Exam 14: From Association to Causation: Deriving Inferences From Epidemiologic Studies

In a hypothetical cross-sectional study,marriage was found to be strongly associated with increased levels of happiness.Authors concluded that marriage was a cause of happiness.However,a reviewer of this study argued that because it is a cross-sectional study,it could not be determined whether marriage caused happiness or happiness caused marriage.What criterion of causal relationships was not met in the study according to the reviewer?

Cardiorespiratory fitness,measured as VO₂ max in mL/kg/min (maximum oxygen consumption),is associated with increased longevity.Recent evidence suggests that higher fitness increases the life span.Those with a low VO₂ max have a life expectancy after 60 years of 7 years,those with moderate VO₂ max of 15 years,and those with a high VO₂ max have a life expectancy after 60 of 23 years.Which of the causal criteria is illustrated with this example?

Human papillomavirus (HPV) infections are known to be a cause of cervical cancer.In most cases,HPV goes away on its own and does not cause any health problems.However,the worldwide HPV prevalence in cervical carcinomas is 99.7%.This indicates that HPV-negative carcinoma is extremely uncommon.In this case,HPV is which of the following?

Temporal relationship is a necessary criterion to establish causality.Which of the following epidemiologic study design allows to evaluate temporal relationship?

Which of the following statements is not evidence suggesting Exposure A as a causative agent on Disease X?

Lack of physical activity is a known factor associated with colon cancer.However,colon cancer develops even among active individuals.Moreover,several individuals who perform very little levels of physical activity never develop colon cancer.Hence,in the causal relationship between physical inactivity and colon cancer,the lack of physical activity is