On Tuesday at the SIDS 2008 Conference (Portsmouth):
New Zealand researchers Professor Barry Taylor and Dr Sally Baddock will participate in conference proceedings.
If mattress-wrapping did not prevent cot death, by now hundreds of cot deaths would have occurred in New Zealand on "wrapped mattresses". But during the 13 years since mattress-wrapping commenced, no such death has been reported.
Furthermore, New Zealand Professor Ed Mitchell's research published in the European Journal of Pediatrics (1) in February 2008 demonstrates the efficacy of mattress-wrapping in preventing cot death (SIDS).
Since the commencement of mattress-wrapping in 1995, in "Case-Control" terms there have been two groups of babies in New Zealand:
Babies who slept on wrapped mattresses: Case babies
Babies who did not sleep on wrapped mattresses: Control babies
Statistical analysis (using Dr Mitchell's data):
Total number of live births in New Zealand from 1995 to 2007 (inclusive): 748,300
Using an incidence of mattress-wrapping of 21.7% (as reported in Dr Mitchell's research):
Number of Case babies: 748,300 x 0.217 = 162,380
Number of Control babies: 748,300 x 0.783 = 585,920
Cot deaths in New Zealand from 1995 to 2007 (inclusive): Around 860 (2)
Reported cot deaths among Case babies (babies who slept on wrapped mattresses): Nil
If mattress-wrapping had nil effect on the incidence of cot death, the number of cot deaths among the Case babies would have been: 860 / 585,920 x 162,380 = 238
Since there has been no cot death among the Case babies, the efficacy of mattress-wrapping in preventing cot death was in the ratio 238 / zero.
However, there is no meaningful solution to the equation x = a/zero where "a" is a real number. This situation is overcome by positing that the number of cot deaths among the Case babies was "very much less than 1”, denoted by the nomenclature <<1.>>1 means “very much greater than 1”.)
Using this nomenclature, the ratio of effectiveness of mattress-wrapping in preventing cot death is:
Effectiveness = 238 divided by <<1,>>238
Thus in statistical terms the efficacy of mattress-wrapping in preventing cot death is: Very much greater than 238 times the efficacy of all other items of cot death prevention advice combined
See http://www.cotlife2000.co.nz/ for further information
1. Eur J Pediatr 2008; 167(2): 251-252. A postal survey conducted among 400 Auckland (New Zealand) mothers regarding practices adopted for cot death prevention reported the incidence of mattress-wrapping as 21.7%.
2. Source of statistics: New Zealand Ministry of Health.
T J Sprott OBE MSc PhD FNZIC
Consulting chemist & forensic scientist
10 Combes Road