Introduction
Methods
Sample
Measures
Weight and shape concern and body dissatisfaction
Disordered eating behaviours
Explanatory individual-level factors
Explanatory school-level factors
Statistical analysis
Age 14 years | Age 16 years | |||
---|---|---|---|---|
Whole sample (N varies by covariate) | Complete case sample (N = 2146) | Whole sample (N varies by covariate) | Complete case sample (N = 1769) | |
Number of ALSPAC girls per school (median, 25th centile, 75th centile) | 1 (1, 2) | 1 (1,2) | 1 (1,2) | 1 (1,2) |
Body Dissatisfaction score (mean, SD) | 23.8 (8.05) (N = 2404) | 23.8 (8.0) | – | – |
Weight and shape concern [N (%) scoring > 7] | 451/2404 (18.8) | 383 (17.9) | – | – |
Purging [N (%)] | – | – | 223/2346 (9.5) | 167 (9.4) |
Binge eating [N (%)] | – | – | 384/2346 (16.4) | 278 (15.7) |
Fasting [N (%)] | – | – | 481/2346 (20.5) | 360 (20.4) |
Any compensatory behaviour [N (%)] | – | – | 972/2346 (41.4) | 718 (40.6) |
Any compensatory behaviour (DSM 5 frequency) [N (%)] | – | – | 285/2346 (12.2) | 202 (11.4) |
Parent-reported fat avoidance/fear of weight gain (N, % scoring ≥ 3) | 232/1940 (12.0) | 205/1770 (11.6) | 242/1778 (13.6) | 183/1441 (12.7) |
First born child (N, %) | 1077/2331 (46.2) | 996 (46.4) | 1074/2274 (47.2) | 841 (47.5) |
Mother’s age at child’s birth (mean, SD) | 28.6 (4.6) (N = 2404) | 28.7 (4.4) | 29.0 (4.6) (N = 2346) | 29.2 (4.4) |
Maternal education of A level or above (N, %) | 908/2327 (39) | 858 (40.0) | 979/2275 (43.0) | 801 (45.3) |
Parental occupational class [class I (N, %] | 288/2216 (13.0) | 278 (13.0) | 332/2176 (15.3) | 289 (16.3) |
Maternal self-report history of ED [N, %] | 110/2404 (4.6) | 98 (4.6) | 86/1995 (4.3) | 71 (4.0) |
Maternal antenatal depression (EPDS) | 298/2265 (13.2) | 271 (12.6) | 262/2212 (11.8) | 200 (11.3) |
Average KS3 point score of their school (mean, SD) | 37.9 (5.8) (N = 1984) | 38.2 (5.6) (N = 1790) | – | – |
Average KS4 point score of their school (mean, SD) | – | – | 470 (130) (N = 2345) | 485 (122) (N = 1768) |
Number of students at their school (mean, SD) | 1224 (317) (N = 2404) | 1234 (316) | 1180 (363) (N = 2270) | 1195 (362) |
Proportion of girls in their school (mean, SD) | 0.51 (0.10) (N = 2404) | 0.52 (0.10) | 0.53 (0.15) (2269) | 0.53 (0.15) |
Attend an all-girl school (N, %) | 91/2404 (3.8) | 82 (3.8) | 187/2269 (8.2) | 147 (8.3) |
Have healthcare staff in their school (N, %) | 945/2404 (39.3) | 867 (40.0) | 792/2270 (34.9) | 631 (35.7) |
At a school where ≥ 5% students have free school meals | 1039/2404 (43.2) | 892 (41.6) | 788/2270 (34.7) | 592 (33.5) |
Age 14 | Age 16 | ||||||||
---|---|---|---|---|---|---|---|---|---|
