Study Designs — Cohort vs Case-Control

Which of the following is a KEY DISADVANTAGE of case-control studies compared to cohort studies in epidemiological research?

A public health researcher in Delhi wants to investigate the association between occupational dust exposure and chronic obstructive pulmonary disease (COPD) among construction workers. The researcher has identified 150 workers with COPD and 150 age-matched workers without COPD, and will collect detailed occupational history from both groups. Which study design is most appropriate for this investigation?

A researcher in Delhi wants to investigate the association between maternal smoking during pregnancy and low birth weight in newborns. She identifies 500 women who delivered low birth weight babies in the past 2 years and 500 women who delivered normal birth weight babies, then compares their smoking history during pregnancy. Which study design is being used, and what is the most common source of bias in this design?

Regarding the advantages of cohort studies compared to case-control studies, all of the following are true EXCEPT:

A public health team in Mumbai conducted a study to identify risk factors for tuberculosis (TB) among healthcare workers (HCWs). They enrolled 200 HCWs diagnosed with TB in the past year and 200 HCWs without TB, then compared their occupational exposure history, use of personal protective equipment (PPE), and work environment conditions. Which statement best describes the primary advantage of this case-control design over a cohort study for this research question?