Table 5.
Risks of total fractures by diet group, stratified by age, sex, menopausal status, physical activity, and BMI
| Stratifying variable | N cases in strata, hazard ratios (95% confidence intervals)a | Test of interactionb | |||
|---|---|---|---|---|---|
| Age at recruitment | < 50 years | ≥ 50 years | |||
| Meat eaters | 690 | Reference | 1778 | Reference | |
| Fish eaters | 204 | 0.86 (0.73, 1.01) | 260 | 0.99 (0.87, 1.14) | |
| Vegetarians | 459 | 1.00 (0.88, 1.13) | 403 | 1.14 (1.01, 1.27) | χ2 = 23.07 |
| Vegans | 80 | 1.31 (1.03, 1.67) | 67 | 1.50 (1.17, 1.93) | p < 0.001 |
| p-heterogeneityc | 0.016 | 0.003 | |||
| Sex | Men | Women | |||
| Meat eaters | 440 | Reference | 2028 | Reference | |
| Fish eaters | 76 | 0.94 (0.73, 1.21) | 388 | 0.95 (0.85, 1.06) | |
| Vegetarians | 202 | 1.06 (0.88, 1.28) | 660 | 1.09 (0.99, 1.20) | χ2 = 6.39 |
| Vegans | 47 | 1.18 (0.85, 1.62) | 100 | 1.53 (1.24, 1.88) | p = 0.09 |
| p-heterogeneityc | 0.64 | < 0.001 | |||
| Menopausal statusd | Premenopausal | Postmenopausal | |||
| Meat eaters | 167 | Reference | 1500 | Reference | |
| Fish eaters | 54 | 0.64 (0.47, 0.87) | 231 | 1.01 (0.88, 1.17) | |
| Vegetarians | 161 | 0.91 (0.73, 1.15) | 325 | 1.13 (0.99, 1.28) | χ2 = 3.74 |
| Vegans | 27 | 1.41 (0.93, 2.15) | 52 | 1.62 (1.22, 2.16) | p = 0.44 |
| p-heterogeneityc | 0.004 | 0.004 | |||
| Physical activity | Inactive/low | Moderate/high | |||
| Meat eaters | 1437 | Reference | 561 | Reference | |
| Fish eaters | 253 | 0.94 (0.82, 1.08) | 144 | 0.96 (0.79, 1.16) | |
| Vegetarians | 495 | 1.09 (0.98, 1.22) | 257 | 1.03 (0.88, 1.22) | χ2 = 0.69 |
| Vegans | 79 | 1.43 (1.13, 1.80) | 50 | 1.34 (0.98, 1.82) | p = 0.88 |
| p-heterogeneityc | 0.006 | 0.25 | |||
| Body mass index | < 22.5 kg/m2 | ≥ 22.5 kg/m2 | |||
| Meat eaters | 762 | Reference | 1593 | Reference | |
| Fish eaters | 210 | 0.95 (0.81, 1.11) | 237 | 0.97 (0.84, 1.11) | |
| Vegetarians | 428 | 1.17 (1.02, 1.33) | 396 | 1.04 (0.92, 1.17) | χ2 = 4.71 |
| Vegans | 95 | 1.66 (1.32, 2.08) | 43 | 1.10 (0.80, 1.49) | p = 0.19 |
| p-heterogeneityc | < 0.001 | 0.76 | |||
aResults shown were for subset analyses by the stratifying variable. Analyses were stratified by sex, method of recruitment (general practice or postal), and region (7 categories), and adjusted for year of recruitment (per year from ≤ 1994 to ≥ 1999), ethnicity (white, other, unknown), Townsend deprivation index (quartiles, unknown), education level (no qualifications, basic secondary (e.g. O level), higher secondary (e.g. A level), degree, unknown), physical activity (inactive, low activity, moderately active, very active, unknown), smoking (never, former, light, heavy, unknown), alcohol consumption (< 1 g, 1–7 g, 8–15 g, 16+ g/day), dietary supplement use (no, yes, unknown), height (5 cm categories from < 155 to ≥ 185 cm, unknown), BMI (< 18.5, 18.5–19.9, 20–22.4, 22.5–24.9, 25–27.4, 27.5–29.9, 30–32.4, ≥ 32.5 kg/m2, unknown), and in women menopausal status (premenopausal, perimenopausal, postmenopausal, unknown), hormone replacement therapy use (never, ever, unknown), and parity (none, 1–2, ≥ 3, unknown), except the stratifying variable where appropriate
bInteractions by age at recruitment, sex, menopausal status, physical activity, and body mass index were investigated by including both strata in the model (e.g. both men and women) and comparing Cox models with and without the appropriate interaction term using likelihood ratio tests
cRepresents heterogeneity in risk between diet groups based on Wald tests
dPremenopausal women included women who were below age 50 years at recruitment if they were perimenopausal or had unknown menopausal status; analyses in premenopausal women were censored at age 50. Postmenopausal women included women above age 50 years at recruitment if perimenopausal or had unknown perimenopausal status