Interaction between bedding and sleeping position in the sudden infant death syndrome: a population based case-control study.

OBJECTIVE--To determine the relation between sleeping position and quantity of bedding and the risk of sudden unexpected infant death. DESIGN--A study of all infants dying suddenly and unexpectedly and of two controls matched for age and date with each index case. The parents of control infants were interviewed within 72 hours of the index infant''s death. Information was collected on bedding, sleeping position, heating, and recent signs of illness for index and control infants. SETTING--A defined geographical area comprising most of the county of Avon and part of Somerset. SUBJECTS--72 Infants who had died suddenly and unexpectedly (of whom 67 had died from the sudden infant death syndrome) and 144 control infants. RESULTS--Compared with the control infants the infants who had died from the sudden infant death syndrome were more likely to have been sleeping prone (relative risk 8.8; 95% confidence interval 7.0 to 11.0; p less than 0.001), to have been more heavily wrapped (relative risk 1.14 per tog above 8 tog; 1.03 to 1.28; p less than 0.05), and to have had the heating on all night (relative risk 2.7; 1.4 to 5.2; p less than 0.01). These differences were less pronounced in the younger infants (less than 70 days) than the older ones. The risk of sudden unexpected death among infants older than 70 days, nursed prone, and with clothing and bedding of total thermal resistance greater than 10 tog was increased by factors of 15.1 (2.6 to 89.6) and 25.2 (3.7 to 169.0) respectively compared with the risk in infants of the same age nursed supine or on their side and under less than 6 tog of bedding. CONCLUSIONS--Overheating and the prone position are independently associated with an increased risk of sudden unexpected infant death, particularly in infants aged more than 70 days. Educating parents about appropriate thermal care and sleeping position of infants may help to reduce the incidence of the sudden infant death syndrome.     

Signs of illness preceding sudden unexpected death in infants.

OBJECTIVE--To determine whether signs of illness reported by parents can be used to identify babies at risk from the sudden infant death syndrome. DESIGN--A two year prospective case-controlled study based in a geographically defined area. SETTING--Four health districts in Avon and north Somerset. SUBJECTS--Babies who had died suddenly and unexpectedly aged between 1 week and 2 years (index babies) and two control babies for each index baby selected from the same health visitor''s list and matched for age, time of year of the interview, and area of residence. MAIN OUTCOME MEASURES--Major and minor signs of illness during two weeks before the index babies'' death, or before the interview for control babies, and consultations with the general practitioner during the same period. RESULTS--Parents reported major and minor signs of illness in the previous week in 66 of the 95 index babies compared with 77 of the 190 controls. No significant difference was found in the incidence of major signs reported (34 out of 95 index babies and 44 out of 190 controls), but a higher proportion of the index babies had been seen by their general practitioner during the previous week (17/95 v 11/190). CONCLUSION--Major and minor signs of illness are neither a sensitive nor a specific indicator of sudden unexpected death of infants and have no predictive value. Better understanding of the reasons why a higher proportion of parents of babies who died took them to their general practitioners may help to identify babies at risk before death.     

Ethnic differences in mortality from sudden infant death syndrome in New Zealand.

OBJECTIVES--To examine the factors which might explain the higher mortality from sudden infant death syndrome in Maori infants (7.4/1000 live births in 1986 compared with 3.6 in non-Maori children). DESIGN--A large nationwide case control study. SETTING--New Zealand. 485 infants who died of sudden infant death syndrome were compared with 1800 control infants. There were 229 Maori and 240 non-Maori cases of sudden infant death syndrome (16 cases unassigned) and 353 Maori and 1410 non-Maori controls (37 unassigned). RESULTS--Maori infants had 3.81 times the risk (95% confidence interval 3.06 to 4.76) of sudden infant death syndrome compared with non-Maori infants. The risk factors for sudden infant death syndrome within groups were remarkably similar. When Maori and non-Maori controls were compared the prevalence of many of the known risk factors was higher in Maori infants. In particular, mothers were socioeconomically disadvantaged, younger, and more likely to smoke and their infants were of lower birth weight and more likely to share a bed with another person. Multivariate analysis controlling for potential confounders found that simply being Maori increased the risk of sudden infant death syndrome by only 1.37 (95% CI = 0.95 to 2.01), not statistically significantly different from 1. Population attributable risk was calculated for prone sleeping position, maternal smoking, not breast feeding, and infants sharing a bed with another person. In total these four risk factors accounted for 89% of deaths from sudden infant death syndrome in Maori infants and 79% in non-Maori infants. CONCLUSION--The high rate of sudden infant death syndrome among Maori infants is based largely on the high prevalence in the Maori population of the major risk factors. Other risk factors, not related to ethnicity, probably explain remaining differences between Maori and non-Maori children.     

