Adults with asthma have about a 70 percent greater risk of developing shingles as compared to those without asthma, according to the results of a recent study published in the Journal of Allergy and Clinical Immunology.
Researchers led by Young Juhn, MD, a general academic pediatrician and asthma epidemiologist at the Mayo Clinic Children’s Research Center in Rochester, MN, recently reported an increased risk of herpes zoster (shingles or zoster) in children with asthma. But little is known about whether asthma is associated with an increased risk of shingles in adults.
The group designed a population-based, case-control study, reviewing the medical records for potential patients with shingles. They identified 371 cases of shingles during the study period and compared them against 742 control subjects, all adults aged 50 years and older who resided in Olmsted County, MN, with an average age of 67.
Of the 371 shingles cases, 23 percent (87 individuals) had asthma, compared with 15 percent (114 of 742 individuals) from the control group. Controlling for pertinent covariates and confounders, there was a significant association between a history of asthma and risk of zoster (adjusted odds ratio, 1.70). The population-attributable risk percentage for asthma was about 10%.
The researchers also noted that accounting for asthma and other atopic conditions, both asthma and atopic dermatitis were found to be independently associated with a higher risk of shingles. Shingles occurred at a rate of 12% in patients with atopic dermatitis (45 of 371 shingles cases) as compared to 8% (58 of 742) of the controls.
“As asthma is an unrecognized risk factor for zoster in adults, consideration should be given to immunizing adults with asthma aged more than 50 years as a target group,” said Jung.
The effect of asthma on the risk of infection or immune dysfunction might very well go beyond the airways, he said.
The underlying mechanisms of the association between asthma and shingles are not clear. However, impairment in innate immune functions in the skin and airways is well-documented in patients with asthma or atopic dermatitis. Jung and colleagues believe that because asthma helps suppress adaptive immunity, it may increase the risk of varicella zoster virus reactivation.
The researchers noted that neither inhaled corticosteroids nor vaccinations were associated with a higher risk of shingles. Rather, zoster vaccination was associated with a lower risk of shingles.
The authors noted that one of the limitations of the study is that the study population was predominantly white and older, mostly born in the 1940s, when asthma incidence was low.
A prospective study with an intervention and a control group would be needed to confirm this association between asthma and shingles. If a prospective study confirms the association and shows that vaccinating earlier could prevent shingles, then studies of the cost-effectiveness of the vaccine in the 50 and older population may be in order.
Kwon HJ, Bang DW, Kim EN. Asthma as a risk factor for zoster in adults: A population-based case-control study. J Allergy Clin Immunol. 2015, Dec 11. pii: S0091-6749(15)01641-3. doi: 10.1016/j.jaci.2015.10.032. [Epub ahead of print]