White British |  | Age at VZV infection | Unadjusted OR (95% CI) | Unadjusted OR (95% CI) n = 378 | Adjusted OR (95% CI) n = 378 | ||
by 12 mths | 12–24 mths | uninfected at 24 mths | |||||
All children, n = 391 | 34 (9%) | 90 (23%) | 267 (68%) |  | |||
Birth order (391) | 1 | 9 (5%) | 27 (15%) | 148 (80%) | 1.0 | 1.0 | 1.0 |
2 | 19 (15%) | 47 (37%) | 62 (48%) | 4.22 (2.58–6.91) | 4.23 (2.56–6.97) | 4.83 (2.68–8.70) | |
3+ | 6 (8%) | 16 (20%) | 57 (72%) | 1.60 (0.87–2.93) | 1.55 (0.83–2.87) | 2.24 (0.92–5.49) | |
Total household members at 12 m (389) | median IQR, range | 4 3–4, 2–5 | 4 3–4, 2–8 | 4 3–4, 2–8 | 1.06 (0.87–1.28) | 1.06 (0.87–1.28) | 0.89 (0.66–1.20) |
No. of children (<16y) in household at 12 m (369) | median IQR, range | 2 1–2, 1–4 | 2 1–2, 1–6 | 1 1–2, 1–5 | 1.26 (1.00–1.58) |  | - |
Duration of breastfeeding (390) | never | 8 (8%) | 21 (21%) | 73 (72%) | 1.0 | 1.0 | 1.0 |
<=4 weeks | 4 (4%) | 21 (21%) | 74 (75%) | 0.82 (0.44–1.52) | 0.83 (0.44–1.56) | 0.88 (0.45–1.72) | |
1–6 months | 11 (12%) | 22 (23%) | 62 (65%) | 1.37 (0.76–2.49) | 1.45 (0.79–2.68) | 1.52 (0.78–2.95) | |
6–12 months | 8 (12%) | 20 (31%) | 37 (57%) | 1.87 (0.99–3.53) | 1.98 (1.04–3.79) | 2.05 (0.98–4.31) | |
>12 months | 3 (10%) | 6 (21%) | 20 (69%) | 1.16 (0.48–2.82) | 1.20 (0.49–2.94) | 0.99 (0.38–2.56) | |
Bedroom sharing in first year (389) | no | 21 (9%) | 50 (23%) | 149 (68%) | 1.0 | Â | - |
yes | 13 (8%) | 38 (22%) | 118 (70%) | 0.89 (0.58–1.37) |  | - | |
Bedroom sharing in second year (391) | No | 20 (8%) | 54 (22%) | 174 (70%) | 1.0 | 1.0 | 1.0 |
yes | 14 (10%) | 36 (25%) | 93 (65%) | 1.26 (0.82–1.94) | 1.25 (0.81–1.93) | 1.11 (0.66–1.85) | |
Bed sharing in second year (391) | No | 31 (8%) | 83 (23%) | 250 (69%) | 1.0 | Â | - |
yes | 3 (11%) | 7 (26%) | 17 (63%) | 1.30 (0.59–2.87) |  | - | |
Formal child care up to 12Â m visit (total hours) (381) | No childcare | 13 (8%) | 35 (22%) | 113 (70%) | 1.0 | 1.0 | 1.0 |
<1165 total hours | 2 (6%) | 9 (26%) | 23 (68%) | 1.08 (0.49–2.35) | 1.08 (0.49–2.36) | 0.94 (0.40–2.19) | |
> = 1165 total hours | 14 (15%) | 28 (29%) | 53 (56%) | 1.90 (0.13–3.18) | 1.90 (1.13–3.18) | 1.69 (0.92–3.11) | |
No formal (only informal) | 4 (4%) | 16 (18%) | 71 (78%) | 0.65 (0.36–1.18) | 0.65 (0.36–1.19) | 0.66 (0.34–1.26) | |
Mother and baby activities in first year (389) | Rarely | 16 (7%) | 44 (21%) | 149 (71%) | 1.0 | Â | - |
At least once a month | 18 (10%) | 44 (24%) | 118 (66%) | 1.31 (0.86–2.00) |  | - | |
Mother and baby activities in second year (389) | Rarely | 18 (11%) | 32 (20%) | 108 (68%) | 1.0 | 1.0 | 1.0 |
At least once a month | 16 (7%) | 57 (25%) | 158 (68%) | 0.94 (0.61–1.44) | 0.91 (0.59–1.41) | 0.75 (0.46–1.23) | |
Age 24 m blood sample taken (mths) (391) | 23.59–24.99 | 7 (8%) | 21 (25%) | 56 (67%) | 1.0 | 1.0 | 1.0 |
25–26.99 | 20 (9%) | 49 (21%) | 159 (70%) | 0.89 (0.52–1.50) | 0.87 (0.51–1.48) | 0.68 (0.38–1.21) | |
