Frequency and distribution of ABO and Rh blood group systems among blood donors at the Northern Zone Blood Transfusion Center in Kilimanjaro, Tanzania: a retrospective cross-sectional study.

OBJECTIVES: ABO and Rh blood group systems are the major factors affecting the blood transfusion safety. The frequency and distribution of these blood group systems vary worldwide. We aimed to determine the frequency and distribution of ABO and Rh blood group systems among first-time blood donors at the Northern Zone Blood Transfusion Center in Kilimanjaro, Tanzania. DESIGN: Cross-sectional descriptive population-based study. SETTING: Data on ABO and Rh blood group systems were obtained and analysed from the Northern Zone Blood Transfusion Center among first-time blood donors. PARTICIPANTS: There were 65 535 first-time blood donors aged 15-55 years who donated at the Northern Zone Blood Transfusion Center from January 2017 to December 2019. OUTCOME MEASURES: The percentage of ABO and Rh blood group systems among different categories of blood donors was calculated. RESULTS: Retrospective data from Blood Establishment Computer System of 65 535 first-time blood donors were analysed in the present study. The mean age of the blood donors was 30.6±11.2 years (range: 15-55 years). The vast majority of the blood donors 84.2% (n=55 210) were men. Also, the majority 69.6% (n=45 595) were aged ≥35 years. Blood group O was the most common blood group which was found in over half 52.4% (n=34 333) of the blood donors and majority 95.3% (n=62 461) of the donors were Rh positive. Moreover, the majority 78.3% (n=51 336) were voluntary donors and the remaining 21.7% (n=14 199) were replacement donors. CONCLUSION: Majority of the donors had blood group O and also the vast majority of the donors were Rh positive. Considering the large size of our study population, this has provided a more comprehensive information regarding the frequency and patterns of ABO and Rh blood group systems in Tanzania. The observed association of blood group A with one of the regions from which donors were coming from, is intriguing and further studies may confirm possible related genetic evolution.

Salivary gland tumors in Uganda: clinical pathological study.

BACKGROUND: The incidence of salivary gland tumors is claimed to be influenced by geographical and racial factors. The pathological classification and nomenclature of salivary gland tumors as defined by WHO classification (1991), is accepted world-wide but little is available in the literature regarding the spectrum of salivary gland tumors in Africa in the basis of this classification. Such efforts would allow comparison and justify any differences between the black African population and the rest of the world. OBJECTIVE: To outline the clinicopathological features of salivary gland tumors in Uganda. SETTING: Makerere University, Faculty of Medicine, Department of Pathology. METHODS: All epithelial tumors from major and minor salivary glands accessioned from 1979 to 1988 were analyzed in respect to sex and age of patients, anatomical location of the tumor and histological type. The histological diagnosis of each individual tumor was based on the 1991 WHO classification of salivary gland tumors. RESULTS: During the span of 10 years, 268 cases of salivary gland tumors were diagnosed. Of these, 113 (42.2%) were males, 148 (55.2%) females and in the remaining seven (2.6%) cases, the sex was not specified. The age range of the 247 patients with recorded ages was from 0.5 to 80 years. The mean age at diagnosis was 38.1 (SD =17.03) with the median of 38.0 years. Thirty four percent of tumors originated from the parotid, 33.2% from the submandibular and 32.8% from minor salivary glands. No tumor was implicated from the sublingual gland. There were a total of 125 (46.6%) malignant tumors and 143 (53.4%) benign tumors. The mean age of patients with malignant lesions (43.1 years; SD=16.75; median=44.00 years) was 9.6 years older than those with benign tumors (mean=33.5 years; SD=16.0; median=30.00 years). Pleomorphic adenoma was the most common benign tumor (74.8%), followed by myoepithelioma (9.8%). No Whartin's tumor was encountered. The malignant tumors were dominated by adenoid cystic carcinoma (28.8%) followed by mucoepidermoid carcinoma (21.6%). CONCLUSION: The pattern of distribution of salivary gland tumors in black African population seems to differ from that of Western series in that; i) females are more affected than males, ii) there is a low proportion of tumors from the parotid gland and high proportion of tumors from the submandibular and minor salivary glands, iii) the parotid and minor salivary gland tumors have more probability of being malignant than those tumors from the submandibular gland iv) the newly categorized pathological entities are common and v) Whartin's tumor is extremely rare in black African population.