Prevalence of selected characteristics of the study population surveyed in 1998 and in 2001
| Variable | n* | Prevalence (%) |
|---|---|---|
| *Number of children (total of replies in each category). | ||
| †A total of 4400 children were selected for the survey in 1998. | ||
| Other covariates examined were preterm birth, breast feeding, father with asthma, gas cooking, presence of pets, number of cigarettes smoked by mother, overcrowding, single parenthood, and diet. | ||
| Age in 1998 survey (years)† | ||
| 1.0–1.99 | 1085 | 25 |
| 2.0–2.99 | 1099 | 25 |
| 3.0–3.99 | 1113 | 25 |
| 4.0–4.99 | 1102 | 25 |
| Boys | 2304 | 52 |
| Girls | 2095 | 48 |
| Mother has asthma | 554 (3203) | 17 |
| Coal heating in the home | ||
| 1998 | 203 (3410) | 6 |
| 2001 | 199 (2735) | 7 |
| Smoking by household member in the home | ||
| 1998 | 1144 (3382) | 34 |
| 2001 | 793 (2543) | 31 |
| Either parent continued education past 16 years of age | 1986 (3012) | 66 |