Thermal environment and sudden infant death syndrome: case-control study.

OBJECTIVE--To compare the thermal environment of infants who died of the sudden infant death syndrome with that of age matched control infants. DESIGN--Case-control study. Infants who died were matched with two controls, one for age and one for age and birth weight. Thermal measurements were conducted at the death scene for cases and at the scene of last sleep for control infants, who were visited unexpectedly within four weeks of the index infant''s death on a day of similar climatic conditions. A follow up questionnaire was administered to parents of cases and controls. SETTING--The geographical area served by the professional Tasmanian state ambulance service, which includes 94% of the Tasmanian population. SUBJECTS--41 infants died of the sudden infant death syndrome at home; thermal observations at death scene were available for 28 (68%), parental questionnaire data were available for 40 (96%). 38 controls matched for age and 41 matched for age and birth weight. RESULTS--Cases had more excess thermal insulation for their given room temperature (2.3 togs) than matched controls (0.6 togs) (p = 0.009). For every excess thermal insulation unit (tog) the relative risk of the sudden infant death syndrome was 1.26 (95% confidence interval 1.05 to 1.52). The average thermal bedding value calculated from parental recall was similar to that observed by attendant ambulance officers (mean difference = 0.4 tog, p = 0.39). Cases were more likely to have been found prone (odds ratio 4.58; 1.48 to 14.11). Prone sleeping position was not a confounder or effect modifier of the relation between excess thermal insulation and the syndrome. CONCLUSIONS--Overheating and the prone sleeping position are independently associated with an increased risk of the sudden infant death syndrome. Further work on infant thermal balance and sudden infant death is required and guidelines for appropriate infant thermal care need to be developed.     

Post-Neonatal Sudden Unexplained Death in a California Community

To gain further insight into the problem of infant sudden death, a study was undertaken to investigate a complete series of cases of infant sudden unexplained death that occurred during a seven-year period in Sacramento County. Needed information was abstracted from autopsy records, Medical Examiner''s records and death certificates. The average death rate for the seven-year period was 1.7 for 1,000 live births. Average age at time of death was 2.8 months. There were no records of sudden death among infants over the age of eight months.Higher than average death rates were observed within many of the low socioeconomic areas of Sacramento County. Also, sudden unexplained deaths appeared to occur more frequently in the winter months than in the spring, summer or fall. In over half the cases the infants had a cold, the sniffles, or other respiratory tract congestion within two weeks of the date of death, which seems to support the oft-quoted contention concerning the possibility of nasal obstruction which could initiate the fatal apnea. An additional notable finding was the very frequent occurrence of petechial hemorrhage in the thymus, heart, and lung tissues.The unique age distribution of these deaths in combination with the high frequency of low socioeconomic groups and the frequency of minor respiratory ailment would suggest approaches that can be taken to identify infants at high risk and thus initiate effective community health programs for prevention.     

Bed sharing,smoking, and alcohol in the sudden infant death syndrome. New Zealand Cot Death Study Group.

OBJECTIVES--To investigate why sharing the bed with an infant is a not consistent risk factor for the sudden infant death syndrome in ethnic subgroups in New Zealand and to see if the risk of sudden infant death associated with this practice is related to other factors, particularly maternal smoking and alcohol consumption. DESIGN--Nationwide case-control study. SETTING--Region of New Zealand with 78% of all births during 1987-90. SUBJECTS--Home interviews were completed with parents of 393 (81.0% of total) infants who died from the sudden infant death syndrome in the postneonatal age group, and 1592 (88.4% of total) controls who were a representative sample of all hospital births in the study region. RESULTS--Maternal smoking interacted with infant bed sharing on the risk of sudden infant death. Compared with infants not exposed to either risk factor, the relative risk for infants of mothers who smoked was 3.94 (95% confidence interval 2.47 to 6.27) for bed sharing in the last two weeks and 4.55 (2.63 to 7.88) for bed sharing in the last sleep, after other confounders were controlled for. The results for infants of non-smoking mothers were inconsistent with the relative risk being significantly increased for usual bed sharing in the last two weeks (1.73; 1.11 to 2.70) but not for bed sharing in the last sleep (0.98; 0.44 to 2.18). Neither maternal alcohol consumption nor the thermal resistance of the infant''s clothing and bedding interacted with bed sharing to increase the risk of sudden infant death, and alcohol was not a risk factor by itself. CONCLUSION--Infant bed sharing is associated with a significantly raised risk of the sudden infant death syndrome, particularly among infants of mothers who smoke. The interaction between maternal smoking and bed sharing suggests that a mechanism involving passive smoking, rather than the previously proposed mechanisms of overlaying and hyperthermia, increases the risk of sudden infant death from bed sharing.     

