Characteristics, head shape measurements and developmental delay in 287 consecutive infants attending a plagiocephaly clinic

AIM

To describe the characteristics, developmental status and severity of head shape deformation in infants presenting to a plagiocephaly clinic.

METHODS

Head shape was measured and neck function assessed in 287 consecutive infants presenting to a plagiocephaly outpatient clinic. Information was obtained on demographic and obstetric factors, plagiocephaly history and current positioning strategies. Development was assessed by the Ages and Stages Questionnaire (ASQ).

RESULTS

After clinical examination, craniosynostosis was suspected in seven infants (2%) and a skull computed tomography (CT) scan was performed; five showed suture abnormalities. Fifty-eight percent of cases had a history of limitation of neck function; this was more likely in plagiocephalic infants than brachycephalic infants. Males, firstborn infants, instrument-delivered infants, supine sleep position and right-sided flattening were predominant. One or more delays on the ASQ were seen in 36% of infants.

CONCLUSION

Physical examination of infants with head shape deformities is essential in order to rule out craniosynostosis. Infants with deformational plagiocephaly frequently have neck muscle dysfunction. We postulate that the higher than expected number of developmental delays may be related to the effects of supine sleep position, low or variable tone, lower activity levels, male gender and neck muscle dysfunction.

What is the mechanism of SIDS? Clues from epidemiology

The cause of sudden infant death syndrome (SIDS) is unknown. Many mechanisms have been postulated, although thermal stress, rebreathing of expired gases and infection/inflammation seem the most viable hypotheses for the causation of SIDS. Deaths from SIDS have reduced dramatically following the recommendation not to place infants to sleep prone. Epidemiological data have shown that prone sleeping position is more risky in winter, colder latitudes, higher altitudes, if the infant is unwell or has excessive bedding or clothing. This suggests prone sleeping position involves either directly or indirectly a thermal mechanism. SIDS caused by an infective/inflammatory mechanism might be associated with deaths occurring during the night. Rebreathing of expired gases, airway obstruction, long QT syndrome and other genetic conditions may explain a small number of sudden unexpected deaths in infancy.

Ethnic differences in time trends in asthma prevalence in New Zealand: ISAAC Phases I and III

SETTING

The International Study of Asthma and Allergies in Childhood (ISAAC) Phase III survey, New Zealand.

OBJECTIVE

To assess the prevalence of asthma symptoms and time trends by ethnicity between ISAAC Phase I (1992-1993) and Phase III (2001-2003).

DESIGN

Information on asthma symptoms and environmental exposures was collected in children aged 6-7 years (n = 10,873) and adolescents aged 13-14 years (n = 13,317).

RESULTS

In children, the prevalence of current wheeze was 28.5% in Māori (prevalence odds ratio [POR] = 1.49, 95%CI 1.32-1.68), and 25.2% in Pacific Islanders (POR 1.28, 95%CI 1.07-1.54) compared with 20.7% in Europeans/Pakeha. In adolescents, 29.9% of Māori (POR = 1.13, 95%CI 1.03-1.23) and 20.8% of Pacific Islanders (POR 0.74, 95%CI 0.62-0.87) experienced current wheeze compared to 28.6% of Europeans/Pakeha. Between Phases I and III, the prevalence of current wheeze increased significantly by 0.49%/year in Pacific Islanders, increased non-significantly by 0.12%/year in Māori, and decreased significantly by 0.25%/year in Europeans/Pakeha children. In adolescents, the prevalence of current wheeze increased by 0.05%/year in Pacific Islanders and decreased by 0.33%/year in Europeans/Pakeha and by 0.07%/year in Māori.

CONCLUSION

Ethnic differences in asthma symptom prevalence in New Zealand have increased. The reasons for this are unclear, but may reflect inequalities in access to health services.

