Systematic reviews are not free of biases. A meta-analysis wasrecently published that examined the association both red andprocessed) meat consumption and colorectal cancer. In their resultsthe authors reported that the publication bias was in the studieson processed meat and colon cancer, noting that small studies withinverse missing. When present publication bias with thesecharacteristics is most likely to lead to:
a over-estimation of the association between an exposure and anoutcome.
b.confounding the association between an exposure and anoutcome.
c.under-estimation of the association between an exposure and anoutcome.
d.lack  of the association between an exposure and anoutcome.
