Heart disease among Greenlandic children and young adults: a nationwide cohort study

BACKGROUND: The incidences of heart disease (HD) and congenital heart disease (CHD) among Inuit in Greenland (GL) and Denmark (DK) are unknown. This study aims to estimate incidence rates (IRs) of HD and CHD among the young Inuit populations in Greenland and Denmark compared with rates among young non-Inuit populations in the same countries. METHODS: A register-based nationwide cohort including all individuals living in Greenland and Denmark from birth to age <40 years through 1989–2014 was formed. Ethnicity was considered Inuit/mixed if at least one parent was registered as being born in Greenland. Information on HD and CHD hospitalization was obtained from national inpatient registers using ICD-8 and ICD-10 codes. RESULTS: HD IR was lower among individuals living in Greenland compared with those living in Denmark, [73.35(GL) (95% confidence interval (CI) 68.07 to 79.03)] vs [88.07(DK) (95% CI 87.38 to 88.76)], whereas CHD IRs were almost similar in the two countries [IR 34.44(GL) (95% CI 30.89 to 38.40) vs IR 34.67(DK) (95% CI 34.24 to 35.10)]. Being of Inuit/mixed ethnicity was associated with an increased risk of both HD and CHD compared with non-Inuit in Greenland and Denmark [adjusted hazard ratio HD 2.07(GL) (95% CI 1.25 to 3.42)] and CHD [2.92(GL) (95% CI 1.34 to 6.38)]. CONCLUSION: HD IR was lower in individuals living in Greenland compared with individuals living in Denmark, whereas the CHD IRs were almost the same for both countries. However, the risk of HD including CHD was higher among individuals of Inuit/mixed ethnicity compared with non-Inuit in both countries, suggesting a role of ethnicity among children and younger adults.