Infant temperament characteristics related to sudden infant death syndrome and its risk factors

Three major components have been repeatedly implicated for the origin(s) of sudden infant death syndrome (SIDS): system, minor sickness and surroundings. All these factors also frame infant temperament, and therefore it seems logical to suppose that the babies who either succumb to or are at risk of SIDS may present with certain behavioural features. The infants who have died of SIDS moved less when lying awake in the crib, during feeding and during nail cutting; less often turned their head away and looked for their mother when held by a new person; were more frequently reported to show an extreme response (either almost never protested or almost always objected) when approached by someone other than main caregiver; and exhibited extreme behavioural patterns when the infant's vocalising on waking up was studied. The infants who died of SIDS had lower activity scores. An unfavourable microenvironment can increase the risk of SIDS, and the babies facing less developmental stimulation had a more negative mood and were less distractible; less organised infants presented with a more negative mood, less distractible behaviour, lower rhythmicity, lower persistence and lower adaptability. The infants born to smoking mothers who are at risk of SIDS had more intensive reactions. The low-birth-weight infants who are at high risk of SIDS were more withdrawing and less adaptable. Infant-parent(s) bed sharing may increase the risk of SIDS, and solitary sleeping infants had a more positive mood and were more persistent. Use of a pacifier may be protective against SIDS, and pacifier users presented with higher rhythmicity. Prone sleep is known to increase the risk of SIDS, and the lowest persistence was a feature of those babies who were usually put to sleep supine and found prone. Infants who snored and/or had noisy breathing in sleep were characterised by more negative mood. Infants with signs of repetitive regurgitation were less distractible.     

深圳市婴儿睡眠现状流行病学研究

【目的】 通过对深圳市婴儿睡眠现状的调查研究,了解婴儿睡眠存在的问题,分析可能影响婴儿睡眠问题的危险因素,为儿科和儿童保健工作者解决婴儿睡眠问题提供科学依据。 【方法】 采用分层随机整群抽样的方法抽取全市5家社区健康服务中心共904名婴儿父母进行问卷调查及气质测试。 【结果】 深圳市婴儿睡眠问题发生率为43.0%; 2) 婴儿睡眠姿势6月龄前以仰卧为主,6月龄后侧卧、不固定姿势均随着月龄增长逐渐增多, 婴儿自行入睡及需外界帮助入睡方式均与月龄无关;3)影响婴儿睡眠问题的主要因素有父母缺乏睡眠知识,婴儿难养型气质、夜间睡眠开灯等。 【结论】 婴儿睡眠问题已引起父母广泛关注,父母缺乏睡眠知识而又过多干预婴儿睡眠,是婴儿建立正常的睡眠模式主要相关危险因素。     

Clinical inquiries: What are safe sleeping arrangements for infants?

Non-supine sleep position and parental tobacco use are known risk factors for sudden infant death syndrome (SIDS). Recent studies show that co-sleeping (bed sharing) slightly increases the overall risk of SIDS (strength of recommendation [SOR]: B) and is greatest for infants less than 11 weeks old (SOR: B). The relationship between bed sharing and SIDS is strongest for infants whose parents use tobacco (SOR: B). Infants who sleep in a room separate from their caregivers or on a couch or an armchair are at increased risk for SIDS (SOR: B). Using bedding accessories such as duvets or pillows may increase an infant's risk of SIDS (SOR: B).     

