Rena Jones

National Cancer Institute

Investigator

PLCO (Learn more about this study)

PLCO-1105

Nov 21, 2022

Greenspace, noise pollution, and cancer risk in the PLCO cohort

According to Healthy People 2030, neighborhood environment is a key social determinant of health [1]. Greenspace, one aspect of neighborhood environment, is beneficial to health through its role in reducing environmental pollutants (e.g., air pollution, heat), helping physiological stress recovery, and encouraging physical activity [2]. Greenspace is therefore hypothesized as a protective factor against chronic diseases, including obesity, cardiovascular disease, diabetes [3-5]. A longitudinal study found that increased greenspace exposure was associated with lower incidence of lethal prostate cancer within a United States cohort [6]. However, a recent meta-analysis of greenspace and cancer risk including 18 studies reported inconsistent evidence for most cancer sites [7]. In addition, many studies have been of cross-sectional design (8 out of 18 studies) [7].
Noise pollution is another aspect of neighborhood environment that can influence health, and has been associated with increased risk of diabetes, hypertension, and ischemic heart disease [8]. There are several potential biologic mechanisms through which noise pollution might increase cancer risk, which are similar pathways that link light at night and breast cancer [9]. For example, noise pollution may disrupt sleep, affecting circadian function which can impact cell proliferation, chronic inflammation, and immune function mechanisms [10]. Longitudinal studies in Denmark have shown transportation noise near the residence was associated with an increased risk of breast cancer but not prostate cancer [11, 12]. Despite accumulating research, studies of any single cancer site are few, and the evidence of associations remain equivocal. Further, the association between noise pollution and cancer incidence has yet to be explored in the United States.

The proposed analysis in the PLCO study will be the first and one of the largest evaluations of greenspace and noise pollution exposure and cancer incidence in the United States. With the cohort’s geographic spread, large numbers of incident cancers, and available linked and ancillary data, we expect this research to be an important contribution to understanding the greenspace-cancer association and an informative first look at the role of noise pollution to cancer risk.

We aim to assess the association between greenspace exposure using the Normalized Difference Vegetation Index (NDVI) (e.g., proportion of greenspace land cover) [13] and site-specific cancer risk in the PLCO cohort. We will also assess the association between noise pollution (e.g., estimated outdoor anthropogenic decibel levels) using a geospatial sound model [14, 15]. Both exposures have previously been linked to the geocoded addresses of participants with available LexisNexis residence histories (approximately ~95,000 participants), and heterogeneity in both measures across the study cites at enrollment indicate these analyses will be reasonably well powered for most major cancer sites. We expect to focus on all major cancer sites with sufficient case numbers for analysis.

We will estimate hazard ratios and 95% confidence intervals from Cox regression analyses of the association between ambient greenspace, noise pollution (individually and in mutually-adjusted models, as appropriate) and cancer risk from the start of follow-up through December 2017 (or latest available time point). Potential confounders and effect modifiers to be evaluated include age, smoking history, education, race and ethnicity, urbanicity, and neighborhood socioeconomic deprivation measured by the Area Deprivation Index (ADI) derived from census variables [16]. Changes in residence will be evaluated for potential sensitivity analyses.

Due to word limit, reference list available upon request.