Smoking during pregnancy and poor antenatal care: two major preventable risk factors for sudden infant death syndrome

[Sudden infant death syndrome: Do the parents follow the recommendations?]

INTRODUCTION

Prone sleeping position is the main known modifiable risk factor for sudden infant death syndrome (SIDS). There are other SIDS recommendations although with less impact. The objective of this study is to describe the prevalence of prone position during sleep as well as other risk factors associated with SIDS in a sample of Spanish babies and infants.

METHODS

Cross-sectional study carried out on 640 families with children from 0 months to 11 months. In addition to the sleep position, the adherence to four other recommendations regarding SIDS was analysed: place where infant sleeps, breastfeeding, use of non-nutritive suction, and maternal smoking.

RESULTS

A total of 41.3% of infants under 6 months and 59.7% of infants aged 6 to 11 months slept in a non-recommended position. Only 6.4% of families analysed followed all five recommendations.

DISCUSSION

There is a high prevalence of modifiable risk factors for SIDS among the studied population. Personalized education should be promoted, along with other campaigns to raise awareness and prevent SIDS.

Sudden infant death syndrome: exposure to cigarette smoke leads to hypomethylation upstream of the growth factor independent 1 (GFI1) gene promoter

PURPOSE

Smoking during pregnancy has long been known as an important risk factor for sudden infant death syndrome (SIDS). However, the precise relationship between the smoking behavior of the mother and SIDS still remains unclear. In this study, the influence of prenatal smoking exposure on the childrens' DNA methylation state of a CpG island located upstream of the promoter of the growth factor independent 1 (GFI1) gene was analyzed.

METHODS

Blood samples of well-defined SIDS cases with non-smoking mothers (n = 11), SIDS cases with smoking mothers during pregnancy (n = 11), and non-SIDS cases (n = 6) were obtained from a previous study and methylation states were determined by bisulfite sequencing.

RESULTS

Significant hypomethylation was observed in this CpG island in SIDS cases with cigarette smoke exposure compared to non-exposed cases. The strongest effect in this CpG island was observed for 49 CpG sites located within a transcription factor binding site. Coding for a transcriptional repressor, GFI1 plays an important role in various developmental processes. Alterations in the GFI1 expression might be linked to various conditions that are known to be associated with SIDS, such as dysregulated hematopoiesis and excessive inflammatory response.

CONCLUSION

Data obtained in this study show that analysis of methylation states in cases of sudden infant death syndrome might provide a further important piece of knowledge toward understanding SIDS, and should be investigated in further studies.

Social Disparities in Maternal Smoking during Pregnancy: Comparison of Two Birth Cohorts (1996-2002 and 2003-2012) Based on Data from the German KiGGS Study

Background: Maternal smoking during pregnancy represents a significant developmental risk for the unborn child. This study investigated social differences in maternal smoking behavior during pregnancy in mothers living in Germany. The study focused on maternal age at delivery, social status and migration background. Method: The evaluation of data was based on two surveys carried out as part of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) carried out in 2003-2006 and in 2009-2012. The study compared the information given by parents of children aged between 0 and 6 years who were born either in the period from 1996 to  2002 (KiGGS baseline study, n = 4818) or in the period from 2003 to 2012 (KiGGS Wave 1, n = 4434). Determination of social status was based on parental educational levels, occupational position and income. Children classified as having a two-sided migration background either had parents, both of whom had immigrated to Germany, or were born abroad and had one parent who had immigrated to Germany; children classified as having a one-sided migration background had been born in Germany but had one parent who had immigrated to Germany. Results: The percentage of children whose mothers had smoked during pregnancy was 19.9 % for the older birth cohort and 12.1 % for the younger birth cohort. In both birth cohorts, the probability of being exposed to tobacco smoke was twice as high for children whose mothers were aged < 25 years at delivery compared to the children of older mothers. Children from socially deprived families were most affected by smoking behavior, and the relative social differences were found to have even increased over time (KiGGS baseline study: OR = 6.34; 95 % CI = 4.53-8.86; KiGGS Wave 1: OR = 13.88; 95 % CI = 6.85-28.13). A two-sided migration background was associated with a lower risk of exposure to smoking. Conclusions: The KiGGS results are in accordance with the results of other national and international studies which have shown that the percentage of mothers who smoke during pregnancy is declining. Because of a change in the method how data are collected for the KiGGS survey (written questionnaire vs. telephone interview) the trend results must be interpreted with caution. Measures aimed at preventing smoking and weaning women off smoking should focus particularly on younger and socially deprived mothers.

