Type 2 diabetes mellitus (T2DM) is one of the most prevalent chronic metabolic disorders worldwide and represents a major public health challenge because of its rapidly increasing incidence and long-term complications. It is characterized by insulin resistance, progressive pancreatic β-cell dysfunction, and chronic hyperglycemia, leading to microvascular and macrovascular complications that significantly increase morbidity and mortality (1). India has emerged as one of the countries with the highest burden of diabetes, with a growing number of newly diagnosed patients each year. Early identification of associated metabolic abnormalities is therefore essential to optimize patient management and reduce the risk of complications (2). Thyroid dysfunction is one of the most common endocrine disorders encountered in patients with diabetes mellitus. Thyroid hormones play a pivotal role in regulating carbohydrate metabolism, lipid metabolism, energy expenditure, and insulin sensitivity (3). Conversely, diabetes can influence thyroid hormone metabolism through alterations in hypothalamic-pituitary-thyroid axis function, insulin resistance, and chronic hyperglycemia. The coexistence of thyroid dysfunction and T2DM may adversely affect glycemic control, increase insulin resistance, aggravate dyslipidemia, and accelerate the development of diabetic complications, thereby increasing the overall disease burden (4). Among patients with T2DM, hypothyroidism, particularly subclinical hypothyroidism, has been reported more frequently than hyperthyroidism. Subclinical thyroid dysfunction often remains asymptomatic and may therefore remain undetected unless thyroid function tests are performed routinely (5). Even mild abnormalities in thyroid hormone levels have been associated with poor metabolic control, increased cardiovascular risk, nephropathy, retinopathy, and impaired quality of life. Early recognition and appropriate treatment of thyroid dysfunction may improve metabolic outcomes and contribute to better long-term prognosis in patients with diabetes (6). Newly detected T2DM patients provide an ideal opportunity to evaluate thyroid status before prolonged disease duration, chronic hyperglycemia, or antidiabetic therapies influence endocrine and metabolic parameters. Assessment of thyroid function at the time of diagnosis may facilitate timely identification of coexisting thyroid disorders, allowing clinicians to institute appropriate therapeutic interventions and individualized follow-up strategies (7). Furthermore, understanding the prevalence and pattern of thyroid dysfunction in newly diagnosed T2DM patients may help formulate recommendations regarding routine thyroid function screening in this population (8). Although several studies have demonstrated an association between diabetes mellitus and thyroid disorders, considerable variation exists in the reported prevalence of thyroid dysfunction across different populations because of differences in ethnicity, iodine status, demographic characteristics, and study methodology (9). Data from the southern Indian population, particularly among newly detected T2DM patients, remain relatively limited. Evaluating thyroid function in this group is therefore clinically relevant and may provide valuable information regarding the burden of thyroid abnormalities in routine clinical practice (10,11). In view of these considerations, the present study was undertaken at K.R. Hospital, Mysuru, to evaluate thyroid function tests in newly detected Type 2 diabetes mellitus subjects. The study aims to determine the thyroid status of these patients and provide evidence regarding the occurrence of thyroid dysfunction at the time of diabetes diagnosis (12,13). The findings are expected to contribute to the existing knowledge on the relationship between thyroid dysfunction and T2DM and may support the incorporation of thyroid function testing into the baseline evaluation of newly diagnosed patients whenever clinically appropriate (14,15). AIMS AND OBJECTIVES • To study Thyroid Function Test in newly detected Type 2 Diabetes Mellitus subjects..

This hospital-based cross-sectional observational study was conducted in the Department of General Medicine, K.R. Hospital, Mysore Medical College and Research Institute (MMCRI), Mysuru, from October 2022 to September 2023. A total of 100 consecutive patients with newly detected Type 2 diabetes mellitus were enrolled after obtaining approval from the Institutional Ethics Committee and written informed consent. The sample size was calculated using the standard formula (n = Z^2pq/d^2), considering a diabetes prevalence of 7%, a 95% confidence interval, and a 5% margin of error. Patients diagnosed with Type 2 diabetes mellitus according to the American Diabetes Association (ADA) guidelines were included. Patients with known thyroid disease, liver failure, acute critical illness, pregnancy, or those receiving medications known to interfere with thyroid function, such as amiodarone, propranolol, corticosteroids, and oral contraceptives, were excluded. A detailed clinical history was obtained, and all participants underwent thorough physical examination and laboratory evaluation. Diabetes mellitus was diagnosed based on ADA criteria using fasting plasma glucose, 2-hour postprandial plasma glucose, random blood glucose with classical symptoms, and glycated hemoglobin (HbA1c). Plasma glucose estimation was performed by the colorimetric method, while HbA1c was measured using high-performance liquid chromatography. Evaluation for diabetic complications included urine albumin-creatinine ratio (UACR) to assess diabetic nephropathy and fundus examination for diabetic retinopathy. Albuminuria was defined as a UACR greater than 30 mg/g, while both non-proliferative and proliferative diabetic retinopathy were considered as diabetic retinopathy. All enrolled subjects underwent thyroid function testing, including serum thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4), using electrochemiluminescence immunoassay. Based on the American Thyroid Association criteria, patients were classified as euthyroid, subclinical hypothyroid, overt hypothyroid, subclinical hyperthyroid, or overt hyperthyroid. Data were entered into Microsoft Excel and analyzed using IBM SPSS Statistics version 29. Categorical variables were presented as frequencies and percentages

