Serum concentrations of the two principle biologically active thyroid hormones, thyroid hormones, thyroxine (T4) and triidothyronine (T3) together with that of thyroid stimulating hormone (TSH) are used to assess thyroid function. It is recommended that each laboratory or hospital should establish its own reference values of T4, T3 and TSH for their clients because these hormones vary with ethnicity, geographical and climatic conditions of a population. Otherwise, choosing unrelated ‘’normal ranges’’ may lead to a false disgnosis. There is no documented study which has been done to determine they thyroid hormones profile in the Ugandan general population.
The main objective of this study was to determine the thyroid hormones profile of students of the faculty of medicine, Makerere University.
A Cross sectional descriptive study was done involving 72 students, with the mean age of 24.17 ± 4.48 years. Subjects who volunteered to participate in the study were interviewed, their height and body weight measured, five millilitres of blood withdrawn, and sera harvested. FT4 and T3 radioimmuno assay (RIA) were done and TSH was assayed using immunoradiometric assay (IRMA) technique. Statistical analysis was performed using SPSS. Statistically significant differences were tested by one way ANOVA and student’s t-test and level of significance was fixed at p<0.05.
Serum concentrations of FT4 ranged 8.897-27.440 pmol/L, with mean of 17.016 ± 3.847 pmolL (95%C1 of 16.112-17.920 pmol/L). For T3, serum concentration ranged 0.076-4.490mm0l/L, with mean of 1.430 ± 0.825 mmol/L (95%C1 of 1.237- 1.624 nmol/L), and serum concentration of TSH varied from 0.080 to 12.260 Uiu/ML, with mean of 2.412 ± 2.284uIU/ml (95% C1 of 1.875-2.948 umol/ml). Serum concentrations of FT4, T3 and TSH did not significantly vary with sex, age or region of origin. Serum contration of T3 varied with ethnicity. It was found to be lowest (0.307 ± 0.027 mmol/L) among Langi and highest (2.177 ± 0.392 nmol/L) among Gishu (p=0.016). There was no association between ethnicity and serum concentrations of FT4 and TSH. Serum concentration of TSH increased with increased BMI. It was 2.073 ± 1.907 Uiu/ml for subjects withBMI of <_ 24.9 Kg/m2, 3.588 ± 1.495 Uiu/ml for subjects with BMI >_30KG/M2 (P=0.009). However, BMI had no effect on serum concentrations of FT4 and T3.
Serum concentrations of FT4 for students in Makerere University faculty of medicine ranged 8.897-27.440pmol/L with the mean of 17.016 ± 3.847 pmol/L. The range is wider and the mean is higher than the values given by institute of isotopes company Ltd. For this population T3 ranged 0.076-4.490 nmol/L with the mean of 1.430 ± 0.825nmol/L. The mean T3 is lower and its range is wider than that given by the institute of isotopes Company Ltd. TSH levels ranged 0.080-12.260 Uiu/ml with the mean 2.412 ± 2.284 Uiu/ml, and its range is wider than the one used in mulago hospital. This study showed that TSH concentration increases with increased BMI. It also showed lack of significant change with age, in serum concentrations of FT4, T3 and TSH among lack of significant change with age, in serum concentrations of FT4, T3 and TSH among adults aged 19-37 years. Furthermore, it showed that T3 levels vary with ethnicity.
A Similar study involving students in faculties of medicine in other Ugandan universities needs to be done. This should then be followed by the similar studies involving communities from various regions and Ugandan population in general so as to establish normal reference values of T4, T3 and TSH for Ugandans. BMI of patients should be taken into consideration during interpretation of serum TSH concentrations results.||en_US