Preliminary investigation of lethally toxic sera of sudden infant death syndrome victims and neutralisation by commercially available immunoglobulins and adult sera

The aim of the study was to test the hypotheses (i) that sudden infant death syndrome sera are toxic to 11-day old chick embryos and (ii) that such a toxicity can be counteracted by immunoglobulin or adult sera. Serum samples from 11 SIDS victims and five controls were tested for lethal toxicity in the chick embryo bioassay. Five serum samples were used to challenge chick embryos injected with the following: sudden infant death syndrome serum plus Hank's balanced salt solution; Hank's balanced salt solution alone; sudden infant death syndrome serum plus 3% w/v commercial immunoglobulin; sudden infant death syndrome serum plus 6% w/v immunoglobulin; sudden infant death syndrome serum plus pooled sera of 40 healthy adults. Results obtained revealed that Hank's balanced salt solution, the pooled adult serum and the commercial immunoglobulin were all non-lethal, in the chick embryo test system. By contrast. 10 sudden infant death syndrome victims yielded sera containing lethal levels of toxin(s) compared to 2/5 controls which was statistically significant (P < 0.05, Fischer's exact test). In the tests of sudden infant death syndrome serum plus immunoglobulin or pooled adult serum, the lethality of sudden infant death syndrome serum was abolished in all cases. The reduction in toxicity of individual sudden infant death syndrome serum plus immunoglobulin or pooled adult serum was often statistically significant (P<0.05-P<0.00005, Fischer's exact test). We conclude that lethal levels of toxin are present in sudden infant death syndrome sera and that they can be neutralised by normal immune serum. These results indicate that passive immunisation is a potential treatment to protect babies considered at risk from sudden infant death syndrome.     

Qualitative interview study of communication between parents and children about maternal breast cancer

Objective To examine parents'' communication with their children about the diagnosis and initial treatment of breast cancer in the mother. Design Qualitative interview study within a cross-sectional cohort. Setting Two breast cancer treatment centers. Participants 32 women with stage I or stage II breast cancer with 56 school-aged children. Main outcome measures Semistructured interview regarding timing and extent of communication with children about the diagnosis and initial treatment of the mother''s illness, reasons for talking to children or withholding information, and help available and requested from health professionals. Results Women were most likely to begin talking to their children after their diagnosis had been confirmed by biopsy, but a few waited until after surgery or said nothing at all. Family discussion did not necessarily include mention of cancer. There was considerable consistency in the reasons given for either discussing or not discussing the diagnosis. The most common reason for not communicating was to avoid children''s questions, particularly those about death. Although most women had helpful discussion with a physician concerning their illness, few were offered help with talking to their children; many would have liked help, particularly the opportunity for both parents to talk to a health professional with experience in understanding and talking to children. Conclusion Parents diagnosed with cancer or other serious illnesses should be offered help to think about whether, what, and how to tell their children and about what children can understand, especially as they may well be struggling themselves to come to terms with their illness.     

Promoting children's home safety.

Home accidents are the main cause of death and morbidity in early childhood. Working-class children are at greatest risk. A study in an inner city area of the effects of a national television campaign about child accident prevention and of a locally designed health education initiative showed that 55% of families with young children in the study area did not watch any of the television programmes. Only 9% of a group specially encouraged to watch the programmes took any action to make their homes safer. In a comparable group who also received a home visit at which specific advice was given 60% took action to make their homes safer. The families studied were well aware before the television campaign of the importance and preventability of children''s accidents. The problems disadvantaged families face are therefore not ones of ignorance or apathy about hazards but practical difficulties in converting their concern into action. Administrative arrangements must be developed for providing health workers--especially health visitors--with detailed local information to pass on to parents.     

Role of respiratory viruses in childhood mortality.

