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Biomedical subjects

David M O Becroft

Publications and source records attributed to David M O Becroft.

7 recordsLinked to original sources

Sudden infant death syndrome: risk factors for infants found face down differ from other SIDS cases.

OBJECTIVE: To test the hypothesis that infants with sudden infant death syndrome (SIDS) found face down (FD) would have SIDS risk factors different from those found in other positions (non-face-down position, NFD). STUDY DESIGN: We used the New Zealand Cot Death Study data, a 3-year, nationwide (1987 to 1990), case-control study. Odds ratios (univariate and multivariate) for FD (n = 154) and NFD SIDS (n = 239) were estimated separately, and statistical differences between the two groups were assessed. RESULTS: Of 12 risk factors for SIDS, there were 8 with a statistically significant difference between FD and NFD infants. After adjustment for the potential confounders, younger infant age, Maori ethnicity, low birth weight, prone sleep position, use of a sheepskin, and pillow use were all associated with a greater risk of SIDS in the FD than the NFD group. Sleeping during the nighttime, maternal smoking, and bed-sharing were associated with a risk of SIDS only in the NFD group. Pacifier use was associated with a decreased risk for SIDS only in the NFD group, whereas being found with the head covered was associated with a decreased risk for SIDS for the FD group. CONCLUSIONS: Infants with SIDS in the FD position appear to be a distinct subgroup of SIDS. These differences in risk factors provide clues to mechanisms of death in both SIDS subtypes.

Analysis of Variance↗

Pulmonary interstitial hemosiderin in infancy: a common consequence of normal labor.

Deposits of hemosiderin are found frequently in the interstitium of the lungs of infants who die suddenly and have been a suggested marker for hypoxia during previous episodes of apnea. We studied the epidemiology of pulmonary interstitial hemosiderin (PIH) in 94 infants with a diagnosis of the sudden infant death syndrome that was established during the New Zealand Cot Death Study. Twenty-seven infants (29%) had widely distributed PIH. Associations were sought between PIH and variables on which information had been obtained from parental interviews or from medical records. Previous suggestions of associations with increasing birth weight and decreasing age at death were confirmed in multivariate analysis (P = 0.0018 and P = 0.03, respectively) and with increasing gestation in univariate analysis (P < 0.0001). PIH was not found in any of the 13 infants delivered by elective cesarean section compared with a 33% incidence in those exposed to labor (P = 0.02). There was no association with previous apnea. We consider that the likely explanation of these findings is that PIH is a residue of interstitial hemorrhage caused by chest compression during labor that occurs particularly in larger infants of greater gestational age and then clears gradually during early infancy.

Adult↗

Pulmonary aspiration of gastric contents and the sudden infant death syndrome.

OBJECTIVE: To determine ante-mortem and post-mortem risk factors for the finding of gastric contents in pulmonary airways (aspiration of gastric contents) at post-mortem examination in the sudden infant death syndrome (SIDS). METHODS: There were 217 post-neonatal deaths in the Auckland region of the New Zealand Cot Death Study. No deaths were certified as due to aspiration of gastric contents. There were 138 SIDS cases. The parents of 110 (80%) of these cases were interviewed. Histological sections from the periphery of the lungs in 99 of the 110 cases were reviewed for evidence of aspiration of gastric contents. A wide range of variables were analysed in SIDS cases with and without aspiration to determine risk factors. RESULTS: Aspiration of gastric contents was identified in 37 (37%) of SIDS cases. Aspiration was of mild-to-moderate degree and in no case was severe and a potential cause of death. Finding infants on their backs at death (P = 0.024) and conducting the post-mortem on the day after the death or subsequently (P = 0.033) were statistically significant variables linked to identification of aspiration. Position placed to sleep, symptoms of gastro-oesophageal reflux and other variables were not related to aspiration. CONCLUSIONS: The only determinants for aspiration of gastric contents identified were agonal or post-mortem events, supporting the contention that aspiration has limited relevance to the mechanism of SIDS.

Asphyxia↗

Placental infarcts, intervillous fibrin plaques, and intervillous thrombi: incidences, cooccurrences, and epidemiological associations.

The incidences, cooccurrences and epidemiological associations at term of the three common focal macroscopic placental lesions, infarcts, intervillous fibrin plaques (IVFP), and intervillous thrombi (IVT) were investigated as part of a population-based case-control study of small-for-gestational age (SGA) infants. Five hundred and nine placentas from women delivering SGA infants (10th percentile or less for gestational age) and 529 placentas from women delivering infants with birthweights appropriate for gestational age were examined using fixed protocols for identification of macroscopic lesions and microscopic diagnoses. One or more of these lesions were found in 280 placentas (28%), including infarcts in 150 (15%), IVFP in 132 (13%), and IVT in 64 (6%). Macroscopic misidentifications, particularly of IVFP as infarcts, emphasize the need for microscopic diagnoses. There were strong associations between the occurrence of any one type of lesion and cooccurrence of either of the other two, and these associations were site-dependent: between central (nonmarginal) infarcts and central IVFP (P = 0.0023); marginal infarcts and marginal IVFP (P < 0.0001); and between IVT (all central) and marginal infarcts (P < 0.0001) and marginal IVFP (P = 0.012). However, a study of associations between the incidences of placentas bearing each of the three lesions and 31 socio-demographic and pregnancy-related factors showed no associations in common. IVFP, an IVFP variant termed "labyrinthine," and IVT did not show any of the independent associations demonstrated between infarcts and SGA, pregnancy-induced hypertension, nonsmoking, age at first pregnancy, and ethnicity. IVFP had no significant associations, and IVT were associated only with male gender. The study has shown that IVFP and IVT do not share the important clinical associations demonstrated for infarcts, but has not identified the pathogenetic factor or factors responsible for the frequent cooccurrence of these lesions. The maternal thrombophilias may have such a role.

Female↗