Table 1

Prevalence of colic (%) and odds ratios (OR) for colic regarding age of the infant, maternal smoking behaviour, and type of feeding

CategoriesNo.1-150 %Unadjusted ORp valueAdjusted OR1-151 p value1-152
Age of infant1-153 0.000
 1 month11159.01.00
 3 months10853.70.39 (0.27 to 0.57)
 6 months11201.30.14 (0.08 to 0.24)
Maternal smoking0.0460.015
 Never25884.31.001.00
 <15 cigarettes/day5135.71.34 (0.88 to 2.04)1.50 (0.97 to 2.29)
 15–50 cigarettes/day1828.22.00 (1.14 to 3.51)2.21 (1.24 to 3.92)
Type of feeding0.2120.053
 Only formula20804.61.001.00
 Mixed breast and formula3653.30.71 (0.39 to 1.31)0.57 (0.31 to 1.06)
 Only breast8715.51.22 (0.85 to 1.74)0.69 (0.48 to 1.01)
Type of feeding by maternal smoking0.1460.023
 Never smokes25884.31.001.00
 Smokes, only formula fed5596.11.45 (0.97 to 2.15)1.81 (1.21 to 2.72)
 Smokes, (partially) breastfed1646.11.45 (0.74 to 2.82)1.18 (0.60 to 2.32)
  • 1-150 Numbers do not always add up to 3345 due to missing values.

  • 1-151 Odds ratio adjusted for age of the infant.

  • 1-152 p value for inclusion of the characteristic in the logistic model, after adjustment for age of the infant.

  • 1-153 Age categories concerned the following intervals: 1 month = 3–5 weeks; 3 months = 11–15 weeks; 6 months = 22–30 weeks.