Table 1.
Demographics and socioeconomic status. Values are numbers (percentages) unless stated otherwise
| Characteristics | Unmatched cohort | Matched cohort | |||||
|---|---|---|---|---|---|---|---|
| Unvaccinated (n=79 925) | Vaccinated (n=6246) | P value | Unvaccinated (n=23 987) | Vaccinated (n=6131) | P value | ||
| No of deliveries in 2009 in hospital: | |||||||
| <500 | 3425 (4.3) | 208 (3.3) | <0.001 | 815 (3.4) | 208 (3.4) | 0.77 | |
| 500-999 | 15 259 (19.1) | 965 (15.5) | 3872 (16.1) | 956 (15.6) | |||
| 1000-1499 | 18 328 (22.9) | 1217 (19.5) | 4736 (19.7) | 1213 (19.8) | |||
| ≥1500 | 42 913 (53.7) | 3856 (61.7) | 14 564 (60.7) | 3754 (61.2) | |||
| Mean (SD) age at delivery, years | 31.7 (5.3) | 32.6 (5.0) | <0.001 | 32.5 (5.0) | 32.6 (5.0) | 0.35 | |
| Age group at delivery: | |||||||
| <20 | 1059 (1.3) | 58 (0.9) | <0.001 | 205 (0.9) | 57 (0.9) | 0.84 | |
| 20-24 | 7385 (9.2) | 354 (5.7) | 1440 (6.0) | 352 (5.7) | |||
| 25-29 | 17 557 (22.0) | 1168 (18.7) | 4588 (19.1) | 1147 (18.7) | |||
| 30-34 | 28 091 (35.2) | 2331 (37.3) | 8829 (36.8) | 2298 (37.5) | |||
| 35-39 | 21 011 (26.3) | 1892 (30.3) | 7274 (30.3) | 1847 (30.1) | |||
| 40-44 | 4632 (5.8) | 422 (6.8) | 1588 (6.6) | 410 (6.7) | |||
| ≥45 | 190 (0.2) | 21 (0.3) | 63 (0.3) | 20 (0.3) | |||
| Italian nationality | 56 605 (70.8) | 4951 (79.3) | <0.001 | 18 996 (79.2) | 4853 (79.2) | 0.95 | |
| Education (mother and/or father): | |||||||
| University degree | 24 576 (30.8) | 2398 (38.4) | <0.001 | 8989 (37.5) | 2342 (38.2) | 0.49 | |
| Secondary school | 54 130 (67.7) | 3790 (60.7) | 14 836 (61.9) | 3744 (61.1) | |||
| Primary school/none | 939 (1.2) | 45 (0.7) | 162 (0.7) | 45 (0.7) | |||
| Mother’s occupational status: | |||||||
| Employed | 54 889 (68.7) | 4668 (74.7) | <0.001 | 18 058 (75.3) | 4592 (74.9) | 0.93 | |
| Unemployed/seeking first occupation | 3551 (4.4) | 245 (3.9) | 922 (3.8) | 241 (3.9) | |||
| Housewife | 20 520 (25.7) | 1269 (20.3) | 4816 (20.1) | 1250 (20.4) | |||
| Student/other | 773 (1.0) | 48 (0.8) | 191 (0.8) | 48 (0.8) | |||
| Mother’s civil status at delivery: | |||||||
| Single | 18 216 (22.8) | 1259 (20.2) | <0.001 | 4961 (20.7) | 1249 (20.4) | 0.94 | |
| Married | 57 555 (72.0) | 4668 (74.7) | 18 028 (75.2) | 4620 (75.4) | |||
| Separated/divorced/widowed | 2475 (3.1) | 200 (3.2) | 751 (3.1) | 198 (3.2) | |||
| Not declared | 936 (1.2) | 66 (1.1) | 247 (1.0) | 64 (1.0) | |||
| Father’s occupational status: | |||||||
| Employed | 74 167 (92.8) | 5847 (93.6) | <0.01 | 22 509 (93.8) | 5748 (93.8) | 0.28 | |
| Unemployed/seeking first occupation | 2142 (2.7) | 135 (2.2) | 492 (2.1) | 133 (2.2) | |||
| Student/other | 281 (0.4) | 14 (0.2) | 79 (0.3) | 13 (0.2) | |||
| Low income allowance | 1840 (2.3) | 154 (2.5) | 0.40 | 505 (2.1) | 149 (2.4) | 0.12 | |
| Consanguinity between mother and father (relationship of fourth, fifth, or sixth degree) | 888 (1.1) | 46 (0.7) | 0.006 | 270 (1.1) | 46 (0.8) | 0.01 | |