Table 3.
Geometric means of plasma prolactin by different levels of lifestyle factors and dietary intake of soy and tea among postmenopausal women, the Singapore Chinese Health Study
| n | Geometric meana | p value | % Difference (p value)† | |
|---|---|---|---|---|
| Soy food, quartiles, g/kcal/day | ||||
| < 38.4 | 111 | 7.32 | ||
| 38.4–< 70.2 | 110 | 6.72 | ||
| 70.2–< 98.9 | 111 | 7.42 | ||
| ≥ 98.9 | 110 | 6.62 | 0.4 | − 9.4 (0.2) |
| Green tea | ||||
| Nondrinker/monthly | 295 | 7.08 | ||
| Daily | 147 | 6.88 | 0.6 | − 2.8 (0.6) |
| Black tea | ||||
| Nondrinker/monthly | 295 | 7.08 | ||
| Daily | 147 | 6.88 | 0.6 | − 2.6 (0.6) |
| Sleep, hours/day | ||||
| ≤ 5 | 49 | 7.08 | ||
| 6 | 120 | 6.42 | ||
| 7 | 146 | 6.56 | ||
| 8 | 101 | 8.02 | ||
| ≥ 9 | 26 | 8.88 | 0.005 | 25.3 (0.09) |
| Body mass index, kg/m2 | ||||
| < 20 | 65 | 7.00 | ||
| 20–< 24 | 218 | 7.02 | ||
| 24–< 28 | 114 | 7.02 | ||
| ≥ 28 | 45 | 6.90 | 0.9 | − 1.6 (0.9) |
a
Geometric means are adjusted for age at blood draw, time since last meal, and time of specimen collection
†
% Difference between last versus first listed categories (e.g., fourth vs. first quartile of soy intake, daily versus nondrinker/monthly green tea intake)
Difference of mean prolactin levels among exposure categories was assessed by F statistics obtained from linear regression models