Clinical and Environmental Factors Affecting Goitre Growth in Sri Lanka

Goitre, an enlarged thyroid gland, is a major health issue in tropical countries, primarily linked to Iodine deficiency. However, clinical, environmental, and genetic factors also contribute to the disease. This study explores the relationship between clinical and environmental factors influencing goitre occurrence in five districts of Sri Lanka: Anuradhapura, Colombo, Kurunegala, Nuwara Eliya, and Rathnapura, covering different climatic zones. The data consists of a hospital-based preliminary study conducted from 2012 to 2014, which involved 994 goitre patients from five base hospitals in Sri Lanka. A structured questionnaire survey recorded clinical examinations and investigation findings. Additionally, 562 water samples for Iodine and 147 samples for Selenium were collected from water sources used for drinking and cooking. The study included patients with a mean age of 43 years, predominantly females (98%), and 36% had a family history of goitre. Grades 3 and 4 were prevalent among the six goitre grades. All climatic zones showed an increasing trend of goitre grade with age. Notably, patients in the wet zone had higher goitre grades at younger ages compared to the other zones. Hierarchical cluster analysis based on environmental factors (Iodine and Selenium concentrations), clinical factors (thyroxine, triiodothyronine, and thyroid-stimulating hormone) and demographic factors identified seven clusters, categorizing patients based on dominant features. The most prominent cluster consisted of patients from Nuwara Eliya district, displaying a significant negative correlation between Iodine and Selenium levels with thyroxine. These clusters challenge the traditional methods of diagnosing endemic Goitre based solely on district and zone. The study provides valuable baseline data for effective planning and intervention strategies to prevent and treat goitre.