TABLE 2.
ORs (95% CIs) for intake of total caffeine and frequency of coffee and tea consumption at baseline on risk of PMS: Nurses’ Health Study II PMS substudy, 1991–20051
| Median, mg/d | Cases, n | Controls, n | Age-adjusted (OR 95% CI) | Multivariable 12 OR (95% CI) | Multivariable 23OR (95% CI) | |
| Total caffeine | ||||||
| Q1 | 18 | 258 | 544 | 1 | 1 | |
| Q2 | 82 | 252 | 586 | 0.90 (0.73, 1.11) | 0.84 (0.67, 1.05) | |
| Q3 | 168 | 253 | 454 | 1.18 (0.95, 1.46) | 1.07 (0.85, 1.35) | |
| Q4 | 354 | 264 | 464 | 1.24 (1.00, 1.53) | 1.00 (0.79, 1.28) | |
| Q5 | 543 | 207 | 378 | 1.20 (0.96, 1.51) | 0.79 (0.61, 1.04) | |
| P-trend | <0.01 | 0.31 | ||||
| Total caffeine, mg/d | ||||||
| <100 | 37 | 420 | 917 | 1 | 1 | |
| 100–199 | 147 | 293 | 590 | 1.09 (0.91, 1.31) | 0.98 (0.80, 1.19) | |
| 200–299 | 236 | 97 | 181 | 1.19 (0.90, 1.56) | 0.99 (0.73, 1.34) | |
| 300–399 | 361 | 203 | 335 | 1.38 (1.17, 1.70) | 1.11 (0.87, 1.41) | |
| 400–499 | 434 | 96 | 186 | 1.16 (0.89, 1.53) | 0.83 (0.61, 1.14) | |
| 500–599 | 542 | 32 | 66 | 1.10 (0.71, 1.70) | 0.78 (0.48, 1.27) | |
| 600–699 | 646 | 46 | 70 | 1.53 (1.03, 2.26) | 1.02 (0.66, 1.57) | |
| ≥700 | 825 | 47 | 81 | 1.36 (0.93, 1.98) | 0.77 (0.49, 1.19) | |
| P-trend | <0.01 | 0.35 | ||||
| Total coffee4 | ||||||
| <1 cup/mo | 362 | 829 | 1 | 1 | ||
| 1 cup/mo–1 cup/wk | 103 | 194 | 1.21 (0.93, 1.59) | 1.25 (0.94, 1.67) | ||
| 2–6 cups/wk | 112 | 232 | 1.11 (0.86, 1.44) | 1.10 (0.83, 1.45) | ||
| 1 cup/d | 181 | 327 | 1.29 (1.04, 1.61) | 1.23 (0.96, 1.57) | ||
| 2–3 cups/d | 359 | 616 | 1.40 (1.17, 1.68) | 1.18 (0.95, 1.47) | ||
| ≥4 cups/d | 117 | 227 | 1.27 (0.98, 1.65) | 0.83 (0.61, 1.14) | ||
| P-trend | 0.01 | 0.43 | ||||
| Caffeinated coffee4 | ||||||
| <1 cup/mo | 471 | 1011 | 1 | 1 | 1 | |
| 1 cup/mo–1 cup/wk | 105 | 192 | 1.17 (0.90, 1.52) | 1.17 (0.88, 1.55) | 1.14 (0.85, 1.52) | |
| 2–6 cups/wk | 87 | 211 | 0.88 (0.67, 1.16) | 0.85 (0.64, 1.15) | 0.85 (0.62, 1.14) | |
| 1 cup/d | 176 | 307 | 1.24 (1.00, 1.54) | 1.18 (0.93, 1.50) | 1.13 (0.88, 1.44) | |
| 2–3 cups/d | 302 | 534 | 1.26 (1.05, 1.50) | 1.03 (0.83, 1.28) | 1.01 (0.81, 1.26) | |
| ≥4 cups/d | 93 | 170 | 1.24 (0.94, 1.64) | 0.80 (0.58, 1.11) | 0.80 (0.57, 1.11) | |
| P-trend | 0.01 | 0.33 | 0.32 | |||
| Decaffeinated coffee4 | ||||||
| <1 cup/mo | 777 | 1551 | 1 | 1 | 1 | |
| 1 cup/mo–1 cup/wk | 193 | 393 | 1.01 (0.83, 1.22) | 1.11 (0.90, 1.37) | 1.08 (0.87, 1.35) | |
