Table 1.
Characteristics of study population by the frequency of any analgesic use at urine collection in the Nurses’ Health Study II (n=603)
| Frequency of any analgesic use (days/week) |
||||
|---|---|---|---|---|
| 0 | 1 | 2 to 3 | 4+ | |
| 194 | 150 | 134 | 125 | |
| Age in years | 42.6 (4.0) | 42.6 (3.7) | 43.1 (3.7) | 43.4 (3.8) |
| Body mass index (kg/m2) | 23.9 (3.7) | 24.7 (4.0) | 25.3 (4.1) | 26.9 (4.9) |
| Height (inches) | 64.9 (2.4) | 65.4 (2.0) | 64.8 (2.3) | 65.2 (2.0) |
| Physical activity (MET-hr/week)a | 23.1 (19.2) | 20.7 (15.7) | 22.4 (15.4) | 22.4 (17.7) |
| Parous, % | 85.8 | 77.8 | 85.4 | 76.0 |
| Parityb | 2.1(1.0) | 1.7(1.0) | 2.0(1.0) | 1.8(1.0) |
| Age at first birthb (years) | 26.5(3.6) | 26.3(4.1) | 26.7(4.2) | 26.2(3.7) |
| Past oral contraceptive use, % | 77.9 | 87.0 | 89.2 | 87.4 |
| Alcohol intake (g/day)c | 3.7(5.2) | 4.3(5.0) | 4.7(6.6) | 3.6(4.4) |
| Current smoker, % | 5.9 | 6.4 | 7.4 | 8.9 |
| Age at menarche <12 yrs, % | 19.2 | 19.9 | 21.2 | 25.7 |
| Menstrual cycle length 26-31 days, % | 72.5 | 60.0 | 67.4 | 74.1 |
| Regular menstrual cyclesd | 97.1 | 92.7 | 96.5 | 93.8 |
| First morning urine, % | 88.3 | 75.3 | 80.2 | 78.5 |
| Luteal day outside 3-10 days before next period, % | 12.7 | 11.8 | 15.9 | 14.1 |
| Anovulatory cycle, % | 9.4 | 5.7 | 7.7 | 14.9 |
| Creatinine, mg/L | 1150 (542) | 1132 (439) | 1170 (503) | 1034 (446) |
Values are means(SD) or percentages and are standardized to the age distribution of the study population.
a
Average of 1997 and 2001 activities.
b
Among parous women.
c
Average of 1995 and 1999 intakes.
d
Menstrual cycles begin within 5 to 7 days of expected