Body Dissatisfaction score (mean, 95% confidence intervals) (N = 2146) | Weight/shape concern above cut off (7) (%, 95% confidence intervals) (N = 2146) | Parental report of fear of/avoidance of fat (% score ≥ 3; 95% Confidence Intervals) (N = 1770) | Fasting (%, 95% confidence intervals) (N = 1769) | Purging (%, 95% confidence intervals) (N = 1769) | Binge eating (%, 95% confidence intervals) (N = 1769) | Any compensatory behaviour (%, 95% confidence intervals) (N = 1769) | Any compensatory behaviour (DSM-5 intensity) (%, 95% confidence intervals) (N = 1769) | Parental report of fear of/avoidance of fat (score ≥ 3) (%, confidence intervals) (N = 1441) | |
Girls at all-girl schools | 22.9 (21.4, 24.4) (N = 82) | 13.4 (5.8, 20.9) (N = 82) | 18.1 (9.0, 27.2) (N = 72) | 21.1 (14.4, 27.8) (N = 147) | 11.6 (6.3, 16.8) (N = 147) | 17.0 (10.9, 23.2) (N = 147) | 48.3 (40.1, 56.5) (N = 147) | 12.9 (7.4, 18.4) (N = 147) | 14.0 (7.9, 20.0) (N = 129) |
Girls at mixed schools | 23.8 (23.5, 24.2) (N = 2313) | 18.0 (16.4, 19.7) (N = 2064) | 11.3 (9.8, 12.8) (N = 1698) | 20.3 (18.3, 22.2) (N = 1622) | 9.2 (7.8, 10.7) (N = 1622) | 15.6 (13.8, 17.4) (N = 1622) | 39.9 (37.5, 42.3) (N = 1622) | 11.3 (9.7, 12.8) (N = 1622) | 12.6 (10.8, 14.4) (N = 1312) |
Girls at schools in top 25% KS3/KS4 point score total | 23.1 (22.4, 23.8) (N = 473) | 14.2 (11.0, 17.3) (N = 473) | 9.5 (6.7, 12.3) (N = 421) | 14.8 (11.4, 18.1) (N = 440) | 8.0 (5.5, 10.5) (N = 440) | 15.2 (11.9, 18.6), N = 440) | 38.6 (34.1, 43.2) (N = 440) | 7.5 (5.0, 10.0) (N = 440) | 11.2 (8.0, 14.4) (N = 376) |
Girls at schools not in top 25% of KS3/KS4 point score total | 24.1 (23.7, 24.6) (N = 1317) (Total N = 1790) | 19.5 (17.4, 21.7) (N = 1317) (Total N = 1790) | 12.2 (10.2, 14.2) (N = 1056) | 22.2 (20.0, 24.5) (N = 1328) (Total N = 1768) | 9.9 (8.3, 11.6) (N = 1328) (Total N = 1768) | 15.8 (13.8, 17.8) (N = 1328) (Total N = 1768) | 41.3 (38.6, 43.9) (N = 1328) (Total N = 1768) | 12.7 (10.9, 14.5) (N = 1328) (Total N = 1768) | 13.3 (11.2, 15.3) (N = 1064) (Total N = 1440) |
Girls at schools with school nurse | 23.4 (22.9, 24.0) (N = 867) | 15.1 (12.7, 17.5) (N = 867) | 10.4 (8.1, 12.6) (N = 723) | 19.5 (16.4, 22.6) (N = 631) | 9.8 (7.5, 12.2), (N = 631) | 15.1 (12.3, 17.9) (N = 631) | 42.2 (38.3, 46.0) (N = 631) | 11.3 (8.8, 13.7) (N = 631) | 11.7 (8.9, 14.5) (N = 513) |
Girls at schools with no school nurse | 24.0 (23.6, 24.5) (N = 1279) | 19.7 (17.5, 21.9) (N = 1279) | 12.4 (10.4, 14.4) (N = 1047) | 20.8 (18.5, 23.2) (N = 1138) | 9.2 (7.5, 10.9) (N = 1138) | 16.1 (13.9, 18.2) (N = 1138) | 39.7 (36.9, 42.6) (N = 1138) | 11.5 (9.7, 13.4) (N = 1138) | 13.3 (11.1, 15.4) (N = 928) |
