Part II: Hypothetical case control

Instead of investigating the chance of going 18 months without a root canal your practice is only interested in the chance of having a root canal given various exposures, so you decide to a case-control study is done.

Suppose that for every root canal case from the previous 18 months, 3 controls were selected and both cases (43) and controls (129) were asked the about various exposures.

**Please note the comparison is with the previous case study where individuals that already had a filling were selected.

a.Fill in the ORs for all the exposures in the table below (counts in the table are for those patients who had the exposure). For each OR use the odds of having the particular exposure in cases compared to controls.

Formula Q . Search Sh O.. exercise_4_ Q Search in Document Home Insert Design Layout References Mailings Review View EndNote X8 Auto Calibri (Body) FIN AaBbCc AaBbCcDdEe AaBbCcDdEe AaBbCcDd AaBbCcDdEc AnBbCCDdFe at Cle Pasto B I Uvabe X2 X ALA = = = = . Heading 2 Normal No Spacing Heading 1 Heading 3 Heading 4 Style pane patients who had the exposure). For each OR use the odds of having the particular exposure in cases compared to controls. (8pts) exposure Cases Controls OR Have gum disease 15 10 6.38 Chew sugarless gum 6 20 0.88 Floss regularly 10 65 0.30 Taken antibiotics in 5 36 0.34 previous 6 months Overweight/obese 20 38 2.08 Recent viral infection 17 51 1.00 b. Which of these exposures appear to be protective and which appear harmful? (2pts) The exposures with an OR 1 appear to be harmful and include: have gum disease and overweight/obese. c. What doesn't appear to have any association? (1pt) Page 3 of 4 1414 Words DE English (US) E + 208% SneeIT Ready WE X Py A S'O EN