Background
Methods
Study population
Exposures
Categorisation of exposure variables
Covariates
Follow up
Outcome
Statistical analysis
Survival analysis
Results
Sample characteristics
Characteristic | BMI category (kg/m2) | All participants | ||
---|---|---|---|---|
< 25 | 25 - < 30 | ≥18 | ||
Total, n (% of all participants) | 42, 077 (44.7) | 34,690 (36.9) | 17,260 (18.3) | 94,124 |
LRE, n (% of all participants) | 102 (31.7) | 123 (38.2) | 97 (30.1) | 322 |
Age at questionnaire return, median years (range) | 63 (52–80) | 64 (53–80) | 64 (53–80) | 64 (52–80) |
IMD, mean (SD) | 17.0 (13.1) | 18.7 (14.1) | 21.3 (15.4) | 18.4 (14.0) |
Smoker, n (%) | 14,632 (34.8) | 12,511 (36.1) | 6548 (37.7) | 33,691 (35.8) |
Hypertension, n (%) | 9382 (22.3) | 11,970 (34.5) | 8307 (47.9) | 29,659 (31.5) |
Heart disease, n (%) | 1698 (4.0) | 2052 (5.9) | 1392 (8.0) | 5142 (5.5) |
Hypercholesterolaemia, n (%) | 7901 (18.8) | 9044 (26.1) | 5369 (30.9) | 22,314 (23.7) |
Stroke, n (%) | 523 (1.2) | 552 (1.6) | 314 (1.8) | 1389 (1.5) |
Diabetes, n (%) | 827 (2.0) | 1653 (4.8) | 2221 (12.8) | 4701 (5.0) |
Rheumatoid arthritis, n (%) | 1592 (3.8) | 1742 (5.0) | 1185 (6.8) | 4519 (4.8) |
Osteoarthritis, n (%) | 5503 (13.1) | 5822 (16.8) | 4016 (23.1) | 15,341 (16.3) |
Osteoporosis, n (%) | 3808 (9.1) | 2082 (6.0) | 770 (4.4) | 6660 (7.1) |
Alcohol consumption (units/week), n (%) | ||||
None | 8365 (19.9) | 8.043 (23.2) | 5432 (31.3) | 21,840 (23.2) |
< 1–15 | 31,567 (75.0) | 25,095 (72.3) | 11,347 (65.4) | 68,009 (72.3) |
16–20 | 1436 (3.4) | 1063 (3.1) | 364 (2.1) | 2863 (3.0) |
≥ 21 | 709 (1.7) | 489 (1.4) | 214 (1.2) | 1412 (1.5) |
Skirt size when aged in 20s, n (%) | ||||
≤ 16 | 41,428 (98.5) | 33,835 (97.5) | 15,691 (90.4) | 90,954 (96.6) |
≥ 18 | 649 (1.5) | 855 (2.5) | 1666 (9.6) | 3170 (3.4) |
Skirt size at time of questionnaire completion, n (%) | ||||
≤ 16 | 40,792 (96.9) | 26,982 (77.8) | 4481 (25.8) | 72,255 (76.8) |
≥ 18 | 1285 (3.1) | 7708 (22.2) | 12,876 (74.2) | 21,869 (23.2) |
Change in skirt size, median (interquartile range) | 0.0244 (0.03) | 0.0408 (0.04) | 0.0667 (0.05) | 0.0323 (0.04) |
Overall change in skirt size, n (%) | ||||
Decrease | 4811 (11.4) | 1153 (3.3) | 362 (2.1) | 6326 (6.7) |
No change | 12,344 (29.3) | 3422 (9.9) | 731 (4.2) | 16,497 (17.5) |
Increase | 24,922 (59.2) | 30,115 (86.8) | 16,264 (93.7) | 71,301 (75.8) |
Distributions of BMI and skirt size
Crude event rates
Exposure | Event rate | |
---|---|---|
BMI (kg/m2) | < 25 | 0.453 (0.369–0.550) |
25- < 30 | 0.661 (0.549–0.788) | |
≥30 | 1.044 (0.847–1.273) | |
Skirt size in 20s | ≤ 16 | 0.621 (0.553–0.696) |
≥ 18 | 1.124 (0.677–1.755) | |
Skirt size at questionnaire completion | ≤ 16 | 0.550 (0.479–0.629) |
≥ 18 | 0.928 (0.762–1.120) | |