Incidence and determinants of sudden infant death syndrome: a population-based study on 37 million births

BACKGROUND

The objective of our study is to measure the incidence of sudden infant death syndrome (SIDS), estimate the birth to death interval, and identify associated maternal and infant risk factors.

METHODS

We carried out a population-based cohort study on 37 418 280 births using data from the Centers for Disease Control and Prevention's "Linked Birth-Infant Death" and "Fetal Death" data files from 1995 to 2004. Descriptive statistics and cox-proportional hazard models were used to estimate the adjusted effect of maternal and newborn characteristics on the risk of SIDS.

RESULTS

There were 24 101 cases of SIDS identified for an overall 10-year incidence of 6.4 cases per 10 000 births. Over the study period, the incidence decreased from 8.1 to 5.6 per 10 000 and appeared to be most common among infants aged 2-4 months. Risk factors included maternal age <20 years, black, non-Hispanic race, smoking, increasing parity, inadequate prenatal care, prematurity and growth restriction.

CONCLUSIONS

While the incidence of SIDS in the US has declined, it currently remains the leading cause of post-neonatal mortality, highlighting an important public health priority. Educational campaigns should be targeted towards mothers at increased risk in order to raise their awareness of modifiable risk factors for SIDS such as maternal smoking and inadequate prenatal care.

Nicotine and cotinine in infants dying from sudden infant death syndrome

The aim of this component of the German Study on Sudden Infant Death was to determine (1) nicotine concentrations in hair (NCH), as a marker of long standing exposure to tobacco, (2) cotinine concentrations in pericardial fluid (CCP) and (3) cotinine concentrations in liquor cerebrospinalis (CCL), the latter measures being markers of recent exposure to tobacco in the last few hours of life. The results obtained were compared with data on parental smoking revealed from interviews. In 100 cases of sudden infant death syndrome, material was taken at autopsy to determine NCH. In 41 cases, NCH and CCP, and in 70 cases, NCH and CCL were determined. Infants of mothers who stated having smoked during pregnancy had higher NCH than infants of non-smoking mothers (p = 0.008). Furthermore, there was a weak but statistically significant relationship between NCH's and the daily cigarette consumption of the mother during pregnancy (n = 64, r = 0.24, p = 0.05). In 43% of infants, nicotine could be detected in their hair, although the mothers had said at the interview that they did not smoke during pregnancy. On the other hand, in 33% of infants whose mother stated they had smoked during pregnancy nicotine was not detectable in the infant's hair. CCP's were strongly correlated with CCL's (r = 0.62, p = 0.0027). For this reason, both parameters were treated as equivalent for the detection of tobacco smoke exposure in the last hours before death. The influence of breast-feeding was evaluated by comparison of the nicotine concentrations in breast fed and non-breast-fed infants from smokers and non-smokers. Fivefold higher nicotine concentrations were determined in non-breast-fed infants of parents who smoked as compared to all other groups. It can be concluded that nicotine intake by passive smoking is much more important than by breast-feeding. We conclude that both interview data and biochemical measures should be sought to understand the true exposure to tobacco smoke.

Simultaneous sudden infant death syndrome

The simultaneous sudden deaths of twins rarely occur and therefore it has received limited attention in the medical literature. When the deaths of the twins meet the defined criteria for sudden infant death syndrome (SIDS) independently and take place within the same 24 h range it can be called as simultaneous SIDS (SSIDS). The case(s): Twin girls (3.5-month-old) were found dead by their mother in their crib, both in supine position. The infants were identical twins and delivered at a hospital by cesarean section. Both infants were healthy and did not have any serious medical history. Two days prior to the incident, the twins had received the second dose of oral polio, DPT and the first dose of hepatitis B vaccines and they had fever on the first day of the vaccination and been given teaspoonful of acetaminophen. Death scene investigation, judicial investigation, parental assessment, macroscopic and microscopic autopsy findings and the toxicological analysis did not yield any specific cause of death. The case(s) were referred to a supreme board composed of multidisciplinary medical professionals at the Institute of Forensic Medicine, Ministry of Justice, in Istanbul. The Board decided that the available data was consistent with SIDS. These SIDS case(s) are presented because twin SIDS are rare and this is the first time that a simultaneous twin SIDS have been reported in Turkey. Simultaneous SIDS cases have many implications regarding definition, diagnosis and medico-legal approach.

