Table 1.
Characteristics of the associations included in the analysis. The numbers of unique studies for each category do not sum to the number of studies in the whole dataset (138), as some studies contribute associations in several categories.
| associations | per cent of associations | unique studies | |
|---|---|---|---|
| adversity type | |||
| disease | 94 | 17.3 | 53 |
| environmental hazard exposure | 11 | 2.0 | 8 |
| nutrition | 87 | 16.0 | 10 |
| psychiatric illness | 81 | 14.9 | 34 |
| smoking | 43 | 7.9 | 34 |
| alcohol consumption | 15 | 2.8 | 11 |
| sleep quality | 20 | 3.7 | 5 |
| physical activity | 16 | 3.0 | 11 |
| psychosocial adversity | 100 | 18.4 | 43 |
| parental care | 8 | 1.5 | 4 |
| socioeconomic status | 45 | 8.3 | 21 |
| other exposures (uncategorized) | 23 | 4.2 | 12 |
| techniques | |||
| qPCR | 467 | 86.0 | 110 |
| Southern blot | 52 | 9.6 | 23 |
| flow-FISH | 10 | 1.8 | 3 |
| Q-FISH | 11 | 2.0 | 3 |
| TelSeq | 3 | 0.6 | 1 |
| tissues | |||
| buccal cells | 11 | 2.0 | 7 |
| white blood cells | 523 | 96.3 | 126 |
| other tissues | 9 | 1.7 | 6 |
| life stage at exposure | |||
| embryonic exposure | 12 | 2.2 | 8 |
| childhood exposure | 77 | 14.2 | 23 |
| adulthood exposure | 450 | 82.9 | 119 |
| age at exposure not reported | 4 | 0.7 | 3 |
| life stage at telomere measurement | |||
| embryonic | 5 | 0.9 | 3 |
| childhood | 53 | 9.8 | 10 |
| adult | 479 | 88.2 | 123 |
| not reported | 6 | 1.1 | 3 |
| sex of sample | |||
| male | 70 | 12.9 | 17 |
| female | 88 | 16.2 | 28 |
| both | 385 | 70.9 | 98 |
| longitudinal design | |||
| cross-sectional | 506 | 93.2 | 133 |
| longitudinal | 37 | 6.8 | 6 |
| experimental study | |||
| correlational | 532 | 98.0 | 135 |
| experimental | 11 | 2.0 | 6 |
| total | 543 | 100 | |