Calibration equations
Quadratic equations were used for the calibration of self-reported weight and height against clinical measures. Clinically measured parameters were considered criterion and self-reported parameters were treated as predictor variables. The constants and coefficients were obtained from clinical assessments at baseline which included both clinically measured and self-reported parameters. They were then used to calibrate weight from self-reported measures at the 18-month and the 10-year follow-up. Due to implausible differences between self-reported and measured height, however, possibly caused by confusion about metric and imperial measures by some participants, we used the clinically measured baseline height for the 18-month follow-up. For the self-reported measure at the 10y follow-up, the calibrated value was used, except when the difference between self-reported and latest objectively measured height was larger than 3cm; these observations were replaced with the latest available clinical measure without calibration.
weightc= -0.209 + 1.036 * weightsr -0.002 * (weightsr)2 , rmse = 2.59 kg
heightc= 7.387+ 0.926* heightsr + 0.0002 * (heightsr)2 , rmse = 1.02 cm
(Abbreviations: subscript c- clinical measure; subscript sr- self-reported; rmse- root mean square error)
In addition, we conducted individual calibration (where applicable) of self-reported weight and height using the following non-quadratic equations and there were no observable differences from the quadratic regression estimates:
weightc= weightsr +offset, with mean (SD) for offset of 1.19 (2.59) kg
heightc= heightsr +offset, with mean (SD) for offset of -1.56 (2.98) cm
Inactive / Moderately inactive / Moderately active / Active / p-value1Men / N / 3586 / 2858 / 2660 / 2502
Age (years) / 62.24 (9.06) / 59.05 (9.46) / 57.64 (8.87) / 56.37 (8.64) / <0.001
Body weight (kg) / 81.39 (12.17) / 80.63 (11.46) / 79.61 (11.11) / 79.45 (10.88) / <0.001
Body mass index (kg/m2) / 26.98 (3.54) / 26.47 (3.25) / 26.24 (3.18) / 26.23 (3.13) / <0.001
Daily energy intake (kJ) / 8864.06 (2772.92) / 9008.12 (2605.11) / 9299.95(2755.34) / 9835.84 (3766.40) / <0.001
Alcohol intake (g/week) / 11.29 (15.83) / 13.29 (16.77) / 11.61 (14.84) / 13.11 (17.05) / <0.001
Cigarette smoking / <0.001
current / 499 (14.04) / 299 (10.54) / 314 (11.87) / 293 (11.77)
former / 2063 (58.06) / 1523 (53.66) / 1413 (53.42) / 1285 (51.63)
never / 991 (27.89) / 1016 (35.80) / 918 (34.71) / 911 (36.60)
Social class / <0.001
professional / 245 (6.99) / 322 (11.39) / 184 (7.00) / 124 (5.02)
manager / 1348 (38.45) / 1292 (45.72) / 950 (36.14) / 767 (31.03)
skilled non-manual / 552 (15.74) / 411 (14.54 ) / 258 (9.81) / 204 ( 8.25)
skilled manual / 810 (23.10) / 483 (17.09) / 740 (28.15) / 851 (34.43 )
semi-skilled / 445 (12.69) / 259 (9.16) / 394 (14.99) / 424 (17.15)
unskilled / 100 (2.85) / 43 (1.52) / 97 (3.69) / 97 (3.92 )
Educational level / <0.001
none/less than O level / 1298 (36.29) / 746 (26.10) / 743 (27.93) / 747 (29.86)
O level / 337 (9.42) / 267 (9.34) / 216 (8.12) / 186 (7.43)
A level / 1475 (41.24) / 1253 (43.84) / 1286 (48.35) / 1263 (50.48)
Degree / 467 (13.06) / 592 (20.71) / 415 (15.60) / 306 (20.23)
Self-reported stroke / 99 (2.76) / 54 (1.89) / 40 (1.50) / 13 (0.52) / <0.001
Self-reported MI / 283 (7.91) / 142 (4.97) / 107 (4.02) / 82 (3.28 ) / <0.001
Self-reported CA / 163 (4.55) / 112 (3.92) / 97 (3.65) / 69 (2.76) / 0.004
Self-reported DM / 172 (4.80) / 81 (2.84) / 66 (2.48) / 44 (1.76) / <0.001
Women / N / 4277 / 4493 / 3117 / 2147
Age (years) / 62.28 (9.21) / 58.05 (9.15) / 59.02 (8.52) / 54.96 (8.19) / <0.001
Body weight (kg) / 69.34 (12.38) / 67.78 (11.61) / 67.03 (11.33) / 66.86 (10.76) / <0.001
