Ischaemic heart disease in first-degree relatives to coeliac patients

Abstract

Coeliac disease (CD) has been linked to an increased risk of ischaemic heart disease (IHD). We examined the risk of IHD in first-degree relatives and spouses to coeliac patients to ascertain the genetic contribution to IHD excess risk. Coeliac disease was defined as having a biopsy-verified villous atrophy (Marsh grade 3) in 1969-2008 (n = 29,096). Coeliac patients were matched to 144,522 controls. Through Swedish registers, we identified all first-degree relatives and spouses to coeliac patients and their controls, in total 87,622 unique coeliac relatives and 432,655 unique control relatives. Our main outcome measure was IHD defined according to relevant international classification of disease codes in the Swedish Inpatient Registry or in the Cause of Death Registry. Hazard ratios (HR) and confidence intervals (CI) were estimated through Cox regression adjusted for sex, age-group and calendar year at study entry of the relative. During a median follow-up of 10·8 years, 2880 coeliac relatives and 13,817 control relatives experienced IHD. First-degree relatives of coeliac patients were at increased risk of IHD (HR = 1·05; 95% CI = 1·00-1·09, P-value = 0·04), while spouses were at no increased risk (HR = 0·99; 95% CI = 0·87-1·12). The excess risk of IHD in coeliac first-degree relatives aged 40-59 years was 70/100,000 person-years. First-degree relatives to coeliac patients seem to be at an increased risk of IHD but the excess risk is so small that it has little clinical relevance.