Metabolic Syndrome and Obesity-related cancer Risk and Survival: An Umbrella Review of Systematic Reviews With Meta-analysis of Observational Studies.
Level 3 - non-randomized controlled study
Umbrella review of systematic reviews and meta-analyses of observational studies
PubMed 41508551 · doi:10.1111/obr.70073
What was done
This umbrella review synthesized evidence from five databases (Medline, Embase, CINAHL, Cochrane Library, and Scopus) evaluating associations between metabolic syndrome (MetS) and obesity-related cancer (ORC) risk and survival. From 2,524 screened records, 21 systematic reviews with meta-analyses of observational studies were included. Summary effect sizes and 95% confidence intervals were re-estimated using random-effects models. Methodological quality, certainty of evidence, and publication bias were assessed using AMSTAR 2, modified Ioannidis criteria, Egger's test, and excess significance tests.
What was found
The authors evaluated 25 associations for ORC risk and 5 for ORC survival: - ORC risk: 4 associations were graded as highly suggestive, 6 as suggestive, 7 as weak, and 8 as nonsignificant. - ORC survival: 1 association was graded as suggestive (worsened colorectal cancer survival), 3 as weak, and 1 as nonsignificant. - Publication bias or excess significance was detected in 8 of 25 (32%) risk associations and 3 of 5 (60%) survival associations. - Specific pooled numerical effect sizes (e.g., relative risks or hazard ratios) were not reported in the abstract.
Why it matters
These findings suggest that metabolic syndrome contributes broadly to the risk of multiple obesity-related cancers and worsens colorectal cancer survival, emphasizing metabolic dysfunction as a prevention target.
Limits
The primary evidence is derived entirely from observational studies, preventing causal conclusions. Most associations were classified as weak or nonsignificant, and potential publication bias or excess significance was present in a substantial fraction of outcomes. The abstract does not provide exact point estimates or confidence intervals.
Cited by
- supports Obesity is established in scientific research as being linked to an increased risk of cancer.