Table 1 Baseline characteristics of study participants by age group and self-reported mammography frequency (n = 93,438)*
From: Mammography screening and mortality by risk status in the California teachers study
|  | Age at baseline 40–49 (n = 31,398) | Age at baseline 50–59 (n = 28,342) | Age at baseline 60–74 (n = 25,674) | Age at baseline 75–85 (n = 8024) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Â | Never/ Less frequent (Row%) | Biennial (Row%) | Annual (Row%) | Never/ Less frequent (Row%) | Biennial (Row%) | Annual (Row%) | Never/ Less frequent (Row%) | Biennial (Row%) | Annual (Row%) | Never/ Less frequent (Row%) | Biennial (Row%) | Annual (Row%) |
Overall | 18.8 | 35.3 | 46.1 | 7.6 | 22.9 | 69.0 | 8.2 | 22.3 | 69.6 | 15.2 | 29.4 | 55.4 |
Mean follow-up time (years) | 18.7 | 18.9 | 18.8 | 17.8 | 17.9 | 18.0 | 15.6 | 16.2 | 16.7 | 9.7 | 11.3 | 12.0 |
Race/ethnicity | ||||||||||||
 White | 17.6 | 35.1 | 47.3 | 7.5 | 22.2 | 70.3 | 8.1 | 21.8 | 70.1 | 15.0 | 29.0 | 56.0 |
 African American | 22.3 | 38.0 | 39.7 | 7.0 | 29.4 | 63.6 | 6.6 | 27.0 | 66.5 | 18.7 | 35.3 | 46.0 |
 Hispanic | 25.3 | 37.3 | 37.4 | 8.9 | 29.2 | 61.9 | 8.1 | 26.0 | 66.0 | 17.5 | 27.5 | 55.0 |
 Asian/Pacific Islander | 22.5 | 36.7 | 40.7 | 8.3 | 27.0 | 64.6 | 10.0 | 27.0 | 63.0 | 11.5 | 41.0 | 47.4 |
 Other | 26.0 | 33.1 | 40.9 | 12.2 | 26.0 | 61.8 | 11.5 | 25.5 | 62.9 | 17.2 | 32.1 | 50.7 |
Number of first-degree relatives diagnosed with breast cancer | ||||||||||||
 0 | 19.7 | 36.3 | 44.0 | 7.9 | 23.8 | 68.3 | 8.4 | 22.7 | 68.9 | 15.3 | 30.1 | 54.5 |
 1+ | 10.0 | 27.3 | 62.7 | 5.4 | 16.8 | 77.8 | 6.4 | 18.4 | 75.2 | 11.8 | 25.6 | 62.6 |
 Unknown | 20.0 | 35.6 | 44.4 | 10.5 | 25.5 | 64.1 | 9.7 | 27.9 | 62.4 | 22.0 | 27.9 | 50.1 |
BMIa | ||||||||||||
 Underweight/normal | 17.2 | 35.2 | 47.6 | 6.6 | 21.9 | 71.5 | 7.6 | 21.2 | 71.2 | 15.0 | 29.2 | 55.8 |
 Overweight | 19.4 | 35.7 | 45.0 | 7.5 | 23.4 | 69.1 | 7.9 | 22.9 | 69.2 | 12.5 | 30.0 | 57.6 |
 Obese | 23.1 | 34.8 | 42.1 | 10.8 | 25.3 | 63.8 | 9.2 | 24.0 | 66.8 | 16.4 | 32.6 | 51.0 |
 Unknown | 21.3 | 38.8 | 39.9 | 10.5 | 26.0 | 63.5 | 12.9 | 23.9 | 63.2 | 20.1 | 26.9 | 53.0 |
Lifetime physical activity (hours/week/year) | ||||||||||||
 ≤0.5 | 17.9 | 35.9 | 46.1 | 8.7 | 23.8 | 67.5 | 9.8 | 23.2 | 67.0 | 18.3 | 29.0 | 52.6 |
 0.51–3.99 | 17.5 | 35.7 | 46.8 | 7.0 | 23.2 | 69.8 | 7.4 | 22.2 | 70.4 | 13.9 | 29.3 | 56.8 |
 ≥4.0 | 19.8 | 34.8 | 45.3 | 8.2 | 22.3 | 69.5 | 8.5 | 21.9 | 69.6 | 14.5 | 29.8 | 55.7 |
Menopause/Hormone therapy | ||||||||||||
 Premenopausal | 21.3 | 35.4 | 43.3 | 12.0 | 26.9 | 61.1 | 23.1 | 38.5 | 38.5 | – | – | – |
 Postmenopausal - HT Never | 22.6 | 34.8 | 42.6 | 21.1 | 27.8 | 51.1 | 17.9 | 26.4 | 55.7 | 24.4 | 31.7 | 43.8 |
 Postmenopausal - HT Former | 15.6 | 36.5 | 47.9 | 10.8 | 29.1 | 60.1 | 10.1 | 26.5 | 63.3 | 14.1 | 31.4 | 54.5 |
 Postmenopausal - HT Current | 7.9 | 35.0 | 57.1 | 3.3 | 20.1 | 76.6 | 3.2 | 19.0 | 77.8 | 6.9 | 25.5 | 67.6 |
 Other | 11.3 | 35.0 | 53.6 | 5.5 | 21.9 | 72.7 | 8.4 | 23.2 | 68.4 | 15.9 | 29.6 | 54.5 |
Alcohol consumption | ||||||||||||
 None | 21.3 | 34.7 | 44.0 | 9.2 | 23.8 | 67.0 | 10.2 | 23.0 | 66.8 | 17.8 | 29.7 | 52.5 |
 < 20 g/day | 17.3 | 35.7 | 47.0 | 7.0 | 22.6 | 70.5 | 7.0 | 21.9 | 71.0 | 12.9 | 28.7 | 58.4 |
 ≥20 g/day | 16.3 | 36.3 | 47.5 | 6.5 | 21.3 | 72.1 | 7.6 | 21.6 | 70.8 | 13.0 | 28.8 | 58.2 |
 Unknown | 19.7 | 31.8 | 48.5 | 8.5 | 25.8 | 65.8 | 9.0 | 22.4 | 68.5 | 16.9 | 31.3 | 51.9 |
Estimated 5-year risk (at baseline) by Gail model (%) | ||||||||||||
 Lowest quintile (0.2–0.9) | 24.2 | 36.0 | 39.8 | 9.9 | 28.0 | 62.1 | 10.8 | 27.1 | 62.1 | 22.9 | 41.7 | 35.4 |
 Second quintile (1.0–1.2) | 15.3 | 37.2 | 47.5 | 8.6 | 24.9 | 66.5 | 11.5 | 24.8 | 63.7 | 20.4 | 28.8 | 50.8 |
 Third quintile (1.3–1.5) | 10.3 | 34.2 | 55.4 | 7.5 | 22.5 | 70.0 | 8.4 | 23.9 | 67.7 | 20.2 | 32.4 | 47.3 |
 Fourth quintile (1.6–1.9) | 8.6 | 29.3 | 62.1 | 6.2 | 21.0 | 72.7 | 8.7 | 22.6 | 68.6 | 17.5 | 30.2 | 52.4 |
 Highest quintile (2.0–11.4) | 6.8 | 23.6 | 69.5 | 4.9 | 16.3 | 78.7 | 7.1 | 20.6 | 72.3 | 12.3 | 28.2 | 59.6 |