Hypothyroidism in Zambia.

Nine patients with clinical and laboratory evidence of hypothyroidism are reported on. All had primary hypothyroidism; 8 were females and 1, the only indigenous Zambian in the group, was male. The mean serum thyroxine (T4) level (+/- 2 SD) in the 9 patients before optimal replacement therapy with L-thyroxine was 3,2 +/- 2,8 microgram/dl. In 3 patients on optimal replacement therapy it was 9,3 +/- 1,2 microgram/dl. This difference is statistically significant (P less than 0,01). The mean serum-tri-iodothyronine (T3) level in the 9 patients before optimal replacement therapy was 56,7 +/- 70 ng/dl, while in 4 patients on optimal replacement therapy it was 141 +/- 36 ng/dl. Although all the optimally treated patients had T3 levels within the normal range, this difference was not statistically significant (P greater than 0,1). In 8 patients the mean serum thyroid-stimulating hormone (TSH) level was elevated before optimal replacement therapy (29,1 +/- 33 microU/ml), while in 2 patients on optimal replacement therapy it was 5,6 +/- 1 microU/ml. The difference between these levels was not statistically significant (P greater than 0,1); however, in the 2 patients on optimal replacement therapy the serum TSH level was within the normal range, while in the 1 patient in whom replacement therapy was suboptimal the TSH level was elevated (16,8 microU/ml), indicating undertreatment of the primary hypothyroidism. In spite of the fact that iodine deficiency goitre is endemic in Zambia primary hypothyroidism appears to be very uncommon among indigenous Zambians.