Thyroid and thorax: prevalence and correlates of interstitial lung abnormalities in hypothyroidism

<bold>Background:</bold> Interstitial lung abnormalities (ILA) encompass a spectrum of parenchymal lung changes, often detected incidentally in imaging studies. While the association between ILA and certain systemic diseases is well-established, the relationship between ILA and hypothyroidism remains unclear. This study aimed to estimate the prevalence of ILA among hypothyroidism patients and identify potential correlates. <bold>Methods:</bold> In this cross-sectional, prospective, observational study a total of 100 hypothyroid patients consecutively enrolled and underwent spirometry and diffusing capacity of the lung for carbon monoxide (DLCO) assessments. Patients with abnormal spirometry and low DLCO underwent high-resolution computed tomography (HRCT) thorax scans to identify ILA. Correlations between ILA and patient's demographic, clinical, and medical data were analyzed. <bold>Results:</bold> ILA was present in 34 (34%) of hypothyroid patients (95% CI: 33.9%-78.2%). Fifty (50%) patients with hypothyroidism exhibited a low percentage of predicted DLCO and 20 (20%) patients showed restrictive defects on spirometry. Positive correlations were found between ILA and the patient's age, TSH levels, duration of hypothyroidism, and DM. However, ILA was negatively correlated with 6-MWD, % predicted DLCO, and FVC. <bold>Conclusion:</bold> These findings suggest a potential link between hypothyroidism and ILA. Therefore, further research is needed to understand the pathophysiology of ILA in hypothyroidism. Advanced age, co-existing DM, uncontrolled and longer duration of hypothyroidism may contribute to its development. Additionally, DLCO appears to be a promising diagnostic tool for detecting diffusion abnormality earlier than HRCT.