The study of pulmonary function tests in patients with hypothyroidism


  • Sivaranjani H. Department of General Medicine, Bangalore Medical College and Research Institute, Bangalore, Karnataka, India
  • Chaitra K. R. Department of General Medicine, Bangalore Medical College and Research Institute, Bangalore, Karnataka, India



Hypothyroid, Obstructive pattern, Pulmonary function test, Restrictive pattern


Background: Hypothyroidism is a common disease with a prevalence rate of 11% in India. It affects all organ systems in the body. Patients with hypothyroidism frequently have symptoms of fatigue and exercise intolerance. These symptoms could arise from a reduced pulmonary reserve, cardiac reserve or decreased muscle strength or increased muscle fatigue. This study aims to study the pulmonary function test in patients with hypothyroidism.

Methods: This is a cross sectional study conducted on 100 patients divided into 2 groups (a) newly detected hypothyroids (b) normal control group. Cases were matched with controls in having similar environment exposure and age group. All patients had routine symptom and clinical assessment. Laboratory investigations such as complete blood picture, pulmonary function test, chest x ray and thyroid function test were done. Data was entered and analysed.

Results: In this study conducted on 100 patients, case group had symptoms of easy fatiguability (36%), breathlessness (20%), menstrual abnormality (20%), weight gain (7%) and generalised body aches (5%). Mean FEV1 levels between cases and controls were 1.34 and 1.72 (p value 0.00), mean FVC were 1.88 and 2.09 (p value 0.114), FEV1/FVC ratio of 70.56, 81.98 respectively (p value 0.00). The distribution of PFT pattern was 32% obstructive, 28% mixed pattern and 22% restrictive pattern.

Conclusions: This study shows that hypothyroidism causes significant decrease in FEV1 and FEV1/FVC ratio, thereby suggesting obstructive patterns of lung involvement .Therefore PFT can be used routinely as a screening test for all hypothyroid patients to detect early respiratory dysfunction and thereby optimise treatment especially in obese patients and patients with pre-existing lung disease as hypothyroidism adds to their respiratory dysfunction.


Bagcchi S. Hypothyroidism in India: more to be done. The lancet diabetes and endocrinol. 2014;2(10):778.

Dashe JS, Mazziotti A, Press M, Cooper DS. Subclinical hypothyroidism (multiple letters). New Eng J Med. 2001 Dec 20;345(25):1855-6.

Kek PC, Ho SC, Khoo DH. Subclinical thyroid disease. Singap Med J. 2003;44(11):595-600.

Werner SC, Ingbar SH, Braverman LE, Utiger RD, editors. Werner and Ingbar's the thyroid: a fundamental and clinical text. Lippincott Williams and Wilkins; 2005.

McQuade C, Skugor M, Brennan DM, Hoar B, Stevenson C, Hoogwerf BJ. Hypothyroidism and moderate subclinical hypothyroidism are associated with increased all-cause mortality independent of coronary heart disease risk factors: A PreCIS database study. Thyroid. 2011;21(8):837-43.

Resta O, Pannacciulli N, Di Gioia G, Stefano A, Barbaro MF, De Pergola G. High prevalence of previously unknown subclinical hypothyroidism in obese patients referred to a sleep clinic for sleep disordered breathing. Nutrit, Metabol Cardiovas Dis. 2004;14(5):248-53.

Zwillich CW, Pierson DJ, Hofeldt FD, Lufkin EG, Weil JV. Ventilatory control in myxedema and hypothyroidism. New Engl J Med. 1975;292(13):662-5.

Siafakas NM, Salesiotou V, Filaditaki V, Tzanakis N, Thalassinos N, Bouros D. Respiratory muscle strength in hypothyroidism. Chest. 1992;102(1):189-94.

Brent GA, Davies T. Hypothyroidism and Thyroiditis. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, Editors. Williams Text book of Endocrinology. 12th ed. Philadelphia WB. Saunders Co; 2011:409.

Warren M. Gold M. Pulmonary Function Tests. In: Murray JF, Nadel JA, Editors. Textbook of Respiratory Medicine. 3rd ed. Philadelphia: WB. Saunders Co.; 2000:781-785.

Duranti R, Gheri RG, Gorini M, Gigliotti F, Spinelli A, Fanelli A, et al. Control of breathing in patients with severe hypothyroidism. The Am J med. 1993;95(1):29-37.

Larsen PR, Kronenberg HM, Melmed, Polonsky KS. William’s Textbook of Endocrinology. 10th ed. Philadelphia: Elsevier Saunders; 2003:424-440.

Datta D, Scalise P. Hypothyroidism and failure to wean in patients receiving prolonged mechanical ventilation at a regional weaning center. Chest. 2004;126(4):1307-12.

Bhuvaneswari T, Banu KK. Evaluation of pulmonary functions in patients with hypothyroidism who are on conservative management. Sch J App Med Sci. 2014;2(2A):495-7.

Çakmak G, Saler T, Sağlam ZA, Yenigün M, Demir T. Spirometry in patients with clinical and subclinical hypothyroidism. Hypothyroidism: Influences and Treatments. 2007;55(3):266-70.

Roel S, Punyabati O, Prasad L, Salam R, Ningshen K, Shimray AJ, et al. Assessment of functional lung impairment in hypothyroidism. IOSR J Dent Med Sci. 2014;13:4-7.

Sharifi F, Amari A. The effect of levothyroxin on pulmonary function tests of hypothyroid patients. Int J Endocrinol Metab. 2005;1:48-51.

Bassi R, v Dhillon S, Sharma S, Sharma A, Tapdiya M. Effect of thyroid hormone replacement on respiratory function tests in hypothyroid women. Pak J Physiol. 2012;8(2):20-3.

Martinez FJ, Bermudez-Gomez M, Celli BR. Hypothyroidism: a reversible cause of diaphragmatic dysfunction. Chest.1989;96(5):1059-63.

Valjevac S, Hadzovic-Dzuvo A, Valjevac A, Kucukalic-Selimovic E, Lepara O. Assessment of lung dysfunction with spirometry in patients with thyroid disorders. Acta Informatica Medica. 2011;19(1):16.






Original Research Articles