Insulin resistance is defined as a glucose homeostasis disorder involving a decreased sensitivity of muscles, adipose tissue, liver and other body tissues to insulin, despite its normal or increased concentration in blood. Insulin resistance may be asymptomatic or occur presenting a variety of disorders, such as: glucose tolerance impairment, type 2 diabetes, as well as hypercholesterolaemia, hypertriglyceridaemia, obesity, and arterial hypertension. Insulin acts via specific receptors present on the surface of most cells of the body. The greatest number of these receptors is found on adipocytes, hepatocytes and striated muscle cells. There are three mechanisms of insulin resistance: pre-receptor, receptor and post-receptor. Multiple methods of assessing insulin resistance are based on the concurrent measurements of glucose and insulin levels in blood serum. The glucose and insulin measurements are conducted in baseline conditions or after intravenous administration of a specific quantity of glucose or insulin. The methods of assessing insulin resistance are divided into direct and indirect. The current 'gold standard' in the assessment of insulin sensitivity is the determination of tissue glucose utilisation using the metabolic clamp technique. The presence of disorders of carbohydrate metabolism has been demonstrated in thyroid disease involving either overt hyperthyroidism or overt hypothyroidism. The severity of the disease is proportional to the severity of these disorders. The possible influence of subclinical forms of both hyperthyroidism and hypothyroidism on carbohydrate disorders is still under discussion. Thyroid hormones have a significant effect on glucose metabolism and the development of insulin resistance. In hyperthyroidism, impaired glucose tolerance may be the result of mainly hepatic insulin resistance, whereas in hypothyroidism the available data suggests that the insulin resistance of peripheral tissues prevails.

Hyperprolactinaemia is the most common dysfunction of the hypothalamic-pituitary axis and occurs more commonly in women. The prevalence of hyperprolactinaemia ranges from 0.4% in the general adult population to as high as 9–17% in women with reproductive diseases. It is accompanied by the phenomenon of insulin resistance (IR), which is also a significant clinical problem nowadays. The prevalence of IR is increasing, particularly in developing countries and in younger populations, with estimates of prevalence ranging from 20 to 40% in different populations. The aim of our review is to summarize recent data on the possible association between IR and hyperprolactinaemia. This review is based on an electronic search of the literature in the PubMed database published from 2000 to 2022 using combinations of the following keywords: IR, hyperprolactinemia or IR and hyperprolactinemia. The references included in previously published review articles were also checked, and any relevant papers were also included. Numerous scientific studies have shown a relationship between IR and hyperprolactinaemia. Increased plasma prolactin (PRL) levels are often associated with an increase in tissue resistance to insulin. There are many scientific theories explaining the probable mechanisms of this phenomenon. One is the finding that glucose and PRL act synergistically in inducing the transcription of insulin genes. It is also suggested that PRL may act as a regulator of insulin sensitivity and metabolic homeostasis in adipose tissue. The topic of the mutual correlation of hyperprolactinaemia and IR is important, and it certainly requires further research and observation. Hyperprolactinaemia is the most common dysfunction of the hypothalamic-pituitary axis and occurs more commonly in women. The prevalence of hyperprolactinaemia ranges from 0.4% in the general adult population to as high as 9–17% in women with reproductive diseases. It is accompanied by the phenomenon of insulin resistance (IR), which is also a significant clinical problem nowadays. The prevalence of IR is increasing, particularly in developing countries and in younger populations, with estimates of prevalence ranging from 20 to 40% in different populations. The aim of our review is to summarize recent data on the possible association between IR and hyperprolactinaemia. This review is based on an electronic search of the literature in the PubMed database published from 2000 to 2022 using combinations of the following keywords: IR, hyperprolactinemia or IR and hyperprolactinemia. The references included in previously published review articles were also checked, and any relevant papers were also included. Numerous scientific studies have shown a relationship between IR and hyperprolactinaemia. Increased plasma prolactin (PRL) levels are often associated with an increase in tissue resistance to insulin. There are many scientific theories explaining the probable mechanisms of this phenomenon. One is the finding that glucose and PRL act synergistically in inducing the transcription of insulin genes. It is also suggested that PRL may act as a regulator of insulin sensitivity and metabolic homeostasis in adipose tissue. The topic of the mutual correlation of hyperprolactinaemia and IR is important, and it certainly requires further research and observation.

