A cohort study is conducted to assess the association between clinical characteristics and the risk of stroke. The study involves n=1,250 participants who are free of stroke at the study start. Each participant is assessed at study start (baseline) and every year thereafter for five years. The following table displays data on hypertension status measured at baseline and hypertension status measured two years later.
2 Years: Not Hypertensive2 Years: Hypertensive
Baseline: Not Hypertensive850148
Compute the prevalence of hypertension at baseline.
Prevalence = __20.16%______
Compute the prevalence of hypertension at 2 years.
Prevalence = ___28.4%_____
Compute the cumulative incidence of hypertension over 2 years.
Incidence = ___14.83%_____
A case-control study is conducted to assess the relationship between heavy alcohol use during the first trimester of pregnancy and miscarriage. Fifty
women who suffered miscarriage are enrolled along with 50 who delivered full term. Each participant’s use of alcohol during pregnancy is ascertained. Heavy drinking is defined as 4 or more drinks on one occasion. The data are shown below.
MiscarriageDelivered Full Term
Heavy Alcohol Use144
No Heavy Alcohol Use3646
Compute the odds of miscarriage in women with heavy alcohol use in pregnancy.
Odds Heavy Use = 0.3889
Compute the odds of miscarriage in women with no heavy alcohol use in pregnancy.
Odds No Heavy Use 2.571
Compute is the odds ratio for miscarriage as a function of heavy alcohol use.
Odds Ratio = 0.1512
In a nursing home, a program is launched in 2005 to assess the extent to which its residents are affected by diabetes. Each resident has a blood test and 48 of the 625 residents have diabetes in 2005. Residents who did not already have diabetes were again tested in 2010 and 57 residents had diabetes.
What is the prevalence of diabetes in 2005?
Prevalence 2005 = 7.68
What is the cumulative incidence of diabetes over 5 years?
Cumulative Incidence 5 Years = 1.44
What is the prevalence of diabetes in 2010 (assume that none of the residents
in 2005 have died or left the nursing home)?
Prevalence 2010 = 9.12