Increased colorectal cancer risk in prediabetes: A meta-analysis.

Background: Previous research yielded conflicting results regarding the association between prediabetes and colorectal cancer (CRC).

Aim: To systematically assess the incidence of CRC in individuals with prediabetes compared with individuals with normoglycemia via a meta-analysis.

Methods: Relevant cohort studies were acquired by searching MEDLINE, Web of Science, and EMBASE. A random-effects model was applied to combine the findings after accounting for heterogeneity. Several subgroup analyses were conducted to assess the impact of study characteristics on the results.

Results: Eleven cohort studies involving 4996352 participants, including 383917 (7.7%) with prediabetes at baseline, were analyzed in this meta-analysis. Over a mean follow-up period of 6.5 years, the combined findings revealed that individuals with prediabetes at baseline had a higher likelihood of developing CRC than those with normoglycemia [risk ratio (RR) = 1.18, 95% confidence interval = 1.11 to 1.25, P < 0.001] with low statistical heterogeneity (I ² = 27%). Subgroup analyses indicated that the association between prediabetes and an increased risk of CRC was mainly observed in studies defining prediabetes using impaired fasting glucose (RR = 1.24) and slightly elevated hemoglobin A1c levels (RR = 1.18) but not in those that defined prediabetes using impaired glucose tolerance (RR = 1.06). Other study characteristics such as design, country, participant age and sex, the duration of follow-up, or adjustment for body mass index did not significantly impact the results (all P > 0.05).

Conclusion: People with prediabetes might have a higher likelihood of developing CRC than individuals with normoglycemia.