Table 1

Comparison of demographics and selected breast cancer risk factors of cases and controls, The Shanghai Breast Cancer Study, 1996–1998

Subjects with missing values were excluded from the analysis.
Casesa (n = 1459)Controlsa (n = 1556) P
Age (yrs)47.8 ± 8.047.2 ± 8.80.03
Education (%)
 No formaleducation3.65.5
 Elementary school8.58.4
 Middle + high school74.375.4
 Professional education, college and above13.610.70.01
Per capita income (Yuan) (%)
 <400019.818.2
 4000–599931.731.9
 6000–799913.013.9
 8000–899920.223.5
 ≥900015.212.40.05
Breast cancer in first-degree relatives (%)3.72.40.05
Ever had breast fibroadenoma (%)9.65.0<0.01
Regular alcohol drinker (%)4.04.10.99
Ever used oral contraceptives (%)21.920.90.51
Ever used hormone replacement therapy (%)2.92.70.76
Exercised regularly (%)18.825.2<0.01
Body mass index23.5 ± 3.423.1 ± 3.4<0.01
WHR0.81 ± 0.060.80 ± 0.06<0.01
Nulliparous (%)5.13.90.13
No. of live birthsb1.5 ± 0.851.5 ± 0.860.54
Age at first live birthb (yrs)26.8 ± 4.226.2 ± 3.9<0.01
Months of breastfeedingc15.1 ± 13.115.9 ± 14.00.81
Menarcheal age (yrs)14.5 ± 1.614.7 ± 1.7<0.01
Menopausal aged (yrs)48.1 ± 4.647.5 ± 4.90.02
Height (cm)158.9 ± 5.10158.5 ± 5.370.07
Adult usual energy intake (kcal/day)1865.9 ± 464.21839.9 ± 464.20.12
Adult usual fat intake (grams/day)36.3 ± 17.435.3 ± 16.20.08
  • a Unless otherwise specified, mean ± SD are presented.

  • b Among women who had live births.

  • c Among women who ever breastfed their children.

  • d Among menopausal women.