Ij Smith

Environment of infants during sleep and risk of the sudden infant death syndrome: results of 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy. Confidential Enquiry into Stillbirths and Deaths Regional Coordinators and Researchers.

Abstract Objective: To investigate the role of sleeping arrangements as risk factors for the sudden infant death syndrome after a national risk reduction campaign. Design: Two year population based case-control study. Parental interviews were conducted for each infant who died and for four controls matched for age and date of interview. Setting: Three regions in England with a total population of 17 million people. Subjects: 195 babies who died and 780 matched controls. Results: Prone and side sleeping positions both carried increased risks of death compared with supine when adjusted for maternal age, parity, gestation, birth weight, exposure to smoke, and other relevant factors in the sleeping environment (multivariate odds ratio = 9.00 (95% confidence interval 2.84 to 28.47) and 1.84 (1.02 to 3.31), respectively). The higher incidence of side rather than prone sleeping led to a higher population attributable risk (side 18.4%, prone 14.2%). More of the infants who died were found with bed covers over their heads (21.58; 6.21 to 74.99). The use of a dummy had an apparent protective effect (0.38; 0.21 to 0.70). Bed sharing for the whole night was a significant risk factor for infants whose mothers smoked (9.25; 2.31 to 34.02). No protective effect of breast feeding could be identified on multivariate analysis. Conclusions: This study confirms the importance of certain risk factors for the sudden infant death syndrome and identifies others—for example, covers over the head, side sleeping position—which may be amenable to change by educating and informing parents and health care professionals. Key messages This large case-control study is the first after the national campaign to reduce the risk of the syndrome The risk of sudden infant death is increased by prone or side sleeping position; loose bedding (particularly duvets), which can slip over the babys head; and bed sharing by mothers who smoke The risk may be reduced by supine sleeping position; placing the baby with feet at the foot of the cot (“feet to foot”); ensuring that bedding is securely tucked in; and avoiding the use of duvets

Smoking and the sudden infant death syndrome: results from 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy

Abstract Objective: To investigate the effects of exposure to tobacco smoke and of parental consumption of alcohol and illegal drugs as risk factors for the sudden infant death syndrome after a national risk reduction campaign which included advice on prenatal and postnatal avoidance of tobacco smoke. Design: Two year population based case-control study. Parental interviews were conducted for each infant who died and four controls matched for age and date of interview. Setting: Three regions in England with a total population of 17 million people. Subjects: 195 babies who died and 780 matched controls. Results: More index than control mothers (62.6% v 25.1%) smoked during pregnancy (multivariate odds ratio = 2.10; 95% confidence interval 1.24 to 3.54). Paternal smoking had an additional independent effect when other factors were controlled for (2.50; 1.48 to 4.22). The risk of death rose with increasing postnatal exposure to tobacco smoke, which had an additive effect among those also exposed to maternal smoking during pregnancy (2.93; 1.56 to 5.48). The population attributable risk was over 61%, which implies that the numbers of deaths from the syndrome could be reduced by almost two third if parents did not smoke. Alcohol use was higher among index than control mothers but was strongly correlated with smoking and on multivariate analysis was not found to have any additional independent effect. Illegal drug use was more common among the index parents, and paternal use of illegal drugs remained significant in the multivariate model (4.68; 1.56 to 14.05). Conclusions: This study confirms the increased risk of the sudden infant death syndrome associated with maternal smoking during pregnancy and shows evidence that household exposure to tobacco smoke has an independent additive effect. Parental drug misuse has an additional small but significant effect. Key messages Exposure of babies to tobacco smoke from other members of the household before or after birth increases the risk of death: the greater the exposure the higher the risk Over 60% of such deaths may be attributable to the effects of exposure to tobacco smoke before and after birth

