Table 2.
Pooled relative risks (RR) and 95% confidence intervals (CI) of ovarian cancer according to quintile of choline and betaine intake in the Nurses’ Health Study (NHS) and NHSIIa
| Quintileb |
||||||
|---|---|---|---|---|---|---|
| 1 (lowest) | 2 | 3 | 4 | 5 (highest) | P trendc | |
| Total choline (mg/day) | ||||||
| Cases (n) | 87 | 98 | 121 | 110 | 110 | |
| Person-years | 400,830 | 405,555 | 413,596 | 433,495 | 480,681 | |
| Multivariate RR (95%CI) d | 1.00 (ref) | 1.05 (0.79–1.41) | 1.27 (0.96–1.68) | 1.10 (0.82–1.46) | 0.98 (0.73–1.31) | 0.79 |
| Lagged RR (95%CI)e | 1.00 (ref) | 1.02 (0.74–1.39) | 1.24 (0.92–1.67) | 0.85 (0.62–1.18) | 0.96 (0.71–1.30) | 0.49 |
| Total betaine (mg/day) | ||||||
| Person-years | 434,793 | 426,722 | 417,769 | 416,778 | 438,093 | |
| Cases (n) | 96 | 106 | 118 | 103 | 103 | |
| Multivariate RR (95%CI) d | 1.00 (ref) | 1.06 (0.80–1.41) | 1.19 (0.90–1.56) | 1.05 (0.79–1.39) | 0.98 (0.74–1.31) | 0.51 |
| Lagged RR (95%CI)e | 1.00 (ref) | 1.17 (0.87–1.56) | 1.26 (0.94–1.70) | 1.04 (0.76–1.41) | 0.99 (0.73–1.33) | 0.39 |
| Total betaine + choline (mg/day) | ||||||
| Cases (n) | 90 | 95 | 122 | 104 | 115 | |
| Person-years | 407,586 | 408,559 | 414,557 | 425,112 | 478,343 | |
| Multivariate OR (95%CI) d | 1.00 (ref) | 0.99 (0.74–1.32) | 1.21 (0.92–1.60) | 1.01 (0.76–1.34) | 0.99 (0.75–1.32) | 0.76 |
| Lagged RR (95%CI)e | 1.00 (ref) | 0.97 (0.72–1.32) | 0.99 (0.73–1.34) | 0.91 (0.67–1.23) | 0.91 (0.68–1.22) | 0.38 |
No heterogeneity in the risk estimates between the NHS and NHSII cohorts (P heterogeneity = 0.76, 0.59, and 0.96, for total choline, total betaine, and total choline+betaine, respectively).
The quintile cutpoints the NHS were: betaine: <70.5, 70.5-<85.7, 85.7-<101.9, 101.9-<127.3, ≥127.3 mg/day; choline: <249.5, 249.5-<278.5, 278.5-<304.9, 304.9-<338.8, ≥338.8 mg/day; total betaine+choline: <339.8, 339.8-<376.2, 376.2-<409.6, 409.6-<453.8, ≥453.8 mg/day. In the NHSII, quintile cutpoints were: betaine: <80.6, 80.6-<97.6, 97.6-<114.4, 114.4-<138.9, ≥138.9 mg/day, choline: <269.7, 269.7-<301.3, 301.3-<330.3, 330.3-<367.3, ≥367.3 mg/day, total betaine+choline: <371.6, 371.6-<411.2, 411.2-<446.2, 446.2-<491.7, ≥491.7 mg/day. These were based on the distribution in the control subjects.
P trend values were determined using the quintile median intake as a continuous variable.
Multivariate analyses adjusted for age at menarche (continuous), parity (continuous), duration of oral contraceptive use (continuous), tubal ligation (yes, no), height (< 1.6, 1.6-<1.65, 1.65-<1.7, 1.7-<1.75, and ≥ 1.75 meters), family history of breast or ovarian cancer (yes, no), caffeine intake (mg/day), hysterectomy (yes, no), postmenopausal hormone use/menopausal status (premenopausal, postmenopausal/never PMH use, postmenopausal/past PMH use, postmenopausal/current PMH use, postmenopausal/missing PMH use, and missing/unknown menopausal status), caloric intake (kcal/day), alcohol consumption (g/day), and BMI (kg/m2).
Excluding cases diagnosed during the first four years of follow-up after dietary intake assessment.