Association between Allergies and Risk of Pancreatic Cancer

Abstract

Background Less than 10% of pancreatic cancer cases survive five years, yet its etiology is not well understood. Studies suggest allergies are associated with reduced pancreatic cancer risk. Our study collected additional information on allergies (including skin prick test results and differentiation of allergic/non-allergic asthma), and is the first to assess possible confounding by allergy medications. Methods A population-based case-control study was designed to comprehensively assess the association between allergy and pancreatic cancer risk. Pancreas cancer cases were diagnosed during 2011-2012, and identified through the Ontario Cancer Registry (345 cases). Population-based controls were identified using random digit dialing and age/sex frequency matched to cases (1285 controls). Questionnaires collected lifetime allergy history (type of allergy, age at onset, skin prick testing results), allergy medications, and established pancreas cancer risk factors. Logistic regression was used to estimate odd ratios and test potential confounders, including allergy medications. Results Hay fever was associated with a significant reduction in pancreatic cancer risk (AOR=0.68, 95% CI: 0.52-0.89), and reduction was greatest for those whose skin prick test was positive for hay fever allergens. No particular patterns were observed as regards age at onset and duration of allergy. Positive dust/mold allergy skin prick test and animal allergies were associated with a statistically significant reduced pancreatic cancer risk; AOR=0.49, 95% CI: 0.31-0.78 and AOR=0.68, 95% CI: 0.46-0.99, respectively. Asthma was not associated with pancreatic cancer risk. Conclusions/Impact These findings support the growing body of evidence that suggests certain allergies are associated with reduced pancreatic cancer risk.

OBSOLETE: Observational Epidemiology

“…If cases come from a defined group such as members of a health maintenance organization, controls without the disease of interest are generally sampled from among other members of the defined group. Cotterchio et al (2014) used a case-control design to evaluate a possible protective effect of allergies against the development of pancreatic cancer. The study included 345 newly diagnosed pancreatic cancer cases during 2011 and 2012 identified from the Ontario Cancer Registry, which collects data on all cancer cases diagnosed in the Province of Ontario, Canada.…”

“…Protective associations were observed for hay fever, dust or mold allergies, and animal or pet allergies, consistent with prior studies, but not for food or medication allergies or allergic asthma. In contrast to the approach of Cotterchio et al, 2014, Amadou et al, 2014 recruited women with newly diagnosed cases of breast cancer from 12 hospitals at the major health care institutions in three large regions in Mexico, and sampled controls from the same five-year age group, the same region and with membership in the same health care institution as the cases. They used this type of case-control approach to determine the association between anthropometric characteristics and breast cancer in Mexico.…”

Associations between Atopic Dermatitis and Risk of Gastric Cancer: A Nationwide Population-based Study

“…[5][6][7][8][9] Over the past few decades, substantial amounts of epidemiologic and clinical data have described the associations between allergic diseases and cancer. [5][6][7][8][9][10][11][12] However, to the best of our knowledge, only a few epidemiologic studies have examined the associations between allergic diseases and gastric cancer. One cohort study that analyzed subjects selected from a hospital discharge registry, reported that asthma was associated with reduced gastric cancer risk; 13 however, this study included patients with only severe asthma, and the number of gastric cancer cases was small.…”

Reduced risk of pancreatic cancer associated with asthma and nasal allergies

“…Other reports have largely replicated the inverse association between PDAC and nasal allergies with only one study reporting a non-significant reduced estimate 21–25. Regarding skin allergies, two additional articles reported reduced estimates but only one showed statistical significance 24 25. Conversely, the association between asthma and PDAC risk has remained inconclusive.…”