The study is a phd-study comprising several substudies focusing on cardiac arrhythmias, mainly atrial fibrillation, among Greenlanders in Greenland.

Some previous studies have indicated that the prevalence may be lower than among Westerners, however; studies have also indicated that atrial fibrillation is underdiagnosed.

These studies aim to:

• Estimate the prevalence of AF among Greenlanders in Greenland aged 55 years or older.
• Estimate the prevalence of well-known risk factors among those found to have AF
• Explore the symptoms of those affected by AF in Greenland
• Among part of the participants: estimate the prevalence of autonomic neuropathy as this may cause arrhythmias.

Atrial fibrillation (AF) is the most common cardiac arrhythmia globally and a major risk factor for ischemic strokes, transient ischemic attacks, increased morbidity and mortality.

Risk factors for AF include diabetes, hyperthyroidism, hypertension, obesity, ischemic heart disease (IHD), age and gender with men generally having a higher risk of developing AF.

The current prevalence of cardiac arrhythmias in Greenland is unknown. From 1962 to 1964 12-lead electrocardiograms (ECGs) were performed on 181 adults and only one of these showed AF. A more recent study from 2013 estimating the incidence of ischemic strokes among Greenlanders found that five percent of this study-population had been diagnosed with AF before the incident, while 32.4 % were diagnosed after the incident, suggesting that AF may be underdiagnosed. Comparing the age of the patients to data from Denmark, the authors found that the incidence rate for stroke was higher among almost all younger age groups in Greenland.

Previous studies have shown that ethnicity may influence the risk of developing AF. The genetic profile of the Greenlandic Inuit has already been shown to have a major impact on the risk of developing type 2 diabetes.

Regarding other AF-related risk factors, hypertension is common with a prevalence of app. 40% among men and 32% among women based on self-reported data, and a study comparing data from ECGs performed in 1963 with more current data has shown a rise in the incidence of IHD.

Furthermore, the number of obese people in Greenland is steadily rising and between 1963 and 2008, the proportion of obese people (BMI≥30) increased from 4.0% to 33.2% for men and 8.3% to 24.5% for women between 50 to 69 years.

In conclusion, the risk factors for cardiac arrhythmias are increasing in Greenland and the overall aim of this study is to estimate the prevalence, risk factors, mortality, morbidity and treatment of arrhythmias in Greenland.

Relevance: as mentioned above, this study aims to estimate the prevalence, risk factors, mortality, morbidity and treatment of arrhythmias in Greenland, all of which is currently unknown. By doing this, the study aims to not only improve the treatment rate of arrhythmias, but also lower the prevalence of diseases such as strokes, which are often caused by arrhythmias. By lowering this prevalence, some deaths and cases of disability can be prevented. Furthermore, the investigators hope to assess whether arrhythmias are influenced differently by ethnicity and risk factors such as diabetes in Greenland than in Europe and if patients with certain diseases and/or symptoms have a higher risk of developing arrhythmias and should be monitored more closely.

Inclusion Criteria:

• At least 50 years old
• Greenlandic ethnicity based on parents' birth place.
• No history of cardiac disease or arrhythmia

Exclusion Criteria:

• Celiac disease (for the SmartPill-study)

People aged 50 years or older living in Nuuk at the time of recruitment (January 2022) will be invited to participate. Ethnicity and eligibility will be assessed when contacting potential participants after the written invitation.