ABSTRACT
Aims: The COVID-19 pandemic has affected lives of Danish citizens in different ways, for example, through social distancing and other public health measures introduced to mitigate SARS-CoV-2 spread or through economic consequences. We assessed changes in self-reported measures of physical and mental health-related quality of life (MCS, PCS), stress levels, quality of sleep and loneliness during the COVID-19 pandemic in Denmark, and identified factors influencing such changes. Methods: This is a nation-wide prospective cohort study including 50,968 participants in the Danish Blood Donor Study, who answered health questionnaires before and during the COVID-19 pandemic. The questionnaires included the 12-Item Short Form Health Survey, Cohen's Perceived Stress Scale 10-item version, the 3-item UCLA loneliness scale, and three selected questions evaluating insomnia. During the pandemic, the questionnaire also contained items on the personality trait stamina, behaviours undertaken to avoid infection, and changes in experienced changes in job situation during the pandemic. Finally, information on socio-demographic factors and previous use of anti-depressive medication was collected for all study participants from national registers. Descriptive statistics, multivariable linear and multinomial logistic regression analyses were applied. Results: Comparing measurements from before March 2020 with those after May 2020, MCS and quality of sleep both worsened, while the overall stress levels decreased. PCS decreased in men and increased in women. The mean level of loneliness increased by 14%. The degree of health changes varied by age, type of job, changes in job situation during the pandemic, previous use of anti-depressive medication and by level of personal stamina. Conclusions: Living under the unusual circumstances that persisted during the COVID-19 pandemic negatively impacted the health of Danish blood donors.Our observations may herald an emerging public health problem.