Asthma and risk of selective IgA deficiency or common variable immunodeficiency: a population-based case-control study.

OBJECTIVE: To determine the association between a history of asthma and a diagnosis of selective IgA deficiency (sIgAD)/common variable immunodeficiency (CVID). PATIENTS AND METHODS: This population-based case-control study included residents of Olmsted County, Minnesota, who met the Pan-American Group for Immunodeficiency/European Society for Immunodeficiencies diagnostic criteria for sIgAD/CVID between January 1, 1964, through December 31, 2008. Each case had 4 age- and sex-matched controls (2 from the community and 2 from a list of individuals who had undergone an immune work-up). We ascertained asthma status by applying predetermined criteria for asthma. RESULTS: We identified 39 cases: 26 (66.7%) had sIgAD and 13 (33.3%) had CVID. Of the 39 cases, 51.3% were men (n=20) and 97.1% were white (33 of 34 patients). The mean age at the index date (the time when criteria were met) of sIgAD/CVID was 34.2 years. Of the 39 cases, 9 (23.1%) had a history of asthma before the index date of sIgAD/CVID; of the 156 controls, 16 (10.3%) had a history of asthma before the index date (odds ratio, 2.77; 95% CI, 1.09-7.06; P=.03). A history of asthma (before or after the index date of sIgAD/CVID) was more prevalent in sIgAD/CVID cases (30.8%; n=12) than in matched controls (11.5%; n=18) (odds ratio, 3.57; 95% CI, 1.50-8.51; P=.01). CONCLUSION: Asthmatic patients are more likely to have a diagnosis of sIgAD/CVID than nonasthmatic individuals. This association may potentially account for the increased risks of bacterial infections in some individuals with asthma.

Asthma and proinflammatory conditions: a population-based retrospective matched cohort study.

OBJECTIVE: To determine the association between asthma and proinflammatory conditions. PARTICIPANTS AND METHODS: This population-based retrospective matched cohort study enrolled all asthmatic patients among Rochester, Minnesota, residents between January 1, 1964, and December 31, 1983. For each asthmatic patient, 2 age-and sex-matched nonasthmatic individuals were drawn from the same population. The asthmatic and nonasthmatic cohorts were followed forward in the Rochester Epidemiology Project diagnostic index for inflammatory bowel disease (IBD), rheumatoid arthritis (RA), diabetes mellitus (DM), and coronary heart disease (CHD) as outcome events. Data were fitted to Cox proportional hazards models. RESULTS: We identified 2392 asthmatic patients and 4784 nonasthmatic controls. Of the asthmatic patients, 1356 (57%) were male, and mean age at asthma onset was 15.1 years. Incidence rates of IBD, RA, DM, and CHD in nonasthmatic controls were 32.8, 175.9, 132.0, and 389.7 per 100,000 person-years, respectively; those for asthmatic patients were 41.4, 227.9, 282.6, and 563.7 per 100,000 person-years, respectively. Asthma was associated with increased risks of DM (hazard ratio, 2.11; 95% confidence interval, 1.43-3.13; P<.001) and CHD (hazard ratio, 1.47; 95% confidence interval, 1.05-2.06; P=.02) but not with increased risks of IBD or RA. CONCLUSION: Although asthma is a helper T cell type 2-predominant condition, it may increase the risks of helper T cell type 1-polarized proinflammatory conditions, such as CHD and DM. Physicians who care for asthmatic patients need to address these unrecognized risks in asthmatic patients.

Assessment of the association between atopic conditions and tympanostomy tube placement in children.

This study assesses the relationship between otitis media and atopic conditions in children by comparing the incidence of tympanostomy tube placement between children with and without atopic conditions: asthma, allergic rhinitis, and atopic dermatitis. Study subjects were a cohort of 323 healthy children who participated in a study of vaccine response. All episodes of tympanostomy tube placement and physician diagnoses of allergic rhinitis and atopic dermatitis were collected through comprehensive medical record review. Asthma status was ascertained through application of established criteria. We compared incidence rates of tympanostomy tube placement between children with and without atopic conditions. We fitted data to a Poisson regression model to calculate relative risk ratios (RRs) and their corresponding 95% confidence intervals (95% CI). Three subjects were excluded who did not have parental authorization for using records for research. Of the remaining 320 subjects, 170 (53%) were male subjects, 268 (94%) were white, 124 (39%) were asthmatic patients, and 20 (6%) had tympanostomy tube placement. Children with asthma before the index date of tympanostomy tube placement were more likely to have tympanostomy tube placement compared with those without asthma (RR, 19.33; 95% CI, 11.41; 32.75; p < 0.001). We found a similar association between asthma ever (before or after index date) and the incidence of tympanostomy tube placement (RR, 1.53; 95% CI, 0.93-2.53; p = 0.095). This was true for children with allergic rhinitis compared with those without allergic rhinitis (RR, 1.70; 95% CI, 1.01-2.86; p = 0.007). Atopic dermatitis was not associated with the incidence of tympanostomy tube placement. Asthma or allergic rhinitis may be unrecognized risk factors for recurrent or persistent otitis media. However, given the small sample size of the study, a cohort study with a larger sample size is necessary.