Factors associated with bed sharing and sleep position in Thai neonates

Background   Sleep in a supine position and in a bed separate from but proximate to adults is recommended, in several Western countries, to prevent Sudden Infant Death Syndrome (SIDS). Cultural differences and a lower rate of SIDS in Asian populations may affect concern with this problem and thus infant sleeping arrangements.
Objective   To study bed sharing and sleep position in Thai neonates and the relationship to infant and maternal characteristics.
Methods   A cross-sectional survey based on interviews with parents of infants aged 21 days old, was conducted under the Prospective Cohort Study of Thai Children.
Results   Of the total sample, 2236/3692 (60.6%) infants shared a bed with their parents. Sixty per cent of the parents placed their infants to sleep in a supine position, 32.2% on their side and 4.9% in a prone position. Bed sharing was associated with older maternal age, higher education, Muslim mother, and with work status of professional career or unemployed. Placing the infants to sleep in a prone position was associated with infant birth weight of greater than 2500 g, older maternal age, higher education, Buddhist mother, mother with professional career and middle-class household economic status.
Conclusions   Infant bed sharing is a common practice in the Thai culture, as in other Asian countries. The prone sleep position is less common than in Western populations. The main factor associated with both bed sharing and putting infants to sleep in the prone position was a higher maternal socioeconomic status (SES), in contrast to previous studies in some Western countries in which both practices were associated with low maternal SES. Cultural differences may play an important role in these different findings.     

Pacifier Use and Sids: Evidence for a Consistently Reduced Risk

Pacifier use at sleep time decreases sudden infant death syndrome (SIDS) risk. It is yet unclear whether pacifier use can modify the impact of other sleep-related factors upon SIDS risk. The objective of this study was to examine the association between pacifier use during sleep and SIDS in relation to other risk factors and to determine if pacifier use modifies the impact of these risk factors. Data source was a population based case–control study of 260 SIDS deaths and 260 matched living controls. Pacifier use during last sleep decreased SIDS risk (aOR 0.30, 95% CI 0.17–0.52). Furthermore, pacifier use decreased SIDS risk more when mothers were ≥20 years of age, married, nonsmokers, had adequate prenatal care, and if the infant was ever breastfed. Pacifier use also decreased the risk of SIDS more when the infant was sleeping in the prone/side position, bedsharing, and when soft bedding was present. The association between adverse environmental factors and SIDS risk was modified favorably by pacifier use, but the interactions between pacifier use and these factors were not significant. Pacifier use may provide an additional strategy to reduce the risk of SIDS for infants at high risk or in adverse sleep environments.     

Evaluation of child care practice factors that affect the occurrence of sudden infant death syndrome: Interview conducted by public health nurses

We examined the child-rearing environmental factors that affect the occurrence of sudden infant death syndrome (SIDS) using a nationwide survey. Infants who died due to SIDS between January 1996 and June 1997 in Japan were identified from death certificates. Controls of the same gender, birthplace, and birth months as the corresponding SIDS were chosen from birth certificates. Interviews of both cases and controls were undergone in January and February, 1998 by public health nurses. The following child-rearing factors exhibited a significant relationship with the occurrence of SIDS: Concerning the sleeping position, the prone position was associated with increased risk compared with the supine position, with an odds ratio of 3.02 (95% c.i. 2.07–4.65). Regarding the feeding method, artificial feeding alone demonstrated a higher risk than breast feeding alone, with an odds ratio of 4.92 (95% c.i. 2.78–9.63). With regard to smoking, infants with both parents who smoked exhibited a higher risk than infants where neither parent smoked, with an odds ratio of 3.50 (95% c.i. 1.74–8.32).     

Infant care practices related to sudden infant death syndrome in South Asian and White British families in the UK

