Distribution of exposure and confounder variables by age groups
| Variables | Age groups | *P value | |||
| 50–54 | 55–59 | 60–64 | 65–70 | ||
| Female gender (% (n)) | 56.92 (13 655) | 56.32 (16 404) | 54.85 (23 623) | 51.73 (19 224) | <0.001 |
| Ethnicity (% (n)) | <0.001 | ||||
| White | 88.85 (21 229) | 92.17 (26 750) | 95.21 (40 825) | 95.22 (35 204) | |
| Black | 4.19 (1001) | 2.32 (672) | 1.33 (569) | 1.47 (544) | |
| East Asian | 0.54 (129) | 0.55 (161) | 0.25 (106) | 0.23 (86) | |
| South Asian | 3.63 (868) | 2.96 (859) | 1.98 (848) | 1.98 (732) | |
| Any Mixed | 1.02 (244) | 0.64 (186) | 0.42 (178) | 0.39 (146) | |
| Other | 1.76 (421) | 1.36 (394) | 0.82 (353) | 0.71 (261) | |
| BMI (mean (CI)) | 27.58 (27.51–27.65) | 27.61 (27.55–27.67) | 27.67 (27.62–27.71) | 27.63 (27.59–27.68) | =0.114 |
| Smoking status (% (n)) | <0.001 | ||||
| Never | 59.37 (14 207) | 55.09 (15 996) | 51.63 (22 147) | 49.34 (18 241) | |
| Previous | 28.39 (6795) | 34.55 (10 031) | 39.89 (17 109) | 43.69 (16 152) | |
| Current | 12.24 (2929) | 10.36 (3009) | 8.48 (3638) | 6.97 (2576) | |
| Systolic BP (mean (CI)) | 133.91 (133.70–134.13) | 137.41 (137.19–137.60) | 141.58 (141.41–141.75) | 145.31 (145.12–145.50) | <0.001 |
| Diastolic BP (mean (CI)) | 82.63 (82.50–82.76) | 82.70 (82.59–82.82) | 82.41 (82.31–82.50) | 81.65 (81.55–81.75) | <0.001 |
| Diabetes (% (n)) | 5.49 (1313) | 6.86 (1992) | 7.66 (3291) | 9.61 (3559) | <0.001 |
| Vascular/Heart disease (% (n)) | 24.47 (5858) | 30.97 (9002) | 37.97 (16 328) | 46.61 (17 281) | <0.001 |
| Waist/Hip ratio (mean(CI)) | 0.87 (0.87–0.87) | 0.88 (0.87–0.88) | 0.88 (0.88–0.88) | 0.89 (0.89–0.89) | <0.001 |
| Pulse rate (mean(CI)) | 69.95 (68.80–69.07) | 68.93 (68.80–69.06) | 69.11 (69.00–69.22) | 69.10 (69.98–69.22) | =0.032 |
| Qualifications (% (n)) | <0.001 | ||||
| None of the above | 9.7 (2300) | 13.4 (3855) | 20.91 (8882) | 29.66 (10 840) | |
| Lower academic/vocational | 35.2 (8344) | 31.9 (9171) | 31.1 (13 206) | 29.0 (10 580) | |
| Higher academic/professional | 55.1 (13 064) | 54.7 (15 733) | 48.0 (20 394) | 41.4 (15 125) | |
| Employment (% (n)) | <0.001 | ||||
| None of the above | 0.72 (171) | 0.84 (243) | 0.61 (262) | 0.43 (160) | |
| In paid employment | 80.9 (19 298) | 68.1 (19 738) | 36.92 (15 841) | 13.2 (4891) | |
| Retired | 3.83 (914) | 15.76 (4568) | 56.24 (24 132) | 85.29 (31 615) | |
| Looking after home and/or family | 4.02 (960) | 4.14 (1201) | 1.15 (492) | 0.47 (492) | |
| Unable to work because of sickness or disability | 6.05 (1444) | 7.14 (2069) | 3.31 (1419) | 0.2 (75) | |
| Unemployed | 3.56 (848) | 3.06 (888) | 1.24 (531) | 0.06 (22) | |
| Doing unpaid or voluntary work | 0.61 (146) | 0.75 (217) | 0.47 (203) | 0.33 (122) | |
| Full or part-time student | 0.3 (72) | 0.21 (60) | 0.07 (28) | 0.02 (8) | |
| Household income (% (n)) | <0.001 | ||||
| Less than 18 000 | 15.81 (3348) | 19.27 (4867) | 28.74 (10 290) | 39.04 (11 591) | |
| 18 000 to 30 999 | 19.76 (4184) | 23.29 (5882) | 30.21 (10 815) | 33.88 (10 059) | |
| 31 000 to 51 999 | 28.26 (5984) | 27.29 (6892) | 23.61 (8452) | 17.96 (5333) | |
| 52 000 to 100 000 | 27.72 (5869) | 23.67 (5976) | 13.88 (4969) | 7.39 (2194) | |
| Greater than 100 000 | 8.44 (1787) | 6.47 (1635) | 3.57 (1278) | 1.74 (516) | |
| Townsend Deprivation Index (mean (CI)) | −0.78 (−0.82 to −0.74) | −1.07 (−1.10 to −1.03) | −1.32 (−1.34 to −1.29) | −1.35 (−1.38 to −1.32) | <0.001 |
*P value from Wilcoxon rank-sum test for continuous variables and Ψ2 test for categorical variables.
BMI, body mass index; BP, blood pressure.