The effects of smoking cessation counseling by midwives on Dutch pregnant women and their partners

OBJECTIVE

Smoking during pregnancy is an important problem in the Netherlands. We tested the effectiveness of a health counseling method by midwives using a RCT.

METHODS

Four provinces with 42 practices including 118 midwives were randomly assigned to the experimental or control condition. Midwives in the experimental group provided brief health counseling, self-help materials on smoking cessation during pregnancy and early postpartum, and a partner booklet. Controls received routine care. The main outcome measures were 7-day abstinence, continuous abstinence, and partner smoking at 6 weeks post-intervention (T1) and 6 weeks postpartum (T2).

RESULTS

Multi-level analysis revealed significant differences between both conditions at T1 and T2 using intention-to-treat analysis. Nineteen percent of the experimental group reported 7-day abstinence compared to 7% of the control group at T1, and 21 and 12%, respectively, at T2. For continuous abstinence these percentages were 12% in the experimental group and 3% in the control group. The partner intervention was not successful.

CONCLUSION

The intervention resulted in significant effects on smoking behavior for pregnant women, but not for partner smoking.

PRACTICE IMPLICATIONS

The program realized short-term effects. An important precondition is that midwives need a proper training.

Spontaneous smoking cessation during pregnancy among ethnic minority women: a preliminary investigation

This study examined the postpartum relapse rates and characteristics of pregnant women who stopped smoking without professional intervention. Baseline characteristics of women who spontaneously quit were compared to women who continued to smoke. Women who spontaneously quit were also randomized to a psychotherapy relapse prevention treatment, or to usual care. The sample was ethnically diverse, containing 141 low-income women who were predominantly Hispanic, 23% (n=33) of whom spontaneously quit smoking. The variables that significantly differentiated between "spontaneous quitters" and ongoing smokers were entered into a regression analysis, which revealed that higher self-confidence, smoking fewer cigarettes per day, and younger age accounted for 25% of the variance in spontaneous cessation. Adding the psychotherapy intervention conferred no additional protection against relapse in this subgroup of spontaneous quitters. The six-month abstinence rate of 36% is similar to that found in Caucasian and higher-income populations. These results extend research with pregnant smokers to a new population and may have implications for healthcare providers and policy makers.

Mucosal immune responses to infections in infants with acute life threatening events classified as 'near-miss' sudden infant death syndrome

This study examined the hypothesis that dysregulation of mucosal immune responses to respiratory infections is a critical event, which could be causal in respiratory arrest of some previously healthy infants. To examine this hypothesis, a prospective study was undertaken of infants presenting to the emergency department of a major teaching hospital with acute life threatening events (ALTE) of unknown cause and classified as "near-miss" SIDS. Salivary immunoglobulin concentrations were measured on admission and again after 14 days. The salivary immunoglobulins were compared with three control groups: infants with a mild upper respiratory tract infection (URTI); bronchiolitis; and healthy age-matched infants. The salivary IgA and IgM concentrations in the ALTE infants at presentation to hospital indicated a significant mucosal immune response had already occurred, with nearly 60% of the IgA concentrations significantly above the population-based reference ranges. The hyper-immune response was most evident in the ALTE infants with pathology evidence of an infection; 87% of these infants had salivary IgA concentrations on average 10 times higher that the age-related median concentration. The most prevalent pathogen identified in the ALTE infants was respiratory syncytial virus (RSV) (64%). RSV was also identified in all subjects with bronchiolitis. Risk factors for SIDS were assessed in each group. The data indicated that the ALTE infants diagnosed as 'near-miss' SIDS were a relatively homogeneous group, and most likely these ALTE infants and SIDS represent associated clinical outcomes. The study identified exposure to cigarette smoke and elevated salivary IgA concentrations as predictors of an ALTE. The study findings support the hypothesis of mucosal immune dysregulation in response to a respiratory infection in some infants with an ALTE. They provide a plausible explanation for certain SIDS risk factors. The underlying patho-physiological mechanism of proinflammatory responses to infections during a critical developmental period might be a critical factor in infants who have life-threatening apnoea or succumb to SIDS. The study raises the possibility of using salivary IgA to test infants who present with mild respiratory infections to identify a substantial number of infants at risk of developing an ALTE or SIDS, thus enabling intervention management to prevent such outcomes.