Cross-sectional survey of risk factors for asthma in 6-7-year-old children in New Zealand: International Study of Asthma and Allergy in Childhood Phase Three

AIM

To identify risk factors for asthma in primary school-aged children in New Zealand.

METHODS

A cross-sectional survey of 10,873 6-7-year-old children in Auckland, Bay of Plenty, Nelson and Christchurch (a response rate of 85.2%). A questionnaire was completed by the parent or care giver.

RESULTS

22.2% of children wheezed in the last 12 months (current wheeze). Maori children were at greater risk of current wheeze compared with European children (adjusted odds ratio (adjOR) = 1.37; 95% confidence interval = 1.18-1.59). Antibiotics and paracetamol used in the first year of life were associated with an increased risk of current wheeze (adjOR = 1.78 (1.56-2.04) and adjOR = 1.31 (1.06-1.61), respectively). Watching television for 5 or more hours per day was associated with an increased risk of current wheeze (adjOR = 1.44 (1.13-1.83)). Milk and egg consumption in the last 12 months was associated with a reduced risk of current wheeze.

CONCLUSIONS

 This study has identified risk factors for asthma in children aged 6-7 years, although causal pathways cannot be established. These associations have important public health implications if causal.

Prevalence and determinants of cytomegalovirus infection in pre-school children

AIM

The aim of this study is to measure the seroprevalence of cytomegalovirus (CMV) infection in 3.5-year-old children, and identify the determinants of seropositivity.

METHODS

A total of 1714 children were enrolled at birth. Approximately half were small for gestational age and half were appropriate for gestational age. Information on the children was collected at birth, 1 year and 3.5 years. At 3.5 years blood was collected and tested for CMV-specific immunoglobulin by an enzyme-linked immunosorbent assay in 530 children.

RESULTS

The weighted seroprevalence of CMV was 32.8% (95% confidence interval (CI) 27.4-38.1%). The seroprevalence of CMV varied markedly by ethnicity (European: 26.5% (95% CI 20.9-32.2%); Maori: 68.0% (44.0-92.0%); Pacific: 74.5% (56.3-92.6%); Indian: 50.0% (20.2-79.8%); Chinese: 47.2% (10.8-83.5%); Other: 21.9% (0.0-52.7%); P < 0.001). Socio-economic factors, number of siblings, day care centres attendance, maternal smoking, breastfeeding and other factors examined were not related to CMV seropositivity.

CONCLUSIONS

The seroprevalence of CMV in New Zealand pre-school children is similar to that reported from other developed countries. The finding of marked ethnic differences is unexplained by socio-economic factors, or other factors that were examined.

Sleep environment risk factors for sudden infant death syndrome: the German Sudden Infant Death Syndrome Study

OBJECTIVE

Our goal was to investigate the risk factors for sudden infant death syndrome in the infants' sleep environment for a population in which few infants sleep prone as a result of education campaigns.

METHODS

This was a population-based sudden infant death syndrome case-control study over 3 years (1998-2001) in Germany.

RESULTS

There were 333 sudden infant death syndrome cases and 998 matched controls. Although only 4.1% of the infants were placed prone to sleep, those infants were at a high risk of sudden infant death syndrome. Those who were unaccustomed to sleeping prone were at very high risk, as were those who turned to prone. Bed sharing (especially for infants younger than 13 weeks); duvets; sleeping prone on a sheepskin; sleeping in the house of a friend or a relative (compared with sleeping in the parental home); and sleeping in the living room (compared with sleeping in the parental bedroom) increased the risk for sudden infant death syndrome; pacifier use during the last sleep was associated with a significantly reduced risk of sudden infant death syndrome.

CONCLUSIONS

This study has clarified the risk factors for sudden infant death syndrome in a population where few infants sleep prone. This study supports the current recommendations of the American Academy of Pediatrics. This study has identified several novel risk factors for sudden infant death syndrome: an increased risk if the infants sleeps outside the parental home, death in the living room, and the high risk when sleeping prone on a sheepskin; however, because the numbers of cases in these groups are small, additional studies are needed to confirm these findings.