Respiratory viruses have been identified at necropsy in the lungs of 13 out of 24 children who died with observed acute respiratory illness. The histological appearances of the lungs supported the association between virus and death in each of these 13 children and suggested an unidentified virus aetiology in a further five cases. Histological appearances compatible with bacterial infection were found in the lungs of only two of the 24 children. Similar virus and histological findings have been reported in about one-third of victims of the sudden infant death syndrome (cot deaths), indicating a rapid unobserved respiratory virus infection as the most likely mode of death in this group. Evidence that respiratory viruses may be involved in a larger proportion of sudden unexpected deaths, perhaps as antigens in a hypersensitivity reaction, is discussed. Respiratory viruses seem the major identifiable agents contributing to the maintenance of the postneonatal mortality rate since acute respiratory illness and the sudden infant death syndrome together account for about two-thirds of deaths at this age.     

Respiratory viruses and sudden infant death.

Viruses were shown to be present in the respiratory tract in 200 of 763 cases of the sudden infant death syndrome studied in the nine years 1974-82. Epidemiological and pathological evidence suggested that the distribution of viruses in the sudden infant death syndrome differs between infants aged 3 months or less and those aged over 3 months: the incidence of detection of virus was 14% in the younger group compared with 39% in the older group. The distribution of the viruses in these two groups was compared with that in 1341 live infants with respiratory virus infections. Adenovirus, influenza virus, parainfluenza virus, and rhinovirus had similar distribution among the victims of the sudden infant death syndrome and live controls. The incidence of detection of respiratory syncytial virus was increased in the older infants dying of the sudden infant death syndrome (90% of the cases detected) compared with the older group of live infants (53%). Antibody studies, detection of virus, and epidemiological data suggest that respiratory syncytial virus may be a precipitating factor of sudden death in older infants.     

Sudden infant death syndrome: links with infant care practices.

OBJECTIVES--To investigate infant care practices in a small ethnic minority population within Britain that might suggest possible factors contributing to the low incidence of the sudden infant death syndrome in Asian populations. DESIGN--Ethnographic interviewing, a qualitative comparative method drawn from social anthropology. SETTING--Central Cardiff. SUBJECTS--Non-random sample of 60 mothers of Bangladeshi or Welsh ethnic origin and working or middle class occupational status, who had infants under one year old. None of the families interviewed had experienced a sudden infant death. RESULTS--Broad cultural contrasts emerged as a series of themes from the interview data: living patterns, family networks, sleeping patterns, and concepts of time and dependence. CONCLUSION--Bangladeshi infants were cared for in a consistently rich sensory environment; Welsh infants, in contrast, were more likely to experience alternating periods of high and low sensory input. Long periods of lone quiet sleep may be one factor that contributes to a higher rate of sudden deaths in white than in Asian infants.     

The common bacterial toxins hypothesis of sudden infant death syndrome

The background to the common bacterial toxin hypothesis of sudden infant death syndrome is presented. The idea is that some cases of sudden infant death syndrome are due to the lethal effects of nasopharyngeal bacterial toxins which can act synergistically to trigger the events leading to death. The concept is consistent with the age distribution of sudden infant death syndrome, the winter excess of cases and the role of prone sleeping and passive exposure to cigarette smoke. A number of laboratory-based investigations are described. There is an increased isolation of staphylococci and Gram-negative bacilli from sudden infant death syndrome infants compared with age- and season-matched healthy infants. Bacteria from sudden infant death syndrome infants interact synergistically to cause sudden death in gnotobiotic weanling rats. Bacterial toxins implicated in sudden infant death syndrome interact synergistically to cause death in chick embryos. Nicotine in very low doses potentiates the lethal effect of toxin combinations in chick embryos. Staphylococcal toxins and endotoxins have been demonstrated in sudden infant death syndrome tissues, antibodies to endotoxins are low in sudden infant death syndrome cases and the prone sleeping position leads to pooling of secretions in the upper airways, increasing the risk of bacterial growth and toxin production. If the hypothesis is correct, then there is the possibility of a further reduction in the incidence of sudden infant death syndrome based on immunisation against the toxins involved.     