A controlled study of the relationship between Bordetella pertussis infections and sudden unexpected deaths among German infants

OBJECTIVE

This was a prospective, controlled, multicenter study to investigate the relationship between Bordetella pertussis infections and sudden unexpected deaths among German infants.

DESIGN

Between 1995 and 1997, all infants who died at 7 to 365 days of age and for whom autopsies were performed in 1 of 8 participating institutes of legal medicine were enrolled. During a standardized autopsy, nasopharyngeal specimens (NPSs) and tracheal specimens were obtained for polymerase chain reaction (PCR) assays to detect B pertussis. The oligonucleotide primers PTp1 and PTp2, which specifically amplify a 191-base pair DNA fragment of the pertussis toxin operon of B pertussis, were used. Two control subjects (matched according to residence, age, gender, and nationality) were enrolled for each case subject, via a network of pediatricians in private practice, and NPSs were obtained from those infants. Parents of case subjects and control subjects were asked to provide specific information on respiratory illnesses of the child, contact with a known case of pertussis, or close contact with a person with a cough illness during the 4 weeks before death or enrollment, as well as the child's pertussis immunization status. The pathologists performing the autopsies were unaware of the PCR results.

RESULTS

Enrolled were 254 infants (66% male) with sudden unexpected deaths and 441 matched control subjects. Autopsies according to protocol were performed for 234 of the case subjects (92%); a diagnosis of sudden infant death syndrome (SIDS) was made for 76%. For the remaining subjects, causes of death were respiratory or other infections (14%), congenital anomalies or organ failures (4%), aspiration (2%), or accidents or traumatic events (4%). PCR results were positive for B pertussis for 12 case subjects (5.1%) (all with SIDS or respiratory infections) and 5.3% of control subjects. Of the 12 case subjects with positive PCR results, 10 (83%) were male. Questionnaires had been returned by the parents of 5 of the 12 infants. Three had experienced a respiratory illness (all with cough), beginning 7, 14, and 19 days before death. None had a known contact with a case of pertussis. Four of 15 control infants (27%) with positive PCR findings for B pertussis had a cough illness, indicating possible pertussis, and 2 of those 4 developed typical symptoms (whooping). Background information was received from 116 parents (46%) of case subjects and from parents of all control subjects. Upper respiratory tract infections within 4 weeks before death were reported for 53% of case subjects and 38% of control subjects. Also, fewer case subjects (33%) than control subjects (68%) had received age-adequate numbers of pertussis vaccine doses.