In the UK, infants of South Asian parents have a lower rate of sudden infant death syndrome (SIDS) than White British infants. Infant care and life style behaviours are strongly associated with SIDS risk. This paper describes and explores variability in infant care between White British and South Asian families (of Bangladeshi, Indian or Pakistani origin) in Bradford, UK (the vast majority of which were Pakistani) and identifies areas for targeted SIDS intervention. A cross-sectional telephone interview study was conducted involving 2560 families with 2- to 4-month-old singleton infants enrolled in the Born in Bradford cohort study. Outcome measures were prevalence of self-reported practices in infant sleeping environment, sharing sleep surfaces, breast feeding, use of dummy or pacifier, and life style behaviours. We found that, compared with White British infants, Pakistani infants were more likely to: sleep in an adult bed (OR = 8.48 [95% CI 2.92, 24.63]); be positioned on their side for sleep (OR = 4.42 [2.85, 6.86]); have a pillow in their sleep environment (OR = 9.85 [6.39, 15.19]); sleep under a duvet (OR = 3.24 [2.39, 4.40]); be swaddled for sleep (OR = 1.49 [1.13, 1.97]); ever bed-share (OR = 2.13 [1.59, 2.86]); regularly bed-share (OR = 3.57 [2.23, 5.72]); ever been breast-fed (OR = 2.00 [1.58, 2.53]); and breast-fed for 8+ weeks (OR = 1.65 [1.31, 2.07]). Additionally, Pakistani infants were less likely to: sleep in a room alone (OR = 0.05 [0.03, 0.09]); use feet-to-foot position (OR = 0.36 [0.26, 0.50]); sleep with a soft toy (OR = 0.52 [0.40, 0.68]); use an infant sleeping bag (OR = 0.20 [0.16, 0.26]); ever sofa-share (OR = 0.22 [0.15, 0.34]); be receiving solid foods (OR = 0.22 [0.17, 0.30]); or use a dummy at night (OR = 0.40 [0.33, 0.50]). Pakistani infants were also less likely to be exposed to maternal smoking (OR = 0.07 [0.04, 0.12]) and to alcohol consumption by either parent. No difference was found in the prevalence of prone sleeping (OR = 1.04 [0.53, 2.01]). Night-time infant care therefore differed significantly between South Asian and White British families. South Asian infant care practices were more likely to protect infants from the most important SIDS risks such as smoking, alcohol consumption, sofa-sharing and solitary sleep. These differences may explain the lower rate of SIDS in this population.     

Airway covering during bed-sharing

Background Parent–infant bed‐sharing is a common practice in Western post‐industrial nations with up to 50% of infants sleeping with their parents at some point during early infancy. However, researchers have claimed that infants may be at risk of suffocation or sudden infant death syndrome related to airway covering or compression in the bed‐sharing environment. To further understand the role of airway covering and compression in creating risks for bed‐sharing infants, we report here on a sleep‐lab trial of two infant sleep conditions. Methods In a sleep‐lab environment 20 infants aged 2–3 months old slept in their parents' bed, and in a cot by the bed, on adjacent nights. Infants' oxygen saturation and heart rate were monitored physiologically while infant and parental behaviours were recorded via ceiling‐mounted infra‐red cameras. Infants served as their own controls. Continuous 8‐h recordings were obtained for covering of infant external airways, levels of infant oxygen saturation, infant heart rate, evidence of parental compression/overlying of infant, circumstances leading up to potential infant airway obstruction, and parental awareness of and responses to infant airway covering. Results The majority of infants (14/20) spent some part of the bed night with their airways (both mouth and nose) covered, compared with 2/20 on the cot night; however, no consistent effect on either oxygen saturation levels or heart rate was revealed, even during prolonged bouts of airway covering. All cases of airway covering were initiated by parents; 70% were terminated by parents, the remainder by infants. Seven bouts of potential compression were observed with parental limbs resting across infant bodies for lengthy periods, however, in only two cases was the full weight of a parental limb resting on an infant, both events lasting less than 15 s, both being terminated by infant movement. Conclusion Although numerous authors have suggested that bed‐sharing infants face risks because of airway covering by bed‐clothes or parental bodies, the present trial does not lend support to this hypothesis.     

Evaluation of child-rearing environmental factors that affect the occurrence of sudden infant death syndrome: interview conducted by public health nurses]

PURPOSE: We examined the child-rearing environmental factors that affect the occurrence of sudden infant death syndrome (SIDS) by using a nation-wide survey. METHOD: Infants who died due to SIDS between January 1996 and June 1997 in Japan were identified from death certificates. Controls of the same sex, birthplace, and birth months as the corresponding SIDS were chosen from birth certificates. Interviews of both cases and controls were undergone in January and February 1998 by public health nurses. RESULTS: The following Child-rearing factors exhibited a significant relationship with the occurrence of SIDS: 1. Concerning the sleeping position, the prone position was associated with increased risk compared to the supine position, with an odds ratio of 3.02 (95% c.i. 2.07-4.65). 2. Regarding the feeding method, artificial feeding only demonstrated a higher risk than breast feeding only, with an odds ratio of 4.92 (95% c.i. 2.78-9.63). 3. With regard to smoking, infants with both parents who smoked exhibited a higher risk than infants where neither parents smoked, with an odds ratio of 3.50 (95% c.i. 1.74-8.32).     

