TABLE 1.
Characteristics of study population and comparisons of FeNO levels
| Variable | N (%) # | Mean of FeNO (S.D.) ¶ | P-Value + |
|---|---|---|---|
| Sex | |||
| Girls | 1146 (51.16) | 11.02 (6.61) | 0.53 |
| Boys | 1094 (48.84) | 11.25 (7.08) | |
| Age (yrs) | |||
| <8 | 703 (31.38) | 10.8 (6.59) | 0.005 |
| 8–9 | 1102 (49.20) | 11.02 (6.5) | |
| >9 | 435 (19.42) | 12.18 (8.28) | |
| Race/Ethnicity | |||
| Non-Hispanic White | 828 (37.01) | 10.28 (5.96) | <0.0001 |
| Hispanic | 1247 (55.74) | 11.59 (7.07) | |
| African American | 61 (2.73) | 11.82 (8.28) | |
| Asian | 86 (3.84) | 14.15 (11.04) | |
| Other | 15 (0.67) | 10.8 (3.89) | |
| Asthma | |||
| Yes | 169 (7.54) | 13.87 (10.41) | <0.0001 |
| No | 2071 (92.46) | 10.91 (6.55) | |
| History of respiratory allergy | |||
| Yes | 1167 (52.10) | 11.94 (8) | <0.0001 |
| No | 1073 (47.90) | 10.38 (5.61) | |
| Questionnaire Language | |||
| Spanish | 531 (23.71) | 12.3 (7.51) | <0.0001 |
| English | 1709 (76.29) | 10.8 (6.59) | |
| Body mass index | |||
| Underweight (<5th percentile) | 49 (2.19) | 10.8 (5.62) | 0.85 |
| Normal (5th to <85th percentile) | 1368 (61.29) | 11.25 (6.97) | |
| Overweight (85th to <95th percentile) | 395 (17.70) | 11.13 (7.13) | |
| Obese (>95th percentile) | 420 (18.82) | 10.91 (6.44) | |
| FeNO collected outside classroom | |||
| Yes | 111 (4.96) | 14.88 (9.82) | <0.0001 |
| No | 2129 (95.04) | 11.02 (6.72) | |
| Parental Education | |||
| Less than High School | 424 (20.06) | 12.55 (7.78) | <0.0001 |
| High School | 390 (18.45) | 11.13 (7.24) | |
| Above High School | 1300 (61.49) | 10.8 (6.48) | |
| Exposure to secondhand smoke | |||
| Yes | 102 (4.55) | 12.06 (7.84) | 0.20 |
| No | 2123 (94.78) | 11.13 (6.79) | |
| In utero exposure to maternal smoking | |||
| Yes | 130 (6.11) | 10.28 (6.06) | 0.11 |
| No | 1998 (93.89) | 11.25 (6.97) | |
#
Numbers do not always add up because of missing data.
¶
Geometric mean and standard deviation obtained from a univariate model testing equality of group means.
+
Tests for the equality of group means (did not include missing category).