Allergies and the Risk of Pancreatic Cancer: A Meta-analysis with Review of Epidemiology and Biological Mechanisms

Abstract

Previous reports suggest that allergic disorders may protect against various types of cancer, but the association between history of allergy and pancreatic cancer risk has not been well studied. We did a systematic review and meta-analysis of published studies to evaluate the association of any type, and specific types, of allergy and the risk of pancreatic cancer. We did a comprehensive literature search using MEDLINE, PUBMED, and the ISI Web of Science databases to identify potential relevant case-control and cohort studies. Pooled relative risks (RR) and 95% confidence intervals (95% CI) were calculated using the fixed-and random-effects model. Fourteen population-based studies (4 cohort and 10 case-control studies) with a total of 3,040 pancreatic cancer cases fulfilled our inclusion criteria. A history of allergy was associated with a reduced risk of pancreatic cancer (RR, 0.82; 95% CI, 0.68-0.99). The risk reduction was stronger for allergies related to atopy (RR, 0.71; 95% CI, 0.64-0.80), but not for asthma (RR, 1.01; 95% CI, 0.77-1.31). There was no association between allergies related to food or drugs and pancreatic cancer (RR, 1.08; 95% CI, 0.74-1.58). Overall, there was no evidence of publication bias. Allergies, in particular those related to atopy, seem to be associated with a decreased risk of pancreatic cancer. The hyperactive immune system of allergic individuals may, therefore, in some way lead to increased surveillance and protect against pancreatic cancer development. (Cancer Epidemiol Biomarkers Prev 2005;14(8):1908 -16)

Allergies are associated with reduced pancreas cancer risk: A population‐based case–control study in Ontario, Canada

“…Similar results were observed in other case-control 19,26 and cohort studies. 17 A recent metaanalysis by Gandini et al (2005) also provides additional support to our findings. We did not observe an association between asthma and pancreas cancer risk.…”

“…13,23 Several studies have examined the association between a history of allergies and pancreas cancer risk. [12][13][14][15][16][17]19,[23][24][25][26][27][28] Among several case-control and cohort studies, a significantly reduced risk was observed with a history of any type of allergy.…”

“…[12][13][14][15][16][17]19,[23][24][25][26][27][28] Among several case-control and cohort studies, a significantly reduced risk was observed with a history of any type of allergy. 12,19,23,26 More specifically, statistically significant decreased risks were observed in individuals with hay fever 12,17 and a slightly decreased risk was observed in individuals who were allergic to house dust, animals, plants, some foods, insect bites or stings and mold 19,26 although some of the confidence intervals (CI) were too wide to interpret. 15,19,24 Decreasing pancreas cancer risk was further associated with an increased number and severity of allergies, older age at onset, and increased duration of exposure to allergens.…”

Relationship between Allergy and Cancer: An Overview

“…Risk reductions were more distinct for this cancer site, by up to more than 50%. The pancreas is accessible to all of the cells required for a successful immunosurveillance, so the hypothesis of enhanced immunosurveillance seems to apply for this type of cancer [61]. The protective effect should be ascribed to the systemic effect of allergies, and not to any local reaction which takes place at the entry location of allergens.…”

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

“…Previous studies that examined the associations between allergies and pancreatic cancer have generated varying results. The findings from one meta-analysis showed that there was no associa-tion between asthma and risk of pancreatic cancer, 20 while the results from another, more recent, meta-analysis showed consistent inverse associations between asthma and risk of pancreatic cancer as well as between nasal allergies and risk of pancreatic cancer. 6 The findings from a recent cohort study, which used a nationwide database, revealed that the associations between allergies and cancer are site specific, and that patients with more than one allergic disease had lower cancer risks compared with those with only one allergic disease.…”