Epidemiological studies

Watch this short YouTube video on the different types of epidemiological studies, then find a peer reviewed journal article that uses one of the types of studies included in the video. Provide a copy of the article (i.e. download it from the source and upload it as an attachment to your discussion board post), an overview of the article and an analysis of how it meets the criteria outlined in the video for that type of study. Do you think it was the correct study design?  Why is it important to be able to determine this?