# The association between air pollution exposure and childhood cancer: a scoping review about the challenges in epidemiological studies

## TL;DR

This review explores why it's hard to link air pollution to childhood cancer, highlighting issues in study methods and data collection.

## Contribution

The paper systematically identifies key methodological challenges in epidemiological studies on air pollution and childhood cancer.

## Key findings

- Most studies use case-control designs, which are prone to recall and selection biases.
- Inconsistent air pollution measurements and exposure time frames limit study validity.
- Many studies fail to adjust for important confounders like socioeconomic status and parental smoking.

## Abstract

Although several studies have investigated the association between various air pollutants and the risk of childhood cancer, particularly leukemia, results are still inconclusive. This scoping review aims to identify and discuss the main methodological challenges observed in publications addressing this topic.

A literature search was conducted in two databases (MEDLINE and Web of Science), focusing on epidemiological studies that examine the association between air pollution exposure and childhood cancer with publication dates ranging from 2009 to 2024. To ensure completeness, we conducted citation tracking and a supplementary Google Scholar search. Relevant publications were evaluated regarding different methodological aspects.

Two independent reviewers screened 1683 abstracts and finally evaluated 32 full-text articles based on predefined criteria. Additionally, two cohort studies were included from citation tracking and one case-control study from Google Scholar. Twenty-three studies investigated the association between air pollutants and childhood cancer, 19 of them were case-control studies. This design poses a risk of recall and selection biases. Many studies face challenges such as inconsistent air pollution measurements, varying exposure time frames, and different data sources. Furthermore, many studies under-adjust important confounders like socioeconomic status, radiation levels, urbanization, and parental smoking habits. These issues limit internal validity and make it difficult to draw firm conclusions about the association.

Further studies should use more robust methodologies including improved exposure assessment, larger study populations, and advanced statistics, to strengthen the association between air pollution and childhood cancer and inform public health policies.