Body mass index (kg/m2) / 27.03 (4.73) / 26.14 (4.25) / 25.74 (4.13) / 25.54 (3.82) / <0.001
Daily energy intake (kJ) / 7990.78 (2614.99) / 8088.58
(2405.94) / 8131.31
(2433.94) / 8427.291
(2645.84) / <0.001
Alcohol intake (g/week) / 4.70 (7.95) / 5.81 (8.65) / 5.90 (8.54) / 6.10 (8.58) / <0.001
Cigarette smoking / <0.001
current / 1023 (13.18) / 786 (10.78) / 676 (11.78) / 499 (10.79)
former / 3505 (45.14) / 2908 (39.88) / 2351 (40.96) / 2908 (43.20)
never / 3236 (41.68) / 3597 (49.33) / 2713 (47.26) / 2127 (46.01)
Social class / <0.001
professional / 419 (5.51) / 637 (8.77) / 435 (7.63) / 263 (5.74)
manager / 2604 (34.23) / 2926 (40.30) / 2110 (37.03) / 1518 (33.12)
skilled non-manual / 1524 (20.03) / 1332 (18.35) / 763 (13.39) / 520 (11.34 )
skilled manual / 1687 (22.17) / 1377 ( 18.97) / 1376 (24.15) / 1331 (29.04 )
semi-skilled / 1040 (13.67) / 799 (11.01) / 778 (13.65) / 744 (16.23 )
unskilled / 306 (4.02) / 160 (2.20 ) / 223 (3.91) / 186 (4.28)
Educational level / <0.001
none/less than O level / 2171 (50.87) / 1768 (39.35) / 1161 (37.26) / 820 (38.21)
O level / 453 (10.61) / 551 (12.26) / 378 (12.13) / 234 (10.90)
A level / 1366 (32.01) / 1636 (36.41) / 1129 (36.23) / 847 (39.47)
Degree / 278 (6.51) / 538 (11.97) / 448 (14.38) / 245 (11.42)
Self-reported stroke / 74 (1.73) / 38 (0.85) / 12 (0.67) / 21 (0.56) / <0.001
Self-reported MI / 113 (2.64) / 65 (1.45) / 22 (0.80) / 17 (0.79) / <0.001
Self-reported CA / 351 (8.21) / 290 (6.46) / 205 (6.58) / 108 (5.04) / <0.001
Self-reported DM / 113 (2.64) / 65 (1.45) / 25 (0.80) / 17 (0.79) / <0.001
Supplementary table 1 Baseline characteristics of the participants by physical activity category; the EPIC-Norfolk study
MI-myocardial infarction; DM-diabetes mellitus type 2; CA-cancer; 1Test for trend and χ2-test were conducted. Continuous variables are shown as mean (SD). Categorical variables are shown as n (%).
Supplementary table 2 Age-adjusted proportions of inactive people in the EPIC-Norfolk by BMI-category
MenBMI category / N (% within BMI category) of inactive people in the EPIC- Norfolk at baseline / Age-adjusted proportion1 of inactive people,
% (95% CI)
<20 kg/ m2 / 80 (55.6) / 57.9
(51.9-63.9)
Normal (20-25 kg/ m2) / 1887 (50.8) / 55.2
(54.0-56.5)
Overweight (25-30 kg/m2) / 3495 (64.8) / 58.2
(57.3-59.2)
Obese (>30 kg/m2) / 982 (69.7) / 61.9
(60.1-63.6)
Women
BMI category / N (% within BMI category) in EPIC- Norfolk at baseline / Age-adjusted proportion of inactive people,
% (95% CI)
<20 kg/ m2 / 260 (62.0) / 66.8
(63.7-70.0)
Normal (20-25 kg/ m2) / 3327 (57.4) / 62.4
(61.5-63.4)
Overweight (25-30 kg/m2) / 3508 (56.6) / 65.9
(65.0-66.9)
Obese (>30 kg/m2) / 1675 (62.3) / 70.8
(69.4-72.2)
BMI- body mass index
1 Estimates were obtained from mixed model with random effects taking into account 3 assessments of physical activity and BMI
Supplementary table 3 Predicted national prevalence of physical inactivity in 2009 and 2020
% (95% CI)
2009 / 2020
Men
<20 kg/ m2 / 1.16
(1.15-1.17) / 0.59
(0.58-0.60)
Normal
(20-25 kg/ m2) / 17.67
(17.49-17.84) / 7.33
(7.25-7.40)
Overweight
(25-30 kg/m2) / 25.61
(25.35-25.87) / 23.76
(23.52-24.00)
Obese
(>30 kg/m2) / 13.62
(13.50-13.74) / 27.79
(27.56-28.02)
Total: 58.04
(57.73-58.36) / Total: 59.46
(59.13-59.80)
Women
<20 kg/ m2 / 1.34
(1.33-1.35) / 2.02
(2.01-2.04)
Normal
(20-25 kg/ m2) / 25.59
(25.37-25.81) / 16.39
(16.24-16.52)
Overweight
(25-30 kg/m2) / 21.74
(21.56-21.94) / 21.30
(21.12-21.47)
Obese
(>30 kg/m2) / 16.99
(16.85-17.13) / 27.17
(26.95-27.39)
Total: 65.65
(65.33-65.97) / Total: 66.89
(66.56-67.21)
1 Monte Carlo simulations with 10000 observations and 1000 repetitions were used to calculate the prevalence of physical inactivity in 2009 and 2020