Please assist me in creating a table for the following Epidemiology question: In
ID: 3178732 • Letter: P
Question
Please assist me in creating a table for the following Epidemiology question: Investigators are interested in the effect of TV watching on obesity rates among young children. They therefore conducted a cohort study in which they enrolled over 1 million children ages 0-23 months in 2008. At the baseline assessment, they asked parents to report the average number of hours of TV the children watched each day. They then followed up with the children 2-3 years later in 2010 and 2011 to assess their BMI (and incidence of obesity). Investigators found an incidence rate of obesity of 14 cases per 100 person-years among children who watched 2 hours or more of TV per day and 8 cases per 100 person-years among children who watched less than 2 hours of TV per day. The overall incidence rate of obesity among this population in the U.S. is estimated to be 10 cases per 100 person-years. What risk could be eliminated in the population if young children stopped watching TV for more than 2 hours each day? ANSWER = 2.00 per 100 person-years
Explanation / Answer
Let the proportion of people who watched TV for 2 hour or more be X. Then proportion of people who watches less than 2 hours would be (1-x) . Therefore from the given number of cases we get:
14*x + 8*(1-x) = 10
14x + 8 - 8x = 10
6x = 2
x = 1/3
Therefore if we stop the population from watching TV greater than 2 hours we would be able to stop extra 6 cases in 1/3 per 100 person years. because x = 1/3 is the proportion of people watching TV greater than or equal to 2 hours. Therefore we get that:
6*(1/3) = 2 per 100 person years.
Note: 6 comes from the fact that people watching TV greater than or equal to 2 hours have 6 more cases per 100 person years than for people watching TV for less than 2 hours .