Children with chronic inflammatory diseases (CIDs) were found to be at increased risk for the same CIDs as their parents, in addition to other related CIDs dependent on disease status of their parents, according to study results published in Clinical Epidemiology.
Study authors conducted a population-based cohort study using data extracted from the Danish Medical Birth Register and the Danish National Patient Register. All individuals born in Denmark between January 1973 and March 2016 were eligible for inclusion in the analysis. The primary outcome was first diagnosis of CID among children, using data from the Danish National Patient Register. The primary exposure was the presence of 1 or more CID among parents. Cox proportional hazard models were used to assess the relationship between parental CID and risk for CID in offspring. Models were adjusted for year of birth, sex, parental age at birth, and type of delivery (caesarean vs vaginal).
The study included data from 2,699,449 children born between January 1973 and March 2016. In total, 228,069 children (8.4%) had a mother with CID and 244,512 children (9.1%) had a father with CID. Among children with at least 1 affected parent, 32.9% developed CID. Among children without affected parents, the prevalence of CID was 15.9%. In regression models, compared with children without affected parents, those with 1 affected parent with 1 CID (hazard ratio [HR], 1.75; 95% CI, 1.72-1.79), 1 affected parent with multiple CIDs (HR, 2.23; 95% CI, 2.11-2.34), and 2 affected parents (HR, 3.10; 95% CI, 2.98-3.22) were at higher risk for CID (all P <.001).
The association between parents and children persisted across multiple types of CIDs. Children with a parent with diabetes mellitus, rheumatoid arthritis (RA), or celiac disease were more likely to have diabetes mellitus and celiac disease. Children of parents with diabetes mellitus or RA were more likely to have RA. Further, children with parents affected by Crohn disease or ulcerative colitis were at increased risk for both diseases. Celiac disease was highly heritable and appeared to vary depending on the sex of the child. Specifically, the relative risk of developing celiac disease was 23.3 (95% CI, 21.0-26.0) among girls with a parent with celiac disease and 14.9 (95% CI, 12.7-17.5) among boys with an affected parent with celiac disease. Overall, having a mother with a CID was associated with greater risk compared with having a father with a CID.
According these data, children of a parent affected by CID were more likely to develop a CID than children of unaffected parents. Although offspring were likely to develop the same CID as their parents, the study authors observed certain cross-disease patterns.
As study limitations, the study authors noted the potential risk for confounding factors. In particular, children with parents with CIDs may have been diagnosed early in life due to parental suspicion of the disease.
“Future studies should explore the causal pathways underlying the disease risk conferred by a parents’ disease since this knowledge may support the development of prevention and [optimized] treatment strategies in CID,” the study authors concluded.
Andersen V, Pedersen AK, Möller S, Green A. Chronic inflammatory diseases – diabetes mellitus, rheumatoid arthritis, coeliac disease, Crohn’s disease, and ulcerative colitis among the offspring of affected parents: a Danish population-based registry study. Clin Epidemiol. 2021;13:13-20.