Background: Nutrition in sport is a priority; it is the basis for maintaining optimal health and a prerequisite for the high performance necessary for competitions. The aim of this study was to assess low energy availability and its possible consequences among female triathletes by using the Low Energy Availability in Females Questionnaire (LEAF-Q). Methods: The study involved 30 female triathetes. The LEAF-Q was used in the study. An analysis of the body composition was carried out with the seca device mBCA 515 medical Body Composition Analyzer. Results: Of the 30 female triathletes studied, 23.3% had a monthly cycle disorder, defined as an amenorrhea state for more than 90 days. No differences were found in injury rates or training days lost to injury due to menstrual disturbances. Menstruation changes were significantly greater due to increases in exercise intensity, frequency, and duration in the group experiencing menstrual disturbances (85.7 [95% CIs: 42.1–99.6] vs. 8.7 [95% CIs: 1.1–28.0]). The menstrual disorder group had a greater incidence of their periods stopping for more than 3 months than the group without menstrual disturbances. Conclusions: The female triathletes did not show abnormalities in body weight or composition, and these were not related to the incidence of menstrual disturbances. However, 20% of the triathletes either had, at the time of the study, or had had in the past monthly cycle disorders that could indicate an immediate risk of low energy availability. The LEAF-Q identified 10% of the triathletes as at risk (score > 8) of low energy availability and the physiological and performance consequences related to relative energy deficiency in sports (RED-S).

Introduction: Metabolic syndrome involves abdominal obesity, arterial hypertension, type 2 diabetes and lipid disorders manifested as atherogenic dyslipidaemia. Abnormal thyroid function affects the severity of MetS components, since regulating metabolism is one of the most important functions of thyroid hormones. In this study, we present the influence of hypothyroidism on lipid and carbohydrate disorders in patients with MetS. Material and methods: The described study was a prospective, two-centre screening study of 24-month duration. The study participants were 441 patients (350 women, 91 men, aged 28–82) with metabolic syndrome diagnosed according to the 2005 IDF. Results: By comparing the study and the control group, statistically significant differences were observed in the mean triglyceride levels (respectively 161,5 vs. 134,8 mg/dL, p = 0.047), mean fasting glycaemia (respectively 111,8 vs. 126,1 mg/dL, p = 0.044) and TG/HDL ratio (4,74 vs. 3,71, p = 0.043). Hypothyroidism shows a positive correlation with the TG levels and TG/HDL-C ratio and a negative correlation with the mean fasting glycaemia in people with MetS. A significantly higher TG/HDL-C ratio and lower mean insulin sensitivity ratio observed in men with hypothyroidism, indicated higher insulin resistance in men. Conclusions: In view of the above, it may be hypothesized that in patients with both MetS and hypothyroidism, especially of male gender, the risk of death of cardiovascular causes is greater due to the severity of MetS components. Moreover, we suggest that in patients recently diagnosed with MetS, active detection of hypothyroidism should be performed by determining the TSH levels, while patients diagnosed with hypothyroidism (apart from replacement therapy) should be monitored for the possible occurrence of MetS in the future. (Endokrynol Pol 2015; 66 (4): 288–294) Introduction: Metabolic syndrome involves abdominal obesity, arterial hypertension, type 2 diabetes and lipid disorders manifested as atherogenic dyslipidaemia. Abnormal thyroid function affects the severity of MetS components, since regulating metabolism is one of the most important functions of thyroid hormones. In this study, we present the influence of hypothyroidism on lipid and carbohydrate disorders in patients with MetS. Material and methods: The described study was a prospective, two-centre screening study of 24-month duration. The study participants were 441 patients (350 women, 91 men, aged 28–82) with metabolic syndrome diagnosed according to the 2005 IDF. Results: By comparing the study and the control group, statistically significant differences were observed in the mean triglyceride levels (respectively 161,5 vs. 134,8 mg/dL, p = 0.047), mean fasting glycaemia (respectively 111,8 vs. 126,1 mg/dL, p = 0.044) and TG/HDL ratio (4,74 vs. 3,71, p = 0.043). Hypothyroidism shows a positive correlation with the TG levels and TG/HDL-C ratio and a negative correlation with the mean fasting glycaemia in people with MetS. A significantly higher TG/HDL-C ratio and lower mean insulin sensitivity ratio observed in men with hypothyroidism, indicated higher insulin resistance in men. Conclusions: In view of the above, it may be hypothesized that in patients with both MetS and hypothyroidism, especially of male gender, the risk of death of cardiovascular causes is greater due to the severity of MetS components. Moreover, we suggest that in patients recently diagnosed with MetS, active detection of hypothyroidism should be performed by determining the TSH levels, while patients diagnosed with hypothyroidism (apart from replacement therapy) should be monitored for the possible occurrence of MetS in the future. (Endokrynol Pol 2015; 66 (4): 288–294)