Health Messaging and African–American Infant Sleep Location: A Randomized Controlled Trial

Infant-parent bedsharing increases the risk of SIDS and other sleep-related deaths. Despite AAP recommendations to avoid bedsharing, public health efforts have been unsuccessful in changing behaviors. African–American infants are more than twice as likely to die from SIDS and other sleep-related deaths, and are also twice as likely to bedshare with their parents. Further, African–American parents have a high degree of self-efficacy with regards to preventing infant suffocation, but low self-efficacy with regards to SIDS risk reduction. It is unclear whether messages emphasizing suffocation prevention will decrease bedsharing. To evaluate the impact of specific health messages on African–American parental decisions regarding infant sleep location. We conducted a randomized, controlled trial of African–American mothers of infants. The control group received standard messaging emphasizing AAP-recommended safe sleep practices, including avoidance of bedsharing, for the purposes of SIDS risk reduction. The intervention group received enhanced messaging emphasizing safe sleep practices, including avoidance of bedsharing, for both SIDS risk reduction and suffocation prevention. Participants completed interviews at 2–3 weeks, 2–3 months, and 5–6 months after the infant’s birth. 1194 mothers were enrolled in the study, and 637 completed all interviews. Bedsharing, both usually (aOR 1.005 [95 % CI 1.003, 1.006]) and last night (aOR 1.004 [95 % CI 1.002, 1.007]) increased slightly but statistically significantly with infant age (p < 0.001). Receipt of the enhanced message did not impact on sleep location. Maternal belief that bedsharing increased the risk of SIDS or suffocation declined over 6 months (p < 0.001) and did not differ by group assignment. African–American mothers who received an enhanced message about SIDS risk reduction and suffocation prevention were no less likely to bedshare with their infants. Clinical Trials Registration: Clinical Trials.gov identifier NCT01361880     

Review of risk factors for sudden infant death syndrome

Sudden infant death syndrome (SIDS) accounts for the largest number of deaths during the first year of life in developed countries. The possible causes of SIDS are numerous and, to date, there is no adequate unifying pathological explanation for SIDS. Epidemiological studies have played a key role in identifying risk factors, knowledge of which has underpinned successful preventive programmes. This review critically assesses information on the main risk factors and causal hypotheses put forward for SIDS, focusing on research published since 1994. The overall picture that emerges from this review is that affected infants are not completely normal in development, but possess some inherent weakness, which may only become obvious when the infant is subjected to stress. Initially there may be some minor impairment or delay in development of respiratory, cardiovascular or neuromuscular function. None of these is likely to be sufficient, in isolation, to cause death and, provided the infant survives the first year of life, may no longer be of any significance. However, when a compromised infant is confronted with one or more stressful situations, several of which are now clearly identified as risk factors, and from which the majority of infants would normally escape, the combination may prove fatal.     

Sudden infant death syndrome and social deprivation: assessing epidemiological factors after post-matching for deprivation

As part of the confidential enquiry into stillbirths and deaths in infancy (CESDI), a 3-year population-based case-control study was specifically designed to look at risk factors associated with sudden infant death syndrome (SIDS) after the dramatic fall in incidence. The study was conducted between 1993 and 1996 in five English Health Regions (population 17 million) with parental interviews for each death and four age-matched controls. The aim of this analysis was to investigate the extent to which epidemiological characteristics associated with SIDS were particular to the syndrome or more general markers for socio-economic deprivation. One control was reassigned to each case post-matched for infant age, time of sleep and socio-economic status using components of the Townsend Deprivation Score. The post-matched analysis involved 323 SIDS infants and 323 controls with a similar socio-economic profile. Notable factors significant in the original univariable analysis that became non-significant after post-matching included young maternal age (median: 23 years 4 months SIDS vs. 23 years 11 months post-matched controls), being an unsupported mother (13.6% SIDS vs. 11.1% post-matched controls) and being bottle-fed (56.7% SIDS vs. 55.4% post-matched controls). Other factors, although clearly related to deprivation, such as parental smoking, remained significant in both the univariable and multivariable post-matched analyses.     

