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Table 3 Associations between internal living environment and hospital admission for an acute respiratory infection during the first five years of life

From: Internal living environment and respiratory disease in children: findings from the Growing Up in New Zealand longitudinal child cohort study

Variable Incidence per 1000 person-years Crude HR (95% CI) Adjusted HR1a (95% CI) Adjusted HR2b (95% CI) Adjusted HR3 (95% CI)
Housing tenure
Owner occupancy 27.73 (25.19-30.46) 1.00 1.00 1.00 1.00
Tenancy 39.11 (36.00-42.43) 1.41 (1.22-1.63) 1.02 (0.88-1.18) 1.02 (0.88-1.18) 1.00 (0.87-1.16)c
Crowding index
<1-2 (low and medium) 29.19 (27.06-31.44) 1.00 1.00 1.00 1.00
2+ (high) 47.68 (42.61-53.19) 1.63 (1.42-1.88) 1.11 (0.95-1.29) 1.07 (0.91-1.25) 1.07 (0.91-1.26)c
Maternal cigarette smoking
Yes 55.23 (48.47-62.66) 1.87 (1.60-2.18) 1.14 (0.90-1.45) 1.06 (0.83-1.36) 1.10 (0.84-1.44)c
No 29.61 (27.57-31.77) 1.00 1.00 1.00 1.00
Cigarette smoking by others in the household
Yes 44.58 (40.36-49.11) 1.57 (1.37-1.80) 0.99 (0.85-1.16) 0.97 (0.83-1.14) 0.94 (0.79-1.11)c
No 28.40 (26.19-30.75) 1.00 1.00 1.00 1.00
Heating the house
Yes 31.41 (29.34-33.58) 0.65 (0.54-0.78) 0.99 (0.82-1.19) 0.87 (0.72-1.06) 0.87 (0.72-1.05)c
No 48.58 (41.35-56.71) 1.00 1.00 1.00 1.00
Form/s of heating used in the housed (N = 5298)
Electric heater
Yes 28.97 (26.87-31.19) 0.56 (0.47-0.68) 0.70 (0.58-0.83) 0.74 (0.61-0.89) 0.74 (0.61-0.89)e
No 51.33 (43.52-60.15) 1.00 1.00 1.00 1.00
Flued gas heater
Yes 31.95 (26.55-38.12) 1.02 (0.83-1.25) 1.12 (0.92-1.37) 1.07 (0.88-1.31) 1.08 (0.89-1.32)e
No 31.32 (29.09-33.67) 1.00 1.00 1.00 1.00
Unflued portable gas heater
Yes 31.91 (26.15-38.55) 1.02 (0.82-1.27) 0.89 (0.73-1.10) 0.92 (0.75-1.13) 0.90 (0.73-1.11)e
No 31.34 (29.13-33.66) 1.00 1.00 1.00 1.00
Wood burner
Yes 26.70 (23.13-30.67) 0.80 (0.68-0.95) 0.79 (0.67-0.94) 0.78 (0.66-0.93) 0.79 (0.66-0.93)e
No 33.19 (30.70-35.83) 1.00 1.00 1.00 1.00
Form/s of heating used in the room where child sleeps at nightd (N = 5298)
No heating
Yes 32.33 (26.89-38.56) 1.03 (0.84-1.27) 0.76 (0.63-0.93) 0.82 (0.67-0.99) 0.82 (0.67-1.00)e
No 31.26 (29.03-33.60) 1.00 1.00 1.00 1.00
Electric heater
Yes 29.27 (27.04-31.64) 0.74 (0.62-0.87) 0.95 (0.81-1.12) 0.94 (0.80-1.11) 0.94 (0.80-1.10)e
No 39.74 (34.68-45.33) 1.00 1.00 1.00 1.00
Flued gas heater
Yes 60.79 (43.81-82.17) 1.98 (1.42-2.77) 1.96 (1.43-2.68) 1.69 (1.21-2.36) 1.69 (1.21-2.36)e
No 30.64 (28.58-32.82) 1.00 1.00 1.00 1.00
Unflued portable gas heater
Yes 70.04 (45.75-102.63) 2.27 (1.49-3.45) 1.78 (1.20-2.64) 1.68 (1.12-2.36) 1.68 (1.12-2.53)e
No 30.87 (28.81-33.05) 1.00 1.00 1.00 1.00
Wood burner
Yes 32.08 (22.81-43.86) 1.02 (0.72-1.44) 0.93 (0.67-1.29) 1.01 (0.73-1.41) 1.02 (0.73-1.42)e
No 31.38 (29.26-33.60) 1.00 1.00 1.00 1.00
Dampness of the house
Never or hardly ever 27.86 (25.15-30.77) 1.00 1.00 1.00 1.00
Not very often 30.79 (27.09-34.85) 1.07 (0.92-1.25) 0.93 (0.79-1.08) 0.95 (0.82-1.11) 0.96 (0.83-1.13)c
Quite often 38.62 (32.71-45.29) 1.47 (1.23-1.75) 1.13 (0.95-1.34) 1.08 (0.91-1.29) 1.13 (0.94-1.36)c
Always or almost always 51.30 (39.81-65.07) 1.81 (1.43-2.30) 1.13 (0.89-1.43) 1.07 (0.84-1.37) 1.15 (0.89-1.50)c
Heavy condensation in the room where child sleeps at night
Never or hardly ever 29.90 (27.12-32.89) 1.00 1.00 1.00 1.00
Not very often 29.61 (25.84-33.76) 1.05 (0.90-1.23) 0.95 (0.81-1.11) 1.00 (0.86-1.17) 1.01 (0.86-1.17)f
Quite often 35.63 (30.12-41.87) 1.29 (1.08-1.54) 1.08 (0.90-1.28) 1.02 (0.86-1.22) 1.05 (0.88-1.27)f
Always or almost always 43.04 (33.15-54.95) 1.47 (1.15-1.86) 0.97 (0.76-1.23) 0.94 (0.74-1.20) 1.00 (0.77-1.31)f
Mould or mildew in the walls or ceilings in the room where child sleeps at night in the past two weeks
Yes 33.88 (27.66-41.08) 1.24 (1.03-1.49) 0.92 (0.77-1.10) 0.88 (0.73-1.41) 0.81 (0.67-0.99)c
No 31.10 (28.92-33.40) 1.00 1.00 1.00 1.00
  1. aAdjusted for all maternal factors (age, ethnicity, education, area of residence, neighbourhood deprivation, pre-pregnancy BMI, pre-pregnancy self-rated health, history of asthma, use of supplements, maternal smoking, parity and pregnancy planning)
  2. bAdjusted for all maternal factors as above and all child factors (gender, gestation, birth-weight, season of birth, proxy-rated health at 9 months, health or developmental problems, feeding practices, time spent outdoors and child immunisation)
  3. cAdjusted for all maternal and child factors as above and each other
  4. dRestricted to those who reported heating the house
  5. eAdjusted for all maternal and child factors as above and environmental factors (household tenure, crowding, household smoking, dampness of the house and mould or mildew in the child’s bedroom)
  6. fAdjusted for all maternal and child factors as above and environmental factors (household tenure, crowding, household smoking, heating the hose and mould or mildew in the child’s bedroom). A separate model was used here as heavy condensation was moderately correlated with dampness of the house