Babies sleeping with parents: case-control study of factors influencing the risk of the sudden infant death syndrome. CESDI SUDI research group

ObjectiveTo investigate the risks of the sudden infant death syndrome and factors that may contribute to unsafe sleeping environments.DesignThree year, population based case-control study. Parental interviews were conducted for each sudden infant death and for four controls matched for age, locality, and time of sleep.SettingFive regions in England with a total population of over 17 million people.Subjects325 babies who died and 1300 control infants.ResultsIn the multivariate analysis infants who shared their parents'' bed and were then put back in their own cot had no increased risk (odds ratio 0.67; 95% confidence interval 0.22 to 2.00). There was an increased risk for infants who shared the bed for the whole sleep or were taken to and found in the parental bed (9.78; 4.02 to 23.83), infants who slept in a separate room from their parents (10.49; 4.26 to 25.81), and infants who shared a sofa (48.99; 5.04 to 475.60). The risk associated with being found in the parental bed was not significant for older infants (>14 weeks) or for infants of parents who did not smoke and became non-significant after adjustment for recent maternal alcohol consumption (>2 units), use of duvets (>4 togs), parental tiredness (infant slept ⩽4 hours for longest sleep in previous 24 hours), and overcrowded housing conditions (>2 people per room of the house).ConclusionsThere are certain circumstances when bed sharing should be avoided, particularly for infants under four months old. Parents sleeping on a sofa with infants should always be avoided. There is no evidence that bed sharing is hazardous for infants of parents who do not smoke.

Key messsages

• Cosleeping with an infant on a sofa was associated with a particularly high risk of sudden infant death syndrome
• Sharing a room with the parents was associated with a lower risk
• There was no increased risk associated with bed sharing when the infant was placed back in his or her cot
• Among parents who do not smoke or infants older than 14 weeks there was no association between infants being found in the parental bed and an increased risk of sudden infant death syndrome
• The risk linked with bed sharing among younger infants seems to be associated with recent parental consumption of alcohol, overcrowded housing conditions, extreme parental tiredness, and the infant being under a duvet

     

Defects of metabolism of fatty acids in the sudden infant death syndrome.

Two hundred consecutive cases of the sudden infant death syndrome were reviewed for the presence of fat in the liver; 14 showed diffuse panlobular microvesicular fatty change indistinguishable from that found in Reye''s syndrome. Samples of frozen liver were available in five of the 14 cases; histochemical analysis showed well preserved cytochrome oxidase and succinate dehydrogenase activity in all five, uncharacteristic of Reye''s syndrome. Fatty acyl-coenzyme A dehydrogenase activity in the liver was assayed biochemically in two of the same five cases with severe hepatic fatty infiltration; both showed a defect in medium chain acyl-coenzyme A dehydrogenase activity using the substrate octanoyl-coenzyme A. Both cases also showed cerebral oedema in association with fatty infiltration of renal tubules, myocardium, and skeletal muscle, characteristic of Reye''s syndrome. It is concluded that diffuse panlobular microvesicular fatty change of the liver in victims of the sudden infant death syndrome, although essentially non-specific, indicates that the state of mitochondrial enzymes should be investigated.     

Endpiece: Genius (1815)

ObjectiveTo examine the proposition that a used infant mattress is associated with an increased risk of sudden infant death syndrome.DesignCase-control study.SettingScotland (population 5.1 million, with about 53 000 births a year).Participants131 infants who died of sudden infant death syndrome between 1 January 1996 and 31 May 2000 and 278 age, season, and obstetric unit matched control infants.ResultsRoutine use of an infant mattress previously used by another child was significantly associated with an increased risk of sudden infant death syndrome (multivariate odds ratio 3.07, 95% confidence interval 1.51 to 6.22). Use of a used infant mattress for last sleep was also associated with increased risk (6.10, 2.31 to 16.12). The association was significantly stronger if the mattress was from another home (4.78, 2.08 to 11.0) than if it was from the same home (1.64, 0.64 to 4.2).ConclusionA valid significant association exists between use of a used infant mattress and an increased risk of sudden infant death syndrome, particularly if the mattress is from another home. Insufficient evidence is available to judge whether this relation is cause and effect.

What is already known about this topic

The major risk factors for sudden infant death syndrome are sleeping prone and parental smokingOne study has suggested that the syndrome is associated with sleeping on an infant mattress previously used by another child

What this study adds

New case-control data show that the association between a previously used infant mattress and sudden infant death syndrome is validWhen source of used mattress is categorised, the association is significant only if the mattress is from another homeInsufficient evidence is available to judge whether this is a cause and effect relation     

Can the fall in Avon's sudden infant death rate be explained by changes in sleeping position?

