Consider the following results from a prospective cohort study,in which the dietary intake of 50,000 people were recorded and the health status,including the occurrence of disease,was monitored for 10 years. $$\begin{array} { | l | l | }
\hline \text { Quintiles } & \text { RR for disease } \
\hline 1 - \text { lowest nutrient intake } & 1 \
\hline 2 & 0.80 \
\hline 3 & 0.72 \
\hline 4 & 0.66 \
\hline 5 \text { - highest nutrient intake } & 0.55 \
\hline
\end{array}$$ Which statement best describes these results?
A)These results are from an intervention trial and illustrate an inverse relationship between nutrient intake and disease risk
B)These results are from an observational study and suggest that there is a direct relationship between nutrient intake and disease risk.
C)These results are from an observational study and suggest that increasing nutrient intake may be associated with reduced risk of disease
D)These results are from an observational study and demonstrate causation between nutrient intake and reduced disease risk.

Question

Consider the following results from a prospective cohort study,in which the dietary intake of 50,000 people were recorded and the health status,including the occurrence of disease,was monitored for 10 years. $$\begin{array} { | l | l | } 
\hline \text { Quintiles } & \text { RR for disease } \
\hline 1 - \text { lowest nutrient intake } & 1 \
\hline 2 & 0.80 \
\hline 3 & 0.72 \
\hline 4 & 0.66 \
\hline 5 \text { - highest nutrient intake } & 0.55 \
\hline
\end{array}$$ Which statement best describes these results?
A)These results are from an intervention trial and illustrate an inverse relationship between nutrient intake and disease risk
B)These results are from an observational study and suggest that there is a direct relationship between nutrient intake and disease risk.
C)These results are from an observational study and suggest that increasing nutrient intake may be associated with reduced risk of disease
D)These results are from an observational study and demonstrate causation between nutrient intake and reduced disease risk.

Quizplus · Accepted Answer

The results are from a prospective cohort study, which is an observational study, not an intervention trial. The relative risk (RR) decreases as the nutrient intake increases (from RR=1 in the lowest quintile to RR=0.55 in the highest quintile), suggesting an inverse relationship between nutrient intake and disease risk, meaning that higher nutrient intake may be associated with a reduced risk of disease. However, observational studies can suggest associations but cannot definitively prove causation.

Consider the Following Results from a Prospective Cohort Study,in Which