Air pollution exposure at the residence and risk of childhood cancers in Denmark: A nationwide register-based case-control study

Abstract

Background The etiology of childhood cancer is poorly understood. The role of environmental factors, including air pollution (AP) exposure, has been addressed previously, but results so far have been inconclusive. In this study, we investigate the association between long-term AP exposures in relation to childhood cancer subtypes in Denmark (1981–2013). Methods We conducted a nationwide register-based case-control study. We identified 7745 incident cases of childhood cancers (<20 years) in the Danish Cancer Registry. Four randomly selected (cancer-free) controls were matched to each case according to sex and date of birth. We modelled concentrations of nitrogen dioxide (NO 2 ), fine particles (PM 2·5 ), and black carbon (BC) at all addresses and calculated a time-weighted average from birth to index-date with a state-of-the-art multiscale AP modelling system. We analyzed the risk of childhood cancer in conditional logistic regression models adjusted for socio-demographic variables obtained from registers at the individual and neighborhood level. Findings The main analyses included 5045 cases and 18,179 controls. For all cancers combined, we observed odds ratios (ORs) and 95% confidence intervals (95% CI) of 0·97 (0·94, 1·01) per 10 µg/m 3 NO 2 , 0·89 (0·82, 0·98) per 5 µg/m 3 PM 2·5 , and 0·94 (0·88, 1·01) per 1 µg/m 3 BC, respectively. Most notably, we observed a higher risk of Non-Hodgkin Lymphoma (NHL) with higher childhood AP exposure with ORs and 95% CIs of 1·21 (0·94, 1·55) per 10 µg/m 3 NO 2 , 2·11 (1·10, 4·01) per 5 µg/m 3 PM 2·5 , and 1·68 (1·06, 2·66) per 1 µg/m 3 BC, respectively. We observed indications of increased risks for other types of childhood cancer, however, with very wide CIs including 1. Interpretations The findings of this nation-wide study propose a role of AP in the development of childhood NHL, but more large-scale studies are needed. Funding NordForsk Project #75007.

Residential Exposure to PM2.5 Components and Risk of Childhood Non-Hodgkin Lymphoma in Denmark: A Nationwide Register-Based Case-Control Study

“…The crude and adjusted odds ratios (ORs) for exposure to PM 2.5 and sub-components and risk of childhood NHL are presented in Table 2. In correspondence with our previous publication [8], the adjusted OR and 95% confidence interval (95% CI) per IQR of PM 2.5 mass was 2.05 (1.10, 3.83) and 1.22 for BC (95% CI: 1.02, 1.46). We also observed an increased risk estimate for SIA (OR: 1.73, 95% CI: 0.68, 4.41), however with wide confidence intervals.…”

“…A recent Danish case-control study reported an association with maternal residential benzene exposure during pregnancy [7]. In a recently published study, we observed an association between residential exposure to ambient fine particulate matter (PM 2.5 ) during childhood and the risk of NHL in Danish children with an observed odds ratio (OR) of 2.11 (95% confidence interval, CI: 1.10, 4.01) per 5 µg/m 3 increments [8]. PM 2.5 , however, arises from various natural and anthropogenic sources and consists of a complex mixture of chemical components, of which some are released directly into the air (primary emitted) while others are formed by chemical reactions in the atmosphere (secondary).…”

“…In the above-mentioned study, we also observed suggestive evidence of a role of the PM 2.5 sub-component BC (black carbon). In two-pollutant models of PM 2.5 mass and BC, an effect of PM 2.5 remained, which indicates an influence of additional sub-components [8]. In order to prevent negative health effects of PM 2.5 , specific evidence on the relative influence of each chemical component is required.…”

Risk Factors for Childhood Leukemia: Radiation and Beyond

“…Among the recognized risk factors are high and low birth weight (128) and sex, with boys more often affected than girls (129). Pesticide exposure (130,131), air pollution (132)(133)(134), paint (135), paternal tobacco smoking (136,137), and prelabour cesarean delivery (138) have been associated with an increased risk for ALL or AML but to date none of them is regarded as an established risk factor. There are also some factors that have been associated with a reduced risk for leukemia in the child, including maternal supplementation with folic acid or vitamins (139), or breastfeeding (140).…”

Efeitos patológicos da exposição de poluentes atmosféricos à saúde humana: uma revisão integrativa

“…Em torno de 95% dos países mundiais, fazem parte de algum acordo que especifica a redução da poluição atmosférica (PNUMA, 2023). Contudo, muitos os negligenciam e desnaturam as condições de ar limpo impostas pelas autoridades mundiais, corroborando para maiores condições patológicas (FALKEMBACH, et al, 2003;HVIDTFELDT, et al, 2020).…”