Validity of self-reported educational level in the Tromsø Study

Abstract

Background: Self-reported data on educational level have been collected for decades in the Tromsø Study, but their validity has yet to be established. Aim: To investigate the completeness and correctness of self-reported educational level in the Tromsø Study, using data from Statistics Norway. In addition, we explored the consequence of using these two data sources on educational trends in cardiometabolic diseases.<p><p> Methods: We compared self-reported and Statistics Norway-recorded educational level (primary, upper secondary, college/university <4 years, and college/university ⩾4 years) among 20,615 participants in the seventh survey of the Tromsø Study (Tromsø7, 2015–2016). Sensitivity, positive predictive value and weighted kappa were used to measure the validity of self-reported educational level in three age groups (40–52, 53–62, 63–99 years). Multivariable logistic regression was used to compare educational trends in cardiometabolic diseases between self-reported and Statistics Norway-recorded educational level. <p>Results: Sensitivity of self-reported educational level was highest among those with a college/university education of 4 years or more (⩾97% in all age groups and both sexes). Sensitivity for primary educational level ranged from 67% to 92% (all age groups and both sexes). The lowest positive predictive value was observed among women with a college/university education of 4 years or more (29–46%). Weighted kappa was substantial (0.52–0.59) among men and moderate to substantial (0.41–0.51) among women. Educational trends in the risk of cardiometabolic diseases were less pronounced when self-reported educational level was used. <p>Conclusions: Self-reported educational level in Tromsø7 is adequately complete and correct. Self-reported data may produce weaker associations between educational level and cardiometabolic diseases than registry-based data.