Brain weight–body weight ratio in sudden infant death syndrome revisited

Abstract

Aims To determine whether the brain–body weight ratio is increased in sudden infant death syndrome (SIDS). Methods Review of autopsy files from Forensic Science SA, South Australia was undertaken over an eight-year period from 1999 to 2006, with classification of cases according to the San Diego definition. Sudden and/or unexpected deaths in previously healthy infants due to asphyxia or infection were selected as controls. Results There were 42 SIDS cases and 25 controls. The SIDS cases were aged from 1 to 42 weeks (mean: 16.26 ± 1.5 weeks) with a male to female ratio of 26:16. The control infants were aged from 3 to 48 weeks (mean: 19.24 ± 2.9 weeks) ( P > 0.05) (M:F = 16:9) and included 13 cases of asphyxia and 12 cases of sepsis. Comparison of the brain–body weight ratios failed to demonstrate a significant difference: SIDS mean = 0.121 ± 0.003; control mean = 0.115 ± 0.003 ( P > 0.05). Conclusion Although, there was a trend towards higher brain–body weight ratios in SIDS infants, this did not reach significance. The role of brain weight in the aetiology of SIDS remains controversial.