Question

A news broadcaster reports the results of a study in which people who took fish oil supplements did not reduce their risk of heart attack.

Two months later, a different broadcaster reports the results of another study claiming that taking fish oil daily decreases the risk of a heart attack by nearly 50 percent.

Which factors could have affected the conflicting results of these studies? Check all that apply.

physical condition of study participants
bias of broadcasters
diet of participants
length of study
education level of study participants
genetic differences in study participants
age of study researchers

Answer 1

Select:
- physical condition of study participants (yes) — baseline health, existing heart disease, or other conditions change how supplements affect risk.
- diet of participants (yes) — background intake of omega-3s or other nutrients can influence the supplement’s effect.
- length of study (yes) — short vs. long follow-up can miss benefits or harms that appear only over time.
- genetic differences in study participants (yes) — genetics can alter how people metabolize or respond to fish oil.

Do not select:
- bias of broadcasters (no) — affects how results are reported, not the underlying study outcomes.
- age of study researchers (no) — researchers’ ages don’t influence biological results.
- education level of study participants (generally no) — education itself isn’t a biological modifier (though it can correlate with lifestyle or adherence, which are covered above).