Prospective case-series analysis of haematological malignancies in goldmining areas in South Africa.

BACKGROUND

South Africa (SA) has a long history of goldmining that has resulted in locally high levels of environmental contamination from uranium and its decay products (radium-226 and radon-222) from the mine tailings. Populations living around mine tailings of the Witwatersrand goldfields may be exposed through various pathways, raising concern about potential health risks associated with haematological malignancies (HMs), for which evidence is inconclusive.

OBJECTIVES

We designed a prospective case-series study of HMs at Chris Hani Baragwanath Academic Hospital (CHBAH), Johannesburg, the major public hospital in the area, to describe demographic and clinical characteristics, lifetime residential history and potential environmental uranium exposure pathways.

METHODS

All patients, male and female, aged ≥18 years and newly diagnosed with any form of leukaemia, lymphoma or myeloma at the CHBAH Haematology Unit in 2014 and 2015 were considered for inclusion in the study. Information on uranium exposure pathways and lifetime residential history was recorded from interviewer-administered questionnaires. These characteristics were described overall and according to subtypes of HM.

RESULTS

Of 556 patients with HMs diagnosed in 2014 and 2015 at CHBAH, 189 patients aged 18 - 90 years were interviewed, mainly with non-Hodgkin's lymphoma (NHL) (37.6%), leukaemia (32.8%) and Hodgkin's lymphoma (HL) (13.8%). HIV status was positive for 39.2% of the patients, mostly with NHL and HL. Potential environmental uranium exposure pathways were identified. Working on goldmines was reported by 12 patients (6.3%). Consumption of soil (geophagia) was a habit of 51 patients (27.0%), particularly during pregnancy. Drinking water was mainly piped water (76.6% in childhood and 97.9% in adulthood). Animal products and vegetables were most frequently obtained from stores (82.0% and 68.7%, respectively, in childhood and 96.3% and 83.6% in adulthood). Patients were referred to CHBAH by government clinic doctors (44.4%), referral hospitals (24.3%) and private doctors (20.1%). Most participants had been born and lived in Gauteng Province and Soweto (94.7% and 58.2%, respectively), and reported two lifetime places of residence on average and living at their current residence for ≥20 years (49.2%).

CONCLUSIONS

We identified potential environmental uranium exposure pathways (occupational, lifestyle related and domestic) among patients with HMs that could have resulted in increased uranium exposure. HIV is common among patients with HMs. Together with the results from a previous retrospective case series of HMs at CHBAH (2004 - 2013), our findings suggest that further research on environmental uranium exposure in mining areas and HM risk in residents is warranted.