Question

1. A study is conducted in which 10,000 women without breast cancer are enrolled, questioned about alcohol consumption, and then followed for future development of breast cancer. The design of this study is best described as:

a. Cohort study

b. Ecologic study

c. Case-control study

d. Cross-sectional study

2. A study is conducted in which 10,000 women without breast cancer are enrolled, questioned about alcohol consumption, and then followed for future development of breast cancer. If heavy alcohol drinkers who would develop breast cancer are selectively lost from this study prior to the diagnosis of breast cancer, the apparent association between alcohol drinking and risk of breast cancer will be:

a. Increased

b. Decreased

c. Unchanged

d. Altered but the direction can't be predicted

Answer 1

1.Ans Cohort study

Cohort study is a longitudinal study to find out cause of disease and establish relatiinship between outcome and risk factors over a period of time

Ecological study used to measure prevalence and incidence of disease

Case control study 2 groups of different outcome are compared.

Cross sectional studies find out exposure to risk factors has any relationship between health outcomes.

2. D

According to rule of thumb, drop out should not exceed 20 % of the results, it may affect internal validity.