TABLE 2.
Hazard ratios of total fracture by quintiles of total vitamin A and retinol intakes among postmenopausal women in the Women's Health Initiative Observational Study1
| Quintiles of intakes |
||||||
| 1 | 2 | 3 | 4 | 5 | P for trend2 | |
| Vitamin A (μg RE/d) | <5055 | 5055–5824 | 5825–6550 | 6551–7507 | ≥7508 | — |
| n | 15,149 | 15,149 | 15,150 | 15,149 | 15,150 | — |
| Cases | 1993 | 2054 | 2102 | 2137 | 2119 | — |
| Age-adjusted HR3 | 1.00 | 1.03 (0.97, 1.10) | 1.07 (1.00, 1.14) | 1.09 (1.02, 1.16) | 1.09 (1.02, 1.16) | <0.001 |
| Multivariate HR4 | 1.00 | 1.02 (0.96, 1.09) | 1.06 (0.99, 1.13) | 1.08 (1.01, 1.16) | 1.09 (1.01, 1.19) | <0.001 |
| Multivariate HR5 | 1.00 | 0.99 (0.92, 1.05) | 1.00 (0.93, 1.07) | 1.00 (0.92, 1.08) | 0.98 (0.89, 1.08) | 0.330 |
| Retinol (μg/d) | <474 | 474–764 | 765–1092 | 1093–1425 | ≥1426 | — |
| n | 15,149 | 15,149 | 15,150 | 15,149 | 15,150 | — |
| Cases | 1977 | 2044 | 2110 | 2152 | 2122 | — |
| Age-adjusted HR3 | 1.00 | 1.05 (0.99, 1.12) | 1.09 (1.03, 1.16) | 1.13 (1.06, 1.20) | 1.10 (1.03, 1.17) | <0.001 |
| Multivariate HR4 | 1.00 | 1.03 (0.96, 1.11) | 1.08 (1.00, 1.15) | 1.11 (1.04, 1.18) | 1.08 (1.01, 1.16) | 0.002 |
| Multivariate HR5 | 1.00 | 1.01 (0.94, 1.08) | 1.03 (0.96, 1.11) | 1.04 (0.96, 1.13) | 1.00 (0.92, 1.10) | 0.800 |
1
A total of 75,747 women contributed 471,062 person-years to this analysis; the total fracture count was 10,405. 95% CIs in parentheses. HR, hazard ratio; RE, retinol equivalent.
2
Test for trend for linear increase in nutrient intake.
3
Risk estimates were adjusted for age.
4
Risk estimates were adjusted for age; energy, vitamin K, protein, alcohol, and caffeine intakes; smoking; BMI; HT use; total METs per week; ethnic group; and region.
5
Risk estimates were adjusted for the variables listed in footnote 4 plus vitamin D and calcium.