Table 2.
Pooled relative risks of type 2 diabetes according to levels of linoleic acid and arachidonic acid biomarkers*
| Studies (n)† | Cases (n)† | Continuous analysis‡
|
Quintile 5 vs quintile 1
|
|||||
|---|---|---|---|---|---|---|---|---|
| I2 (%) | Relative risk fixed effect | Relative risk random effect | I2 (%) | Relative risk fixed effect | Relative risk random effect | |||
| Linoleic acid | ||||||||
|
| ||||||||
| Phospholipids | 14 | 2979 | 58·4% | 0·69 (0·61-0·77) | 0·64 (0·53–0·78) | 56·3% | 0·60 (0·52-0·70) | 0-57 (0-45-0-72) |
| Total plasma or serum | 6 | 1220 | 40·7% | 0·55 (0·47-0·64) | 0-55 (0-44-0-69) | 1·0% | 0·47 (0·38-0·59) | 0·47 (0·38-0·59) |
| Cholesterol esters | 4 | 624 | 0% | 0·58 (0·46-0·73) | 0·58 (0·46-0·73) | 0% | 0·54 (0·41-0·73) | 0·54 (0·41-0·73) |
| Adipose tissue | 1 | 99 | .. | 0·82 (0·49-1·35) | 0·82 (0·49-1·35) | .. | 0·76 (0·38-1·53) | 0·76 (0·38-1·53) |
| Overall | 20 | 4347 | 53·9% | 0·65 (0·60-0·72) | 0·64 (0·56-0·74) | 46·3% | 0·57 (0·51-0·64) | 0·57 (0·48-0·67) |
|
| ||||||||
| Arachidonic acid | ||||||||
|
| ||||||||
| Phospholipids | 14 | 2979 | 64·2% | 0·99 (0·89-1·10) | 1·01 (0·84-1·22) | 54·6% | 0·99 (0·86-1·14) | 0·97 (0·78-1·22) |
| Total plasma or serum | 6 | 1220 | 63·8% | 0·73 (0·62-0·86) | 0·74 (0·54-1·03) | 66·5% | 0·64 (0·52-0·79) | 0·65 (0·43-0·99) |
| Cholesterol esters | 4 | 624 | 12·3% | 1·12 (0·90-1·40) | 1·14 (0·90-1·46) | 0% | 1·22 (0·94-1·59) | 1·22 (0·94-1·59) |
| Adipose tissue | 1 | 99 | .. | 1·56 (0·84-2·89) | 1·56 (0·84-2·89) | .. | 1·67 (0·72-3·91) | 1·67 (0·72-3·91) |
| Overall | 20 | 4347 | 63·0% | 0·96 (0·88-1·05) | 1·01 (0·87-1·18) | 61·2% | 0·93 (0·83-1·04) | 0·96 (0·79-1·17) |
Data are relative risk (95% CI).
*
Effect estimates were pooled using inverse-variance weighted or random effects meta-analysis.
†
Multiple biomarkers were available in some studies, but only one biomarker per study was included for estimation of overall relative risks, therefore the overall number of studies and cases does not equal the sum of studies and cases per biomarker.
‡
Fatty acids were modelled as continuous variables and relative risks were estimated per interquintile range (ie, the distance between the midpoints of the first and fifth quintiles).