Table 2. Potential risk factors for Mycobacterium tuberculosis infection (MTI) among 1797 Greenlandic schoolchildren, 2005–2007.
| Risk factor | Children |
Age- and sex-adjusted |
P | Fully adjusteda |
P | ||||
|---|---|---|---|---|---|---|---|---|---|
| Without MTI | With MTI | OR | 95% CI | OR | 95% CI | ||||
| Sex | 1797 | 152 | 0.83 | 0.93 | |||||
| Female | 903 | 77 | 0.96 | 0.69–1.35 | – | 1.02 | 0.72–1.42 | – | |
| Maleb | 894 | 75 | 1 | – | – | 1 | – | – | |
| Age (years) | 1797 | 152 | – | – | 0.002 | – | – | 0.01 | |
| 5–7b | 282 | 19 | 1 | – | – | 1 | Reference | – | |
| 8–10 | 500 | 30 | 1.01 | 0.57–1.78 | – | 1.03 | 0.59–1.77 | – | |
| 11–13 | 596 | 49 | 1.42 | 0.81–2.48 | – | 1.36 | 0.80–2.32 | – | |
| 14–15 | 296 | 36 | 2.19 | 1.24–3.87 | – | 2.19 | 1.26–3.82 | – | |
| ≥ 16 | 123 | 18 | 2.52 | 1.23–5.16 | – | 1.89 | 0.94–3.80 | – | |
| OR per additional year of age | – | – | 1.12 | 1.05–1.19 | 0.0003 | 1.10 | 1.04–1.17 | 0.002 | |
| Ethnicity | 1797 | 152 | – | – | 0.007 | – | – | 0.005 | |
| Inuit | 1593 | 148 | 3.88 | 1.44–10.5 | – | 4.22 | 1.55–11.5 | – | |
| Non-Inuitb | 204 | 4 | 1 | – | – | 1 | – | – | |
| Mother’s age (years) at birth of study child | 1797 | 152 | – | – | 0.009 | – | – | 0.14 | |
| 15–19 | 228 | 29 | 1.73 | 1.14–2.61 | – | 1.44 | 0.88–2.34 | – | |
| ≥ 20b | 1569 | 123 | 1 | – | – | 1 | – | – | |
| Type of residence | 1662 | 136 | – | – | 0.17 | – | – | 0.37 | |
| Familyb | 1513 | 111 | 1 | – | – | 1 | – | – | |
| Orphanage, dorm | 102 | 18 | 1.63 | 0.87–3.03 | – | 1.40 | 0.75–2.63 | – | |
| Foster family | 47 | 7 | 1.76 | 0.77–4.00 | – | 1.58 | 0.68–3.70 | – | |
| No. of adults in household (CF 1) | 1608 | 128 | – | – | 0.28 | – | – | 0.43 | |
| 1–2b | 1273 | 104 | 1 | – | – | 1 | – | – | |
| 3+ | 335 | 24 | 0.72 | 0.45–1.26 | – | 0.82 | 0.50–1.34 | – | |
| Average no. of people per room (CF 2) | 1408 | 100 | – | – | 0.08 | – | – | 0.10 | |
| < 1 | 268 | 14 | 0.71 | 0.36–1.41 | – | 0.84 | 0.42–1.69 | – | |
| 1–1.49b | 610 | 39 | 1 | – | – | 1 | – | ||
| ≥ 1.50 | 530 | 47 | 1.44 | 0.91–2.27 | – | 1.57 | 0.95–2.58 | – | |
| Study child in own room (CF 3) | 1653 | 137 | – | – | 0.23 | – | – | 0.15 | |
| Yesb | 894 | 72 | 1 | – | – | 1 | – | – | |
| No | 759 | 65 | 1.28 | 0.72–1.48 | 1.33 | 0.90–1.97 | |||
| Sum of CFsc | 1797 | 152 | – | – | 0.74 | – | – | 0.76 | |
| 0 CFb | 734 | 61 | 1 | – | – | 1 | – | – | |
| 1 CF | 587 | 54 | 1.23 | 0.83–1.83 | – | 1.21 | 0.81–1.81 | – | |
| 2 CFs | 391 | 29 | 1.04 | 0.62–1.74 | – | 1.11 | 0.67–1.86 | – | |
| 3 CFs | 85 | 8 | 1.25 | 0.53–2.93 | – | 1.33 | 0.61–2.90 | – | |
| OR per additional CF | – | – | 1.05 | 0.86–1.28 | 0.63 | 1.08 | 0.89–1.31 | 0.44 | |
| Age difference (years) with next older siblingd | 1235 | 95 | – | – | 0.03 | – | – | 0.03 | |
| < 1 (including twin) | 61 | 12 | 2.04 | 1.00–4.16 | – | 2.08 | 1.07–4.04 | – | |
| 1b | 287 | 25 | 1 | – | – | 1 | – | – | |
| 2 | 218 | 10 | 0.50 | 0.25–1.01 | – | 0.50 | 0.24–1.04 | – | |
