Demographic characteristics by study group
| Group 1 | Group 2 | Group 3 | p Value* | |
|---|---|---|---|---|
| N=175, mean (SD) or n (%) | n=180, mean (SD) or n (%) | n=151, mean (SD) or n (%) | ||
| Age at first spirometry | 5.3 (0.2) | 5.3 (0.2) | 5.4 (0.3) | <0.0001 |
| Baseline height (cm) | 97 (4.1) | 97 (4.2) | 98 (4.4) | 0.70 |
| Number of spirometry sessions per child | 3.8 (1.1) | 3.7 (1.1) | 3.2 (1.3) | <0.0001 |
| Gender | ||||
| Male | 85 (49) | 88 (49) | 72 (48) | 0.98 |
| Female | 90 (51) | 92 (51) | 79 (52) | |
| Maternal education | ||||
| None | 61 (35) | 69 (38) | 43 (28) | 0.28 |
| Elementary school | 107 (61) | 108 (60) | 106 (70) | |
| Middle school | 4 (2) | 1 (1) | 1 (1) | |
| High school | 3 (2) | 2 (1) | 1 (1) | |
| Paternal education | ||||
| None | 18 (11) | 24 (14) | 18 (12) | 0.73 |
| Elementary school | 126 (76) | 123 (71) | 107 (71) | |
| Middle school | 8 (5) | 6 (3) | 7 (5) | |
| High school | 14 (8) | 20 (12) | 149 (13) | |
| Unknown | 9 (5) | 7 (4) | 0 (0) | |
| Asset index (0–7) | 1.67 (1.0) | 1.72 (1.1) | 1.55 (1.0) | 0.36 |
| Smoker present in home | 13 (7) | 22 (12) | 14 (9) | 0.31 |
| Child use of temazcal | ||||
| Always | 142 (81) | 135 (75) | 114 (76) | 0.38 |
| Sometimes | 123 (13) | 31 (17) | 230 (20) | |
| Never | 10 (6) | 14 (8) | 7 (6) | |
*Comparing all three groups, using analysis of variance for continuous variables and χ2 tests for categorical variables.