Table 1.
Distribution of baseline characteristics for cases and controls: the EpiGEICAM study.
| Characteristics | Total (N = 1578) | Controls (N = 799) | Cases (N = 779) | P valuea |
|---|---|---|---|---|
| Alcohol consumption, g/day, mean (±SD) | ||||
| Adolescence | 2.8 ± 5.7 | 2.4 (±4.0) | 3.3 (±7.0) | <0.01 |
| Young adulthood | 5.4 ± 8.4 | 4.8 (±6.6) | 6.1 (±9.9) | <0.01 |
| Adulthood | 6.8 ± 10.0 | 6.0 ± (8.3) | 7.6 (±11.4) | <0.01 |
| Age, years, mean (±SD) | 49 ± 9 | 49 (±9) | 49 (±9) | 0.87 |
| Body mass index, Kg/m2, mean (±SD) | 25.2 ± 4.6 | 25.1 (±4.4) | 25.3 (±4.7) | 0.42 |
| Postmenopausal, n (%) | 653 (41.4) | 352 (44.1) | 301 (38.6) | 0.03 |
| Educational level, n (%) | 0.05 | |||
| Primary school or less | 239 (15.2) | 116 (14.5) | 123 (15.8) | |
| Secondary school | 815 (51.7) | 395 (49.4) | 420 (53.9) | |
| University graduate or higher | 524 (33.2) | 288 (36.1) | 236 (30.3) | |
| Smoking status, n (%) | 0.35 | |||
| Never smoker | 568 (36.0) | 281 (35.2) | 287 (36.9) | |
| Ex-Smoker (≥6 months) | 465 (29.5) | 233 (29.2) | 231 (29.7) | |
| Smoker (or ex-smoker <than 6 months) | 545 (34.5) | 285 (35.6) | 260 (33.4) | |
| Physical activity, n (%) | 0.07 | |||
| Sedentary/lightly active | 541 (34.2) | 247 (31.0) | 292 (37.6) | |
| Moderately active | 598 (37.9) | 326 (40.8) | 273 (35.0) | |
| Active/very active | 439 (27.8) | 226 (28.2) | 214 (27.4) | |
| Calories, kcal/day, mean (±SD) | 1952 (±633) | 1906 (±632) | 2000 (±622) | <0.01 |
| Adherence to the Mediterranean dietary pattern, score 1–10, mean (±SD) | 5.9 (±1.4) | 6.0 (±1.4) | 5.8 ± (1.3) | 0.06 |
| Age at menarche, years, mean (±SD) | 12 (±1.5) | 12 (±1.5) | 12 (±1.5) | 0.11 |
| Age at first birth, years, mean (±SD) | 26 (±5.0) | 26 (±5.0) | 27 (±5.0) | 0.08 |
| Number of children, mean (±SD) | 1.6 (±1.2) | 1.6 (±1.2) | 1.5 (±1.1) | 0.22 |
| Chronic diseases, n (%) | 635 (40.2) | 341 (42.7) | 294 (37.7) | 0.05 |
| Previous benign breast problems, n (%) | 316 (20.0) | 152 (19.0) | 164 (21.1) | 0.31 |
| Family history of breast cancer, n (%) | 358 (22.7) | 153 (19.2) | 205 (26.3) | <0.01 |
| Hormone replacement therapy use, n (%) | 161 (10.2) | 77 (9.6) | 84 (10.8) | 0.43 |
Data correspond to observed values for age, number of children, menopausal status, chronic diseases, family history of breast cancer and alcohol consumption, and to imputed values for the remaining variables in the table.
Bold values indicate statistical significance p ≤ 0.05.
SD standard deviation
aP value resulting from Pearson Chi-Square test (categorical variables with no missing values), from Student’s t test (continuous variables with no missing values), and from logistic regression models (variables with imputed values).