Risk factors and social inequalities in severity of COVID-19 from a life course perspective

Background: Coronavirus disease 2019 (COVID-19) has spread rapidly worldwide, with serious consequences for the community. There have been a number of reports and cross-sectional studies regarding risk factors for severe COVID-19.

However, large prospective cohort studies identifying exposures that are important for understanding the course of the disease are lacking.Aims: Our overall aim is to investigate prospectively the extent to which early cardiovascular disease, body weight, physical fitness, and muscle strength, as well as occupational exposures and socioeconomics can predict risk of severe COVID-19.

In addition, we aim to investigate the interplay between socio-occupational factors and potentially modifiable risk factors.Implementation:To address these aims we will utilize:1) The Swedish Conscript Register which comprises more than 1.5 million men examined in late adolescence during 1968-2005 who were alive on January 1, 2020, with current age in the range of 33–70-years.

Information is available on weight, height, blood pressure, muscle strength, cognitive ability and results of fitness tests on a bicycle.

For a sub-cohort of 416,735 men, we have linked supplementary data from health profile assessments.2) A cohort of 4.2 million women who gave birth in Sweden, alive on January 1, 2020, with current age in the range of 18–100-years.These two cohorts are linked to other nationwide registries including international standard classification of occupations, job exposure matrices, National Patient and Death Registers and the Swedish Intensive Care Register.

Hence, we have access to very detailed phenotype data, as well as COVID-19 outcomes, and both cohorts will be followed until the end of the pandemic.Impact: The results will be of importance for understanding the effects of early risk factors and social inequalities on the course of COVID-19 disease, to design preventative measures, and may be applicable to other viral respiratory infections.