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.

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.