Table 1. Characteristics of included studies.
APOE = Apolipoprotein E genotype, investigated (+) or not investigated (-); TA = telomerase activity, investigated (+) or not investigated (-); ∈3 & ∈4 = APOE alleles; MDD = Major Depressive Disorder; a = Age was not given for imaging subsample, age for whole healthy subsample substituted; b = Median and interquartile range.
| Study and group | Year | Ref. | n | Female, n | Age, mean (SD) | Covariates | APOE | TA |
|---|---|---|---|---|---|---|---|---|
| Grodstein | 2008 | 20 | 26 | 26 (100%) | 79.2 (2.2) a | age, education | - | - |
| Wikgren ∈3/ ∈3 | 2012 | 12 | 29 | 18 (62%) | 62.1 (8.5) | age, body size | + | - |
| Wikgren ∈4 | 2012 | 12 | 28 | 18 (64%) | 61.1 (8.5) | age, body size | + | - |
| King | 2014 | 22 | 1960 | 1153 (59%) | 50 (42 – 58) b | age, sex, race/ethnicity | + | - |
| Wolkowitz MDD | 2015 | 21 | 19 | 12 (63%) | 37.8 (12.0) | age, sex | - | + |
| Wolkowitz control | 2015 | 21 | 17 | 11 (59%) | 34.9 (9.6) | age, sex | - | + |
| Jacobs non- ∈4 | 2015 | 13 | 28 | 28 (100%) | 58.0 (4.7) | age, education, BMI | + | + |