Another commonly used design used in epidemiology is a cross sectional study. With this design, assessments of disease and risk factors are performed at the same time. This gives you a ‘snapshot’ of the prevalence of disease and potential risk factors in a community at a particular time.

Example:
Individuals who were diagnosed with type 1 diabetes between 2000 and 2007 were recruited from a large outpatient clinic. The were examined to determine if they had diabetes retinopathy (DR) and had ever smoked cigarettes. The prevalence of DR in this population was 40%. The prevalence of smoking among those with and without DR was 10% and 12%, respectively. Therefore, in this population, smoking did not appear to be a risk factor for DR.