Does breastfeeding reduce the risk of sudden infant death syndrome?

BACKGROUND

In the last 20 years, the prevention campaigns to reduce the risk of sudden infant death syndrome were very successful. In some countries the advice to breastfeed is included in the campaigns' messages, but in other countries it is not.

OBJECTIVE

To examine the association between type of infant feeding and sudden infant death syndrome.

METHODS

The German Study of Sudden Infant Death is a case-control study of 333 infants who died of sudden infant death syndrome and 998 age-matched controls.

RESULTS

A total of 49.6% of cases and 82.9% of controls were breastfed at 2 weeks of age. Exclusive breastfeeding at 1 month of age halved the risk, partial breastfeeding at the age of 1 month also reduced the risk of sudden infant death syndrome, but after adjustment this risk was not significant. Being exclusively breastfed in the last month of life/before the interview reduced the risk, as did being partially breastfed. Breastfeeding survival curves showed that both partial breastfeeding and exclusive breastfeeding were associated with a reduced risk of sudden infant death syndrome.

CONCLUSIONS

This study shows that breastfeeding reduced the risk of sudden infant death syndrome by approximately 50% at all ages throughout infancy. We recommend including the advice to breastfeed through 6 months of age in sudden infant death syndrome risk-reduction messages.

Head covering - a major modifiable risk factor for sudden infant death syndrome: a systematic review

BACKGROUND

Some victims of sudden infant death syndrome (SIDS) are found with their heads covered with bedclothes, but the significance of this is uncertain. The aim of this review is to describe the prevalence of head covering, the magnitude of the risk and how far the suggested causal mechanisms agree with current epidemiological evidence.

METHODS

Systematic review of population-based age-matched controlled studies.

RESULTS

Controlled observations of head covering for the final sleep were found in 10 studies. The pooled prevalence in SIDS victims was 24.6% (95% CI 22.3% to 27.1%) compared to 3.2% (95% CI 2.7% to 3.8%) among controls. The pooled univariate odds ratio (OR) was 9.6 (95% CI 7.9 to 11.7) and the pooled adjusted OR from studies mainly conducted after the fall in SIDS rate was 16.9 (95% CI 12.6 to 22.7). The risk varied in strength but was significant across all studies. In a quarter of cases and controls head covering had occurred at least once previously (pooled adjusted OR = 1.1; 95% CI 0.9 to 1.4). The population attributable risk (27.1%; 95% CI 24.7% to 29.4%) suggests avoiding head covering might reduce SIDS deaths by more than a quarter.

CONCLUSIONS

The epidemiological evidence does not fully support postulated causal mechanisms such as hypoxia, hypercapnoea and thermal stress, but neither does it support the idea that head covering is part of some terminal struggle. Head covering is a major modifiable risk factor associated with SIDS deaths and parental advice to avoid this situation should be emphasised.

Supplementation with Lactobacillus rhamnosus or Bifidobacterium lactis probiotics in pregnancy increases cord blood interferon-gamma and breast milk transforming growth factor-beta and immunoglobin A detection

BACKGROUND

This study explored the effects of maternal probiotic supplementation on immune markers in cord blood (CB) and breast milk.

METHODS

CB plasma and breast milk samples were collected from a cohort of women who had received daily supplements of either 6 x 10(9) CFU/day Lactobacillus rhamnosus HN001 (n=34), 9 x 10(9) CFU/day Bifidobacterium lactis HN019 (n=35) or a placebo (n=36) beginning 2-5 weeks before delivery and continuing for 6 months in lactating women. CB plasma and breast milk (collected at 3-7 days, 3 months and 6 months postpartum) were assayed for cytokines (IL-13, IFN-gamma, IL-6, TNF-alpha, IL-10, TGF-beta1) and sCD14. Breast milk samples were also assayed for total IgA.

