USA: Allergic rhinitis decreases risk for multiple cancers including cancer of hypopharynx, esophagus (squamous cell), cervix, tonsil/oropharynx, and vagina/vulva, according to a recent study in the journal Cancer Epidemiology, Biomarkers & Prevention. Additionally, the study found that asthma decreases the risk of liver cancer.
Some studies have demonstrated that allergic conditions may prevent some cancers by promoting immune surveillance. Monica D’Arcy, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, and colleagues conducted the study to examine associations of allergic rhinitis, asthma, and eczema with cancer risk among elderly Americans.
For this purpose they used Surveillance Epidemiology and End Results (SEER)-Medicare linked data. From SEER registries, individuals with a first cancer diagnosis were identified (1992–2013; aged 66–99 years; N=1,744,575). From Medicare, 100,000 cancer-free controls were randomly chosen and matched based on sex, age, and selection year. Allergic conditions were identified using Medicare claims, and logistic regression was used to estimate adjusted ORs (aOR) with significance gauged with a Bonferroni P cutoff.
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Key findings of the study include:
- Allergic rhinitis, asthma, and eczema were present in 8.40%, 3.45%, and 0.78% of controls, respectively.
- For allergic rhinitis, strong inverse associations (aORs, 0.66–0.79) were observed for cancers of the hypopharynx, esophagus (squamous cell), cervix, tonsil/oropharynx, and vagina/vulva.
- More modest but significant inverse associations were noted for cancers of the esophagus (adenocarcinoma), stomach, colon, rectosigmoid/rectum, liver, gallbladder, lung, uterus, bladder, and miscellaneous sites.
- Associations were stronger in analyses requiring a dispensed medication to confirm the presence of allergic rhinitis.
- Asthma was associated with reduced risk of liver cancer, whereas eczema was associated with elevated risk of T-cell lymphoma.
“Inverse associations with allergic rhinitis are present for multiple cancers and require etiologic investigation,” write the authors, adding that understanding of mechanisms by which allergic conditions reduce cancer risk may advance cancer prevention and treatment.
For detailed study log on to 10.1158/1055-9965.EPI-18-0887