Table 2 Age-standardiseda characteristics in 1988 (Nurses' Health Study) and 1989 (Nurses' Health Study II) by body size measures and study population

From: Body size in early life and risk of epithelial ovarian cancer: results from the Nurses' Health Studies

 

Average childhood body fatness b

BMI at the age of 18 years, kg m −2

Height, m

Birthweight, lbs

 

1

⩾5

<20

⩾25

<1.6

⩾1.75

<5.5

⩾8.5

Nurses' Health Study (NHS)

Sample size at baselinec

19 371

4633

29 077

8212

24 877

5165

3312

6868

Means

 Age (years)

55.4

53.9

54.4

54.6

55.0

53.8

53.6

54.9

 Age at menarche (years)

12.8

12.2

12.8

12.2

12.3

12.9

12.4

12.6

 Parity (among parous women)

3.2

3.0

3.1

3.1

3.2

3.0

3.1

3.1

 Duration of oral contraceptive use (months)

24.6

24.0

25.2

23.2

22.9

23.2

25.9

24.7

 Current body mass index (kg m−2)

24.4

28.1

23.4

30.8

25.7

25.1

25.5

26.1

Percentages

 Parous

93.0

92.3

92.5

90.8

92.4

90.5

92.6

92.5

 Premenopausal

31.6

31.7

27.8

27.1

25.2

25.5

34.2

33.3

 Postmenopausal

68.2

68.2

70.1

70.6

69.3

69.7

65.0

65.8

 Family history of ovarian cancerd

2.6

2.8

2.5

2.9

2.2

2.7

3.0

2.6

 History of tubal ligation

17.4

17.9

17.0

18.3

17.0

15.5

19.3

18.2

 Current postmenopausal hormone user (among postmenopausal women)

25.3

22.3

27.8

20.9

25.2

26.8

23.4

24.8

Nurses' Health Study II (NHSII)

Sample size at baselinec

19 220

6984

44 078

11 745

21 440

8922

2834

11 467

Means

 Age (years)

34.6

34.8

34.3

34.3

34.5

34.0

35.0

33.7

 Age at menarche (years)

12.8

12.0

12.7

12.0

12.2

12.7

12.3

12.5

 Parity (among parous women)

2.1

2.0

2.1

2.0

2.0

2.0

2.1

2.1

 Duration of oral contraceptive use (months)

46.9

43.0

45.6

39.3

42.7

44.1

45.7

43.3

 Current body mass index (kg m−2)

22.1

27.6

21.4

31.3

24.3

23.9

24.1

24.5

Percentages

 Parous

69.9

62.5

70.8

56.7

70.2

64.8

68.0

67.3

 Premenopausal

99.0

98.6

99.0

98.3

98.7

99.1

98.7

98.8

 Family history of ovarian cancerd

1.5

1.9

1.5

1.8

1.5

1.6

1.8

1.5

 History of tubal ligation

16.5

16.1

15.1

14.9

17.3

13.6

17.1

14.5

  1. aAll factors except age were age-standardised in 5-year intervals for each cohort.
  2. bAverage childhood body fatness was calculated by taking the average of each participant's body fatness at ages 5 and 10 years, using a nine-level figure drawing.
  3. cBaseline for each analysis was the year when the body size measure was assessed (see Table 1).
  4. dMother or sister had ovarian cancer according to the participant's response on the questionnaire; family history was evaluated using data from 1992 for NHS and 1993 for NHSII because it was not available in previous cycles.
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