Table 1.
Characteristics of study subjects and their risk of developing of IPD
| Characteristics | Cases (n = 35) | Controls (n = 70) | OR (95% CI) | P value |
|---|---|---|---|---|
| Gender (n = 105), n (%), male | 20 (57) | 40 (57) | 1·00 (0·44–2·27) | 1·00 |
| Age, years (n = 105) | ||||
| Mean (s.d.) | 4·34 (4·98) | 4·31 (5·00) | 1·47 (0·35–6·16) | 0·63 |
| Median (IQR) | 2·39 (1·16–5·10) | 2·31 (0·91–5·23) | ||
| Ethnicity (n = 91), n (%) | ||||
| Caucasians | 26 (79) | 51 (88) | Referent | 0·57 |
| Non-Caucasians | 7 (21) | 7 (12) | 1·38 (0·46–4·17) | |
| Maternal education, years (n = 45) | ||||
| Mean (s.d.) | 13·30 (1·89) | 14·49 (2·06) | 0·77 (0·50–1·19) | 0·24 |
| Median (IQR) | 12 (12–14) | 14 (12–16) | ||
| High risk conditions prior to index date (n = 105), n (%) | 9 (26) | 2 (3) | 9·00 (1·95–41·65) | 0·005 |
| Parental cigarette smoking at home (n = 52), n (%) | 4 (29) | 12 (32) | 1·30 (0·32–5·28) | 0·72 |
| Pneumococcal vaccination prior to index date (n = 105), n (%) | ||||
| PCV7 | 7 (20) | 13 (19) | — | — |
| PPV23 | 2 (6) | 0 | ||
| Both | 1 (3) | 0 | ||
| Neither | 25 (71) | 57 (81) | ||
| Pneumococcal vaccinations prior to index date (n = 105), n (%)* | ||||
| PCV7 or PPV23 | 10 (28·57) | 13 (18·57) | Referent | 0·094 |
| Neither | 25 (71·43) | 57 (81·43) | 6·43 (0·73–56·71) | |
| Housing characteristics | ||||
| HOUSES index in z score (n = 97) | ||||
| Mean (s.d.) | −0·20 (1·16) | 0·26 (0·14) | 0·22 (0·05–0·89) | 0·034 |
| Median (IQR) | 0·30 (−0·04 to 0·33) | 0·32 (0·24–0·34) | ||
| Range | −5·25 to 0·39 | −0·40 to 0·40 | ||
| HOUSES index in tertile, (n = 97), n (%)† | ||||
| HOUSES group1 (lowest SES) | 15 (47) | 18 (28) | Referent | |
| HOUSES group2 (middle SES) | 9 (28) | 23 (35) | 0·47 (0·17–1·32) | 0·151 |
| HOUSES group3 (highest SES) | 8 (25) | 24 (37) | 0·40 (0·14–1·14) | 0·088 |
| Household income in census tract in 1999 (n = 98) (US$1000) | ||||
| Mean (s.d.) | 53 523 (21 357) | 55 550 (17 460) | 0·99 (0·97–1·02) | 0·52 |
| Median (IQR) | 51 094 (37 446–62 250) | 55 483 (40 278–63 583) | ||
| Air conditioning using central air circulation (n = 99), n (%) | ||||
| Yes | 14 (42·42) | 41 (62·12) | 0·39 (0·15–0·97) | |
| No | 19 (57·58) | 25 (37·88) | Referent | 0·042 |
| Heating using central air circulation (n = 99), n (%) | ||||
| Yes | 17 (51·52) | 49 (74·24) | 0·39 (0·16–0·95) | |
| No | 16 (48·48) | 17 (25·76) | Referent | 0·038 |
| Number of rooms per child (n = 72) | ||||
| Mean (s.d.) | 2·35 (0·95) | 2·43 (1·06) | 0·78 (0·42–1·46) | 0·44 |
| Median (IQR) | 2 (1·58–3·16) | 2·5 (1·58–3·16) | ||
| Amount of square feet per child (n = 72) | ||||
| Mean (s.d.) | 12 866 (30 388) | 4415 (8270) | ||
| Median (IQR) | 2724 (1542–5444) | 2648 (1676–3629) | 1·00 (0·99–1·00) | 0·15 |
IPD, Invasive pneumococcal disease; OR, odds ratio; CI, confidence interval; IQR, interquartile range; SES, socioeconomic status.
Parameter estimates were based on matched analysis.
*
Parameter estimate for children who had received any pneumococcal vaccinations (PCV7, PPV23, or both PCV7 and PPV23) using children who had never received pneumococcal vaccinations.
†
Parameter estimates based on unmatched logistic regression.