Impact of delay in asthma diagnosis on chest X-ray and antibiotic utilization by clinicians.

OBJECTIVE: To evaluate the effect of the timeliness of asthma diagnosis on chest X-ray (CXR) and antibiotic utilization in children. PATIENTS AND METHODS: This was a retrospective cohort study of 276 asthmatic children aged 5-12 years from Rochester, Minnesota. From the time when children met our predetermined asthma criteria, the frequency of CXR and antibiotic utilizations for respiratory illnesses were collected from medical records until age 18 years. Using a Poisson regression model, the frequency of CXR and antibiotic utilizations were compared in children with timely, delayed, or no clinician diagnosis of asthma. RESULTS: Of the 276 asthmatic patients, 97 (35%) had a timely diagnosis, 122 (44%) had a delayed diagnosis, while 57 patients (21%) had no clinician diagnosis of asthma. There was no significant difference in CXR or antibiotic utilization for respiratory illness between these groups. In addition, this was true for the comparison between the timely diagnosed group and the delayed diagnosed group combining both the group with a delay in asthma diagnosis and the group who never had asthma diagnosis. CONCLUSIONS: A delay in the diagnosis of asthma in children is common and overall it may not influence antibiotic and CXR utilization for respiratory symptoms by clinicians. However, its impact on access to asthma-related therapies and other healthcare utilizations could be possible and was not assessed in this study. Given the limitations of our study, a larger prospective study needs to be considered.

Serum 25-hydroxyvitamin D is associated with enhanced pneumococcal antibody levels in individuals with asthma.

Recent studies suggest that vitamin D modulates innate immunity and reduces the risk of microbial infections. Little is known about the role of vitamin D in antipneumococcal immunity in individuals with asthma. We determined the correlation between serum 25-hydroxyvitamin D (25[OH]D) levels and pneumococcal antibody levels in individuals with asthma, atopic dermatitis, or allergic rhinitis, and atopic sensitization status. A cross-sectional study was conducted for 21 subjects with asthma and 23 subjects without asthma. Pearson's correlation coefficient between serum 25(OH)D concentrations and the number of positive serotype-specific antibody levels was calculated among individuals with and without asthma, atopic dermatitis, and/or allergic rhinitis and atopic sensitization status. The overall correlation between serum 25(OH)D concentrations and positive pneumococcal antibody levels in all subjects regardless of asthma was not significant (r = -0.14; p = 0.38). Stratified analysis results showed that there was a positive correlation between serum 25(OH)D concentrations and positive pneumococcal antibody levels in asthmatic patients (r = 0.45; p < 0.05) and an inverse correlation was observed in nonasthmatic patients (r = -0.53; p < 0.05). These trends were similar for subjects with and without atopic dermatitis and/or allergic rhinitis (r = 0.58 and p = 0.008 versus r = -0.63 and p = 0.001). Despite similar trends in the correlation between serum 25(OH)D and pneumococcal antibody concentrations among those with and without atopic sensitization status (r = 0.27 and p = 0.19 versus r = -0.41 and p = 0.08), they did not reach statistical significance. The 25(OH)D may enhance humoral immunity against Streptococcus pneumonia in subjects with atopic conditions but not without atopic conditions. Atopic conditions may have an important effect modifier in the relationship between serum 25(OH)D concentrations and immune function.

Inflammatory bowel disease and asthma: a population-based, case-control study.

BACKGROUND: A few cross-sectional studies reported an increased risk of inflammatory bowel disease (IBD) among asthmatics. We conducted a population-based, case-control study that applied predetermined criteria for asthma and IBD to determine whether asthma, as a T-helper 2 (Th2) condition, reduces the risk of IBD, a Th1 condition. METHODS: This was a population-based, case-control study using criteria-based ascertainment for IBD and asthma. Subjects were all Rochester, Minnesota, residents who had developed IBD between 1964 and 1983 and their age- and gender-matched controls, using 1:1 matching. Controls were randomly selected from the community using the Rochester Epidemiology Project database and confirmed not to have IBD. All cases and controls were merged with the database comprising all Rochester residents with or without asthma between 1964 and 1983. RESULTS: Of the 231 IBD cases, 55% had ulcerative colitis and the remainder had Crohn's disease. Of these, 50.4% were male and 98.1% were Caucasians. The mean age at the time of IBD diagnosis was 33.8 years. Four cases (1.7%) had asthma prior to the index date of IBD, whereas two controls (0.9%) had asthma (unadjusted odds ratio [OR]: 3.0, 95% confidence interval [CI]: 0.31-28.84, P = 0.34). Similarly, 16 IBD cases (6.9%) had asthma ever while 12 controls (5.2%) had asthma ever (unadjusted OR: 1.4, 95% CI: 0.62-3.38, P = 0.40). CONCLUSIONS: Asthma as a Th2 condition does not reduce the risk of IBD as a Th1 condition. Because of the limitations of our study and others, the association between asthma and IBD needs to be further studied.