Girls at schools with ≤ 5% of students entitled to free school meals | 23.7 (23.2, 24.1) (N = 1254) | 17.0 (14.9, 19.1) (N = 1254) | 11.1 (9.2, 13.0) (N = 1045) | 20.4 (18.1, 22.7) (N = 1177) | 9.8 (8.1, 11.5) (N = 1177) | 15.6 (13.6, 17.7) (N = 1177) | 41.2 (38.4, 44.0) (N = 1177) | 11.5 (9.6, 13.3) (N = 1177) | 12.3 (10.2, 14.3) (N = 978) |
Girls at schools with > 5% on free school meals | 23.9 (23.4, 24.5) (N = 892) | 19.1 (16.5, 21.6) (N = 892) | 12.3 (9.9, 14.7) (N = 725) | 20.3 (17.0, 23.5) (N = 592) | 8.8 (6.5, 11.1) (N = 592) | 15.9 (12.9, 18.8) (N = 592) | 39.4 (35.4, 43.3) (N = 592) | 11.3 (8.8, 13.9) (N = 592) | 13.6 (10.5, 16.7) (N = 463) |
Age 14 | Age 16 | ||||||||
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Body Dissatisfaction score (regression coeff, 95% Confidence Interval) (N = 1790) | Weight/shape concern above cut off (7) (OR, 95% confidence interval) (N = 1790) | Parental report of fear of/avoidance of fat (score ≥ 3) (OR, 95% confidence interval) (N = 1477) | Fasting (OR, 95% confidence interval) (N = 1759) | Purging (OR, 95% confidence interval) (N = 1759) | Binge eating (OR, 95% confidence interval) (N = 1768) | Any compensatory behaviour (OR, 95% confidence interval) (N = 1768) | Any compensatory behaviour (DSM-5 intensity) (OR, 95% confidence interval) (N = 1768) | Parental report of fear of/avoidance of fat (score ≥ 3) (OR, confidence interval) (N = 1436) | |
All girls versus mixed schools | − 0.06 (− 0.16, 0.04), p = 0.26 | 0.62 (0.27, 1.39), p = 0.24 | 1.88 (0.90, 4.02), p = 0.08 | 1.14 (0.74, 1.76), p = 0.55 | 1.43 (0.81, 2.51), p = 0.22 | 1.10 (0.69, 1.77), p = 0.68 | 1.48 (1.04, 2.10), p = 0.03 | 1.30 (0.76, 2.22), p = 0.33 | 1.11 (0.64, 1.93), p = 0.71 |
Top 25% versus bottom 75% KS point score total | − 0.02 (− 0.06, 0.02), p = 0.27 | 0.83 (0.60, 1.14), p = 0.24 | 0.88 (0.59, 1.32), p = 0.54 | 0.61 (0.45, 0.83), p = 0.001 | 0.76 (0.51, 1.13), p = 0.18 | 0.95 (0.70, 1.30), p = 0.76 | 0.88 (0.70, 1.10), p = 0.26 | 0.59 (0.40, 0.89), p = 0.01 | 0.82 (0.56, 1.19), p = 0.30 |
School nurse versus no school nurse | − 0.03 (− 0.06, 0.01), p = 0.15 | 0.83 (0.63, 1.08), p = 0.16 | 0.86 (0.60, 1.22), p = 0.39 | 0.93 (0.72, 1.19), p = 0.55 | 1.08 (0.77, 1.53), p = 0.65 | 0.94 (0.71, 1.24), p = 0.66 | 1.12 (0.92, 1.38), p = 0.26 | 0.98 (0.72, 1.35), p = 0.93 | 0.90 (0.64, 1.26), p = 0.54 |
≤ 5% versus > 5% on free school meals | − 0.003 (− 0.04, 0.04), p = 0.89 | 0.97 (0.75, 1.26), p = 0.84 | 1.00 (0.71, 1.41), p = 0.99 | 0.97 (0.75, 1.26), p = 0.82 | 0.95 (0.65, 1.37), p = 0.77 | 1.00 (0.75, 1.34), p = 0.99 | 0.98 (0.79, 1.22), p = 0.89 | 0.91 (0.65, 1.28), p = 0.59 | 1.12 (0.79, 1.60), p = 0.52 |