A study found that an inverse relation exists between consumption of vegetables containing beta-carotene and development of cancer. This finding could also be because of other factors like fibers, which are also consumed by people along with the vegetables and which also prevents the development of cancer. This is an example of:
Ans. c. Confounding factor In the given study, protective factor is being studied. But as high fiber content of vegetarian food is protective against carcinoma colon, it can confound or disto the observed protective role of beta-carotene present in vegetarian food. Thus this is an example of confounding factor. "In an epidemiological study, in addition to the exposures that the study is investigating, there may be other factors that is associated with the exposure and independently affects the risk of developing disease. If the prevalence of these other factors differs between grouped being compared, they will disto the observed association between the disease and exposure under study. These distoing factors are called confounding factors or variables." Confounding Any factor associated with both exposure and outcome, and has an independent effect in causation of outcome is a confounderQ It is found unequally distributed between the study and control groups Is associated with both exposure and outcome Has an independent effect in causation of outcome (thus is a risk factor itself)
Multifactorial association
Differential misclassification
Confounding factor
Common association