If an ecological study shows a strong positive correlation between per capita alcohol consumption and breast cancer incidence rates in European countries we can draw
The following conclusion:
A)Alcohol consumption is a risk factor for breast cancer
B)Breast cancer rates are higher in countries with higher alcohol consumption
C)We cannot draw any conclusions because the association could be due to selection bias
D)We cannot draw any conclusions because the measurement of alcohol consumption is likely to be unreliable
E)Women who drink more alcohol are more likely to develop breast cancer but this does not mean that the association is causal

Question

Quizplus · Accepted Answer

Breast cancer rates are higher in countries with higher alcohol consumption.
This ecological study compared the prevalence of breast cancer and alcohol
consumption among different European countries; it did not relate alcohol
consumption to breast cancer directly in individual women.It is impossible to
determine whether the two factors are truly associated, and thus also impossible to
determine causality from an ecological study because there may be other explanations
for the observed association.However it does raise the hypothesis as one worth
pursuing.(And in fact alcohol has been recognised by the World Cancer Research Fund
as a cause of breast cancer, albeit a weak one.)

If an Ecological Study Shows a Strong Positive Correlation Between