The haematological profile of urban black Africans aged 15-64 years in the Cape Peninsula

A stratified probability sample (n=986) with quotas was drawn from black residential areas in the Cape Peninsula, South Africa. Subjects (n=819) aged 15-64 years, participated in a coronary heart disease (CHD) risk factor survey, the BRISK Study. Nutritional status and prevalence of CHD was determined in this population undergoing rapid urbanization. Full blood and differential white blood cell counts provided data to calculate population reference values based on the 95% reference limits of the haematological parameter. Mean haemoglobin concentrations (Hb) in men (14.0 g/dl) and women (12.4 g/dl) were ±1.5 g/dl lower than previous South African reports. Mean BRISK Hb values were very similar to the World Health Organization's Hb cutoff criteria (<13 g/dl men; <12 g/dl women), indicating a possible high prevalence of anaemia. Significantly higher (P<0.05) mean values for red cell indices were confirmed in men, which also reflected equally higher red blood cell counts (RBC), haematocrit (HCT) and mean corpuscular haemoglobin (MCH) values. Mean Hb values were significantly lower in the younger (15-24 years) and older (55-64 years) men compared with 25-54 year-olds (P<0.05). Hypochronic microcytic anaemia was more prevalent in women, possible due toiron deficiency (ID), while macrocytic anaemia was more prevalent in men. No significant differences were noted in mean total and differential white blood cell counts (WBC) between men and women. Haematological values were notably different compared with previously published reference values (95% coverage) for healthy black South Africans (Basotho) and textbook values based mainly on white populations, emphasizing the importance of age, gender and population-specific reference values. The well-documented apparent neutropenia in black Africans was confirmed. Chronic inflammatory disease, helminthic manifestation and anaemia could have influenced their health status, physical development and productivity adversely. Prevention and screening strategies for early detection of ID and anaemia should be considered routinely in primary health care services