Climate factors associated with cancer incidence: An ecological study covering 33 cancers from population-based registries in 37 countries

Abstract

Cancer etiology is multifactorial, with climate change and environmental factors such as extreme weather events and ozone layer destruction potentially increasing cancer risk. Investigating climate factors with cancer incidence can provide valuable insights for prevention and future disease burden prediction. We conducted a population-based ecological study using data from the World Health Organization’s Cancer Incidence in Five Continents (CI5plus, 89 cancer registries from 1998 to 2012) and the Surveillance, Epidemiology, and End Results (SEER, 607 US counties from 2000 to 2018) Program. We tracked climate factors through satellite-based remote sensing, including green space, stratospheric ozone concentration, solar radiation, precipitation, and temperature. We performed linear panel regression models to estimate the effects of both long-term exposure, lag effect, and change rate of climate factors on cancer incidences. We adjusted for smoking prevalence, air pollution, and gross domestic product (GDP) per capita to account for potential confounding factors. Our study included more than 430 million underlying populations across 37 countries. Higher green space exposure (per 0.1-unit normalized difference vegetation index, NDVI) was associated with decreased incidence of lung cancer (up to 6.66 cases [95%CI 4.38–8.93] per 100,000) and prostate cancer (up to 10.84 cases [95% CI 7.73–13.95] per 100,000). Increased solar radiation was associated with a higher incidence of melanoma, but a lower incidence of prostate cancer. No evidence was found to suggest associations between temperature or precipitation and cancer incidence. However, a rapid increase in temperature was linked to higher incidences of corpus uteri cancer and melanoma. Long-term exposure and rapid changes in climate factors may influence changes in cancer incidence, particularly lung and prostate cancers. While some associations were supported by existing evidence (such as solar radiation and melanoma), further research is necessary to investigate the etiology of novel cancer risk factors.