TABLE 1.

Baseline characteristics of control and case subjects in the E3N-EPIC Study, France, 1995–1998

Characteristic	Controls (n = 702)	Cases (n = 363)	p value*
Mean age (years) at blood collection	56.8 (6.3)†	56.8 (6.3)	0.31
Mean body mass index at blood collection ‡	24.1 (3.6)	23.8 (3.7)	0.14
Mean adult height (cm)	160.4 (5.6)	161.1 (6.0)	0.05
Age (years) at menarche (%)
<12	19.1	19.1	0.97
12–13	53.1	52.7
≥14	27.7	28.2
Combined age at first birth and parity (%)
Nulliparous	12.8	16.0	0.03
First birth before age 30 years, 1–2 children	46.7	46.3
First birth before age 30 years, ≥3 children	30.6	24.0
First birth after age 30 years	9.8	13.8
Age (years) at menopause (%)
Premenopausal	24.6	23.1	0.43
≤45	7.6	8.3
46–54	61.1	59.8
>54	6.7	8.8
Ever use of menopausal hormones (%)	57.8	63.6	0.02
Years of education (%)
<12	11.4	11.1	0.05
12–14	46.6	48.3
15–16	22.9	16.5
≥17	19.1	24.2
History of benign breast disease (%)	31.8	41.1	0.002
Familial history of breast cancer (%)	14.4	21.2	0.007
Smoking status at blood collection (%)
Nonsmoker (never or former smoker)	93.5	92.3
Smoker	6.6	7.7	0.46

^*Baseline characteristics of cases and controls were compared using Student’s t test for continuous variables and the chi-squared test for categorical variables.

^†Numbers in parentheses, standard deviation.

^‡Weight (kg)/height (m)².