Table 3.

Characteristics of Mexican controls by socioeconomic status, 2004 to 2007

Socioeconomic statusP*
LowMediumHigh
European ancestry (%)<0.001
    0-2547.433.828.7
    26-5042.754.051.9
    51-759.911.317.5
    76-1000.00.91.8
Age (y)51.1 (10)51.5 (9)50.5 (8)0.391
BMI premenopausal women30.5 (6)30.4 (5)29.3 (5)0.111
BMI postmenopausal women30.6 (5)31.0 (5)30.5 (5)0.616
Age at menarche (y)12.9 (2)12.9 (2)12.7 (2)0.040
No. of full-term pregnancies3.5 (2)3.2 (2)2.6 (2)<0.001
Ever breast-fed (%)88.593.285.30.005
Family history of breast cancer (%)2.24.74.50.142
Benign breast disease (%)4.47.810.10.020
Postmenopausal HRT use (%)§9.915.315.40.222
Postmenopausal (%)53.660.251.10.047
Alcohol consumption (ever in past year/never; %)7.59.813.80.03
Education (%)<0.001
    None12.110.73.6
    Some elementary school36.228.813.9
    Completed elementary school28.830.928.4
    High school graduate20.723.732.3
    College graduate2.23.911.2
    Postgraduate studies0.02.110.6
Caloric intake (kcal/d)1773.9 (558)1909.6 (630)2034.0 (711)<0.001
  • *P values are for bivariate Fisher's exact tests in 2 × 2 tables (for categorical variables) and for ANOVA tests (for continuous variables).

  • Mean (SD).

  • Women who had at least one full-term pregnancy.

  • §Proportion of menopausal women that use hormone replacement therapy.