PM2.5, vegetation density, and childhood cancer: a case-control registry-based study from Texas 1995-2011

Environmental health disparities in pediatric cancer: a report from the Fourth Symposium on Childhood Cancer Health Disparities

The 4th Symposium on Childhood Cancer Health Disparities was held at Texas Children's Hospital in Houston, Texas, on September 26, 2023. The symposium registered 94 attendees from different backgrounds (e.g. clinicians, epidemiologists, exposure assessment scientists, geospatial experts) with an interest in environmental health disparities of pediatric cancer susceptibility and treatment outcomes. The focus of the symposium was to provide an overview of the role of environmental risk factors in studies of pediatric cancer, introduce novel exposure assessment tools that can be applied to the field, and highlight opportunities to study the impact of environmental health disparities in pediatric cancer susceptibility and outcomes. This report summarizes the scientific content of the symposium and highlights priorities to advance the field.

Perinatal exposure to ambient fine particle air pollution and risk of childhood ewing sarcoma in a population-based case-control study in California (1988-2015)

BACKGROUND

Incidence of childhood Ewing sarcoma, a rare cancer affecting bones and soft tissues, is increasing. Environmental exposures during the perinatal period, like air pollution, may play a role. We examined exposure to perinatal ambient fine particulate matter (PM2.5) and childhood Ewing sarcoma risk in a case-control linkage study nested within a California birth cohort.

METHODS

The study included 388 children born in California (1982-2015) and diagnosed with Ewing sarcoma at age 0-19 years (1988-2015), and 19,341 California-born cancer-free controls frequency-matched to cases on birth year (50:1 ratio). Ambient PM2.5 concentrations at the maternal residence were averaged separately over two time periods, gestation and the first year after birth, using a validated ensemble-based model (categorized as quartiles). We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for the association between perinatal PM2.5 exposure and Ewing sarcoma risk, adjusting for sex, birth year, race, ethnicity, birth weight, and maternal education and stratifying by Hispanic ethnicity to assess potential disparities in PM2.5-related cancer risk.

RESULTS

In the overall population, perinatal ambient PM2.5 exposure was not associated with Ewing sarcoma risk when considering exposure during gestation or the year after birth. Among Hispanic children, who experienced greater air pollution exposure compared to non-Hispanic children, higher PM2.5 levels during gestation yielded elevated odds of Ewing sarcoma compared to the first quartile (Q2 OR [95% CI] = 1.53 [0.94-2.51]; Q3 = 1.56 [0.95-2.56]; Q4 = 1.39 [0.79-2.47]). Hispanic children also experienced elevated risk in relation to exposure during the year after birth.

CONCLUSION

Our results provide new suggestive evidence that ambient PM2.5 may contribute to Ewing sarcoma risk, although these findings were not statistically significant and were specific to Hispanic children. These findings require replication and underscore the need to further evaluate the potential role of ethnicity in the PM2.5-cancer relationship with genetic ancestry measures and through the lens of environmental justice.

Associations of green and blue spaces with visual acuity in youths from Shandong Province, China: A large population-based study

While growing evidence highlights the benefits of green and blue spaces for physical and mental health, their combined effects on youth visual acuity remain unclear. This study aimed to evaluate the associations of green and blue spaces with visual acuity in youths. We analyzed data from the 2023 Common Disease and Health Risk Factors Surveillance and Intervention Program among students in Shandong Province, China. Generalized linear mixed-effects models were employed to investigate the independent associations of green and blue spaces with visual acuity in youths. To explore potential interactions, an interaction term for green and blue spaces was incorporated. Quantile g-computation (Qgcomp) models were applied to evaluate their combined effects. Compared to the lowest quartile, higher quartiles (Q2, Q3, and Q4) of the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), normalized difference water index (NDWI), and modified normalized difference water index (MNDWI) were significantly associated with improved visual acuity in both eyes. Additionally, each 0.1 unit increase in NDVI500, EVI500, NDWI500, and MNDWI500 was associated with 0.008 (95 % confidence interval [CI]: 0.007, 0.010), 0.003 (0.002, 0.004), 0.054 (0.028, 0.080), and 0.010 (0.002, 0.018) improvements in right-eye visual acuity, with similar findings for the left eye. A significant interaction was observed between NDVI and NDWI (all P for interaction < 0.001), and combined exposure to green and blue spaces was positively associated with visual acuity (all P < 0.001). Furthermore, demographic and lifestyle factors modified the associations of blue and green spaces with visual acuity levels in youths. Greater exposure to green and blue spaces may benefit visual health in youths, with potential interactive and combined effects. Implementing policies to enhance the availability of green and blue spaces around schools may offer opportunities to alleviate visual impairment in youths.

Neighborhood socioeconomic disparities in cancer incidence following a hypothetical intervention to increase residential greenspace cover in the UK Biobank cohort

BACKGROUND

Higher greenspace exposure has been associated with lower risk of certain cancers. However, few studies have evaluated potential benefits of increasing population-level exposure to greenspace on cancer disparities. We estimated the impact of a hypothetical intervention to increase residential greenspace cover on neighborhood socioeconomic disparities in total, breast, colorectal, lung, and prostate cancer incidence.

METHODS

Our study included 411,787 cancer-free UK Biobank participants. Percentage of greenspace around baseline residential addresses (300m, 1000m distance buffers) was derived by combining domestic gardens and greenspace cover from the Generalized Land Use Database. We categorized neighborhood socioeconomic deprivation using the Index of Multiple Deprivation (2010). We estimated hazard ratios (HR) and 95% confidence intervals (CI) of each cancer associated with greenspace, adjusting for sociodemographic and lifestyle factors. We additionally adjusted for air pollution in supplementary analyses as we a-priori hypothesized that it was on the causal pathway between greenspace and cancer. Further, we used parametric g-computation to calculate the standardized 10-year risk of each cancer, comparing the least to most socioeconomically disadvantaged participants, both without any hypothetical greenspace intervention and under a hypothetical intervention to increase residential greenspace cover to a favorable threshold (75th percentile amongst the least socioeconomically deprived participants).

RESULTS

We documented 40,519 incident cases of cancer over 4,210,008 person-years follow-up. An interquartile range increase in greenspace cover within 300m was associated with lower incidence of total (HR 0.98; 95% CI 0.97, 1.00) and lung (HR 0.96; 95% CI 0.92, 0.99) cancer, and was suggestively associated with lower prostate and breast cancer incidence, but not colorectal cancer. Additional adjustment for fine particulate matter air pollution (PM2.5) weakened lung cancer associations but strengthened breast and prostate cancer associations (e.g., greenspace 1000m breast cancer HR 0.94; 95% CI 0.89 0.99; 1000m prostate cancer HR 0.91; 95% CI 0.86, 0.95). The hypothetical intervention to increase greenspace (300m) resulted in 1.3 fewer total cancer cases per 1000 (95% CI 1.0, 1.6) in the most compared to least deprived group, a 23% reduction in the socioeconomic disparity gap.

DISCUSSION

Higher residential greenspace cover was associated with lower total and lung cancer incidence, and suggestively associated with lower breast and prostate cancer incidence. Policies to increase residential greenspace cover may reduce the risk of certain cancers, particularly among socioeconomically disadvantaged groups.