Epidemiology of SIDS and Explained Sudden Infant Deaths

Objectives. To establish whether epidemiologic characteristics for sudden infant death syndrome (SIDS) have changed since the decrease in death rate after the “Back to Sleep” campaign in 1991, and to compare these characteristics with sudden and unexpected deaths in infancy (SUDI) from explained causes. Design. Three-year, population-based, case-control study. Parental interviews were conducted soon after the death and for 4 controls matched for age and date of interview. All sudden unexpected deaths were included in the study and the cause of death was established by a multidisciplinary panel of the relevant health care professionals taking into account past medical and social history of the mother and infant, the circumstances of death, and a full pediatric postmortem examination. Contributory factors and the final classification of death were made using the Avon clinicopathologic system. Setting. Five regions in England, with a total population of >17 million people, took part in the study. The number of live births within these regions during the particular time each region was involved in the study was 473 000. Study Participants. Three hundred twenty-five SIDS infants (91.3% of those available), 72 explained SUDI infants (86.7% of those available), and 1588 matched control infants (100% of total for cases included). Results. Many of the epidemiologic features that characterize SIDS infants and families have remained the same, despite the recent decrease in SIDS incidence in the United Kingdom. These include the same characteristic age distribution, few deaths in the first few weeks of life or after 6 months, with a peak between 4 and 16 weeks, a higher incidence in males, lower birth weight, shorter gestation, and more neonatal problems at delivery. As in previous studies there was a strong correlation with young maternal age and higher parity and the risk increased for infants of single mothers and for multiple births. A small but significant proportion of index mothers had also experienced a previous stillbirth or infant death. The majority of the SIDS deaths (83%) occurred during the night sleep and there was no particular day of the week on which a significantly higher proportion of deaths occurred. Major epidemiologic features to change since the decrease in SIDS rate include a reduction in the previous high winter peaks of death and a shift of SIDS families to the more deprived social grouping. Just more than one quarter of the SIDS deaths (27%) occurred in the 3 winter months (December through February) in the 3 years of this study. In half of the SIDS families (49%), the lone parent or both parents were unemployed compared with less than a fifth of control families (18%). This difference was not explained by an excess of single mothers in the index group. Many of the significant factors relating to the SIDS infants and families that distinguish them from the normal population did not distinguish between SIDS and explained SUDI. In the univariate analysis many of the epidemiologic characteristics significant among the SIDS group were also identified and in the same direction among the infants dying as SUDI attributable to known causes. The explained deaths were similarly characterized by the same infant, maternal, and social factors, 48% of these families received no waged income. Using logistic regression to make a direct comparison between the two index groups there were only three significant differences between the two groups of deaths: 1) a different age distribution, the age distribution of the explained deaths peaked in the first 2 months and was more uniform thereafter; 2) more congenital anomalies were noted at birth (odds ratio [OR] = 3.14; 95% confidence intervals [CI]: 1.52–6.51) among the explained deaths (20%) compared with the SIDS (8%), which was not surprising given that 10% of these deaths were explained by congenital anomalies; and 3) a higher incidence of maternal smoking during pregnancy among the SIDS mothers, the proportion of smokers within the explained SUDI group was much higher (49%) than the controls (27%), but among SIDS mothers the proportion of smokers was higher still (66%) and this difference was significant (66% vs 49%; OR = 2.03; 95% CI: 1.16–3.54). The largest subgroup of explained SUDI deaths were those attributable to infection (46%). There was a winter peak of deaths from infection, the highest number occurring in December (21%) but this was not significant. A multivariate model of these deaths showed parental unemployment to be the most significant factor (OR = 27.74; 95% CI: 3.19–241.34). Short gestational age (OR = 11.67; 95% CI: 1.84–74.14), neonatal problems (OR = 14.27; 95% CI: 1.89–107.81), and higher prevalence of males (OR = 9.26; 95% CI: 1.63–52.52) were also significant. Half of the deaths from infection occurred in crowded households (>1 adult or child per room excluding hallways, toilets, bathrooms, and kitchens if not used as a dining room) which was also a significant factor (OR = 10.37; 95% CI: 1.08–99.59). Conclusions. The study identifies changes in the epidemiologic characteristics of SIDS that have followed the “Back to Sleep” campaign, and confirms that many underlying factors are similar between infants who die as SIDS and those dying suddenly of explained causes. Many studies investigating SIDS have reported numerous epidemiologic characteristics and risk factors strongly associated with SIDS when compared with live control infants. It has been generally assumed that these factors are specific to SIDS to the extent that the syndrome has been described as an “epidemiologic entity.” Many of the factors associated with SIDS that were significantly different from the control population were not significantly different when compared with the explained deaths. This suggests that SUDI share some of the same underlying factors irrespective of the clinical or pathologic findings, and challenges a rigid concept of SIDS as an epidemiologic entity. The particular finding that the incidence of maternal smoking during pregnancy, although high among mothers of explained SUDI infants, was significantly higher among SIDS mothers, lends weight to the mounting evidence that the association between smoking and SIDS may be part of a causal mechanism.

Sudden infant death syndrome and sleeping position in pre-term and low birth weight infants: an opportunity for targeted intervention

Aims: To determine the combined effects of sudden infant death syndrome (SIDS) risk factors in the sleeping environment for infants who were “small at birth” (pre-term (<37 weeks), low birth weight (<2500 g), or both). Methods: A three year population based, case-control study in five former health regions in England (population 17.7 million) with 325 cases and 1300 controls. Parental interviews were carried out after each death and reference sleep of age matched controls. Results: Of the SIDS infants, 26% were “small at birth” compared to 8% of the controls. The most common sleeping position was supine, for both controls (69%) and those SIDS infants (48%) born at term or ⩾2500 g, but for “small at birth” SIDS infants the commonest sleeping position was side (48%). The combined effect of the risk associated with being “small at birth” and factors in the infant sleeping environment remained multiplicative despite controlling for possible confounding in the multivariate model. This effect was more than multiplicative for those infants placed to sleep on their side or who shared the bed with parents who habitually smoked, while for those “small at birth” SIDS who slept in a room separate from the parents, the large combined effect showed evidence of a significant interaction. No excess risk was identified from bed sharing with non-smoking parents for infants born at term or birth weight ⩾2500 g. Conclusion: The combined effects of SIDS risk factors in the sleeping environment and being pre-term or low birth weight generate high risks for these infants. Their longer postnatal stay allows an opportunity to target parents and staff with risk reduction messages.

