Some Researchers Want to Investigate the Association of Work Stress

Some researchers want to investigate the association of work stress and risk of cardiovascular mortality.Investigators selected a systematic sample of 902 participants in strata by sex,age,and occupational group from the Valmet factories in Jyväskylä,in central Finland.Baseline examination in 1973 determined cases of cardiovascular disease,behavioral and biologic risks,and stressful characteristics of work.Follow-up examinations included measurement of blood pressure,cholesterol concentration,and body mass index in 1978 and in 1983.Work stress and risk of cardiovascular mortality: a study of industrial employees What kind of study design is this?

A) Cross-sectional study
B) Prospective cohort study
C) Case-control study
D) Randomized trial
E) Case report