Evaluation of Respiratory Functions in Subclinical and Clinical Hypothyroidism

Abstract

Aim: Subclinical hypothyroidism reflects the earliest stage of thyroid dysfunction with subjects having normal or decreased fT4, normal fT3 and decreased thyroid stimulating hormone levels. Thyroid hormones have effects on the respiratory system functions. It is well known that thyroid hormones have effects on the respiratory system functions however there are few studies concerning the effect of subclinical hypothyroidism on the respiratory system. We aimed to investigate the respiratory functions in patients diagnosed with subclinical and clinical hypothyroidism. Material and Methods: A total of 61 patients with clinical (n=31) or subclinical (n=30) hypothyroidism and 27 healthy subjects as a control group were included in the present study. Respiratory functions were evaluated by simple spirometry. All respiratory parameters including FVC, FVC%, FEV1, FEV1%, FEV1/FVC, FEF25-75, FEF25-75%, PEF, PEF% were assessed. Additionally, free triiodothyronine (FT3), free thyroxin (FT4) and thyroid stimulating hormone (TSH) levels were measured in all subjects. Results: Patients in the clinical hypothyrodism, subclinical hypothyroidism and control groups were homogenous in terms of age and gender distribution. Body mass index (kg/m2) was determined to be significantly higher in patients with clinical hypothyroidism when compared to control subjects (p<0.05). Spirometric evaluation of the respiratory function revealed significantly lower values for FVC (L; p<0.05), FVC (%; p<0.05), FEV1 (L; p<0.05) and FEV1 (%; p<0.05) in all hypothyroid patients regardless of the clinical type when compared to control subjects. Conclusions: Respiratory function tests seem to be beneficial in the evaluation of respiratory functional state in hypothyroidism. We think that community screening with simple spirometry may be helpful for patients with risk of subclinical hypothyroidism. Key words: Subclinical Hypothyroidism; Clinical Hypothyroidism; Respiratory Functions.

Keywords

• Subclinical Hypothyroidism; Clinical Hypothyroidism; Respiratory Functions.

Klinik Ve Subklinik Hipotiroidizimde Solunum Fonksiyonlarının Değerlendirilmesi

Öz

Amaç: Subklinik hipotiroidizm tiroid disfonksiyonlarının erken evresidir ve hastaların ft4 düzeyleri normal veya düşük, ft3 düzeyleri normal ve tiroid stimulan hormonu düzeyleri azalmıştır. Tiroid hormonlarının solunum sistemi fonksiyonları üzerinde etkileri vardır. Titoid hormonlarının solunum sistemi fonksiyonları üzerine olan etkisi iyi bilinirken, Subklinik hipotiroidinin solunum sistemin üzerindeki etkilerini araştıran çok az çalışma vardır. Biz klinik ve subklinik hipotiroidi tanısı almış hastalarda solunum fonksiyonlarını araştırmayı amaçladık. Gereç ve Yöntemler: Çalışmamıza, 31 klinik ve 30 subklinik hipotiroidili olmak üzere toplam 61 hasta ve 27 sağlıklı birey kontrol grubu olarak alındı. Solunum fonksiyonları basit spirometrik testler ile ile değerlendirildi. Tüm solunum parametreleri, FVC, FVC%, FEV1, FEV1%, FEV1/FVC, FEF25-75, FEF25-75%, PEF, PEF% değerlendirildi. Ayrıca, serbest triiodotironin (ST3) ve serbest tiroksin( ST4) ve tiroid stimule edici hormon (TSH) tüm bireylerde ölçüldü. Bulgular: Klinik hipotroidili, subklinik hipotiroidili hastalar ve kontrol grubu yaş ve cinsiyet dağılımı açısından homojendi. BMI (kg/m2) klinik hipotiroidili hastalarda kontrol grubu ile kıyaslandığında önemli düzeyde yüksekti (p<0.05). Solunum fonksiyonlarının değerlendirilmesinde FVC (L; p<0.05), FVC (%; p<0.05), FEV1 (L; p<0.05) and FEV1 (%; p<0.05) değerleri kontrol grubu ile karşılaştırıldığında, tüm hipotiroidili hastalarda klinik tipten bağımsız olarak önemli düzeyde düşüktü. Sonuç: Solunum fonksiyon testleri, hipotiroidizmli hastaların solunum fonksiyon durumunun değerlendirilmesinde faydalıdır. Basit spirometre ile toplum taramasının subklinik hipotroidi riski taşıyan hastaların tespiti açısından faydalı olacağını düşünüyoruz. Anahtar kelimeler: Hipotiroidizm; Klinik Hipotiroidizm; Solunum Fonksiyonları.

Anahtar Kelimeler

• Hipotiroidizm; Klinik Hipotiroidizm; Solunum Fonksiyonları.

Kaynakça

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