Table 1.
General characteristics of the study sample.
| Characteristics | (n) | Cases | (n) | Controls | P-value |
|---|---|---|---|---|---|
| Child | |||||
| Sex, girls % | (57) | 52.29 | (100) | 39.68 | 0.026 |
| Age, months [mean ± SD] | (109) | 15.46 ± 7.30 | (252) | 18.48 ± 9.63 | 0.004 |
| Birth weight, grams [mean ± SD] | (109) | 3,144.78 ± 400.69 | (252) | 2,938.07 ± 610.89 | 0.001 |
| Breastfeeding, yes % | (96) | 88.07 | (226) | 89.68 | 0.651 |
| Breastfeeding, months [p50(p10,p90)] | (109) | 6.00 (0.00,15.00) | (252) | 7.00 (0.00,18.00) | 0.242 |
| Mother | |||||
| Age at pregnancy, years [mean ± SD] | (109) | 25.94 ± 6.41 | (252) | 25.58 ± 6.33 | 0.615 |
| Education, years [p50 (p10,p90)] | (109) | 9.00 (6.00,15.00) | (252) | 10.00 (7.00,13.60) | 0.833 |
| Smoking before pregnancy, yes % | (31) | 28.44 | (77) | 30.56 | 0.687 |
| Smoking during pregnancy, yes % | (4) | 3.67 | (7) | 2.78 | 0.740 |
| Alcohol consumption during pregnancy, yes % | (4) | 3.67 | (31) | 12.30 | 0.011 |
| Iron supplement during pregnancy, yes % | (76) | 69.72 | (216) | 85.71 | 0.000 |
| Vitamins supplement during pregnancy, yes % | (98) | 89.91 | (238) | 94.44 | 0.119 |
| Drug use for genital infection, yes % | (15) | 13.76 | (34) | 13.49 | 0.945 |
| Father | |||||
| Age at pregnancy, years [mean ± SD] | (105) | 28.79 ± 7.87 | (250) | 28.85 ± 7.39 | 0.944 |
| Education, years [p50 (p10,p90)] | (104) | 10.50 (6.00,15.00) | (245) | 9.00 (6.00,14.00) | 0.226 |
| Smoking before pregnancy, yes % | (48) | 47.06 | (141) | 58.02 | 0.062 |
| Alcohol consumption before pregnancy, yes % | (88) | 85.44 | (222) | 90.61 | 0.158 |
| Family | |||||
| State of residence, % | |||||
| Mexico City | (42) | 38.53 | (132) | 52.38 | 0.016 |
| State of Mexico | (67) | 61.47 | (120) | 47.62 | |
| Health institution, % | |||||
| Ministry of health* | (62) | 56.88 | (164) | 65.08 | 0.139 |
| Mexican Institute of Social Security | (47) | 43.12 | (88) | 34.92 | |
| Person/room ratio, [p50(p10,p90)] | (109) | 2.50 (1.50,5.00) | (252) | 3.00 (1.67,6.00) | 0.047 |
*Includes Secretary of Health, Secretary of Health of Mexico City, State of Mexico Institute of Health (ISEM, by its acronym in Spanish), Institute of Security and Social Services for State Workers (ISSSTE, by its acronym in Spanish). Shadowed numbers correspond to case-control differences within the variable with a p value <0.05.