Childhood obesity is one of the most important public health threats nowadays. Obesity in childhood is strongly related to obesity-related trajectories (Di Cesare et al., 2019; Rundle et al., 2020) and with increased risk for various physical and mental health disorders over the life course (Bendor et al., 2020; Di Cesare et al., 2019). Such trends have profound societal and financial implications. The identification of modifiable risk factors for childhood obesity, even as early as the period of gestation is a research priority, as accumulating evidence shows that programming of obesity begins prenatally (Sutton et al., 2016). Such modifiable risk factors include chemical environmental exposures that are increasingly implicated in obesity programming (Vrijheid et al., 2016).

Emerging evidence specifically supports that particulate air pollution, a pro-oxidant environmental exposure, plays a role in the pathogenesis of obesity. In utero air pollution exposure has been linked to low birth weight, a potential predecessor of overweight/obesity in later life (Bell et al., 2007; Kloog et al., 2012; Lakshmanan et al., 2015; Padula et al., 2012). Nonetheless, results from human studies examining the association between prenatal traffic-related air pollution exposure and childhood body mass index (BMI) or obesity, remain inconclusive, reporting positive, negative and no associations (Chiu et al., 2017; Fleisch et al., 2015, 2017, 2019; Fossati et al., 2020; Frondelius et al., 2018; Guangyun et al., 2017; Guo et al., 2023; Huang et al., 2019; Kim et al., 2018; Patterson et al., 2021; Sun et al., 2021; Tan et al., 2021; Vrijheid et al., 2020; Zhou et al., 2021). These discrepancies are mostly attributed to differences of the exposure levels and possibly other characteristics of the study populations.

Antioxidants play a critical role in the defense against the air pollutant-induced inflammation and oxidative stress (Schichlein et al., 2023; Son et al., 2020). Fruits and vegetables (FV) are important dietary sources of antioxidants and related compounds, including vitamin C, carotenoids, and other phytochemicals. In fact, the WHO and other health organizations recommend increased intake of FV (≥5 servings/day) to improve overall health and reduce the risk of non-communicable diseases, including, diabetes, and obesity (WHO, 2002).

Findings from epidemiological studies provide supporting evidence that increased FV consumption might mitigate the adverse health effects of exposure to air pollutants. In particular, FV and antioxidants intake may protect against the adverse cardiovascular and respiratory effects of particulate matter (PM) (Raaschou-Nielsen et al., 2012; Schulz et al., 2015). Furthermore, studies have demonstrated that the protective role of higher FV intake against air-pollution related adverse health effects can be transferred from the mother to the fetus (Esplugues et al., 2013; Guxens et al., 2012; Lee et al., 2020). To date, no study has examined whether maternal FV intake might modify the associations between prenatal PM exposure and childhood BMI/obesity.

In the present study we aimed to investigate if prenatal PM exposure is associated with childhood adiposity related outcomes among 4 and 6-year-old children from the prospective Rhea cohort in Crete, Greece. Further, we hypothesized that higher maternal intake of FV may mitigate the adverse effects of air pollutants.