Univariate test for all parameters was adjusted relative to gender and age to check difference between the means of two groups. Chisquare test was used to determine statistical difference in qualitative variables. P value less than 0.05 was considered as statistically significant.

Results
This study was performed on 148 patients with Graves' disease. In stress induced Graves' group 53 patients and in non-stress induced Graves' group 95 patients selected. Basic demographic information (before drug therapy) was extracted from the patients' records. Demographic information such as age at the time of diagnosis, thyroid size (estimated by endocrinologist), TSH, FT4 and anti-TPO is shown in Table 1. Patients were divided into two groups according to PSS score. The mean ± standard deviation of PSS score in 53 patients in stress induced Graves' group was 40.24 ± 6.53 and in 95 patients in nonstress induced Graves' group was 18.47 ± 3.90 (P < 0.001). The average age of patients in stress induced Graves' group was 27.81 ± 7.49 and in 95 patients in non-stress induced Graves' group was 26.06 ± 7.05 (P = 0.16) was not significantly different (Table 1).
Average dose of methimazole per day and average duration of treatment per months are shown in Table 1. The mean ± standard deviation methimazole consumption in the stress induced Grave's group was 5.3 mg/d and in the non-stress induced Graves' disease group was 6.59 mg/d. The duration of taking methimazole in the stress induced Graves' disease and non-stress induced Graves' disease group was 11.92 months and 14.49 months respectively ( Table 1). The thyroid size in the stress induced Graves' disease group was smaller than non-stress induced Graves' disease group (34 ± 10.21 g versus 44.94 ± 9.03 g; P=0.002).
In the stress induced Grave's group, percent of men was higher than in non-stress induced Graves' disease group (26.4% versus 12.6%; P=0.02) however, there was no significant difference in recurrence and ablation therapy between two groups (Table 1).
In this study, 122 patients were women and 26 patients were men. All of demographic data by gender are shown in Tables 2 and 3.
As seen in Tables 2 and 3 in male and female groups, methimazole dosage and duration, thyroid size, anti-TPO antibodies were significantly different between stress induced and non-stress induced Graves' disease group.

Discussion
In this study, clinical and biochemical aspects were compared between stress and non-stress induced Graves' disease group. So far, there has been no comprehensive study on the comparison between two groups. One of the important findings in this study was the proportion of men to women. Numerous studies showed that Graves' disease is higher in women than in men. Thus, men account for 10% of Graves' disease patients (14)(15)(16)(17). However in this study, the percentage of men in stress induced Graves' disease group was 26% and in non-stress induced Graves' disease group was 12% (P= 0.002). Whether stress in men has contributed more to development of Graves' disease is not yet proven. Our study showed that in stresses induced Graves' disease, FT4 was significantly higher than nonstress induced Graves' disease. The level of TSH in the stress induced Graves' disease group was lower than the non-stress induced Graves' disease group, however this finding was not significant.
Falgarone et al reported the important role of emotional stress in development of Graves' disease (18). They recommended reduction of stress for better response to treatment. Benzodiazepine is given occasionally to reduce stress. Propranolol in addition to reducing heart rate and decreased peripheral conversion of T4 to T3 reduces stress and can also be beneficial by affecting mood. However, some investigators do not accept this theory (5,7,15,16,).
Methimazole dosage and duration of treatment were evaluated between the two groups. The first step in the treatment of Graves' disease is drug therapy. The duration of drug therapy in these patients is 1 to 2 years. If patients do not respond to treatment during this period, Variables are expressed as mean ± standard deviation (SD). * Statistically significant (P < 0.05); ** Statistically significant (P < 0.001) a Chi-square test; b Univariate test all parameters were adjusted relative to gender and age. Variables are expressed as mean ± standard deviation (SD). * Statistically significant (P < 0.05); ** Statistically significant (P < 0.001) a Independent samples t test.
methimazole should be discontinued and final treatment (ablation therapy) should be given to them (15,19). The discontinuation of methimazole in our patients was due to improvement or because of lack of response to drug and then, ablation was conducted. In some cases, lack of response to a medication was not due to time of drug therapy alone, while it could be due to inability to reduce methimazole dosage during a specified time, which in such cases ablation was performed. Ablation therapy with iodine 131 occurred in both groups, which was not statistically significant. Nevertheless ablation therapy with surgery only occurred in non-stress induced Graves' disease.
Clinical aspects of Graves' disease are more strongly associated with higher levels of FT4 (7,10,17). The onset of Graves' disease is more severe (higher FT4) in stress induced Graves' disease, however, the level of anti-TPO was significantly lower than of non-stress induced Graves' disease. The hypothesis in this regard is that stress is a trigger for the autoimmune Graves' disease.
In this study the dosage and duration of methimazole therapy in the stress induced Graves' group was shorter than non-stress induced Graves' disease group.
Another important finding in this study was a shorter period of treatment in stress induced Graves' disease group. In this group, size of thyroid was smaller and anti-TPO was lower than another group. Another hypothesis for these findings is response to treatment in stress induced Graves' disease group. Our observation showed that treatment in this group occurred faster.
Overall, according to evidence of this study, Graves' disease is somewhat milder in stress induced Graves' disease.
Unfortunately, in our country, thyroid-stimulating immunoglobulin antibody (TSI Ab) is not routinely measured. If we could measure TSI Ab in our study, the reasons for difference between two groups were more specific.
In this study, the parameters were measured separately between men and women with stress and non-stress induced Graves' disease group. There were no significant differences in the parameters in men and women group except in methimazole dose, which was less in women with stress induced Graves' disease group than non-stress induced Graves' disease group.
Several parameters are involved in developing and severity of Graves' disease, such as thyroid size, free T4, free T3, TSI Ab and exophthalmia (3,9,18,19). In our study, stress was a major contributor to severity of disease and duration of treatment.

Conclusion
The stress induced Graves' disease had initially more severe manifestation, but severity of disease is lower in this group. In addition, in stress induced Graves' disease goiter was smaller and anti-TPO was lower than nonstress induced Graves' group. Additionally, doses and duration of treatment with methimazole were also lower. While stress affects Graves 'disease, therefore management of stress is an important part of therapy.

Limitations of the study
Unfortunately, in Iran, TSI Ab is not routinely measured. If we could measure TSI Ab in our study, the reasons for difference between two groups were more specific.
Author's contribution MN and FN contributed to literature search, study design, data collection, data analysis, data interpretation and writing. FN and MZ participated in the literature search and data collection. MN contributed to study design and data analysis. FN and MZ participated in study design and data interpretation. All authors read and signed the final manuscript. Variables are expressed as mean ± standard deviation (SD). * Statistically significant (P < 0.05); ** Statistically significant (P < 0.001); a Independent samples t test.