TSH reference intervals in Sub-Saharan adults: A pilot study in Cameroon

Introduction: Thyroid disorders are widespread across Africa, with iodine deficiency disorders being the most prevalent subtype. In many African countries, access to diagnostic tools and medical expertise is limited, and reference intervals appropriate for the African population are lacking. Thyroid-stimulating hormone (TSH) is the primary marker used to diagnose thyroid dysfunction; however, reference values for TSH remain undefined in sub-Saharan Africa. This study aimed to establish reference ranges for serum uric acid and TSH levels in adults residing in Yaoundé. Materials and Methods: From November 2019 to June 2020, we conducted a cross-sectional study of 292 individuals aged 18 to 65 years. The assays were performed on a Cobas 6000® machine. Using Stata 15 and SPSS 26, we determined the upper and lower limits of normal at the 2.5th and 97.5th percentiles, respectively. We assessed the effects of sex, age, ethnicity, and educational level. Results: The mean age of the 292 volunteers was 31.51 years, with a sex ratio of 1.7 females to males. The majority had a university degree (66.1%). The overall TSH reference range was 0.2 to 2.9 mIU/L, which was consistent with the American Association of Clinical Endocrinologists ranging from 92% of the time. TSH values were significantly influenced by university education (p = 0.005), with a specific reference interval of 0.25 to 3.13 mIU/L. Conclusion: Our results are broadly in line with those of American learned societies. These results could be used in routine practice by African practitioners based on clinical features and could serve as a pilot study for other sub-Saharan countries.