Grandmothers’ Beliefs and Practices in Infant Safe Sleep

Background Sudden infant death syndrome (SIDS) and suffocation are leading causes of infant mortality. Supine sleep position and use of appropriate sleep surfaces reduce SIDS risk but are not universally practiced. Mothers’ decisions about sleep position and environment may be influenced by guidance provided by infants’ grandmothers and other caregivers. Methods A survey was conducted of a convenience sample of grandmothers aged 30–70 years who provide care at least weekly for an infant grandchild <6 months old. The survey was distributed through community partners of a university-based research team. Respondents received home safety items as compensation. Analyses focused on the relationship of grandmother demographic characteristics and beliefs on their reported practices related to infant sleep. Results Among the 239 grandmothers, 45 % reported placing infants to sleep supine on an appropriate sleep surface at the grandmother’s house, while 58 % reported doing so when the infant was sleeping in the mother’s house. After adjusting for other factors, respondents were less likely to adhere to recommended guidelines when they believed supine position increased choking risk (OR 0.34, 95 % CI 0.18–0.62) or believed infants are more comfortable or sleep longer when on their stomachs (OR 0.51, 95 % CI 0.28–0.93). Discussion Grandmothers do not universally observe evidence-based safe sleep practices, particularly if the infant is not sleeping in the home of the parent. Interventions for senior caregivers focused on perceived choking risk, infant comfort in the supine position, and other recent changes in recommended safety practices are warranted.     

Sudden infant death syndrome: the times are changing

Case-control studies of sudden infant death syndrome (SIDS) in the Netherlands have shown a number of important risk factors, including prone sleeping position, the use of a duvet, the use of sedating antihistamines, and bed-sharing with parents. After issuing preventive advice to avoid these risk factors, the SIDS mortality rate has decreased dramatically in the Netherlands, from 100 cases per 100,000 live births per year in the 1980s to 10-15 cases in recent years. Recent cohort studies of SIDS infants suggest that new risk factors are emerging. For example, SIDS now occurs increasingly while the infants are in day care. Such associations should be examined in case-control studies before preventive advice can be given. The Dutch SIDS risk-factor studies are an example of how epidemiologic studies can have a great impact on public health.     

Infant nutrition – protein and its influence on growth rate

Breastfeeding provides the optimum nutrition for young infants and one of the aims of the new UK‐World Health Organization growth charts is to encourage healthcare professionals and parents to see breastfed infants' growth rate as the norm. Formula‐fed infants gain weight more quickly than breastfed infants in the first year of life, and this may be because of the greater quantity of protein in infant formula. Childhood obesity rates are increasing and obesity is probably the result of a multitude of factors. Observational studies have indicated that rapid growth in infancy may contribute to a later risk of obesity. New randomised controlled studies have shown that lower protein levels in infant formula can slow infants' weight gain, and this may offer short‐ and long‐term health benefits. New innovations in protein quality now allow reductions in the total protein content of infant formula.     

Risk factors for sudden infant death syndrome in the US Collaborative Perinatal Project

Risk factors for sudden infant death syndrome (SIDS) were studied among infants born to the nearly 56,000 women enrolled in the US Collaborative Perinatal Project from 1959 through 1966. The 193 SIDS cases identified in the cohort were compared with 1930 controls randomly selected from infants who survived the first year of life. The previously documented excess risk associated with black race disappeared after adjusting for maternal education and family income. Maternal smoking, maternal anaemia during pregnancy, and lack of early prenatal care were all positively associated with SIDS. After adjustment for gestational age, infants with low weight and length at birth were still at increased SIDS risk, suggesting that intrauterine growth retardation may be a risk factor. Neurological abnormalities diagnosed before death were associated with SIDS, but much of the association was removed by adjusting for birthweight. The negative association of breastfeeding with SIDS was much reduced upon adjustment by maternal education and birthweight. These findings may have important implications in our understanding of the epidemiology of SIDS.     

