Question

1.Many different study designs are used in epidemiological research. State which study design is being used in each of the scenarios described below. Your choices are as follows: *EXPERIMENTAL STUDY *RETROSPECTIVE COHORT STUDY *PROSPECTIVE COHORT STUDY *CASE-CONTROL STUDY *CROSS-SECTIONAL STUDY *ECOLOGICAL STUDY

(a) A hospital-based study of antidepressant medication use during pregnancy and the risk of cleft lip in the offspring. Investigators are currently enrolling two groups of women: those who just delivered an infant with a cleft lip and a sample of women who just delivered an infant without any birth defects. The presence or absence of birth defects is based on the newborn physical exam. All mothers are being interviewed to determine their use of antidepressant medications during the pregnancy that just ended?

(b)A study of infertility in young adult men after treatment for testicular cancer. Investigators are currently enrolling two groups of men who were treated for cancer between 1990 and 2000: (1) those who were treated with surgery combined with chemotherapy and (2) those who were treated with surgery combined with radiation. The frequency of infertility occurring from the time of treatment through December 2016 is being evaluated in the two groups?

(c)A study of the impact of different educational strategies to reduce the consumption of soft drinks among teenagers. The investigators are currently enrolling healthy teens and assigning them to one of two groups: those who view a film on the health risks of soft-drink consumption and those who read printed material on these risks. The frequency of soft drink consumption is being measured at enrollment and six months later. Any changes over time are being compared between the two groups?

(d)A study of the impact of needle exchange programs on the transmission of HIV. The needle exchange programs allow drug users to obtain clean needles and syringes free of charge. The investigators are comparing the incidence of new HIV infections in U.S. cities with and without needle-exchange programs. Information on HIV incidence in each city is being obtained from the Centers for Disease Control and Prevention. Information on the presence or absence of needle exchange programs in each city is being obtained from health officials in each city.

Answer 1

1. Case control study: Two different groups (mothers of healthy newborn and mothers of newborn with cleft lip) are assessed to identify the exposure with supposed causative factor, use of anti-depressant during pregnancy.
2. Prospective cohort study- Group of similar individuals (all are affected with testicular cancer) but differ in certain factors (undergone surgery with chemotherapy and surgery with radiation during 1990-2000) are assessed for a certain outcome (infertility) till December 2016. Here the study progresses to future to identify whether the outcomes occurs or not hence it is prospective in nature.
3. Experimental study- An intervention (education program on strategies to reduce soft drink consumption among teenagers) is introduced and studies the effect of intervention in the population. It is an experimental study.
4. Cross-sectional study- Data gathered regarding the occurrence of HIV infection with or without needle exchange program across US cities. Data is assessed as, how many are infected and not infected, with or without needle exchange program at a specific point of time.