Change in skirt size/year | Decrease | 0.3867 (0.206–0.661) |
No change | 0.599 (0.449–0.784) | |
Increase | 0.669 (0.590–0.757) |
Survival analysis
Cox proportional model estimates for each potential confounder
Cox proportional model estimates for each exposure
Variable | Hazard ratio (95% CI) | |||
---|---|---|---|---|
Skirt size when aged in 20s | Univariate | Continuous | 1.062 (1.022–1.104) p = 0.002 | |
Categorical | ≤ 16 | Reference | ||
≥ 18 | 1.806 (1.136–2.871) p = 0.012 | |||
Adjusted for smoking, deprivation | ≤ 16 | Reference | ||
≥ 18 | 1.681 (1.057–2.675) p = 0.028 | |||
Adjusted for age, smoking, deprivation, hypertension, heart disease, hypercholesterolaemia, stroke, diabetes, rheumatoid arthritis, osteoarthritis, osteoporosis, alcohol abstinence, alcohol ≥21 units/week | ≤ 16 | Reference | ||
≥ 18 | 1.390 (0.868–2.226) p = 0.171 | |||
Skirt size at time of questionnaire completion | Univariate | Continuous | 1.091 (1.062–1.121) p < 0.0005 | |
Categorical | ≤ 16 | Reference | ||
≥ 18 | 1.690 (1.342–2.129) p < 0.0005 | |||
Adjusted for smoking, deprivation | ≤ 16 | Reference | ||
≥ 18 | 1.579 (1.250–1.995) p < 0.0005 | |||
Adjusted for age, smoking, deprivation, hypertension, heart disease, hypercholesterolaemia, stroke, diabetes, rheumatoid arthritis, osteoarthritis, osteoporosis, alcohol abstinence, alcohol ≥21 units/week | ≤ 16 | Reference | ||
≥ 18 | 1.369 (1.071–1.749) p = 0.012 | |||
BMI (kg/m2) | Univariate | Continuous | 1.063 (1.044–1.082) p < 0.0005 | |
Categorical | < 25 | Reference | ||
≥ 25 - < 30 | 1.461 (1.123–1.899) p = 0.005 | |||
≥ 30 | 2.308 (1.748–3.047) p < 0.0005 | |||
Adjusted for smoking, deprivation | < 25 | Reference | ||
≥ 25 - < 30 | 1.403 (1.076–1.830) p = 0.012 | |||
≥ 30 | 2.162 (1.631–2.864) p < 0.0005 | |||
Adjusted for age, smoking, deprivation, hypertension, heart disease, hypercholesterolaemia, stroke, diabetes, rheumatoid arthritis, osteoarthritis, osteoporosis, alcohol abstinence, alcohol ≥21 units/week | < 25 | Reference | ||
≥ 25 - < 30 | 1.353 (1.034–1.770) p = 0.028 | |||
≥ 30 | 1.880 (1.395–2.533) p < 0.0005 | |||
Change in skirt size/year | Univariate | Categorical | Decrease | Reference |
No change | 1.554 (0.847–2.850) p = 0.155 | |||
Increase | 1.736 (0.994–3.031) p = 0.052 | |||
Adjusted for smoking, deprivation | Decrease | Reference | ||
No change | 1.714 (0.915–3.211) p = 0.092 | |||
Increase | 1.873 (1.050–3.343) p = 0.034 | |||
Adjusted for age, smoking, deprivation, hypertension, heart disease, hypercholesterolaemia, stroke, diabetes, rheumatoid arthritis, osteoarthritis, osteoporosis, alcohol abstinence, alcohol ≥21 units/week | Decrease | Reference | ||
No change | 1.781 (0.950–3.337) p = 0.072 | |||
Increase | 1.799 (1.007–3.214) p = 0.047 |