The relationship between seasonality and the diagnosis of acute leukaemia in central South Africa

Abstract

Background: Leukaemias are haematological malignancies resulting from the abnormal clonal proliferation of haematopoietic precursors. Their incidence is influenced by various environmental and genetic factors.

Aim: With this retrospective descriptive study, the authors aimed to explore the possible influence of seasonality on the type and number of acute leukaemia (AL) diagnoses made at the Universitas Academic Hospital (UAH) National Health Laboratory Service (NHLS) from 01 January 2018 to 31 December 2021.

Setting: Universitas Academic Hospital, Bloemfontein, South Africa.

Methods: Archived laboratory reports of all patients diagnosed with lymphoid and myeloid during the study period were included. Patients’ age, sex, ethnicity, final diagnosis and date of diagnosis were recorded. Information was pseudonymised to maintain confidentiality. A descriptive statistical analysis was performed to explore the possible influence of seasonality on the number of cases and type of leukaemia diagnosed.

Results: In all, 249 patients were included. Acute myeloid leukaemia (AML) was the most common AL subtype (n = 117; 47.0%). Over the 4-year study period, all AL subtypes were more frequently diagnosed in summer (n = 131; 52.6%). However, the monthly number of AL diagnoses was relatively consistent over the 4 years for all subtypes (p = 0.7603), with consistent peaks of AML cases during January and February (summer) and May (autumn).

Conclusion: No statistically significant association between the different seasons and AL diagnosis was noted.

Contribution: Further studies using a larger study population and a wider geographical area, conducted over a more extended period, might affect the observations made in this study