RESULTS

Neonates of mothers who received a probiotic had higher CB IFN-gamma levels (P=0.026), and a higher proportion had detectable blood IFN-gamma levels, compared with the placebo group (P=0.034), although levels were undetectable in many infants. While this pattern was evident for both probiotics, when examined separately only the L. rhamnosus HN001 group showed statistically significant higher IFN-gamma levels (P=0.030) compared with the placebo group. TGF-beta1 levels were higher in early breast milk (week 1) from the probiotic groups (P=0.028). This was evident for the B. lactis HN019 group (P=0.041) with a parallel trend in the L. rhamnosus HN001 group (P=0.075). Similar patterns were seen for breast milk IgA, which was more readily detected in breast milk from both the B. lactis HN019 (P=0.008) and the L. rhamnosus HN001 group (P=0.011). Neonatal plasma sCD14 levels were lower in the B. lactis HN019 group compared with the placebo group (P=0.041).

CONCLUSION

The findings suggest that supplementation with probiotics in pregnancy has the potential to influence fetal immune parameters as well as immunomodulatory factors in breast milk.

Head covering and the risk for SIDS: findings from the New Zealand and German SIDS case-control studies

OBJECTIVES

The aim of this investigation was to identify risk factors for being found with the head covered in sudden infant death syndrome cases and determine whether head covering was likely to be an agonal event or potentially part of the causal pathway in some cases. By using the data from 2 sudden infant death syndrome case-control studies, consistency of the findings could be assessed.

METHODS

Two case-control studies were assessed: (1) the New Zealand Cot Death Study (1987-1990, 393 sudden infant death syndrome cases) and (2) a German SIDS case-control study (1998-2001, 333 sudden infant death syndrome cases).

RESULTS

The proportion of sudden infant death syndrome cases in which infants were found with their head covered was 15.6% in the New Zealand study and 28.1% in the German study. Being found with head covering was associated with older infant age. In both studies, being found with head covering was associated with being very sweaty when found. Head covering was also associated with the incidence and severity of thymic petechiae in both studies. Both the position in which the child was placed to sleep and the position in which the child was found were not associated with head covering.

CONCLUSIONS

The finding that sudden infant death syndrome cases in which infants were found with their heads covered were often very sweaty suggests that head covering was not an agonal event and that it preceded the death and may have been causally related to the death. Infants who were found with their head covered were older, which probably reflects motor development.

Prone sleeping position increases the risk of SIDS in the day more than at night

BACKGROUND

SIDS mortality is higher during the night than in the day.

AIM

(1) To examine risk factors for SIDS by time of day and (2) to see if the proportion of deaths at night has changed from prior to the 'Back to Sleep' campaign, which recommended infants sleep supine.

METHODS

A large population-based SIDS matched case-control (GeSID) study conducted from 1998 to 2001 (when the prevalence of infants placed prone to sleep was 4.1%). The reference sleep of the controls was matched for the estimated time of death for the case. Risk factors for SIDS were examined for night-time and day-time deaths. The estimated time of death was compared with that from an earlier study in Germany (1990-1994 when prevalence of prone sleeping was 32.2%).

RESULTS

There were 333 SIDS cases and 998 matched controls. The increased risk with placed prone to sleep was significantly different during the day [adjusted OR = 18.15 (95% CI = 5.91-55.69)] compared with during the night [adjusted OR = 3.49 (95% CI = 1.46-8.39; p-value for interaction = 0.011)]. There was no significant difference in the other risk factors examined by time of day in the multivariate analysis. The mean time found dead was 09:07. In the earlier study the mean time found dead was 08:54 and the difference was not significant (p = 0.57).

CONCLUSIONS

This study confirms previous observations that prone sleeping position carries a greater risk during the day than at night. However, the reduction in infants sleeping prone has not been associated with a reduced number of deaths in the day in Germany.

