Table 1.
Study characteristics among populations‐based controls by study population and DNA extraction method
| N | Gender | Age | BMI | Smoking ever (%) | LTL median (IQR) | ||
|---|---|---|---|---|---|---|---|
| Male (%) | Mean years (SD) | Mean kg/m2 (SD) | |||||
| Study [reference number] | |||||||
| The Study of Reflux Disease (SRD) 12 | 100 | 60 (60.0) | 51.7 (12.5) | 27.7 (4.7) | 48 (48.0) | 1.03 | (0.92–1.21) |
| The Factors Influencing the Barrett's/Adenocarcinoma Relationship (FINBAR) Study 13 | 91 | 82 (90.1) | 61.7 (13.8) | 27.1 (4.0) | 55 (60.8) | 0.80 | (0.70–0.96) |
| The Study of Digestive Health (SDH) 14 | 104 | 75 (72.1) | 61.3 (11.0) | 27.4 (5.1) | 56 (53.9) | 0.87 | (0.77–0.97) |
| The Epidemiology and Incidence of Barrett's Oesophagus (EIBO) Study 15 | 100 | 71 (71.0) | 64.0 (10.1) | 28.7 (4.6) | 59 (59.0) | 0.98 | (0.89–1.11) |
| The Los Angeles Multi‐ethnic (LAM) Study 16 | 53 | 47 (88.7) | 61.0 (9.8) | 25.9 (5.2) | 33 (62.3) | 0.71 | (0.67–0.84) |
| The Australian Cancer Study (ACS) 17 | 242 | 225 (92.9) | 63.3 (9.5) | 27.7 (4.7) | 148 (61.2) | 0.94 | (0.84–1.06) |
| The Swedish Esophageal and Cardia Cancer (SECC) Study 18 | 46 | 40 (87.0) | 66.6 (8.2) | 23.5 (1.9) | 25 (54.4) | 0.87 | (0.76–0.99) |
| DNA extraction method (company/reference) | |||||||
| Gentra Puregene DNA purification kit (Qiagen, Hilden, Germany)a | 237 | 193 (81.4) | 63.6 (11.5) | 27.1 (4.4) | 139 (59.1) | 0.91 | (0.77–1.03) |
| Protein Salting Out 19, b | 346 | 300 (86.7) | 62.7 (10.0) | 27.6 (4.8) | 204 (59.0) | 0.92 | (0.80–1.03) |
| Qiagen QIAamp DNA Blood kit (Qiagen)c | 53 | 47 (88.7) | 61.0 (9.8) | 25.6 (5.2) | 33 (62.3) | 0.71 | (0.67–0.84) |
| 5‐Prime (5‐Prime, Hilden, Germany)d | 100 | 60 (60.0) | 51.7 (12.5) | 27.5 (4.7) | 48 (48.0) | 1.03 | (0.92–1.21) |
| Total | 736 | 604 (82.1) | 61.4 (11.5) | 27.3 (4.7) | 425 (57.8) | 0.92 | (0.79–1.04) |
Extraction method used in aFINBAR, EIBO, and SECC study; bSDH and ASC study; cLAM study; dSRD study. LTL, leukocyte telomere length; IQR, interquartile range; SD, standard deviation; BMI, body mass index.