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Use of the moist oral snuff product known as snus was not associated with a greater risk for pancreatic cancer in a pooled analysis of nine prospective studies involving more than 400,000 men.

The lack of association was seen for all durations and intensities of use, Marzieh Araghi, PhD, of the Karolinska Institute in Stockholm, Sweden, and colleagues reported in the

"Our findings, from the largest sample to date, do not support a role of snus use in the development of pancreatic cancer in men."

The findings also bolster the evidence that the non-nicotine carcinogens associated with cigarette smoke combustion are the causal agents that explain the increased risk of pancreatic cancer in smokers, the team wrote.

Snus is widely used in Sweden, and the products, marketed by Swedish Match North America, were approved for sale in the U.S. by the Food and Drug Administration (FDA) several years ago.

The manufacturer petitioned the agency to allow the products to be marketed as safer than cigarettes, but in December 2016 the FDA deferred a ruling on granting Swedish Match a modified risk tobacco product (MRTP) status.

Although cigarette smoking is a recognized risk factor for pancreatic cancer, the evidence linking smokeless tobacco use and pancreatic risk is mixed, the researchers explained.

Snus products are moist tobacco enclosed in small packets, which are placed under the upper lip to deliver nicotine.

A , including two Scandinavian studies of Swedish snus, found the use to be associated with a moderate increase in pancreatic cancer risk, but several recent meta-analyses of case-control studies failed to show an association.

The new published pooled analysis was conducted by researchers in Sweden who had conducted snus studies. The nine pooled prospective cohort studies included men recruited at different time periods from across Sweden, and the studies all had information on snus use and cigarette smoking. Because snus use among women is rare, the studies included only men.

The average age of the men in the pooled analysis was 40 (range of 18 to 99), and the sample yielded 9,276,054 person-years of observation. A total of 1,423 incident cases of pancreatic cancer were identified.

Among the main findings:

• After adjusting for smoking status, the analysis did not support any relationship between snus use and pancreatic cancer risk (HR 0.93, 95% CI, 0.82-1.06 comparing ever- to never-snus users)
• A sub-analysis with further adjustments for alcohol consumption, physical activity, and interaction between alcohol consumption had a hazard ratio of 1.32 (95% CI, 0.8-2.08)
• When the analytical sample was restricted to never smokers, the adjusted HR of pancreatic cancer in current snus users was 1.07 (95% CI, 0.77-1.50)

Study limitations cited by the researchers included the self-reporting of smoking and snus use, which was only assessed at baseline.

Sweden has the lowest smoking prevalence in Europe, with approximately 11% of adults in that country identifying as smokers, compared with the European Union average of 28%, according to a

Surveys also suggest that roughly one in five Swedish men are daily snus users.

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