Table 2.
Distribution of Covariates by Postnatal Cell Phone Exposure
| Postnatal Exposure (n=18,935) |
No Postnatal Exposurea (n=33,466) |
Unknown Exposureb (n=279) |
Total (n=52,680) |
||||||
|---|---|---|---|---|---|---|---|---|---|
| n | % | n | % | OR [95% CI] | n | % | n | % | |
| Prenatal cell phone use | |||||||||
| Yes | 9,781 | 51.7 | 10,690 | 31.9 | 2.40 [2.31–2.49] | 11 | 3.9 | 20,482 | 38.9 |
| Noa | 8,213 | 43.4 | 21,507 | 64.3 | 74 | 26.5 | 29,794 | 56.6 | |
| Prenatal smoking | |||||||||
| Yes | 5,380 | 28.4 | 7,047 | 21.1 | 1.51 [1.45–1.58] | 87 | 31.2 | 12,514 | 23.8 |
| Noa | 12,113 | 64.0 | 24,017 | 71.8 | 162 | 58.1 | 36,292 | 68.9 | |
| Prenatal alcohol use | |||||||||
| Yes | 6,254 | 33.0 | 11,386 | 34.0 | 0.97 [0.93–1.01] | 91 | 32.6 | 17,731 | 33.7 |
| Noa | 10,615 | 56.1 | 18,762 | 56.1 | 145 | 52.0 | 29,522 | 56.0 | |
| Fever during pregnancy | |||||||||
| Yes | 4,678 | 24.7 | 8,115 | 24.2 | 1.05 [1.01–1.09] | 73 | 26.2 | 12,866 | 24.4 |
| Noa | 12,352 | 65.2 | 22,477 | 67.2 | 167 | 59.9 | 34,996 | 66.4 | |
| Child ever had ear infection up to age 18 months |
|||||||||
| Yes | 6,082 | 32.1 | 10,767 | 32.2 | 1.05 [1.01–1.10] | 80 | 28.7 | 16,929 | 32.1 |
| Noa | 7,298 | 38.5 | 13,564 | 40.5 | 106 | 38.0 | 20,968 | 39.8 | |
| Child ever had inner ear inflammation up age 7 years |
|||||||||
| Yes | 11,889 | 62.8 | 20,177 | 60.3 | 1.11 [1.07–1.15] | 176 | 63.1 | 32,242 | 61.2 |
| Noa | 7,018 | 37.1 | 13,218 | 39.5 | 98 | 35.1 | 20,334 | 38.6 | |
| Social-occupational Status | |||||||||
| High | 11,782 | 62.2 | 22,891 | 68.4 | 0.56 [0.51–0.62] | 157 | 56.3 | 34,830 | 66.1 |
| Medium | 5,436 | 28.7 | 8,294 | 24.8 | 0.71 [0.64–0.79] | 85 | 30.5 | 13,815 | 26.2 |
| Lowa | 797 | 4.2 | 866 | 2.6 | 16 | 5.7 | 1,679 | 3.2 | |
| Mother's age at birth of child | |||||||||
| Older than 35 years | 2,235 | 11.8 | 4,614 | 13.8 | 0.52 [0.49–0.56] | 39 | 14.0 | 6,888 | 13.1 |
| 31 to 35 years | 6,198 | 32.7 | 12,478 | 37.3 | 0.54 [0.50–0.57] | 103 | 36.9 | 18,779 | 35.6 |
| 26 to 30 years | 7,865 | 41.5 | 13,527 | 40.4 | 0.63 [0.59–0.67] | 106 | 38.0 | 21,498 | 40.8 |
| 25 years or youngera | 2,637 | 13.9 | 2,847 | 8.5 | 31 | 11.1 | 5,515 | 10.5 | |
| Mean (SD) | 30.1 (4.4) | 30.9 (4.1) | 30.8 (4.6) | ||||||
| Gestational age at birth | |||||||||
| Post-term (>42 weeks) | 304 | 1.6 | 602 | 1.8 | 0.80 [0.67–0.94] | 3 | 1.1 | 909 | 1.7 |
| Normal (37–42 weeks) | 17,919 | 94.6 | 31,730 | 94.8 | 0.89 [0.81–0.98] | 264 | 94.6 | 49,913 | 94.7 |
| Pre-term (< 37 weeks)a | 667 | 3.5 | 1,051 | 3.1 | 10 | 3.6 | 1,728 | 3.3 | |
| Mean (SD) | 40.0 (1.8) | 40.0 (1.7) | 39.9 (2.0) | ||||||
| Sex of child | |||||||||
| Boy | 8,876 | 46.9 | 17,968 | 53.7 | 0.76 [0.73–0.79] | 144 | 51.6 | 26,988 | 51.2 |
| Girla | 10,059 | 53.1 | 15,498 | 46.3 | 135 | 48.4 | 25,692 | 48.8 | |
| Child was breast fed | |||||||||
| Yes | 11,091 | 58.6 | 21,379 | 63.9 | 0.82 [0.78–0.86] | 148 | 53.0 | 32,618 | 61.9 |
| Noa | 4,270 | 22.6 | 6,745 | 20.2 | 68 | 24.4 | 11,083 | 21.0 | |
Percentages do not sum to 100% due to missing responses
a
Reference
b
Unknown exposure refers to children whose mothers did not report their child’s cell phone exposure