Epidemiology for Public Health Practice 5th Edition by Robert Friis,Thomas Sellers

تمرين 8

An investigator wanted to determine whether vitamin deficiency was associated with birth defects. By reviewing the birth certificates during a single year in a large U.S. county, the researcher located 189 infants born with NTDs. A total of 600 other births were selected at random from the certificates. Mothers were given a dietary questionnaire. Among mothers who gave birth to an infant with an NTD, 84 reported no use of supplementary vitamins; a total of 137 control mothers did not use a vitamin supplement. Construct the appropriate 2 by 2 table and calculate the OR between vitamin use and NTDs.