Cooking-smoke as a factor affecting thyroid metabolism and oxygen transport capability.

1. Young Bedouin women found to be prone to illnesses of the thyroid gland and lungs. It was surmised that the cause of both complaints had the same origin: the smoke from cooking over a fire. 2. Laboratory rats were placed in the cooking space in a Bedouin encampment for 2 months. These rats (termed "smoke" animals) were smaller and less active than normal siblings. 3. The smoke animals had increased secretion of thyroid hormones and TSH and the thyroid glands were enlarged, when compared to body weight. 4. Histology of the thyroid showed areas of atrophy, areas of hypertrophy and cysts. There was increased erythropoiesis, allowing for enhanced oxygen transport capability. 5. It is concluded that the smoke, directly, or indirectly by hampering normal lung function, caused a reaction in the thyroid gland, which in turn led to increased production of hemoglobin, probably to guarantee sufficient oxygen for basic cell metabolism.