CONCLUSIONS

The concept of infection as a factor in SIDS is supported by a number of observations, including the seasonal distribution of the occurrence of SIDS; the high incidence of concurrent upper respiratory tract infections among infants dying as a result of SIDS; the peak age at 3 to 4 months; nicotine use in a child's household, which predisposes children to respiratory infections such as otitis media; and the protective role of breastfeeding. A prominent role might be suspected for B pertussis, for several reasons. 1) B pertussis infections in infancy are frequently associated with apneic spells, which are occasionally life-threatening and, if leading to death, might be reported as SIDS. 2) Epidemiologic evidence from the United Kingdom, Sweden, and Norway indicates that SIDS is associated with B pertussis infection. 3) In a previously published study, we detected B pertussis DNA in the nasopharynx of 9 of 51 consecutive infants (18%) with sudden unexpected deaths. This is the first prospective, controlled study to investigate the possible etiologic role of B pertussis in SIDS. Clinically unrecognized B pertussis infections were relatively frequent (5.3%) among control infants during the course of our study. The rate of infection was similar or perhaps greater for control subjects, compared with case subjects (1.7%), when only NPS results were compared. This may seem surprising but is supported by other studies, in which asymptomatic infections or mild respiratory illnesses were observed among infants exposed to B pertussis. Careful autopsies, including histologic evaluations of organ specimens and use of PCR to detect B pertussis in NPSs and tracheal specimens, represented a strength of this study. Our general findings were as expected. The majority of cases were classified as SIDS. The second largest group included infants for whom respiratory infections were found. The findings of various other diagnoses, which in several instances would have been undiscovered otherwise, emphasize the need for autopsies after unexpected infant deaths. What is the significance of the identified B pertussis infections in 12 cases? Several pieces of evidence support the plausibility of a cause-and-effect relationship. Eight of the 12 case subjects died before 6 months of age, the typical age for death attributable to pertussis. In autopsies, 9 of the subjects were found to have signs of respiratory infections; for 2 infants, the autopsies suggested that death was attributable to a respiratory infection. One additional infant (data not shown) had brain edema (which could have been attributable to hypoxemia during pertussis). Lower rates of completed primary series or age-adequate numbers of pertussis vaccine doses among case subjects than among control subjects may indicate that immunization against pertussis protects children from death attributable to unrecognized B pertussis infection. Moreover, a recent study indicated that immunization with diphtheria-tetanus-pertussis vaccine induces antibodies that cross-react with pyrogenic staphylococcal toxins, which have been implicated in several cases of SIDS. Other microorganisms may be involved in the sudden death of infants, as suggested in this study by the higher rate of a history of concurrent upper respiratory tract infections among case subjects, compared with control subjects. Similarly, in a Scandinavian study, 48% of 244 SIDS case subjects, compared with 31% of 869 control subjects, exhibited symptoms of upper airway infection during the last week before death or interview, respectively. Because SIDS is a diagnosis of exclusion, every attempt should be made to identify a cause of death during autopsy. This should include the search for pathogenic microorganisms in the respiratory tract with the use of PCR and other sensitive tests. In conclusion, B pertussis infection was found for 12 of 234 infants (5.1%) with unexpected deaths, and the infections might have contributed to the deaths.

German study on sudden infant death (GeSID): design, epidemiological and pathological profile

The German study on sudden infant death (GeSID) is a multi-centre case-control study aiming at the assessment of etiological factors and risk factors of SIDS. This report describes the study design and the methods applied and presents some general findings. Between 1998 and 2001, 455 cases of sudden and unexpected death of infants aged between 8 and 365 days were recruited into the study. The study comprised at least 11 out of the 16 German states with 18 centres involved. In 1999 and 2000, 75% of all SIDS cases registered with the Federal Office of Statistics (ICD 10/R95, n=384) in the study area were recruited into the study (n=286). A standardised autopsy including extended histology, microbiology, virology, toxicology and neuropathology investigations was carried out. Of the parents 82% (n=373) agreed to fill in an extensive questionnaire containing 120 questions reflecting all important aspects of the infant's development. For each SIDS case, the parents of three living control infants were interviewed. These controls were matched for age, gender and region (n=1,118). The response rate of the controls was 58.7%. Data were linked with medical records obtained from obstetrics departments, the children's hospitals, and general practitioners. Death scene investigation was performed in 4 study areas (cases: n=64, controls: n=191). All cases were classified into one of 4 categories using defined criteria: 7.3% of the children were assigned to category 1 (no pathological findings: SIDS), 61.1% to category 2 (minor findings: SIDS+), 20.4% to category 3 (severe findings: SIDS+) and 11.2% to category 4 (findings which explained the death: non-SIDS). In case conferences the previous history and circumstantial factors were included and an extended category (E-cat.) was defined. The consideration of these factors for the final classification is of great importance in the causal explanation of some cases. An analysis of 18 main variables in cases of categories 1-3 (SIDS) compared to the cases of category 4 (non-SIDS) showed significant differences for the sleeping position, coughing the day before death and breast-feeding indicating that the cases of both groups should be separated for further analyses.

