Objectives: Earlier research has suggested a positive association between Addison's disease (AD) and celiac disease (CD). We have here investigated the risk of AD in individuals with CD from a general population cohort.

Methods: Through the Swedish national registers we identified 14,366 individuals with a diagnosis of CD (1964-2003) and 70,095 reference individuals matched for age, sex, calendar year and county of residence. We used Cox regression to estimate hazard ratios (HRs) for subsequent AD. Analyses were restricted to individuals with more than one year of follow-up and without AD prior to study entry or within one year after study entry. Conditional logistic regression estimated the odds ratio (OR) for CD in individuals with prior AD.

Results: There was a statistically significantly positive association between CD and subsequent AD (HR = 11.4; 95% CI = 4.4-29.6). This risk increase was seen in both children and adults, and did not change with adjustment for diabetes mellitus or socioeconomic status. When we restricted reference individuals to inpatients, the adjusted HR for AD was 4.6 (95% CI = 1.9-11.4). Individuals with prior AD were at increased risk of CD (OR = 8.6; 95% CI = 3.4-21.8).

Conclusions: This study found a highly increased risk of AD in individuals with CD. This relationship was independent of temporal sequence. We therefore recommend that individuals with AD should be screened for CD. We also suggest an increased awareness of AD in individuals with CD.