Table 3

Rate of hospitalisation for selected child outcomes and smoking status at first booking for respiratory infections, asthma and bronchiolitis for (A) the whole period of follow-up; and for two separate periods of follow-up: (B) from birth to first birthday and (C) from first birthday to fifth birthday

(A) Follow-up from birth to fifth birthday
Smoking status at first bookingInfants at risk (N)Acute upper and lower respiratory infectionsAsthmaBronchiolitis
NColumn %Row %NColumn %Row %NColumn %Row %
697 00356 615100.08.17549100.01.124 088100.03.5
Never smoked391 86130 54954.07.8367848.70.911 35447.12.9
Current smoker159 81914 94526.49.4241232.01.5793933.05.0
Former smoker59 32649668.88.46548.71.118217.63.1
Unknown/missing85 997615510.97.280510.70.9297412.33.5
(B) Follow-up from birth to first birthdayPAF (%)
Acute upper and lower respiratory infectionsAdmission for specified outcomeInfants at risk (N)Crude HRAdjusted* HR
NColumn %Row %
18 541100.02.7697 003HR (95% CI)HR (95% CI)
Never smoked957351.62.4391 8611.00 (reference)1.00 (reference)6.7
Current smoker553729.93.5159 8191.43 (1.38 to 1.48)1.29 (1.25 to 1.34)
Former smoker14848.02.559 3261.02 (0.97 to 1.08)0.97 (0.92 to 1.03)
Unknown/missing194710.52.385 9970.93 (0.89 to 0.98)0.89 (0.84 to 0.93)
Asthma606100.00.1697 003
Never smoked24239.90.1391 8611.00 (reference)1.00 (reference)21.9
Current smoker24840.90.2159 8192.51 (2.10 to 3.00)2.15 (1.80 to 2.57)
Former smoker467.60.159 3261.25 (0.91 to 1.72)1.18 (0.86 to 1.62)
Unknown/missing7011.60.185 9971.33 (1.02 to 1.73)1.29 (0.99 to 1.69)
Bronchiolitis20 399100.02.9697 003
Never smoked949946.62.4391 8611.00 (reference)1.00 (reference)10.1
Current smoker686133.64.3159 8191.79 (1.73 to 1.84)1.43 (1.38 to 1.48)
Former smoker15347.52.659 3261.07 (1.01 to 1.13)1.03 (0.97 to 1.08)
Unknown/missing250512.32.985 9971.21 (1.16 to 1.27)1.15 (1.09 to 1.21)
(C) Follow-up from first birthday to fifth birthdayPAF (%)
Acute upper and lower respiratory infectionsAdmission for specified outcomeInfants at risk (N)†Crude HRAdjusted* HR
NColumn %Row %
38 074100.05.7662 454HR (95%  CI)HR (95%  CI)
Never smoked20 97655.15.6373 4361.00 (reference)1.00 (reference)−0.2
Current smoker940824.76.2151 0101.09 (1.07 to 1.12)0.99 (0.97 to 1.02)
Former smoker34829.16.156 6451.09 (1.06 to 1.13)1.04 (1.00 to 1.08)
Unknown/missing420811.15.281 3630.95 (0.92 to 0.98)0.90 (0.87 to 0.94)
Asthma6943100.01.0679 588
Never smoked343649.50.9382 3271.00 (reference)1.00 (reference)7.1
Current smoker216431.21.4156 1231.51 (1.43 to 1.59)1.29 (1.22 to 1.37)
Former smoker6088.81.058 0251.16 (1.07 to 1.27)1.10 (1.00 to 1.20)
Unknown/missing73510.60.983 1131.04 (0.96 to 1.12)1.01 (0.92 to 1.10)
Bronchiolitis3689100.00.6660 119
Never smoked185550.30.5373 2191.00 (reference)1.00 (reference)4.0
Current smoker107829.20.7149 6091.45 (1.34 to 1.56)1.16 (1.08 to 1.25)
Former smoker2877.80.556 5611.02 (0.90 to 1.15)0.98 (0.87 to 1.11)
Unknown/missing46912.70.680 7301.18 (1.06 to 1.30)1.11 (1.01 to 1.24)
  • *Adjusted for: maternal age; infant gender, SIMD; mothers socioeconomic status; fathers socioeconomic status; parity; mode of delivery, infant feeding at 6–8 weeks and country of birth.

  • †The number of infants at risk from their first birthday to fifth birthday is the total number of infants aged 0–1 year (697 003) minus the specific outcome cases and any deaths or migration from 0–1 year.

  • PAF, population attributable fraction; SIMD, Scottish Index of Multiple Deprivation.