Long‐term exposure to air pollution and liver cancer incidence in six European cohorts

Abstract

Particulate matter air pollution and diesel engine exhaust have been classified as carcinogenic for lung cancer, yet few studies have explored associations with liver cancer. We used six European adult cohorts which were recruited between 1985 and 2005, pooled within the "Effects of low-level air pollution: A study in Europe" (ELAPSE) project, and followed for the incidence of liver cancer until 2011 to 2015.The annual average exposure to nitrogen dioxide (NO 2 ), particulate matter with diameter <2.5 μm (PM 2.5 ), black carbon (BC), warm-season ozone (O 3 ), and eight elemental components of PM 2.5 (copper, iron, zinc, sulfur, nickel, vanadium, silicon, and potassium) were estimated by European-wide hybrid land-use regression models at participants' residential addresses. We analyzed the association between air pollution and liver cancer incidence by Cox proportional hazards models adjusting for potential confounders. Of 330 064 cancer-free adults at baseline, 512 developed liver cancer during a mean follow-up of 18.1 years. We observed positive linear associations between NO 2 (hazard ratio, 95% confidence interval: 1.17, 1.02-1.35 per 10 μg/m 3 ), PM 2.5 (1.12, 0.92-1.36 per 5 μg/m 3 ), and BC (1.15, 1.00-1.33 per 0.5 10 À5 /m) and liver cancer incidence. Associations with NO 2 and BC persisted in two-pollutant models with PM 2.5 . Most components of PM 2.5 were associated with the risk of liver 1888 SO ET AL.

Exposure to Outdoor Particulate Matter Air Pollution and Risk of Gastrointestinal Cancers in Adults: A Systematic Review and Meta-Analysis of Epidemiologic Evidence

“…The earliest of the 20 studies included was published in 2005 ( Table 3 ). 13 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 Baseline data collection began in 1982 to 2016, and follow-up periods ranged from 5 to 27 y. All included studies were retrospective or prospective cohort analyses except for one nested case–control study 48 and one time-series analysis with individual-level medical records, 47 and exposures were directly linked to individuals or geographic area (e.g., county, ZIP code).…”

“…All included studies were retrospective or prospective cohort analyses except for one nested case–control study 48 and one time-series analysis with individual-level medical records, 47 and exposures were directly linked to individuals or geographic area (e.g., county, ZIP code). All included studies were conducted in the northern hemisphere: Asia, 13 , 40 , 44 , 46 , 47 , 48 , 51 Europe, 33 , 36 , 39 , 41 , 45 , 50 the United States, or Canada. 34 , 35 , 37 , 38 , 42 , 43 , 49 …”

“…All but two studies included some estimate of exposure (i.e., rather than ), 33 , 36 and all but two estimated risk in relation to a continuous exposure metric. 33 , 40 Many studies relied on a single year of data to reflect exposure over a longer time period, 33 , 36 , 38 , 39 , 43 , 50 and others estimated exposure during the full study period. 35 , 46 , 49 No studies estimated exposure for a period prior to recruitment or study start.…”

“…Only 2 studies assessed PM components, and they found statistically significant associations between sulfur PM species and gastric cancer incidence, 45 as well as liver cancer and copper, iron, zinc, sulfur, nickel, vanadium, and silicon components. 50 …”

Is the short-term lethal effect of NO2 ignored?Focus on the relationship between short-term exposure to NO2 and tumor death in Shenyang, China

“…In the analysis of different age groups in our study, we observed the signi cant risk effect of NO 2 on the death of elderly patients with lung cancer; In different genders, NO 2 has a risk effect on both male and female lung cancer patients, but the effect on male patients is mostly on Lag1 and for women is mostly on Lag3 Epidemiologic studies suggest air pollutants as a risk factor in liver cancer. In a study with six European cohorts, it was estimated per a 10µg/m 3 increase in NO 2 concentrations was associated with a 17% (95% CI: 2%-35%) increase in liver cancer incidence in the fully adjusted model (So et al 2021). However, the relationship between NO 2 and liver cancer was still inconclusive.…”