Question

use the following abstract to answer questions 15 through 19. note: the content of this abstract has been modified from its original format. objective to assess whether high school football played between 1946 and 1956, when headgear was less protective than today, was associated with development of neurodegenerative diseases later in life. methods all male students who played football from 1946 to 1956 in the high schools of rochester, minnesota, plus a non - football - playing referent group of male students in the band, glee club, or choir were identified. using the records - linkage system of the rochester epidemiology project, we reviewed (from october 31, 2010, to march 30, 2011) all available medical records to assess later development of dementia, parkinsons disease, or amyotrophic lateral sclerosis (als). results we found no increased risk of dementia, parkinsons disease, or als among the 438 football players compared with the 140 non - football - playing male classmates. parkinson disease and als were slightly less frequent in the football group, whereas dementia was slightly more frequent, but not significantly so. what study design was used to conduct this study? (2 points) a cross - sectional b rct c prospective cohort d retrospective cohort e case - control

Explanation:

• Cross - sectional: Studies a population at a single point in time. This study looks at past (football playing from 1946 - 1956) and future (disease development) events, so not cross - sectional.
• RCT (Randomized Controlled Trial): Involves random assignment of participants to treatment or control groups. There is no mention of random assignment here.
• Prospective cohort: Follows participants forward in time from exposure. Here, the exposure (football playing) was in the past, so not prospective.
• Retrospective cohort: Identifies exposure (football playing 1946 - 1956) in the past and looks at outcomes (neurodegenerative diseases) later. This matches the study design.
• Case - control: Starts with cases (diseased) and controls (non - diseased) and looks back at exposure. The study starts with exposed (football players) and unexposed (non - football players) groups, not cases and controls.

Answer:

D. Retrospective cohort