Table 1

Characteristics of 109,267 premenopausal Nurses' Health Study II participants in 1989 according to body fatness at age 10 years
Characteristic
 Figure at age 10 years


1
 2
 3
 4
 ≥ 5
Number participants (%)
 20,554 (18.8)
 33,512 (30.7)
 24,666 (22.6)
 17,274 (15.8)
 13,261 (12.1)
Mean
     Age (years)
 34.6
 34.0
 34.1
 34.3
 34.7
     Total caloric intake in high school (kilocalories)a
 2737
 2746
 2745
 2746
 2781
     Animal fat intake in high school (% energy)a
 26.0
 25.7
 25.8
 25.9
 26.2
     Vegetable fat intake in high school (% energy)a
 14.4
 14.7
 14.8
 15.0
 15.0
     Age at menarche (years)
 12.8
 12.6
 12.3
 12.1
 12.0
     Height (inches)
 64.9
 64.9
 64.8
 64.8
 65.0
     BMI at age 18 years (kg/m2)
 19.3
 20.2
 21.5
 22.9
 24.3
     Current BMI (kg/m2)
 22.0
 22.7
 24.4
 26.1
 27.1
     Age at first birth (years)b
 25.4
 25.5
 25.6
 25.6
 25.4
     Parityb
 2.1
 2.1
 2.1
 2.1
 2.0
Percentage
     Birthweight ≥ 8.5 lb
 8.3
 9.4
 11.7
 12.9
 13.7
     ≥ 3 years from menarche until regular menstrual cycles
 19.5
 18.5
 17.7
 17.9
 19.6
     Irregular menstrual cycles/no periods ages 18–22 years
 9.7
 9.0
 8.8
 10.2
 11.2
     Menstrual cycle length ≥ 40 days ages 18–22 years
 7.1
 7.1
 7.3
 8.2
 8.6
     Strenuous activity 10–12 months/year in high school
 28.7
 28.0
 26.2
 21.4
 17.6
     BMI at age 18 years ≥ 25 kg/m2
 1.8
 3.1
 8.9
 19.5
 32.2
     Current BMI ≥ 30 kg/m2
 3.0
 4.9
 11.2
 20.2
 24.6
     Nulliparous
 29.6
 29.2
 29.3
 31.3
 35.0
     Current oral contraceptive user
 13.8
 14.0
 12.6
 12.7
 11.6
     Current smoker
 13.1
 11.5
 12.3
 14.2
 18.6
     Alcohol consumption ≥ 10 g/day
 9.7
 9.0
 9.1
 9.1
 9.9
     First-degree family history of breast cancer
 5.9
 6.0
 5.7
 5.9
 6.3
     History of benign breast disease
 30.3
 28.1
 27.6
 27.5
 28.0

All means and percentages refer to the 1989 time period unless otherwise noted. Participants who had a diagnosis of cancer (other than nonmelanoma skin cancer) and those for whom body fatness data were missing at ages 5, 10, or 20 years were excluded. aAmong participants who completed the high school diet questionnaire in 1998. bAmong participants who reported that they were parous in 1989. BMI, body mass index.

Baer et al. Breast Cancer Research 2005 7:R314   doi:10.1186/bcr998

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