Thyroid and obesity: survey of some function tests in a large obese population.

Tests of thyroid function in 493 obese patients were compared with thyroid function in 3076 non-obese patients. No differences in 131I uptake by the thyroid were observed at 6 h or 24 h; the frequency distribution was gaussian or normal in both populations; the frequencies of normal, high or low T3 and T4 values in the two populations were likewise comparable. Further, no correlation was found in the obese subjects between 131I uptake (6 h and 24 h), T3, T4 and overweight; on the other hand, there was a significant negative correlation between 131I uptake (6 h and 24 h) and age. It would appear that thyroid function is normal in obesity.