Introduction: Autoimmune thyroid diseases (AITD), including Hashimoto’s thyroiditis (HT), are the most common organ specific autoimmune disorders. Vitamin D (vit-D) is a steroid molecule, mainly produced in the skin, which regulates the expression of many genes. The vitamin D receptor (VDR) is found in most tissues and cells in the body. Many studies suggests that vit-D deficiency, which is common worldwide, could also play an important role in autoimmune diseases, including HT. The aim of our study was to show the potential differences in vit-D levels between healthy women and individuals with hypothyroidism and HT. Additionally, we assessed the correlation between vit-D concentration and the level of TSH and anti-thyroid antibodies in females diagnosed with HT. Material and methods: The study group included 370 subjects. The group was divided into 3 subgroups: (125 — healthy individuals, 111 — hypothyreosis, 134 — HT). Anthropometric measurements including height and weight were obtained in all participants. Body mass index (BMI) was calculated as body weight (in kilograms) divided by the square of body height (in metres). The measurement of the thyroid gland was performed using an ultrasound scan with a 10-MHz linear probe by one endocrinologist (Vivid S60N). Results: We noticed that a lower level of vit-D was connected with a higher level of TSH in each subgroup. There was also strong, negative correlation between TSH and vit-D levels in all the study groups. Moreover, there was a weak, negative correlation between antithyroid peroxidase antibody (anti-TPO) and antithyroglobulin antibody (anti-TG) and vit-D levels in females with HT regardless of vit-D status: < 20 ng/mL, 20–30 ng/mL, and > 30 ng/mL. Conclusions: To our knowledge, the current study is the first in Poland to compare vit-D status in healthy patients and patients with hypothyroidism, taking into account the level of antibodies (anti-TPO and anti-TG). The results of our study suggest that vit-D supplementation in patients with hypothyroidism, especially in the course of AITD, although determining its optimal, safe dose requires further research. Introduction: Autoimmune thyroid diseases (AITD), including Hashimoto’s thyroiditis (HT), are the most common organ specific autoimmune disorders. Vitamin D (vit-D) is a steroid molecule, mainly produced in the skin, which regulates the expression of many genes. The vitamin D receptor (VDR) is found in most tissues and cells in the body. Many studies suggests that vit-D deficiency, which is common worldwide, could also play an important role in autoimmune diseases, including HT. The aim of our study was to show the potential differences in vit-D levels between healthy women and individuals with hypothyroidism and HT. Additionally, we assessed the correlation between vit-D concentration and the level of TSH and anti-thyroid antibodies in females diagnosed with HT. Material and methods: The study group included 370 subjects. The group was divided into 3 subgroups: (125 — healthy individuals, 111 — hypothyreosis, 134 — HT). Anthropometric measurements including height and weight were obtained in all participants. Body mass index (BMI) was calculated as body weight (in kilograms) divided by the square of body height (in metres). The measurement of the thyroid gland was performed using an ultrasound scan with a 10-MHz linear probe by one endocrinologist (Vivid S60N). Results: We noticed that a lower level of vit-D was connected with a higher level of TSH in each subgroup. There was also strong, negative correlation between TSH and vit-D levels in all the study groups. Moreover, there was a weak, negative correlation between antithyroid peroxidase antibody (anti-TPO) and antithyroglobulin antibody (anti-TG) and vit-D levels in females with HT regardless of vit-D status: < 20 ng/mL, 20–30 ng/mL, and > 30 ng/mL. Conclusions: To our knowledge, the current study is the first in Poland to compare vit-D status in healthy patients and patients with hypothyroidism, taking into account the level of antibodies (anti-TPO and anti-TG). The results of our study suggest that vit-D supplementation in patients with hypothyroidism, especially in the course of AITD, although determining its optimal, safe dose requires further research.

Introduction: Metabolic syndrome (MetS), which includes abdominal obesity, hypertension, hypertriglyceridaemia, low high-density lipoprotein cholesterol and elevated fasting plasma glucose, is now well understood. The prevalence of MetS is increasing all over the world. Central obesity is the main and the most common component of MetS. The most simple, practical, and frequently used tool for assessing body weight is body mass index. The aim of our study was to show the correlation between waist circumference (WC) and BMI in women with MetS depending on its components. Material and methods: It was a study of 36-month duration (2016–2019) conducted in University Hospital No. 1 in Bydgoszcz, Poland. The study included 696 women with diagnosed MetS according to the 2009 International Diabetes Federation criteria. Results: In the study group, WC was found to be significantly correlated with BMI according to the arterial hypertension, T2DM, IFG, lower HDL-C, and higher TG level. Conclusion: We should consider changing the WC guidelines for Europeans, but for this we need more prospective studies. Introduction: Metabolic syndrome (MetS), which includes abdominal obesity, hypertension, hypertriglyceridaemia, low high-density lipoprotein cholesterol and elevated fasting plasma glucose, is now well understood. The prevalence of MetS is increasing all over the world. Central obesity is the main and the most common component of MetS. The most simple, practical, and frequently used tool for assessing body weight is body mass index. The aim of our study was to show the correlation between waist circumference (WC) and BMI in women with MetS depending on its components. Material and methods: It was a study of 36-month duration (2016–2019) conducted in University Hospital No. 1 in Bydgoszcz, Poland. The study included 696 women with diagnosed MetS according to the 2009 International Diabetes Federation criteria. Results: In the study group, WC was found to be significantly correlated with BMI according to the arterial hypertension, T2DM, IFG, lower HDL-C, and higher TG level. Conclusion: We should consider changing the WC guidelines for Europeans, but for this we need more prospective studies.