Evidence of spatial clustering of childhood acute lymphoblastic leukemia cases in Greater Mexico City: report from the Mexican Inter-Institutional Group for the identification of the causes of childhood leukemia

Front Oncol. 2024 Feb 14:14:1304633. doi: 10.3389/fonc.2024.1304633. eCollection 2024.

Abstract

Background: A heterogeneous geographic distribution of childhood acute lymphoblastic leukemia (ALL) cases has been described, possibly, related to the presence of different environmental factors. The aim of the present study was to explore the geographical distribution of childhood ALL cases in Greater Mexico City (GMC).

Methods: A population-based case-control study was conducted. Children <18 years old, newly diagnosed with ALL and residents of GMC were included. Controls were patients without leukemia recruited from second-level public hospitals, frequency-matched by sex, age, and health institution with the cases. The residence address where the patients lived during the last year before diagnosis (cases) or the interview (controls) was used for geolocation. Kulldorff's spatial scan statistic was used to detect spatial clusters (SCs). Relative risks (RR), associated p-value and number of cases included for each cluster were obtained.

Results: A total of 1054 cases with ALL were analyzed. Of these, 408 (38.7%) were distributed across eight SCs detected. A relative risk of 1.61 (p<0.0001) was observed for the main cluster. Similar results were noted for the remaining seven ones. Additionally, a proximity between SCs, electrical installations and petrochemical facilities was observed.

Conclusions: The identification of SCs in certain regions of GMC suggest the possible role of environmental factors in the etiology of childhood ALL.

Keywords: SaTScan software to analyze spatial; child; developing countries; electromagnetic fields; environmental exposure; leukemia; spatial clustering; urban population.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the Consejo Nacional de Ciencia y Tecnología [grant numbers: SALUD-2010-1-141026, FIS/IMSS/PROT/895; PDCPN2013-01-215726, FIS/IMSS/PROT/1364; SALUD 2015-1-262190, FIS/IMSS/PROT/1533; CB-2015-1-258042, FIS/IMSS/PROT/1548] and FONCICYT/37/2018, FIS/IMSS/PROT/1782]; and by the Instituto Mexicano del Seguro Social [grant numbers: FIS/IMSS/PROT/PRIO/11/017, FIS/IMSS/PROT/G12/1134, FIS/IMSS/PROT/PRIO/14/031, FIS/IMSS/PROT/MD13/1254, FIS/IMSS/PROT/PRIO/15/048, FIS/IMSS/PROT/MD15/1504, FIS/IMSS/PROT/G15/1477, FIS/IMSS/PROT/PRIO/18/080 and FIS/IMSS/PROT/PRIO/19/088]. National Institutes of Health (Administrative Supplement 3R01CA262263 to JM-A, 2U24ES028524 sub-award number 00011320 to JM-A), and the Consejo Nacional de Humanidades, Ciencias y Tecnologías (CONAHCYT, CF-2023-G-1399 to JM-A; and the FORDECYT-PRONACES: 303019 to JN-E). The funders had no role in the study design, in the collection and analysis of data, in the writing of the report, and in the decision to submit the article for publication and to the Instituto Nacional de Medicina Genómica (INMEGEN) (2024-01) for the payment of the publication.