Asthma and Risk of Appendicitis in Children: A Population-Based Case-Control Study.

OBJECTIVE: To assess whether asthma is associated with risk of appendicitis in children. METHODS: We used a population-based case-control study design using a comprehensive medical record review and predetermined criteria for appendicitis and asthma. All children (age younger than 18 years of age) who resided in Olmsted County, Minnesota, and developed appendicitis between 2006 and 2012 were matched to controls (1:1) with regard to birthday, gender, registration date, and index date. Asthma status was ascertained using predetermined criteria. Active (current) asthma was defined as the presence of asthma symptoms or asthma-related events (eg, medication use, clinic visits, emergency department, or hospitalization) within 1 year before the index date. Inactive asthma was defined as subjects without these events. A conditional logistic regression model was used. RESULTS: Among the 309 appendicitis cases identified, when stratified according to asthma status, active asthma was associated with significantly increased risk of appendicitis compared with inactive asthma (odds ratio [OR] = 2.48; 95% confidence interval [CI], 1.22-5.03) and to no asthma (OR = 1.88; 95% CI, 1.07-3.27; overall P = .035). When controlling for potential confounders such as gender, age, and smoking status, active asthma was associated with a higher odds of developing appendicitis compared with nonasthmatic patients (adjusted OR = 1.75; 95% CI, 0.99-3.11) whereas inactive asthma was not (overall P = .049). Tobacco smoke exposure within 3 months was associated with an increased risk of appendicitis (adjusted OR = 1.66; 95% CI, 1.02-2.69). Among asthma medications, leukotriene receptor antagonists reduced the risk of appendicitis (OR = 0.18; 95% CI, 0.04-0.74). CONCLUSIONS: Active asthma might be an unrecognized risk factor for appendicitis in children whereas a history of inactive asthma does not pose such risk. Further investigation exploring the underlying mechanisms is warranted.

A novel measure of socioeconomic status using individual housing data to assess the association of SES with rheumatoid arthritis and its mortality: a population-based case-control study.

OBJECTIVES: To assess whether HOUSES (HOUsing-based index of socioeconomic status (SES)) is associated with risk of and mortality after rheumatoid arthritis (RA). DESIGN: We conducted a population-based case-control study which enrolled population-based RA cases and their controls without RA. SETTING: The study was performed in Olmsted County, Minnesota. PARTICIPANTS: Study participants were all residents of Olmsted County, Minnesota, with RA identified using the 1987 American College of Rheumatology criteria for RA from 1 January 1988, to 31 December 2007, using the auspices of the Rochester Epidemiology Project. For each patient with RA, one control was randomly selected from Olmsted County residents of similar age and gender without RA. PRIMARY AND SECONDARY OUTCOME MEASURE: The disease status was RA cases and their matched controls in relation to HOUSES as an exposure. As a secondary aim, post-RA mortality among only RA cases was an outcome event. The associations of SES measured by HOUSES with the study outcomes were assessed using logistic regression and Cox models. HOUSES, as a composite index, was formulated based on a summed z-score for housing value, square footage and number of bedrooms and bathrooms. RESULTS: Of the eligible 604 participants, 418 (69%) were female; the mean age was 56±15.6 years. Lower SES, as measured by HOUSES, was associated with the risk of developing RA (0.5±3.8 for controls vs -0.2±3.1 for RA cases, p=0.003), adjusting for age, gender, calendar year of RA index date, smoking status and BMI. The lowest quartile of HOUSES was significantly associated with increased post-RA mortality compared to higher quartiles of HOUSES (HR 1.74; 95% CI 1.10 to 2.74; p=0.017) in multivariate analysis. CONCLUSIONS: Lower SES, as measured by HOUSES, is associated with increased risk of RA and mortality after RA. HOUSES may be a useful tool for health disparities research concerning rheumatological outcomes when conventional SES measures are unavailable.