Aim To examine the association between socioeconomic position and the risk of atrial fibrillation (AF) in different stages of life in a population of Danish citizens.
Methods Register-based study. We followed all individuals turning 35, 50, 65 or 80 years from 1 January 1996 to 31 December 2005 until AF, death, emigration or the end of study period (31 December 2015). Exposure was education and income. We used Cox regression for the HRs (95% CI) and the pseudo-observation method for the adjusted risk difference (RD) (%).
Results A total of 2 173 857 participants were enrolled and 151 340 incident cases of AF occurred over a median of 13.6 years of follow-up. Adjusted HR (95% CI) of incident AF for the youngest age group with the highest education (ref lowest) was 0.62 (0.50 to 0.77) (women) and 0.85 (0.76 to 0.96) (men). The associations attenuated with increasing age, that is, HRs for the oldest age group were 1.04 (0.97 to 1.10) and 0.98 (0.96 to 1.04), respectively. The corresponding adjusted RDs (%) were: −0.28 (−0.43 to −0.14), −0.18 (−0.36 to −0.01), 3.04 (−0.55 to 6.64) and −0.74 (−3.38 to 2.49), respectively. Similar but weaker associations were found for income.
Conclusion Higher level of education and income was associated with a lower risk of being diagnosed with AF in young individuals but the association decreased with increasing age and was almost absent for the oldest age cohort. However, since AF is relatively rare in the youngest the RDs were low.
- atrial fibrillation
- social inequality
- socioeconomic position
- cohort study
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Contributors EDL, AMJ, SLC, KF, SPJ, MLL, MBJ and SR contributed to the planning, design, analysis and interpretation of data. EDL drafted the manuscript. EDL, AMJ, SLC, KF, SPJ, MLL, MBJ and SR revised the manuscript critically. EDL, AMJ, SLC, KF, SPJ, MLL, MBJ and SR gave approval for the final manuscript.
Funding This study was partly funded by the Karen Elise Jensen Foundation, The Obel Family Foundation and by internal funding.
Disclaimer The funders had no role in the planning, design, analyses of data or writing of the study.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Ethical approval is not needed for register-based studies in Denmark.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available.
It is not possible to share data according to Danish law. Access are only granted to researchers directly responsible for conducting the specific study.
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