Differences in sociodemographic characteristics between cases and controls
| Cases(n = 133), n (%) | Controls(n = 266), n (%) | p Value | |
|---|---|---|---|
| NA, not applicable; RMB, RenMinBi. | |||
| Age group (years) | NA | ||
| 1–4 | 64 (48.1) | 128 (48.1) | |
| 5–9 | 40 (30.1) | 80 (30.1) | |
| 10–14 | 29 (21.8) | 58 (21.8) | |
| Sex | N/A | ||
| Male | 80 (60.2) | 160 (60.2) | |
| Female | 53 (39.8) | 106 (39.8) | |
| Does the child attend school / kindergarten? | 0.076 | ||
| Yes | 72 (54.1) | 119 (44.7) | |
| No | 61 (45.9) | 147 (55.3) | |
| Did the child have severe disease (eg, high blood pressure) | 0.036 | ||
| Yes | 3 (2.3) | 0 (0) | |
| No | 130 (97.7) | 266 (100) | |
| Father’s occupation | 0.847 | ||
| Farmer | 121 (91.0) | 243 (91.4) | |
| White-collar worker | 7 (5.3) | 14 (5.3) | |
| Other | 5 (3.8) | 9 (3.4) | |
| Father’s education level | 0.927 | ||
| Senior high school or above | 12 (9.0) | 27 (10.2) | |
| Junior high school | 38 (28.6) | 77 (28.9) | |
| Primary school or lower | 83 (62.4) | 162 (60.9) | |
| Mother’s education level | 0.496 | ||
| Senior high school or above | 9 (6.8) | 21 (7.9) | |
| Junior high school | 33 (24.8) | 79 (29.7) | |
| Primary school or lower | 91 (68.4) | 166 (62.4) | |
| Annual household income (RMB) | 0.650 | ||
| ⩽3000 | 71 (53.4) | 129 (48.5) | |
| 3001–5000 | 39 (29.3) | 85 (32.0) | |
| >5000 | 23 (17.3) | 52 (19.5) | |