Epidemiology of substance use disorders in women

Significant gender differences exist in the prevalence of substance use disorders in the United States. There is a trend among boys and girls aged 12 to 17 years toward comparable rates of use and initiation for alcohol, cocaine, heroin, and tobacco. If this trend continues, over time there may be a narrowing of the male-to-female prevalence ratios of substance abuse in the older age groups. This possibility is particularly disturbing because women have a heightened vulnerability to medical, physical, mental, and social consequences of substance use. Women also carry additional unique risks during pregnancy because of the effect on neonates. In addition, they have certain gender-specific cancer risks. Given this and the declining age of initiation of substance use in women, prevention and treatment efforts especially geared toward women (eg, education of all medical and paramedical staff, screening in primary care clinics, detection of drug use early in pregnancy or before conception, brief interventions and treatment programs that integrate women's needs) are exceedingly important to stop and ultimately reverse this growing trend.

A method to guide community planning and evaluation efforts in tobacco control using data on smoking during pregnancy

BACKGROUND

Effective community based tobacco control programmes are critical for state and nationwide impact. However, there is little discussion in the literature of methods for setting local objectives which use locally collected data and account for historical variation in progress.

OBJECTIVES

To develop and illustrate a method that uses locally available birth certificate data to model trends in tobacco use during pregnancy among women giving birth, predict future prevalence, and use predictions to set community specific tobacco control objectives.

DATA SOURCE

Vital statistics. Wisconsin standard birth certificates, 1990-2000, which record the smoking status of the mother during pregnancy.

DATA ANALYSIS

Trends in the prevalence of smoking during pregnancy in Wisconsin statewide and in all counties (n = 72) were modelled using linear regression of log prevalence on year. Model fit was assessed using R(2). Regression slopes, indicating estimated relative annual percentage change in prevalence, were used to predict prevalence in 2005, and objectives were calculated as a 20% reduction from the predicted prevalence in 2005.

CONCLUSIONS

Modelling trends in the prevalence of smoking using locally collected data enables communities to set reasonable future tobacco control objectives that account for historical trends in progress.

Treating nicotine dependence during pregnancy and postpartum: understanding clinician knowledge and performance

This study investigated the relationship of clinicians' knowledge of treatments for nicotine dependence during pregnancy and postpartum and explored what provider characteristics are associated with knowledge levels. Survey data from community health center (CHC)-based prenatal, pediatric (PED), and WIC program (Special Supplemental Nutrition Program for Women, Infants, and Children) providers participating in a randomized clinical study were used. Providers reported low awareness of the health risks of smoking to the developing fetus/child of pregnant and postpartum women and of the effectiveness of nicotine replacement therapy (NRT) for doubling quit rates. Obstetric (OB) and WIC providers were more aware than PED providers that provider-delivered interventions are effective. Confidence in using counseling steps was significantly associated with general and NRT-related knowledge. NRT-related knowledge, but not general knowledge, was associated with higher performance of intervention steps. Educational programs targeting OB, WIC, and PED providers' knowledge about effective smoking cessation counseling strategies and their confidence in being effective with patients are needed.

Spontaneous cessation of smoking and alcohol use among low-income pregnant women

BACKGROUND

Despite the strong evidence of harmful effects, tobacco and alcohol use during pregnancy continue to be major public health challenges. Some women, however, do stop spontaneously when they learn of their pregnancy. No study has investigated spontaneous cessation of both behaviors in a low-income predominantly unmarried U.S. population.

OBJECTIVE

To describe the prevalence of spontaneous cessation of cigarette and alcohol use alone and in combination and associated factors among low-income pregnant women.

METHODS

Subjects (N=601) were currently smoking or smoking when they became pregnant and participating in Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) programs in the greater Boston, Massachusetts, area. Baseline interviews assessed the factors being studied and the spontaneous cessation of cigarette and alcohol use with pregnancy. Saliva cotinine verified self-reported smoking status.

RESULTS

Spontaneous cessation of smoking and alcohol use was reported by 28% and 80% of the women, respectively; 25% spontaneously quit both, and 15% stopped neither. Multivariable analyses indicated that smoking cessation was less likely in women who had previous births, had a husband or partner who smoked, were born in the United States, were black (non-Hispanic, non-Portuguese), had less than a high school education, were highly addicted, reported lower perceived risk to the fetus, and reported "too many other problems in life to stop." Hispanic ethnicity, younger age, and more social support to quit smoking were related to spontaneous alcohol abstinence.

