TABLE 2.
Rates and hazard ratios of incidence of Helicobacter pylori infection: univariate analysis
| Baseline characteristics | Cases/person-years at risk | Incidence rate | HR (95% CI)* | P |
|---|---|---|---|---|
| Age, y | ||||
| 5–8 | 40/609.6 | 6.56 | Ref | |
| 9–13 | 21/349.3 | 6.01 | 0.96 (0.54–1.70) | 0.882 |
| Sex | ||||
| Male | 25/386.1 | 6.47 | Ref | |
| Female | 36/572.8 | 6.28 | 0.97 (0.58–1.62) | 0.898 |
| Iron status | ||||
| Normal† | 45/836.2 | 5.38 | Ref | |
| Anemia‡ | 3/9.4 | 31.72 | 6.76 (1.63–28.01) | 0.008 |
| Iron deficiency without anemia§ | 12/108.6 | 11.05 | 2.07 (1.10–3.91) | 0.025 |
| Height for age|| | ||||
| Normal | 48/726.9 | 6.60 | Ref | |
| ≤−1 SD | 13/222.5 | 5.84 | 0.87 (0.48–1.60) | 0.662 |
| Body mass index¶ | ||||
| Normal | 47/691.8 | 6.79 | Ref | |
| Overweight or obese | 14/257.1 | 5.44 | 0.80 (0.44–1.43) | 0.447 |
| No. siblings | ||||
| 0 or 1 | 33/529.4 | 6.23 | Ref | |
| ≥2 | 27/426.7 | 6.33 | 1.01 (0.60–1.70) | 0.964 |
| Mother’s education level | ||||
| Middle school or more | 12/291.1 | 4.12 | Ref | |
| Secondary or less | 47/634.5 | 7.41 | 1.75 (0.92–3.34) | 0.090 |
| Crowding | ||||
| <3 people/room | 32/530.1 | 6.04 | Ref | |
| ≥3 people/room | 28/420.5 | 6.66 | 1.07 (0.64–1.79) | 0.793 |
CI = confidence interval; HR = hazard ratio; SD = standard deviation.
*
Crude hazard ratios obtained through proportional hazard regression with robust standard error.
†
Hemoglobin ≥11.5 g/dL in schoolchildren younger than 12 years or hemoglobin ≥ 12.0 g/dL in schoolchildren 12 years or older and ferritin ≥ 12 ng/mL.
‡
Hemoglobin <11.5 g/dL in schoolchildren younger than 12 years or hemoglobin <12.0 g/dL in schoolchildren 12 years or older.
§
Ferritin <12 ng/mL and hemoglobin ≥ 11.5 g/dL in schoolchildren younger than 12 years or hemoglobin ≥ 12.0 g/dL in schoolchildren 12 years or older.
||
Population of reference WHO 2007 (17).