Folate status in tuberculosis: a study in the Guinea Savanna of Nigeria

Information about folate status in tuberculosis in developing countries is scanty. It was therefore decided to study serum and red cell folate (SF and RCF) levels in this infection. SF and RCF measurements were carried out by a microbiological (L. casei) method on 152 patients before treatment and on 94 patients (58 defaulted) at varying intervals during treatment. Mean SF (3.9 micrograms/l) of tuberculous subjects was significantly lower than that of the normal mean (6.8 micrograms/l; P less than 0.001) but their mean RCF (212.9 micrograms/l) was not significantly different from the normal mean RCF (220 micrograms/l). These findings indicate at least a state of incipient folate depletion. Though the mean RCF was normal, 32 patients had low RCF values of less than 120 micrograms/l while in 16 patients RCF levels were less than 100 micrograms/l. Only 10 ill subjects--all with disseminated disease--showed both very low SF (less than 2.0 micrograms/l) and low RCF (less than 120 micrograms/l). Thus, established folate deficiency was also clearly demonstrated in a proportion of the affected individuals. In the patient population as a whole, however, no relationship was detected between folate levels (SF, RCF) and (a) extent of disease (b) haemoglobin or haematocrit. Antituberculous treatment was accompanied by a rise in mean SF and RCF which, however, were still less than the normal mean values.