OBJECTIVE--To examine the impact of changing practice with regard to infant sleeping position on mortality from the sudden infant death syndrome. DESIGN--A population based study of all infants dying suddenly and unexpectedly during February 1990 to July 1991, and two groups of controls; one comprising every 125th baby born to Avon residents and the other comprising pairs of infants matched to each index case for age, neighbourhood, and date of study. Information about sleeping position was collected at home visits soon after the index baby''s death or, for the population based controls, on several occasions in the first six months of life. The design was comparable to that of an earlier study of the same population. SETTING--County of Avon. SUBJECTS--35 infants who died suddenly and unexpectedly (32 of the sudden infant death syndrome), 70 matched controls, and 152 population based controls. RESULTS--The prevalence of prone sleeping in the matched controls was much lower than that found in an earlier study in Avon (28% (18/64) 1990-1 v 58% (76/131) 1987-9; p less than 0.001) and was comparable with the prevalence in population based controls (29%). This would be expected to lead to a reduction in the incidence of the sudden infant death syndrome to 2.0/1000 live births (95% confidence interval 1.8/1000 to 2.5/1000). The actual mortality fell from 3.5/1000 in 1987-9 to 1.7/1000. CONCLUSION--The fall in mortality can be almost entirely accounted for by the reduction in prone sleeping, suggesting a causal relation exists between them. Side and supine positions confer protection but the side position is unstable and the infant may roll prone. We therefore recommend supine as the safest sleeping position for babies.     

Qualitative interview study of communication between parents and children about maternal breast cancer

ObjectiveTo examine parents'' communication with their children about the diagnosis and initial treatment of breast cancer in the mother.DesignQualitative interview study within cross sectional cohort.SettingTwo breast cancer treatment centres.Participants32 women with stage I or stage II breast cancer with a total of 56 school aged children.ResultsWomen were most likely to begin talking to their children after their diagnosis had been confirmed by biopsy, but a minority waited until after surgery or said nothing at all. Family discussion did not necessarily include mention of cancer. There was considerable consistency in the reasons given for either discussing or not discussing the diagnosis. The most common reason for not communicating was avoidance of children''s questions and particularly those about death. While most mothers experienced helpful discussion with a doctor concerning their illness, few were offered help with talking to children; many would have liked help, particularly the opportunity for both parents to talk to a health professional with experience in understanding and talking to children.ConclusionsParents diagnosed with cancer or other serious illnesses should be offered help to think about whether, what, and how to tell their children and about what children can understand, especially as they may well be struggling themselves to come to terms with their illness.     

Exeter Project for Handicapped Children

A project in Exeter has tried to increase the contribution of the paediatric department of a district general hospital to the long-term care, support, and treatment of handicapped children and their families. They include an infant care unit, day units for handicapped children, and holiday projects, and are based on close links with the educational and social services. The availability of such a family support unit may diminish the strain on the families of handicapped children and help them to maintain normal family and social relationships.     

Microbiology in sudden infant death syndrome (SIDS) and other childhood deaths

The usefulness of post-mortem microbiology in the assessment of sudden unexpected deaths in infants and children has been debated by many pathologists. In our centre, microbiological investigations have been part of the post-mortem protocol for investigation of sudden deaths in infants and children for the past 12 years. The objective of this study was to review the microbiological findings for infants and children examined by our unit during the past 4 years in relation to gross and histological findings of the autopsy and the medical and social histories of the children. We reviewed 57 consecutive sudden deaths in infants and children examined by our Referral Centre between November 1994 and October 1998. These 57 sudden deaths were aged from 1 day to 4 years and 9 months including 40 cases of sudden infant death syndrome (SIDS) and 17 non-SIDS deaths. Results of the microbiological investigations of tissues and body fluids were assessed during the case review with reference to histological shock signs, severe gastric aspiration, and signs of acute thymic involution. Bacteria alone or in association with viruses were identified in 45/57 (79%) cases including 34/40 (85%) SIDS. The most frequent bacterial isolate was Escherichia coli (27), and the virus identified most frequently was enterovirus (8). C-reactive protein was increased in 10 out of the 42 cases tested including 8/32 (25%) SIDS. Significant gastric content aspiration was found in 17/57 (29.8%) including 13/40 (32.5%) SIDS. Histological signs of shock were present in 33/55 (60%) cases including 22/39 SIDS (56.4%). The microbiological findings were positive for 27/33 (81.8%). We conclude that post-mortem microbiology is essential in sudden death investigation. The conclusion that a death is unexplained if no microbiology was done is not valid, even if in some cases it may be difficult to know precisely in what way the pathogen contributed to the death.