Pacifier use and sudden infant death syndrome: results from the CESDI/SUDI case control study

OBJECTIVES To investigate the relation between pacifier use and sudden infant death syndrome (SIDS). DESIGN Three year population based, case control study with parental interviews for each death and four age matched controls. SETTING Five regions in England (population > 17 million). SUBJECTS 325 infants who had died from SIDS and 1300 control infants. RESULTS Significantly fewer SIDS infants (40%) than controls (51%) used a pacifier for the last/reference sleep (univariate odds ratio (OR), 0.62; 95% confidence interval (CI), 0.46 to 0.83) and the difference increased when controlled for other factors (multivariate OR, 0.41; 95% CI, 0.22 to 0.77). However, the proportion of infants who had ever used a pacifier for day (66% SIDS v 66% controls) or night sleeps (61% SIDS v 61% controls) was identical. The association of a risk for SIDS infants who routinely used a pacifier but did not do so for the last sleep became non-significant when controlled for socioeconomic status (bivariate OR, 1.39 (0.93 to 2.07)). CONCLUSIONS Further epidemiological evidence and physiological studies are needed before pacifier use can be recommended as a measure to reduce the risk of SIDS. Key messages There was no difference between victims of SIDS and control infants in routine use of a pacifier (“dummy” or “soother”) for day or night sleeps The use of a pacifier was associated with a lower prevalence and shorter duration of breast feeding, lower socioeconomic status, and mothers who smoked more heavily There was no association between pacifier use and sleeping position More control infants used a pacifier for the last/reference sleep, giving an apparent “protective” effect against SIDS; the significance of this association increased when controlled for other factors Further epidemiological evidence and physiological studies are needed before we can recommend pacifier use as protective against SIDS

The UK accelerated immunisation programme and sudden unexpected death in infancy: case-control study

Abstract Objectives: To investigate whether the accelerated immunisation programme in the United Kingdom is associated, after adjustment for potential confounding, with the sudden infant death syndrome. Design: Population based case-control study, February 1993 to March 1996. Parental interviews were conducted for each death and for four controls matched for age, locality, and time of sleep. Immunisation status was taken from records held by the parents. Setting: Five regions in England with a combined population of over 17 million. Subjects: Immunisation details were available for 93% (303/325) of infants whose deaths were attributed to the sudden infant death syndrome (SIDS); 90% (65/72) of infants with explained sudden deaths; and 95% (1515/1588) of controls. Results: After all potential confounding factors were controlled for, immunisation uptake was strongly associated with a lower risk of SIDS (odds ratio 0.45 (95% confidence interval 0.24 to 0.85)). This difference became non-significant (0.67 (0.31 to 1.43)) after further adjustment for other factors specific to the infants sleeping environment. Similar proportions of SIDS deaths and reference sleeps (corresponding to the time of day during which the index baby had died) among the controls occurred within 48 hours of the last vaccination (5% (7/149) v 5% (41/822)) and within two weeks (21% (31/149) v 27% (224/822)). No longer term temporal association with immunisation was found (P=0.78). Of the SIDS infants who died within two weeks of vaccination, 16% (5/31) had signs and symptoms of illness that suggested that medical contact was required, compared with 26% (16/61) of the non-immunised SIDS infants of similar age. The findings for the infants who died suddenly and unexpectedly but of explained causes mirrored those for SIDS infants. Conclusions: Immunisation does not lead to sudden unexpected death in infancy, and the direction of the relation is towards protection rather than risk. What is already known on this topic Some studies have suggested a link between the sudden infant death syndrome and primary immunisation, but most have failed to show a link Potential bias in the studies includes lack of a comparative control group with similar low immunisation uptake and misclassification of cause of death What this study adds This study investigated explained sudden infant deaths as well as the sudden infant death syndrome and took into account potential bias After confounding was controlled for, immunisation uptake was lowest among the infants who died, with no temporal relation or correlation with signs and symptoms of illness

A clinical comparison of SIDS and explained sudden infant deaths: how healthy and how normal?

