Well, no. They have indexes (PDI, hPDI, and uPDI) which are used to measure the extent to which an individual's diet matches a certain pattern.

> Higher adherence to the PDI, particularly the hPDI, was associated with a lower risk of colorectal cancer, whereas greater adherence to the uPDI was associated with a higher risk of colorectal cancer. Compared with the lowest quintile, the adjusted ORs in the highest quintile were 0.79 (95% CI: 0.66-0.95) for the PDI, 0.45 (95% CI: 0.38-0.55) for the hPDI, and 1.45 (95% CI: 1.18-1.78) for the hPDI, respectively.

So people whose diets scored highest on the PDI were less likely to have colorectal cancer than people whose diets scored lowest (although this was just barely statistically significant), and people whose diets scored highest on the hPDI (healthy PDI) had about half the risk as people whose diets scored lowest. On the other hand, people whose diets scored highest on the uPDI (unhealthy PDI, which I assume means lots of unhealthful plant foods and not much animal food) had significantly higher risk of colon cancer than those who scored lowest.

The ORs are not the result of comparing different PDIs to each other.

The main takeaway here seems to be that healthy diets reduce risk of colon cancer, and unhealthy diets increase it; the effect of vegan vs. omnivorous diet was much weaker and barely statistically significant.

Also, this probably indicates an underpowered study rather than sex differences in how diet affects cancer risk.

> In stratified analysis, the inverse association between the PDI and colorectal cancer risk was not observed in women, and the positive association between the uPDI and colorectal cancer risk was not observed in men.