Methodological approaches to the study of cancer risk in the vicinity of pollution sources: the experience of a population-based case–control study of childhood cancer

Abstract

Background Environmental exposures are related to the risk of some types of cancer, and children are the most vulnerable group of people. This study seeks to present the methodological approaches used in the papers of our group about risk of childhood cancers in the vicinity of pollution sources (industrial and urban sites). A population-based case–control study of incident childhood cancers in Spain and their relationship with residential proximity to industrial and urban areas was designed. Two methodological approaches using mixed multiple unconditional logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) were developed: (a) “ near vs. far ” analysis, where possible excess risks of cancers in children living near (“near”) versus those living far (“far”) from industrial and urban areas were assessed; and (b) “ risk gradient ” analysis, where the risk gradient in the vicinity of industries was assessed. For each one of the two approaches, three strategies of analysis were implemented: “ joint ”, “ stratified ”, and “ individualized ” analysis. Incident cases were obtained from the Spanish Registry of Childhood Cancer (between 1996 and 2011). Results Applying this methodology, associations between proximity (≤ 2 km) to specific industrial and urban zones and risk (OR; 95% CI) of leukemias (1.31; 1.04–1.65 for industrial areas, and 1.28; 1.00–1.53 for urban areas), neuroblastoma (2.12; 1.18–3.83 for both industrial and urban areas), and renal (2.02; 1.16–3.52 for industrial areas) and bone (4.02; 1.73–9.34 for urban areas) tumors have been suggested. Conclusions The two methodological approaches were used as a very useful and flexible tool to analyze the excess risk of childhood cancers in the vicinity of industrial and urban areas, which can be extrapolated and generalized to other cancers and chronic diseases, and adapted to other types of pollution sources.

Persistently high incidence rates of childhood acute leukemias from 2010 to 2017 in Mexico City: A population study from the MIGICCL

“…Importantly, MC generally has highly harmful levels of air pollution ( 152 – 155 ) due to its geographic, climatic, and social conditions ( 49 , 156 ). Prior studies have reported that living in an urban area or near an industrial zone ( 157 – 159 ) and being exposed to either vehicular traffic ( 160 ) or benzene derivatives ( 161 , 162 ), are factors potentially contributing to the development of childhood AL ( 126 , 163 – 166 ). On the other hand, we observed a relatively lower AL incidence rates in the municipalities located south and east of MC, such as Milpa Alta, Xochimilco, and Tláhuac, which are characterized by preserved areas of agricultural land production ( 60 – 62 ).…”

Particulate Air Pollution and Osteoporosis: A Systematic Review

“… 2–7 Recently studies also showed that air pollution predisposed the public to a higher risk of breast cancer and childhood leukaemia, apart from lung cancer. 8 , 9 Besides, air pollution is estimated to contribute to 7 million deaths worldwide in 2016. 1…”

Looking Towards 2030: Strengthening the Environmental Health in Childhood–Adolescent Cancer Survivor Programs

“…This will also make it possible to continue using GIS to perform cluster analyses and explore spatial dependence in the distribution of cancer cases. The extensive information available can also be used for further multivariate analysis of childhood cancer incidence with associated variables such as family income, cancer type, and environmental exposures [70].…”