西安市婴儿睡眠问题与母亲睡眠质量和情绪的相关性研究

【目的】 通过对婴儿睡眠情况的调查,了解西安市婴儿睡眠问题现况,探讨婴儿母亲可能影响婴儿睡眠的危险因素,为促进婴儿健康睡眠提供科学依据。 【方法】 对2011年9-11月在陕西省妇幼保健院儿童保健门诊体检的1 196名1~12个月龄健康婴儿进行睡眠评估,对其中1、6、12月婴儿母亲采用匹兹堡睡眠质量指数(pittsburgh sleep quality index,PSQI)量表和抑郁自评(Self-Rating Depression Scale,SDS)量表分别进行睡眠质量和抑郁症状评估。 【结果】 西安市婴儿睡眠问题发生率为40.47%;睡眠问题组婴儿的母亲PSQI总分整体高于正常组婴儿母亲,主要表现在睡眠质量、睡眠时间、睡眠效率和日间功能等因子上,以及睡眠障碍因子(6月)和入睡时间因子(12月)得分高于正常组;1月、6月睡眠问题组婴儿母亲SDS标准分明显高于正常组。 【结论】 1~12月婴儿睡眠问题的发生率较高,婴儿睡眠问题与母亲的睡眠质量和情绪状态有关,应及时发现不良因素,以预防婴儿睡眠问题的发生,促进婴儿健康发育。     

Infant sleeping position and the sudden infant death syndrome: systematic review of observational studies and historical review of recommendations from 1940 to 2002

BACKGROUND: Before the early 1990s, parents were advised to place infants to sleep on their front contrary to evidence from clinical research. METHODS: We systematically reviewed associations between infant sleeping positions and sudden infant death syndrome (SIDS), explored sources of heterogeneity, and compared findings with published recommendations. RESULTS: By 1970, there was a statistically significantly increased risk of SIDS for front sleeping compared with back (pooled odds ratio (OR) 2.93; 95% confidence interval (CI) 1.15, 7.47), and by 1986, for front compared with other positions (five studies, pooled OR 3.00; 1.69-5.31). The OR for front vs the back position was reduced as the prevalence of the front position in controls increased. The pooled OR for studies conducted before advice changed to avoid front sleeping was 2.95 (95% CI 1.69-5.15), and after was 6.91 (4.63-10.32). Sleeping on the front was recommended in books between 1943 and 1988 based on extrapolation from untested theory. CONCLUSIONS: Advice to put infants to sleep on the front for nearly a half century was contrary to evidence available from 1970 that this was likely to be harmful. Systematic review of preventable risk factors for SIDS from 1970 would have led to earlier recognition of the risks of sleeping on the front and might have prevented over 10 000 infant deaths in the UK and at least 50 000 in Europe, the USA, and Australasia. Attenuation of the observed harm with increased adoption of the front position probably reflects a "healthy adopter" phenomenon in that families at low risk of SIDS were more likely to adhere to prevailing health advice. This phenomenon is likely to be a general problem in the use of observational studies for assessing the safety of health promotion.     

慈溪市农村婴幼儿营养不良影响因素及防治措施研究

【目的】 了解慈溪市农村婴幼儿营养不良现状和主要影响因素,为制定农村婴幼儿营养不良的预防策略和干预措施提供科学依据。【方法】 采用多层机械抽样,以农村婴幼儿为研究对象,测量其身长和体重,并对婴幼儿家长进行问卷调查。【结果】 多因素分析显示,男童、双胎、年龄越大、早产、低出生体重、疾病、父母年龄大、文化程度低、父母职业为农民工的婴幼儿易发生营养不良。【结论】 防治农村婴幼儿营养不良需在发展农村经济的同时,加强妇幼保健,降低早产和低出生体重儿的发生率,普及科学育儿知识。