Short sleep duration in middle childhood: risk factors and consequences

STUDY OBJECTIVES

To measure sleep duration in 7-year-old children; identify the determinants of sleep duration; and assess the association between short sleep duration and obesity, cognitive functioning, and behaviour.

DESIGN

Longitudinal study with disproportionate sampling of the participants.

SETTING

Community.

PARTICIPANTS

591 seven-year-old children, of whom 519 had complete sleep data.

INTERVENTIONS

Not applicable.

MEASUREMENTS

Sleep duration was assessed by actigraphy. Other measurements included height, weight, BMI, percentage body fat as assessed by bioimpedance assay, intelligence (WISC-III) and behaviour (Strengths & Difficulties questionnaire, parent and teachers Conners Rating Scales).

RESULTS

Mean time in bed according to parental report was 10.9 hours (SD 0.8). Mean sleep duration by actigraphy was 10.1 (SD 0.8) hours. In multivariable analysis, sleep duration was longer on weekdays vs. weekend nights (31.5 min, P = 0.002), in winter (40.5 min), autumn (31.1 min), and spring (14.8 min) compared with summer (P <0.0001), and in those with younger siblings (11.7 min, P = 0.03). Sleep duration was shorter when bedtime was after 21:00 (-41.1 min, P <0.0001). In multivariable analysis, sleep duration <9 hours was associated with being overweight/ obese (BMI: OR = 3.32; 95% CI = 1.40, 7.87) with an increase of 3.34% body fat (P = 0.03), and this was not explained by physical activity or television watching. Short sleep duration was also associated with higher emotional lability scores (Conners Rating Scale Parent Form; P = 0.03). IQ (WISC-III) and attention deficit / hyperactivity disorder scores (both parent and teachers Conners Rating Scales) did not differ with sleep duration.

CONCLUSIONS

Sleep duration in 7-year-old children varies considerably among individuals. The duration is affected by weekday, season, and having younger siblings. Importantly, short sleep duration was shown to be an independent risk factor for obesity/overweight.

Wrapping a cot mattress in plastic does not explain the continuing fall in SIDS mortality

In 2005 in Auckland, New Zealand, the prevalence of wrapping cot mattresses in polythene, which has been recommended for sudden infant death syndrome (SIDS) prevention by proponents of the toxic gas theory, was 21.7%. This cannot account for the 63% decline in SIDS from 1994 to 2004.

Risk factors for asthma at 3.5 and 7 years of age

BACKGROUND

It has been suggested that factors in early life including exposure to allergens and microbes may influence the development of asthma.

OBJECTIVE

To identify risk factors for asthma in early childhood. Methods Eight-hundred and seventy-one children of European mothers were enrolled at birth, of whom 385 (44.2%) were born small for gestational age (SGA) and 486 were appropriate for gestational age (AGA). Data were collected at birth, 12 months, 3.5 years of age (y) and 7 y. The outcome of interest (current wheeze) was defined as a positive response to the question: 'Has your child had wheezing or whistling in the chest in the last 12 months?'

RESULTS

Participation rate was 85.4% at 1 y, 63.1% at 3.5 y and 68.0% at 7 y. The prevalence of asthma was 23.8% at 3.5 y and 18.1% at 7 y. Antibiotic use in the first year of life and day care in the first year of life were associated with increased risk of wheeze at 7 y [odds ratio (OR)=4.3 95% confidence interval (CI) (1.8-10.1) and OR=2.8 95% CI (1.2-6.5), respectively], but not at 3.5 y. Exposure to dogs was a risk factor for asthma at both ages [OR=2.1 95% CI (1.1-3.8)] as was sleeping on a used cot mattress in the first year of life [OR=1.8 95% CI (1.0-3.2)].