CONCLUSIONS

Targeted multiple strategies, including those aimed at increasing participation of partners, are needed for low-income pregnant smokers.

Heart rate changes in response to mild mechanical irritation of the high cervical spinal cord region in infants

Alterations in the heart rate were monitored before, during and after the application of a unilateral mechanical impulse to the high cervical spinal cord region which was administered strictly in connection with the so called manual therapy (diagnosis= KISS). The investigation is based on a survey of 695 infants between the ages of 1 and 12 months. A notable change in the heart rate was evident in 47.2% of all examined infants (n= 695). In 40.1% of these infants, the change in heart rate was characterized by heart rate decrease of 15-83% compared to control conditions. Infants in their first 3 months of life responded more often with a severe bradycardia (50-83% decrease), older infants (7-12 months) more often with a mild bradycardia (15-49.9% decrease). This comparison revealed a significantly increased occurrence of severe bradycardia in the younger age group compared to the group of children >3 months (significance 0.0017). In 12.1% (n= 84) of the infants, the bradycardia was accompanied by an apnea. We discuss the hypothesis that mechanical irritation of the high-cervical region serves as a trigger that may be involved in sudden infant death (SID).

Sudden unexpected infant deaths in Dundee, 1882-1891: overlying or SIDS?

Using a cohort study of all deaths in infants under 12 months in Dundee born between 1882-91 we set out to compare the aetiology of sudden unexpected infant deaths in Dundee at the end of the 19th Century with the aetiology of present day Sudden Infant Death Syndrome (SIDS). During 1882-1891, 361 infants died suddenly and unexpectedly and without obvious cause while in bed with their parents. The sex ratio of deaths was even (0.51 male) whereas the typical male fraction of SIDS today is 0.61. The mean age at death was almost two and one-half weeks younger in the Dundee cohort than for SIDS in modern Scotland. The infants in the Dundee cohort were discovered more frequently early in the morning than is typical. Their social class distribution was different in that no overlying cases were found in the higher classes whereas SIDS affects all classes. The overlying rate for illegitimate infants was lower than that reported for SIDS today. The epidemiological characteristics of the Dundee cohort and of those dying from present day SIDS differ considerably. The Dundee cohort apparently died from overlying rather than from SIDS as it is classified today. Present day advice that co-sleeping is safe should be given more cautiously until the safety of co-sleeping is resolved. It might be prudent to inform parents that co-sleeping is a risk factor for SIDS and that it should therefore be avoided.

Smoking cessation counseling with pregnant and postpartum women: a survey of community health center providers

OBJECTIVES

This study assessed providers' performance of smoking cessation counseling steps with low-income pregnant and postpartum women receiving care at community health centers.

METHODS

WIC (Special Supplemental Nutrition Program for Women, Infants, and Children) program staff, obstetric clinicians, and pediatric clinicians at 6 community health centers were asked to complete surveys. Smoking intervention practices (performance), knowledge and attitudes, and organizational facilitators were measured. Factors associated with performance were explored with analysis of variance and regression analysis.

RESULTS

Performance scores differed significantly by clinic and provider type. Providers in obstetric clinics had the highest scores and those in pediatric clinics had the lowest scores. Nurse practitioners and nutritionists had higher scores than other providers. Clinic type, greater smoking-related knowledge, older age, and perception of smoking cessation as a priority were independently related to better counseling performance.

CONCLUSIONS

Mean performance scores demonstrated room for improvement in all groups. Low scores for performance of steps beyond assessment and advice indicate a need for emphasis on the assistance and follow-up steps of national guidelines. Providers' own commitment to helping mothers stop smoking was important.

