| Characteristic | Mean difference (with 95% CI) in blood lead level (natural log units) | |||||
|---|---|---|---|---|---|---|
| Age of family home < 50 years | Age of family home ≥ 50 years | |||||
| Number† | Mean difference (95% CI) | P | Number† | Mean difference (95% CI) | P | |
| House‐related factors | ||||||
| Exterior: weatherboard (v other) | 8/150 | –0.05 (–0.36 to 0.27) | 0.77 | 45/72 | 0.24 (–0.01 to 0.49) | 0.06 |
| Flooring in child's bedroom: wall‐to‐wall carpet (v other) | 131/150 | –0.20 (–0.41 to 0.01) | 0.06 | 44/72 | –0.18 (–0.42 to 0.07) | 0.16 |
| Flooring in main living room: wall‐to‐wall carpet (v other) | 75/150 | –0.01 (–0.15 to 0.14) | 0.94 | 20/72 | 0.07 (–0.20 to 0.34) | 0.61 |
| Renovations in past two years | ||||||
| Major renovation (any room) | 20/208 | –0.16 (–0.36 to 0.04) | 0.11 | 20/95 | 0.22 (–0.04 to 0.48) | 0.10 |
| Any renovation of child's bedroom | 42/208 | –0.03 (–0.17 to 0.12) | 0.72 | 22/94 | 0.23 (–0.02 to 0.48) | 0.07 |
| Any renovation of living room | 48/209 | –0.14 (–0.28 to –0.00) | 0.046 | 24/95 | 0.18 (–0.07 to 0.42) | 0.15 |
| Any renovation of kitchen | 25/208 | –0.14 (–0.32 to 0.04) | 0.13 | 23/95 | 0.07 (–0.18 to 0.33) | 0.56 |
| Any renovation of parent bedroom | 26/208 | –0.10 (–0.27 to 0.08) | 0.26 | 20/95 | 0.07 (–0.19 to 0.34) | 0.58 |
| Any household pet at 4 years | 154/208 | 0.04 (–0.09 to 0.18) | 0.51 | 63/95 | 0.38 (0.17 to 0.60)‡ | < 0.001 |
| Child hand–mouth and hygiene behaviours | ||||||
| Eats or drinks things that are not food§ | 12/175 | –0.17 (–0.43 to 0.08) | 0.19 | 11/87 | 0.43 (0.12 to 0.75) | 0.007 |
| Chews on things that are not edible§ | 59/175 | 0.02 (–0.11 to 0.16) | 0.73 | 33/87 | 0.13 (–0.10 to 0.35) | 0.26 |
| Contact with sand most weeks | 95/199 | 0.02 (–0.10 to 0.14) | 0.69 | 47/90 | 0.33 (0.12 to 0.54) | 0.003 |
| Contact with soil most weeks | 118/201 | 0.11 (–0.01 to 0.23) | 0.07 | 57/91 | 0.23 (–0.00 to 0.45) | 0.05 |
| Bath or shower frequency (per category increase)¶ | N = 208 | 0.00 (–0.11 to 0.10) | 0.92 | N = 95 | –0.21 (–0.40 to –0.03) | 0.026 |
| Handwashing frequency (per category increase)** | N = 208 | 0.00 (–0.09 to 0.09) | 0.98 | N = 95 | –0.02 (–0.18 to 0.14) | 0.80 |
CI = confidence interval.
Total number of children: 307. As not all parents answered all questions, data are missing for some variables.
Number reporting factor/number for whom information for this category was available.
Similar effect size for cat (23 of 95 children: mean difference, 0.17 natural log units; 95% CI, –0.07 to 0.42 natural log units) and dog ownership (45 of 95 children: mean difference, 0.17 natural log units; 95% CI, –0.05 to 0.38 natural log units).
Sometimes or often true v not true.
Average of frequency categories reported at 2 and 4 years of age: hardly ever, once a week, several times a week but not every day, once a day, more than once a day.
Average of frequency categories reported at 2 and 4 years of age: not at all, 1–2 times, 3–4 times, 5 or more times per day.