Research from NY highlights pollution as a key factor in rising cancer rates among youth

In a recent study published in Scientific Reports, researchers investigated cancer incidence trends among adults in the New York State (NYS) and associations with common population-level exposures.

Study: Cancer incidence trends in New York State and associations with common population-level exposures 2010–2018: an ecological study. Image Credit: nyker/Shutterstock.com

Background

In the United States (US), cancer remains the leading cause of morbidity and mortality. Exogenous factors, like lifestyle factors and environmental exposures, account for 70% to 90% of cancer risk and can influence cancer trends. Cancer incidence in the US has increased over time.

Identification of modifiable exogenous factors driving these increases could inform cancer prevention. Studies have demonstrated that higher-level environmental exposures can elevate cancer risks.

Environmental carcinogens exist at low levels in water and air and can potentially contribute to cancer risk. Some studies have revealed associations between air pollutants and specific cancers, and fewer studies have evaluated water contaminants, yielding mixed findings.

However, the impact of low-dose, persistent, chronic environmental exposure on the risk of cancer is understudied.

About the study

The present study examined cancer incidence trends in NYS and associations with common exposures. They used cancer incidence data from 2010 to 2018 and risk factor data between 2000-09, accounting for an induction time of 10 years. They focused on cancers with the highest incidence rates in NYS and selected ten cancers.

Cancers included 1) colorectal, 2) thyroid, 3) kidney and renal pelvis, 4) non-Hodgkin lymphoma, 5) melanoma, 6) leukemia, and 7) lung and bronchus cancer for both sexes, 8) prostate cancer in males, and 9) breast and 10) corpus uteri cancer in females.

Age-standardized incidence rates were calculated by sex and age group across 62 NYS counties. Statewide sex- and site-specific annual rates of cancer incidence for each year.

Risk factor data were compiled from several sources. They included six types of measures – 1) environmental exposure, 2) socioeconomic status (SES) and race composition, 3) general health conditions, 4) community characteristics, 5) lifestyle factors, and 6) spatial differences.

Temporal incidence trends were analyzed in the 25–49 age group to examine changes in early-onset cancers. Linear regression models were used to assess associations with exposures.

Findings

The NYS shared the nine most prevalent cancers with the US. Incidence rates for most cancers in the NYS were higher than in the US overall, ranging from 0.2% higher for lung and bronchus cancer to 36.6% higher for thyroid cancer.

Incidence rates in the 25–49 age group were also higher by 24.1% for non-Hodgkin lymphoma, 25% for prostate cancer, and 39.7% for thyroid cancer.

The incidence of six cancers (breast, prostate, corpus uteri, thyroid, colorectal, and kidney and renal pelvis) significantly increased between 2000 and 2018.

The models explained ≥ 30% variation in incidence data for six, five, and four cancers in the 25–49, 50–69, and 70–84 age groups, respectively. Moreover, models revealed a positive association between various PM_2.5-related variables and several cancers in males.

Moreover, for breast cancer cases in the 25–49 age group, a positive association was observed with ambient PM_2.5 levels.

Among 15 environmental variables, positive associations were observed between ambient ozone levels and prostate cancer; mineral dust levels and acute toxic substance release rate were associated with melanoma in males. In females, the percentage of land used for agriculture was negatively associated with thyroid cancer.

Among race and SES variables, counties with lower insurance coverage and higher poverty had reduced incidence rates of breast cancer and thyroid cancer.

Counties with increased proportions of white residents had higher melanoma incidence rates in both sexes and across age groups; these counties also had higher incidence rates of uterine cancer across age groups.

Among four lifestyle factors, smoking was positively associated with lung cancer in both sexes and across age groups. Besides, physical inactivity was positively associated with thyroid cancer in the 25–49 age group in both sexes.

Two spatial patterns were identified; counties in northern NYS had higher incidence rates of lung cancer and lower incidence rates of thyroid cancer.

Conclusions

In sum, the study found positive associations between ambient air pollutants and melanoma, breast cancer and prostate cancer, physical inactivity and thyroid cancer, and smoking and lung cancer.

In general, models could better explain the variation in incidence data in the 25–49 age group than in older age groups. This reflects higher relative risk contributions of exogenous factors during younger ages than for older ages when aging may have more influence on cancer risk.