Moossavi et al. Page 268

The current opioid epidemic is an unequivocal and serious public health issue. Drug overdoses are now the leading cause of death for Americans under 50 years old, with most of the fatalities due to opioid overdoses. However, few studies have focused on the carcinogenic effects of long-term opium consumption. Moossavi and colleagues examined the association between opium consumption and pancreatic cancer incidence in a large-scale prospective cohort in Iran. This long-term case–control study confirmed opium carcinogenicity and revealed chronic opium use as a risk factor for pancreatic cancer. More studies should be organized to assess the carcinogenicity of long-term opioid use.

Mahabir et al. Page 233

International and ethnic differences in cancer rates exist, and they are minimally explained by genetic factors. A substantial portion of the differences in cancer rates can be explained by modifiable factors, while other factors, such as the microbiome and the metabolome, are emerging as important intermediary components in cancer prevention. To refine current concepts, researchers have started incorporating emerging technologies for measuring diet and physical activity in human populations. Questions remain regarding reported associations and the best methods to assess associations. This position paper from Mahabir and colleagues highlights the state of the science and priorities for future research.

Berkowitz et al. Page 245

Routine testing of colorectal cancer (CRC) starting at age 50 saves lives, but local CRC screening data are not widely available. Multilevel regression post-stratification for small-area estimation with 2014 Behavioral Risk Factor Surveillance System and Census 2014 county population data revealed substantial county-level variations in the prevalence of being up-to-date with CRC screening: it ranged from 40.1% to 79.8%, with a median of 65.5%. More than 80% of 3,142 counties had <70% up-to-date screening, far from the national goal of 80% by 2018. This study by Berkowitz and colleagues suggests a great need for locally targeted interventions for counties with very low CRC screening prevalence.

Czoli et al. Page 262

Tobacco-specific nitrosamines (TSNAs) are carcinogens found in tobacco products. Recent evidence indicates that levels of the TSNA NNK have increased in Canadian cigarettes. The current study by Czoli and Hammond examined whether these increases translated into differences in exposure among Canadian tobacco users, using urinary metabolite measures from the Canadian Health Measures Survey. The findings indicate that exposure to the TSNA NNK among Canadian tobacco users increased considerably from 2007–09 through 2012–13, in parallel to NNK increases in the tobacco of Canadian cigarettes. The findings raise questions about the commitment of tobacco manufacturers to minimize carcinogen levels to the full extent possible.