Table 2

Routine pacifier use stratified by age, socioeconomic status, breast feeding duration, and maternal smoking after pregnancy

Proportion of infants who had ever used a pacifier (day or night)
SIDS Controls
Infant age2-150 n % n %
 0–8 weeks53/8860.2211/29272.3
 9–14 weeks70/8681.3253/35671.1
 15–22 weeks54/7572.0202/30167.1
 23 weeks or older40/6958211/35060.3
 χ2 test for trendp > 0.5p < 0.001
 Test for departure from linearityNAp > 0.1
 Mantel-Haenszelp > 0.9
Socioeconomic status n % n %
 V or never employed57/7081.477/9382.8
 III or IV134/19867.7541/76071.2
 I or II26/4953.1256/44357.8
 χ2 test for trendp < 0.001p < 0.001
 Test for departure from linearity p > 0.900.75 > p > 0.50
 Mantel-Haenszelp > 0.90
Duration of breast feeding2-160 n % n %
 Never attempted130/18171.8413/52478.8
 1–2 weeks29/4170.7128/16975.7
 3–6 weeks28/4168.3129/18968.3
 7–12 weeks17/3056.7121/20459.3
 More than 12 weeks13/2552.086/21240.6
 χ2test for trendp < 0.025p < 0.001
 Test for departure from linearity 0.50 > p > 0.25p < 0.012-165
 Mantel-Haenszelp > 0.10
Maternal smoking n % n %
 Does not smoke62/10360.2597/93164.1
 1–9 cigarettes60/8669.8119/15875.3
 10–19 cigarettes52/7074.3106/14274.6
 20 or more cigarettes43/5972.954/6681.8
 χ2 test for trend0.10 > p > 0.05p < 0.001
 Test for departure from linearityNA0.10 > p > 0.05
 Mantel-Haenszel0.25 > p > 0.10

  • Maternal smoking refers to smoking after pregnancy.

  • ↵2-150 Using approximate 25th, 50th, and 75th centiles of whole data set as a cut off.

  • ↵2-160 Using approximate 25th, 50th, and 75th centiles of all breast feeders as a cut off.

  • ↵2-165 When quadratic transformation was fitted p > 0.25.