OBJECTIVES To compare the clinical characteristics associated with sudden infant death syndrome (SIDS) and explained sudden unexpected deaths in infancy (SUDI). DESIGN Three year population based, case control study with parental interviews for each death and four age matched controls. SETTING Five regions in England (population, > 17 million; live births, > 470 000). SUBJECTS SIDS: 325 infants; explained SUDI: 72 infants; controls: 1588 infants. RESULTS In the univariate analysis, all the clinical features and health markers at birth, after discharge from hospital, during life, and shortly before death, significant among the infants with SIDS were in the same direction among the infants who died of explained SUDI. In the multivariate analysis, at least one apparent life threatening event had been experienced by more of the infants who died than in controls (SIDS: 12% v 3% controls; odds ratio (OR) = 2.55; 95% confidence interval (CI), 1.02 to 6.41; explained SUDI: 15% v 4% controls; OR = 16.81; 95% CI, 2.52 to 112.30). Using a retrospective illness scoring system based on “Baby Check”, both index groups showed significant markers of illness in the last 24 hours (SIDS: 22%v 8% controls; OR = 4.17; 95% CI, 1.88 to 9.24; explained SUDI: 49% v 8% controls; OR = 31.20; 95% CI, 6.93 to 140.5). CONCLUSIONS The clinical characteristics of SIDS and explained SUDI are similar. Baby Check might help identify seriously ill babies at risk of sudden death, particularly in high risk infants. Key messages There are clinical features and health markers characterising increased vulnerability of infants who die suddenly and unexpectedly that are evident at birth, during life, and just before death These features, important among the infants with sudden infant death syndrome, are in the same direction among the explained sudden unexpected deaths Clinical features common to both groups of explained and unexplained deaths after controlling for possible confounders included a higher prevalence of an apparent life threatening event and ill health in the 24 hours before death “Baby Check” might help identify seriously ill babies at risk of sudden death, particularly in high risk infants

Commissioning complementary medicine.

The opportunities presented to commissioning health authorities to decide what health care to purchase for local people has also provided an opportunity to rethink old prejudices. The old prejudices against complementary medicine are being rethought for several reasons. Firstly, many commissioning authorities and fundholding general practitioners are either commissioning or providing complementary medicine as part of routine contracting.1 Financially, this is marginal activity, costing typically less than pounds sterling20000 a year out of an average authority budget of pounds sterling200m. Also some complementary medicines, such as acupuncture and homoeopathy, have been part of normal NHS activity for many years and this has blurred the margins between conventional and complementary medicine. Secondly, the medical profession has relaxed its attitude toward complementary medicine over the past decade.2 Thirdly, both main political parties support the development of …

Weight gain and sudden infant death syndrome: changes in weight z scores may identify infants at increased risk

AIMS To investigate patterns of infant growth that may influence the risk of sudden infant death syndrome (SIDS). DESIGN Three year population based case control study with parental interviews for each death and four age matched controls. Growth was measured from prospective weight observations using the British 1990 Growth Reference. SETTING Five regions in England (population greater than 17 million, more than 470 000 live births over three years). SUBJECTS 247 SIDS cases and 1110 controls. RESULTS The growth rate from birth to the final weight observation was significantly poorer among the SIDS infants despite controlling for potential confounders (SIDS mean change in weight z score (δzw) = −0.38 (SD 1.40)v controls = +0.22 (SD 1.10), multivariate: p < 0.0001). Weight gain was poorer among SIDS infants with a normal birth weight (above the 16th centile: odds ratio (OR) = 1.75, 95% confidence interval (CI) 1.48–2.07, p < 0.0001) than for those with lower birth weight (OR = 1.09, 95% CI 0.61–1.95, p = 0.76). There was no evidence of increased growth retardation before death. CONCLUSIONS Poor postnatal weight gain was independently associated with an increased risk of SIDS and could be identified at the routine six week assessment. Key messages The lower weight of SIDS infants compared to the control infants which was apparent at birth was even more notable in the two weeks before death SIDS infants, particularly those of normal birth weight, exhibited poorer weight gain than their controls Although poor growth was evident among SIDS infants there was no evidence of accelerated retardation in the weeks prior to death The difference in growth between SIDS and control infants was apparent within the first five to seven weeks of life

Development of a real-time acoustic backscatter system for solids concentration measurement during nuclear waste cleanup

The measurement of the concentration of solid particles in suspension without physical sampling is a necessary tool for the nuclear industry involved with cleanup of a significant quantity of legacy waste in the form of sludge. This paper presents the work of a project to develop acoustic instrumentation for the in-situ characterization of such sludge. The measurement principle and signal processing employed is presented along with the design of a custom acoustic instrument for deployment in nuclear and industrial environments. The paper presents experimental results demonstrating the ability of the technique for the online measurement of mass concentration in a suspension of glass power in water.