| ≥ 3 | 669 | 48 | 0.83 | 0.52–1.30 | – | 0.88 | 0.56–1.40 | – | |
| Mother’s education | 1104 | 75 | – | – | 0.33 | – | – | 0.31 | |
| 8th grade and no further schooling | 117 | 12 | 1.26 | 0.53–3.00 | – | 1.61 | 0.69–3.78 | – | |
| 8th grade and skilled labour | 243 | 18 | 1.09 | 0.56–2.10 | – | 1.04 | 0.53–2.02 | – | |
| 10th grade and skilled labourb | 492 | 35 | 1 | – | – | 1 | – | – | |
| 10th grade, 3 years vocational training & courses and bachelor’s degreee | 6 | 1 | 2.80 | 0.40–19.5 | – | 1.84 | 0.18–18.7 | – | |
| High school and skilled labour | 154 | 5 | 0.43 | 0.17–1.08 | – | 0.41 | 0.15–1.11 | – | |
| High school and bachelor’s/master’s degree | 92 | 4 | 0.65 | 0.22–1.90 | – | 0.71 | 0.24–2.09 | – | |
| OR per additional level of maternal education | – | – | 0.83 | 0.6–1.03 | 0.09 | 0.80 | 0.64–1.01 | 0.06 | |
| Region | 1797 | 152 | – | – | < 0.0001 | – | – | < 0.0001 | |
| Eastb | 367 | 28 | 1 | – | – | 1 | – | – | |
| South | 1100 | 118 | 1.44 | 0.90–2.32 | – | 1.51 | 0.94–2.42 | – | |
| West | 420 | 6 | 0.18 | 0.07–0.44 | – | 0.20 | 0.08–0.48 | – | |
| BMI (kg/cm2)f | 1777 | 148 | – | – | 0.63 | 0.49 | |||
| Underweight | 16 | 1 | 1.13 | 0.24–5.33 | – | 1.83 | 0.31–10.7 | – | |
| Normalb | 1398 | 111 | 1 | – | – | 1 | – | – | |
| Overweight | 295 | 25 | 0.97 | 0.61–1.53 | – | 0.95 | 0.60–1.50 | – | |
| Obese | 68 | 11 | 1.58 | 0.77–3.22 | – | 1.69 | 0.78–3.65 | – | |
| Obese (measured by BMI)g | 1777 | 148 | – | – | 0.20 | – | – | 0.16 | |
| Nob | 1709 | 137 | 1 | – | – | 1 | – | – | |
| Yes | 68 | 11 | 1.59 | 0.79–3.21 | – | 1.71 | 0.80–3.66 | – | |
BMI, body mass index; CF, crowding factor; CI, confidence interval; OR, odds ratio.
a Adjusted for sex, age, ethnicity, mother’s age, region and difference in age between study child and next older sibling.
b Reference category.
c The sum of the CFs was obtained by adding the three CFs given in the table, as follows: CF 1 was added when 3 or more adults lived in the household; CF 2, when the average number of people per room was at least 1.5; and CF 3, when the study child did not have their own room.
d Subanalysis for < 1 year difference versus ≥ 1 year difference between the age of the study child and that of the next older sibling: OR = 2.48 (95% CI: 1.33–4.63).
e Instead of qualifying for entrance to a bachelor’s programme through three years of upper secondary school, children in Denmark and Greenland can qualify for entrance by completing three years of certified vocationally oriented training and courses.
f BMI categories were defined according to age- and sex-specific percentiles evaluated by Centers for Disease Control and Prevention BMI-for-age growth charts for girls and boys. Definitions were as follows: underweight, < 5th percentile; normal weight, 5th percentile to < 85th percentile; overweight, 85th percentile to < 95th percentile; obese, ≥ 95th percentile.
g Obesity was defined as in previous footnote; underweight, normal weight and overweight were combined into a single category.