Which among the following is TRUE about confounding factor?: (A) It is found equally between study and the control groups, (B) It is itself a risk factor for the disease, (C) Confounding can be eliminated by selecting a small group, (D) It is associated with either the exposure or the disease
Answer is B. A confounding factor is defined as one which is associated both with exposure and disease, and is distributed unequally in study and control groups. More specifically a confounding factor is one that, although associated with exposure under investigation, is itself, independently of any such association, a risk factor for the disease. Ref: Park's Textbook of Preventive and Social Medicine, 19th edition, Page 67.