Table.
Mendelian randomisation estimates of the association between 1 SD lower 25(OH)D concentrations and glycaemic traits
| n | Effect size (95% CI) | p value | |
|---|---|---|---|
| All four SNPs (CYP2R1 rs10741657, DHCR7 rs12785878, DBP rs4588, and CYP24A1 rs17217119) | |||
| Fasting glucose (mmol/L) | 46 186 | −0·02 (−0·04 to 0·01) | 0·28 |
| 2-h glucose (mmol/L) | 15 234 | 0·08 (−0·06 to 0·22) | 0·25 |
| Fasting insulin (% difference)* | 46 186 | −1·04 (−3·91 to 1·83) | 0·48 |
| HbA1c (%) | 46 368 | 0·01 (−0·04 to 0·05) | 0·80 |
| Two SNPs near genes related to 25(OH)D synthesis (CYP2R1 rs10741657 and DHCR7 rs12785878) | |||
| Fasting glucose (mmol/L) | 46 186 | −0·03 (−0·08 to 0·02) | 0·21 |
| 2-h glucose (mmol/L) | 15 234 | 0·11 (−0·13 to 0·35 | 0·36 |
| Fasting insulin (% difference)* | 46 186 | −5·44 (−10·64 to −0·24) | 0·04 |
| HbA1c (%) | 46 368 | 0·02 (−0·03 to 0·06) | 0·48 |
| Two SNPs within or near genes related to 25(OH)D metabolism (DBP rs4588 and CYP24A 1 rs17217119) | |||
| Fasting glucose (mmol/L) | 46 186 | −0·01 (−0·04 to 0·03) | 0·70 |
| 2-h glucose (mmol/L) | 15 234 | 0·07 (−0·11 to 0·24) | 0·44 |
| Fasting insulin (% difference)* | 46 186 | 1·46 (−2·13 to 5·06) | 0·43 |
| HbA1c (%) | 46 368 | −0·03 (−0·06 to 0·01) | 0·11 |
For single nucleotide polymorphisms (SNPs) and glycaemic traits, summary data from MAGIC21 were used; for SNPs and 25-hydroxyvitamin D (25[OH]D) concentrations, data from the Ely16 and EPIC-Norfolk4 studies were used. Sample sizes varied between SNPs. 1 SD of 25[OH]D concentration was 25·0 nmol/L.
*
Effect size is presented as a percentage difference in log-transformed fasting insulin concentration.