| 2–6 cups/wk | 93 | 192 | 1.00 (0.77, 1.30) | 0.95 (0.71, 1.26) | 0.94 (0.70, 1.26) | |
| 1 cup/d | 92 | 156 | 1.24 (0.94, 1.62) | 1.33 (0.99, 1.79) | 1.28 (0.94, 1.73) | |
| ≥2 cups/d | 79 | 133 | 1.28 (0.96, 1.72) | 1.14 (0.83, 1.57) | 1.09 (0.79, 1.51) | |
| P-trend | 0.05 | 0.25 | 0.41 | |||
| Total tea5 | ||||||
| <1 cup/mo | 165 | 393 | 1 | 1 | ||
| 1 cup/mo–1 cup/wk | 158 | 440 | 0.90 (0.69, 1.16) | 0.92 (0.69, 1.22) | ||
| 2–6 cups/wk | 135 | 276 | 1.18 (0.90, 1.56) | 1.20 (0.89, 1.62) | ||
| 1 cup/d | 85 | 185 | 1.13 (0.82, 1.54) | 1.19 (0.84, 1.69) | ||
| ≥2 cups/d | 102 | 255 | 0.98 (0.73, 1.31) | 0.97 (0.70, 1.34) | ||
| P-trend | 0.85 | 0.9 | ||||
| Caffeinated tea4 | ||||||
| <1 cup/mo | 400 | 819 | 1 | 1 | 1 | |
| 1 cup/mo–1 cup/wk | 308 | 576 | 1.10 (0.91, 1.32) | 1.10 (0.90, 1.34) | 1.09 (0.89, 1.33) | |
| 2–6 cups/wk | 183 | 366 | 1.02 (0.82, 1.26) | 1.08 (0.85, 1.36) | 1.08 (0.85, 1.36) | |
| 1 cup/d | 173 | 348 | 1.01 (0.81, 1.25) | 0.95 (0.75, 1.20) | 0.93 (0.73, 1.18) | |
| ≥2 cups/d | 170 | 316 | 1.11 (0.89, 1.38) | 1.06 (0.84, 1.36) | 1.04 (0.82, 1.34) | |
| P-trend | 0.58 | 0.98 | 0.89 | |||
| Herbal tea5 | ||||||
| <1 cup/mo | 370 | 956 | 1 | 1 | ||
| 1 cup/mo–1 cup/wk | 117 | 298 | 1.06 (0.83, 1.35) | 1.20 (0.91, 1.57) | ||
| 2–6 cups/wk | 87 | 131 | 1.76 (1.31, 2.38) | 2.06 (1.48, 2.86) | ||
| ≥1 cups/d | 71 | 164 | 1.13 (0.83, 1.53) | 1.19 (0.85, 1.66) | ||
| P-trend | 0.09 | 0.06 |
PMS, premenstrual syndrome; Q, quintile.
Multivariable logistic regression models adjusted for diagnosis year (1993, 1994–1995, 1996–1997, 1998–1999, or 2000–2001); age; pack-years of smoking (0, 1–5, 6–10, 11–15, 16–20, or ≥21); parity (0, 1–2, 3–4, or ≥5); duration of oral contraceptive use (never or 1–23, 24–71, 72–119, or ≥120 mo); history of childhood trauma score (5, 6–10, 11–15, or ≥16); depression before PMS, depression medication; BMI [in kg/m2 (<20.0, 20.0–22.4, 22.5–24.9, 25.0–27.4, 27.5–29.9, or ≥30)]; physical activity (<3, 3 to <9, 9 to <18, 18 to <27, 27 to <42, or ≥42 metabolic equivalent task–hours/wk); and total intake of alcohol (0, >0 to <5, 5 to <10, 10 to <15, or ≥15 g/d), calcium, vitamin D, vitamin B-6, and potassium.
Multivariable model l plus intake of caffeinated coffee, decaffeinated coffee, and caffeinated tea mutually adjusted for each other.
Control count does not sum to 2426 because of missing data.
Herbal tea was not assessed until 1995; baseline for total and herbal tea is 1995.