Table I.
Demographic and lifestyle characteristics of the CPRD study sample.
| Cases (N=156) | Controls (N=608) | OR (95%CI) | P | |
|---|---|---|---|---|
| Sexa | 0.86 | |||
| Male | 112 (71.8) | 432 (71.0) | ||
| Female | 44 (28.2) | 176 (29.0) | ||
|
| ||||
| Age at index/selection date, yearsa | 0.92 | |||
| Mean (SD) | 48.4 (23.3) | 48.2 (23.2) | ||
| Range | 2.0–87.0 | 2.0–87.0 | ||
|
| ||||
| Age group at index date, yearsa | 0.99 | |||
| <20 | 27 (17.3) | 108 (17.8) | ||
| 20–59 | 69 (44.2) | 268 (44.1) | ||
| 60+ | 60 (38.5) | 232 (38.2) | ||
|
| ||||
| Year at index datea | 0.99 | |||
| 1992–1999 | 14 (9.0) | 52 (8.5) | ||
| 2000–2005 | 29 (18.6) | 112 (18.4) | ||
| 2006–2010 | 58 (37.2) | 228 (37.5) | ||
| 2011–2016 | 55 (35.3) | 216 (35.5) | ||
|
| ||||
| Years since registered in the CPRDb | 0.005 | |||
| mean (SD) | 17.4 (15.3) | 20.9 (13.9) | ||
|
| ||||
| Region of residencec | 0.99 | |||
| West Midlands | 20 (12.8) | 80 (13.2) | ||
| South Central | 21 (13.5) | 76 (12.5) | ||
| Scotland | 20 (12.8) | 80 (13.2) | ||
| Others | 95 (60.9) | 372 (61.1) | ||
|
| ||||
| BMI (Tertiles) | ||||
| T1 (=<25.08) | 33 (21.2) | 97 (16.0) | Ref. | |
| T2 (25.08 to <28.82) | 26 (16.7) | 102 (16.8) | 0.73 (0.40 – 1.34) | 0.31 |
| T3 (>28.82) | 29 (18.6) | 98 (16.1) | 0.91 (0.51 – 1.61) | 0.74 |
| (Missing: 379) | 68 (43.6) | 311 (51.1) | N/A | |
| Ptrend | 0.99 | |||
|
| ||||
| Smoking status before diagnosis | ||||
| Never | 50 (32.0) | 106 (17.4) | Ref. | |
| Former | 64 (41.0) | 246 (40.5) | 0.47 (0.29 – 0.76) | 0.002 |
| Current | 15 (9.6) | 121 (19.9) | 0.24 (0.12 – 0.46) | <0.0001 |
| (Missing: 162)d | 27 (17.3) | 135 (22.2) | N/A | |
| Ptrend | <0.0001 | |||
|
| ||||
| Alcohol status before diagnosis | ||||
| Former/current | 15 (9.6) | 38 (6.2) | Ref. | |
| Never | 3 (1.9) | 27 (6.6) | 1.43 (0.75 – 2.73) | 0.274 |
| (Missing: 238) | 40 (25.7) | 198 (32.6) | N/A | |
| Ptrend | ||||
Controls were matched to cases based on age at cohort entry (defined as two years before index/selection date), gender, race, general practice, and index date.
Due to matching, odds ratios, and 95% confidence intervals not assessed.
Duration of registration in CPRD before the index date. Characteristics were evaluated at least two years before the index date.
About 40% of participants were from three regions (contributing most cases), including West Midlands, South Central, & Scotland.
Majority of the patients missing smoking data were aged <20 years old.
Abbreviations: 95% CI: 95% Confidence Interval: BMI: body mass index; CPRD: Clinical Practice Research Datalink; N/A: not applicable: due to missing data, odds ratios and 95% confidence intervals not assessed; OR: Odds ratio; P: P value for heterogeneity; Ptrend: P value for trend across categories; Ref.: Reference category; SD: standard deviation; T1, T2, T3: First, second and third tertile, based on cut off values calculated in the controls