Digitizing Paper-based Military health records from Norwegian males born in 1950 – assessments of data quality and applicability in research

Abstract Aim This study aims to present and assess the quality of military health data extracted from paper-based personnel files of Norwegian men born in 1950, proposing avenues for future research. Background Archived military documents contain health information that can enrich the Norwegian Armed Forces Health Registry (NAFHR) with more detailed clinical measurements of older birth cohorts. However, uncertainty exists about the preservation of digital reproduction and the accuracy of clinical measurements for research purposes. Methods To establish an infrastructure at the National Archives of Norway, we digitized military health information covering approximately 60% (n = 17 324) of Norwegian men born in 1950. Health records were manually transcribed, and transcribed data were controlled for registered data in the NAFHR. Clinical measures were compared with results from comparable national health surveys, and variations between the conscription board health examinations and the examinations on the first day of service were explored. Transcribed cardiovascular disease (CVD) risk factor data were tested with logistic regression models to assess their predictive ability. Results The transcribed data showed good compliance and readability, with overall accurate and valid clinical measurements. While some variations existed between the two examination settings, the measurements generally aligned with the national health survey results. Several of the CVD risk factors in the cohort showed the expected associations with CVD mortality. Conclusion This study highlights the readability and accuracy of digitized military health data, emphasizing its potential for public health and future research through the NAFHR. Further digitization efforts promise enhanced communication and expanded research opportunities.