Table 1: Distribution of Study Subjects According to Age Group, Gender, and Body Mass Index (BMI) among Newly Detected Type 2 Diabetes Mellitus Subjects Variable Category n % Age group (years) 35–44 29 29.0 45–54 33 33.0 55–64 28 28.0 65–74 8 8.0 >75 2 2.0 Gender Male 45 45.0 Female 55 55.0 BMI (kg/m²) Normal (18.5–24.9) 28 28.0 Overweight (25–29.9) 36 36.0 Obese (>30) 36 36.0 In the present study, among the 100 newly detected Type 2 Diabetes Mellitus subjects, 71.0% (n=71) were euthyroid, while 29.0% (n=29) had thyroid dysfunction. Thus, the majority of the study subjects were euthyroid, whereas 29.0% had thyroid dysfunction. Table 3: Distribution of Study Subjects According to Thyroid Function Status among Newly Detected Type 2 Diabetes Mellitus Subjects Thyroid Function Status n % Euthyroid 71 71.0 Subclinical Hypothyroidism 16 16.0 Hypothyroidism 9 9.0 Subclinical Hyperthyroidism 3 3.0 Hyperthyroidism 1 1.0 100 100.0 In the present study, among the 100 newly detected Type 2 Diabetes Mellitus subjects, 71.0% (n=71) were euthyroid, 16.0% (n=16) had subclinical hypothyroidism, 9.0% (n=9) had hypothyroidism, 3.0% (n=3) had subclinical hyperthyroidism, and 1.0% (n=1) had hyperthyroidism. Thus, euthyroid status was the most common thyroid function status, followed by subclinical hypothyroidism, hypothyroidism, subclinical hyperthyroidism, and hyperthyroidism.

The present study evaluated thyroid function among newly detected Type 2 diabetes mellitus (T2DM) subjects and demonstrated that 29% of patients had thyroid dysfunction, while 71% were euthyroid. Subclinical hypothyroidism was the most common abnormality (16%), followed by overt hypothyroidism (9%), subclinical hyperthyroidism (3%), and hyperthyroidism (1%). These findings suggest that thyroid dysfunction is relatively common even at the time of diagnosis of T2DM, emphasizing the importance of early thyroid function assessment. The study population predominantly comprised individuals aged 45–54 years (33%), followed by 35–44 years (29%), with a slight female predominance (55%). Most participants (72%) were either overweight or obese. These findings are consistent with the growing burden of T2DM reported by Chauhan et al. (2025), who highlighted the increasing prevalence of diabetes in India, particularly among middle-aged adults. Similarly, the systematic review by Samant et al. (2025) identified advancing age and obesity as important risk factors contributing to the development of T2DM (2,1). In the present study, thyroid dysfunction was observed in 29% of newly detected T2DM subjects. This finding is comparable with reports by Kandel et al. (2024) and Haider et al. (2025), who also demonstrated a considerable prevalence of thyroid dysfunction among patients with T2DM (8,10). Likewise, K VB et al. (2025) reported a significant burden of thyroid abnormalities in diabetic patients attending a tertiary care hospital (5). The close association between diabetes mellitus and thyroid dysfunction has been extensively reviewed by Biondi et al. (2019), who described these conditions as interconnected endocrine disorders sharing common metabolic pathways (3). Subclinical hypothyroidism was the most frequent thyroid abnormality identified in the present study. Similar observations have been reported by Yaseri et al. (2025) and Patel et al. (2025), who found subclinical hypothyroidism to be the predominant thyroid disorder among patients with T2DM (13,7). The higher prevalence of hypothyroid disorders may be explained by increased insulin resistance, altered thyroid hormone metabolism, and chronic low-grade inflammation associated with diabetes. Kahaly et al. (2025) further emphasized that hypothyroidism contributes to adverse cardiometabolic outcomes through its effects on glucose metabolism, lipid profile, and vascular function (6). Overall, the findings of the present study support the existing evidence that thyroid dysfunction, particularly subclinical hypothyroidism, is common among newly detected T2DM subjects. Assessment of thyroid function in newly detected T2DM subjects may help identify coexisting thyroid abnormalities at the time of evaluation.

The present study demonstrated that thyroid dysfunction was present in 29% of newly detected Type 2 diabetes mellitus subjects, while 71% were euthyroid. Subclinical hypothyroidism was the most common thyroid abnormality, observed in 16% of subjects, followed by hypothyroidism in 9%, subclinical hyperthyroidism in 3%, and hyperthyroidism in 1%. These findings demonstrate the occurrence of thyroid dysfunction among newly detected Type 2 diabetes mellitus subjects, with hypothyroid disorders being more frequent than hyperthyroid disorders. Assessment of thyroid function in newly detected Type 2 diabetes mellitus subjects may help identify coexisting thyroid abnormalities at the time of evaluation..

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