Research paper
Plasma Vitamin C and Type 2 Diabetes: Genome-Wide Association Study and Mendelian Randomization Analysis in European Populations
- Ju-Sheng Zheng
- J. Luan
- E. Sofianopoulou
- F. Imamura
- I. Stewart
- F. Day
- M. Pietzner
- E. Wheeler
- L. Lotta
- T. Gundersen
- P. Amiano
- E. Ardanaz
- M. Chirlaque
- G. Fagherazzi
- P. Franks
- R. Kaaks
- N. Laouali
- F. Mancini
- P. Nilsson
- N. Onland-Moret
- A. Olsen
- K. Overvad
- S. Panico
- D. Palli
- F. Ricceri
- O. Rolandsson
- A. Spijkerman
- M. Sánchez
- M. Schulze
- N. Sala
- S. Sieri
- A. Tjønneland
- A. Tjønneland
- R. Tumino
- Y. T. V. D. Schouw
- E. Weiderpass
- E. Riboli
- J. Danesh
- A. Butterworth
- S. Sharp
- C. Langenberg
- N. Forouhi
- N. Wareham
Study answer
What this study found
Observationally, plasma vitamin C is inversely associated with incident type 2 diabetes (HR 0.88 per 1-SD; 95% CI 0.82–0.94). Genetically predicted higher plasma vitamin C is not associated with type 2 diabetes risk (OR 1.03 per 1-SD; 95% CI 0.96–1.10) after excluding the FADS1 variant due to pleiotropy. No evidence of directional pleiotropy; MR sensitivity analyses yielded similar results. There is discordance between biochemically measured and genetically predicted plasma vitamin C in relation to type 2 diabetes; No strong evidence that vitamin C supplementation prevents type 2 diabetes in…
- Study & population
- Adults of European ancestry from multiple cohorts (Fenland, EPIC-InterAct, EPIC-Norfolk, EPIC-CVD, UK Biobank, and DIAMANTE).
- Key limitation
- Lead SNPs explained ~1.87% of plasma vitamin C variance (mean); instrument strength adequate (F statistic ~30.5) but explained variance is small, potentially limiting power.
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Open PDFOriginal abstract
OBJECTIVE Higher plasma vitamin C levels are associated with lower type 2 diabetes risk, but whether this association is causal is uncertain. To investigate this, we studied the association of genetically predicted plasma vitamin C with type 2 diabet…