Exposure to cigarette smoke, a major risk factor for sudden infant death syndrome: effects of cigarette smoke on inflammatory responses to viral infection and bacterial toxins

Exposure to cigarette smoke is a major risk factor for sudden infant death syndrome and also for respiratory infections in children. It has been suggested that toxigenic bacteria colonizing the respiratory tract might play a role in some cases of sudden infant death syndrome and nicotine has been demonstrated to enhance the lethality of bacterial toxins in a model system. Pyrogenic toxins of Staphylococcus aureus have been identified in tissues of infants who died of sudden infant death syndrome. It has been suggested that some of these deaths were due to induction of inflammatory mediators by infectious agents during a period when infants are less able to control these responses. The aim of this study was to assess the effects of a water-soluble cigarette smoke extract on the production of tumor necrosis factor alpha and nitric oxide from human monocytes in response to staphylococcal toxic shock syndrome toxin 1 or infection of the monocytes with respiratory syncytial virus. Cell culture supernatants were examined by a bioassay using mouse fibroblasts (L-929 cell line) for tumor necrosis factor alpha activity and by a spectrophotometric method for nitrite. Compared with monocytes incubated with medium only, monocytes incubated with any of the factors or their combinations tested in the study released higher levels of tumor necrosis factor alpha and lower levels of nitric oxide. Incubation with cigarette smoke extract increased tumor necrosis factor alpha from respiratory syncytial virus-infected cells while it decreased tumor necrosis factor alpha from cells incubated with toxic shock syndrome toxin. Incubation with cigarette smoke extract decreased the nitric oxide production from respiratory syncytial virus-infected cells while it increased the nitric oxide production from cells incubated with toxic shock syndrome toxin. Monocytes from a minority of individuals demonstrated extreme tumor necrosis factor alpha responses and/or very high or very low nitric oxide. The proportion of samples in which extreme responses with a very high tumor necrosis factor alpha and very low nitric oxide were detected was increased in the presence of the three agents to 20% compared with 0% observed with toxic shock syndrome toxin 1 or 4% observed with cigarette smoke extract or respiratory syncytial virus.

Animal models used to test the interactions between infectious agents and products of cigarette smoked implicated in sudden infant death syndrome

Animal test systems are reviewed that have relevance to sudden infant death syndrome (SIDS) are reviewed. These test interactions between infectious agents (or their toxins) and products of cigarette smoke. Infectious agents implicated in SIDS include members of the enterobacteria and clostridia, Staphylococcus aureus and Streptococcus pyogenes. Smoking is thought to be the single most preventable cause of SIDS. Tobacco smoke contains many extremely toxic products including cyanide and nicotine. Many animal test systems are available to examine the potency of bacterial toxins and smoke-derived components. These include mice, hamsters, rats and chick embryos. Such systems reveal synergy between bacterial toxins, especially endotoxin and superantigens. They have also demonstrated potentiation of low levels of bacterial toxin by low levels of both nicotine and its primary metabolite, cotinine. These findings suggest a possible causal explanation for the fact that passive exposure to cigarette smoke is a risk factor in sudden infant death syndrome.

Passive smoking and sudden infant death syndrome: review of the epidemiological evidence

BACKGROUND

This paper provides a systematic, quantitative review of the epidemiological evidence relating parental smoking and sudden infant death.

METHODS

Thirty two relevant publications were identified after consideration of 692 articles selected by electronic search of the Embase and Medline databases using keywords and Mesh headings relevant to passive smoking in children. Eleven further articles were identified from reviews and by talking to authors. The search was completed in April 1997 and identified 39 studies.

RESULTS

The unadjusted pooled odds ratio for prenatal maternal smoking was 2.77 (95% CI 2.45 to 3.13). After adjustment for a variety of confounders the pooled odds ratio was reduced to 2.08 (95% CI 1.83 to 2.38) and was similar in cohort and case-control studies. Four studies reported on maternal postnatal smoking after controlling for prenatal maternal smoking (pooled odds ratio 1.94 (95% CI 1.55 to 2.43)). Of three studies reporting on the risk of paternal smoking where the mother was a non-smoker, two found significant effects while one found no effect. Dose-response relationships with both prenatal and postnatal maternal smoking were present in most studies which provided data.

CONCLUSIONS

Maternal smoking doubles the risk of sudden infant death syndrome. The relationship is almost certainly causal. There is good evidence that postnatal exposure to environmental tobacco smoke from both mother and father are important. Because prenatal smoking is almost invariably associated with postnatal smoking, the role of prenatal smoking per se will be difficult to resolve using epidemiological studies.