Table 1.
Age and age-standardized characteristics of 3,647 study participants in the Nurses’ Health Study (NHS) and the NHSII, according to self-reported average body fatness at ages 5–10 years
| Childhood body fatness (average at ages 5–10 years) | |||||
|---|---|---|---|---|---|
| Level 1 (N=835) | Level 1.5–2 (N=1063) | Level 2.5–3 (N=851) | Level 3.5–4 (N=565) | Level ≥4.5 (N=333) | |
| Mean (SD) or Percentage | |||||
| Age at mammogram*, years | 55.0 (9.1) | 51.8 (8.9) | 51.1 (8.6) | 51.7 (8.4) | 51.9 (8.4) |
| Non-White, % | 4.9 | 3.2 | 4.4 | 2.4 | 1.4 |
| Height, inches | 64.7 (2.4) | 64.8 (2.4) | 64.8 (2.5) | 64.7 (2.4) | 64.7 (2.5) |
| BMI at age 18 years, kg/m2 | 19.6 (2.0) | 20.4 (2.2) | 21.5 (2.6) | 22.8 (3.0) | 23.8 (3.2) |
| BMI at mammogram#, kg/m2 | 24.2 (4.1) | 25.0 (4.7) | 26.3 (5.3) | 27.9 (6.2) | 28.7 (6.3) |
| Predicted body fat mass at mammogram#, kg | 24.3 (7.0) | 25.7 (7.9) | 27.4 (9.0) | 30.4 (10.4) | 31.1 (9.7) |
| Predicted percent body fat mass at mammogram# | 36.8 (3.9) | 37.5 (4.3) | 38.3 (4.7) | 40.0 (5.6) | 40.4 (5.2) |
| Age at menarche, years | 12.8 (1.4) | 12.5 (1.4) | 12.4 (1.4) | 12.2 (1.4) | 11.9 (1.3) |
| Parous#, % | 88.5 | 88.8 | 90.5 | 88.1 | 85.9 |
| Among parous women# | |||||
| - Paritya# | 2.8 (1.3) | 2.8 (1.3) | 2.7 (1.3) | 2.8 (1.3) | 2.8 (1.3) |
| - Age at first birtha#, years | 25.5 (3.6) | 25.5 (3.9) | 25.7 (4.0) | 25.4 (3.8) | 25.5 (4.0) |
| - Total breastfeedinga#, % | |||||
| <1 month | 35.7 | 32.3 | 31.5 | 32.8 | 28.3 |
| 1–6 months | 22.0 | 18.7 | 20.0 | 17.8 | 22.0 |
| 7–12 months | 14.3 | 13.4 | 12.6 | 13.9 | 18.6 |
| ≥13 months | 28.0 | 35.6 | 35.8 | 35.5 | 31.0 |
| Postmenopausal#, % | 53.2 | 54.7 | 52.5 | 53.6 | 53.8 |
| Among postmenopausal women# | |||||
| - Postmenopausal hormone useb# | |||||
| Never users | 33.7 | 31.4 | 38.8 | 34.9 | 41.3 |
| Former users | 19.8 | 18.8 | 18.1 | 19.9 | 19.8 |
| Current users | 46.5 | 49.8 | 43.0 | 45.2 | 38.9 |
| - Age at menopauseb#, years | 45.2 (6.6) | 44.9 (7.5) | 46.1 (6.8) | 45.2 (7.2) | 45.4 (7.4) |
| Alcohol intake#, g/d | |||||
| 0 | 32.2 | 33.0 | 35.8 | 35.4 | 35.4 |
| 0.1–4.9 | 33.0 | 34.7 | 32.4 | 30.2 | 34.6 |
| 5.0–14.9 | 19.2 | 19.7 | 19.8 | 20.8 | 16.3 |
| ≥15.0 | 8.4 | 7.0 | 6.6 | 7.7 | 8.3 |
| Missing | 7.3 | 5.6 | 5.5 | 5.9 | 5.3 |
| Smoking#, % | |||||
| Never | 56.9 | 60.8 | 57.5 | 56.1 | 51.1 |
| Former | 33.5 | 31.6 | 34.1 | 35.5 | 37.3 |
| Current | 9.6 | 7.5 | 8.4 | 8.4 | 11.6 |
| Personal history of benign breast disease#, % | 21.9 | 21.2 | 19.1 | 19.4 | 14.0 |
| Family history of breast cancer#, % | 11.0 | 11.1 | 9.4 | 11.3 | 7.4 |
| Percent mammographic density# | 35.9 (19.4) | 35.8 (19.2) | 31.0 (19.6) | 27.8 (19.1) | 23.6 (18.7) |
| Absolute dense area#, cm2 | 43.3 (26.8) | 43.7 (27.9) | 40.1 (27.6) | 38.8 (28.5) | 32.9 (26.6) |
| Absolute nondense area#, cm2 | 91.5 (61.8) | 93.8 (64.9) | 111.8 (78.8) | 124.8 (77.8) | 135.7 (78.4) |
| V measures | 0.12 (0.91) | 0.09 (0.95) | −0.12 (0.98) | −0.27 (1.00) | −0.58 (0.90) |
Values are means(SD) or percentages, standardized to the age distribution of the study population, except for age. Values of polytomous variables may not sum to 100% due to rounding.
*
Value is not age adjusted
#
At the time of mammogram
a
Among parous women only
b
Among postmenopausal women only
Note: V measures = V75 erosion, low resolution; V measures can take negative values because of the mapping.