27–32.89 | 7 (9%) | 20 (25%) | 52 (66%) | 1.04 (0.55–1.97) | 1.01 (0.53–1.92) | 0.73 (0.37–1.47) | |
Pakistani |  | by 12 mths | 12–24 mths | uninfected at 24 mths | Unadjusted OR (95% CI) | Unadjusted OR (95% CI) n = 466 | Adjusted OR (95% CI) n = 466 |
All children, n = 472 | 46 (10%) | 65 (14%) | 361 (76%) |  | |||
Birth order (472) | 1 | 5 (4%) | 12 (10%) | 109 (87%) | 1.0 | 1.0 | 1.0 |
2 | 13 (12%) | 22 (21%) | 72 (67%) | 3.06 (1.61–5.83) | 3.07 (1.61–5.86) | 3.75 (1.89–7.43) | |
3+ | 28 (12%) | 31 (13%) | 180 (75%) | 2.17 (1.21–3.91) | 2.16 (1.20–3.89) | 3.05 (1.53–6.09) | |
Total household members at 12 m (468) | median IQR, range | 6 5–7, 4–13 | 5 4–7, 3–11 | 6 5–7, 2–15 | 0.99 (0.90–1.09) | 0.99 (0.90–1.09) | 0.98 (0.88–1.09) |
No. of children (<16y) in household at 12 m (456) | median IQR, range | 3 2–3, 1–5 | 3 2–4, 1–6 | 3 2–4, 1–8 | 1.06 (0.91–1.25) | - | - |
Duration of breastfeeding (468) | never | 12 (14%) | 11 (13%) | 61 (73%) | 1.0 | 1.0 | 1.0 |
<=4 weeks | 6 (7%) | 11 (12%) | 74 (81%) | 0.58 (0.29–1.18) | 0.59 (0.29–1.20) | 0.64 (0.31–1.35) | |
1–6 months | 11 (9%) | 15 (12%) | 95 (79%) | 0.70 (0.37–1.34) | 0.70 (0.37–1.34) | 0.86 (0.44–1.66) | |
6–12 months | 10 (9%) | 16 (16%) | 76 (75%) | 0.87 (0.45–1.65) | 0.88 (0.46–1.68) | 1.03 (0.52–2.02) | |
>12 months | 7 (10%) | 11 (16%) | 52 (74%) | 0.88 (0.43–1.79) | 0.88 (0.43–1.79) | 0.97 (0.47–2.02) | |
Bedroom sharing in first year (468) | no | 2 (6%) | 3 (10%) | 26 (84%) | 1.0 | - | - |
yes | 44 (10%) | 61 (14%) | 332 (76%) | 1.64 (0.62–4.37) |  | - | |
Bedroom sharing in second year (472) | no | 3 (13%) | 2 (8%) | 19 (79%) | 1.0 | 1.0 | 1.0 |
yes | 43 (10%) | 63 (14%) | 342 (76%) | 1.12 (0.41–3.05) | 1.12 (0.41–3.07) | 0.96 (0.33–2.79) | |
Bed sharing in second year (471) | No | 26 (10%) | 35 (13%) | 206 (77%) | 1.0 | Â | - |
yes | 20 (10%) | 30 (15%) | 154 (75%) | 1.09 (0.71–1.66) |  | - | |
Any regular child care arrangement up to 24Â m visit (472) | no | 40 (11%) | 54 (14%) | 286 (75%) | 1.0 | 1.0 | 1.0 |
yes | 6 (7%) | 11 (12%) | 75 (81%) | 0.68 (0.38–1.21) | 0.64 (0.36–1.16) | 0.78 (0.42–1.44) | |
Mother and baby activities in first year (468) | Rarely | 42 (10%) | 56 (14%) | 307 (76%) | 1.0 | Â | - |
At least once a month | 4 (6%) | 8 (13%) | 51 (81%) | 0.72 (0.37–1.40) |  | - | |
Mother and baby activities in second year (472) | Rarely | 23 (9%) | 30 (12%) | 200 (79%) | 1.0 | 1.0 | 1.0 |
At least once a month | 23 (10%) | 35 (16%) | 161 (74%) | 1.34 (0.88–2.04) | 1.37 (0.90–2.10) | 1.43 (0.92–2.21) | |
Maternal age at recruitment (472) | Mean, SD, range | 28.0, 4.48 19–39 | 28.8, 5.23 19–41 | 28.9, 5.38 17–44 | 0.98 (0.95–1.02) | 0.98 (0.94–1.02) | 0.95 (0.90–0.99) |
Age 24 m blood sample taken (mths) (472) | 23.59–24.99 | 7 (8%) | 12 (13%) | 72 (79%) | 1.0 | 1.0 | 1.0 |
25–26.99 | 20 (8%) | 35 (15%) | 185 (77%) | 1.12 (0.63–2.01) | 1.08 (0.60–1.94) | 1.13 (0.62–2.08) | |
27–32.89 | 19 (13%) | 18 (13%) | 104 (74%) | 1.41 (0.75–2.63) | 1.39 (0.75–2.61) | 1.42 (0.74–2.73) |