Role of gamma-glutamyl transferase (GGT) in diagnosis of impaired glucose tolerance and metabolic syndrome: A prospective cohort research from the Kerman Coronary Artery Disease Risk Study (KERCADRS)

About 8% of the general population suffers from autoimmune diseases, from which 78%
are women. One of the most important causes of thyroid diseases is autoimmunity in origin,
and it seems that people with thyroid diseases present more signs of asthma. This study was
therefore designed to investigate the frequency of autoimmune thyroid diseases in women
suffering from bronchial asthma.
In a cross-sectional study, 100 women with asthma and 100 women as control group
were tested for thyroid function and anti-thyroid peroxidase antibody (anti-TPO Ab)
measurements. The asthmatic patients were selected based on having chronic cough,
dyspnea, wheezing and clinical examination of the chest. The diagnosis was confirmed by
pulmonary function tests. Blood tests were done by electrochemiluminescence immunoassay
method.
No hyperthyroid patient was found in either group. Serum TSH and Total T4 levels were
not statistically different between the two groups, but serum anti-TPO Ab levels in women
with asthma (74±13.6 IU/ml) was significantly higher than control group (45.24±10.56
IU/ml). After adjusting the effect of age and BMI, the relationship between asthma and anti-
TPO Ab (>50 IU/ml) was statistically significant (OR=3.3, P<0.01). Positive anti-TPO Ab in asthmatic patients may show presence of a hidden autoimmune thyroiditis in these patients. We suggested checking asthmatic patients for thyroid diseases. Keywords: Anti-thyroid peroxidase antibody; Asthma; Thyroid function test; Women