Researchers Studying the Effects of Hormone Replacement Therapy (HRT) on the Risk

question 114

Multiple Choice

Researchers studying the effects of hormone replacement therapy (HRT) on the risk of myocardial infarction (MI) among postmenopausal women calculate the relative risk (RR) of MI to be 1.30 (p = 0.07) among women who are taking HRT compared to those who are not.  The researchers conclude that there is no statistically significant increased risk of MI with HRT (based on a cutoff of α = 0.05) .  Subsequently, the results of a meta-analysis determine that there actually is an increased risk of MI, with an overall RR = 1.32 (p = 0.03) among postmenopausal women who are taking HRT compared to those who are not.  Which of the following was the most likely problem in the first study?

• A)Berkson's bias
• B)Placebo effect
• C)Poor blinding
• D)Researcher expectancy
• E)Sample size