CONCLUSIONS

There was a significant association between antibiotic use and day care in the first year of life and wheezing at 7 y but not at 3.5 y. This strengthens the argument that these factors increase the risk of asthma. We have also made the novel observation that sleeping on a used mattress in the first year of life is a risk factor for wheezing at 3.5 and 7 y. Capsule summary This prospective study of 871 children made the novel observation that sleeping on a used mattress in the first year of life was a risk factor for wheezing at 3.5 and 7 y.

Risk factors for obesity in 7-year-old European children: the Auckland Birthweight Collaborative Study

OBJECTIVE

To identify risk factors associated with obesity in primary school children, with a particular focus on those which can be modified. To identify critical periods and growth patterns in the development of childhood obesity.

METHODS

871 New Zealand European children were enrolled in a longitudinal study at birth and data were collected at birth, 1, 3.5 and 7 years of age. Data collected at 7 years included weight, height, bioelectrical impedance analysis (BIA), television viewing time and a 24 h body movement record (actigraphy). The outcome measure was percentage body fat (PBF), which was calculated at 3.5 and 7 years using BIA. Univariate and multiple regression analyses were carried out using PBF as a continuous variable.

RESULTS

Multivariable analysis found maternal overweight/obesity, maternal age, female gender, sedentary activity time and hours of television viewing to be independently associated with PBF at 7 years. Growth variables (birth weight, rapid weight gain in infancy, early (1-3.5 years) and middle childhood (3.5-7 years)) were also independently associated with adiposity at 7 years. There was a strong correlation between PBF at 3.5 years and PBF at 7 years.

CONCLUSIONS

Many primary school aged children start on the trajectory of obesity in the preschool years, which suggests interventions need to start early. Maternal overweight/obesity, television watching, sedentary activity time and rapid weight gain in infancy, early and middle childhood are risk factors for childhood obesity, and are all potentially modifiable.

Long QT and Brugada syndrome gene mutations in New Zealand

BACKGROUND

Genetic testing in long QT syndrome (LQTS) is moving from research into clinical practice. We have recently piloted a molecular genetics program in a New Zealand research laboratory with a view to establishing a clinical diagnostic service.

OBJECTIVE

This study sought to report the spectrum of LQTS and Brugada mutations identified by a pilot LQTS gene testing program in New Zealand.

METHODS

Eighty-four consecutive index cases referred for LQT gene testing, from New Zealand and Australia, were evaluated. The coding sequence and splice sites of 5 LQTS genes (KCNQ1, HERG, SCN5A, KCNE1, and KCNE2) were screened for genomic variants by transgenomics denaturing high-performance liquid chromatography (dHPLC) system and automated DNA sequencing.

RESULTS

Forty-five LQTS mutations were identified in 43 patients (52% of the cohort): 25 KCNQ1 mutations (9 novel), 13 HERG mutations (7 novel), and 7 SCN5A mutations (2 novel). Forty patients had LQTS, and 3 had Brugada syndrome. Mutations were identified in 14 patients with resuscitated sudden cardiac death: 4 KCNQ1, 5 HERG, 5 SCN5A. In 17 cases there was a family history of sudden cardiac death in a first-degree relative: 8 KCNQ1, 6 HERG, 2 SCN5A, and 1 case with mutations in both KCNQ1 and HERG.

CONCLUSION

The spectrum of New Zealand LQTS and Brugada mutations is similar to previous studies. The high proportion of novel mutations (40%) dictates a need to confirm pathogenicity for locally prevalent mutations. Careful screening selection criteria, cellular functional analysis of novel mutations, and development of locally relevant control sample cohorts will all be essential to establishing regional diagnostic services.

The continuing decline in SIDS mortality

The "Back to Sleep" campaign resulted in a dramatic decrease in sudden infant death syndrome (SIDS) worldwide. SIDS mortality has continued to decline (in New Zealand by 63% from 1993 to 2004), but the reason for this has not been explained. A postal survey found that the proportion of infants sleeping on their back has increased substantially (from 24.4% in 1992 to 72.3% in 2005), and this could account for the 39%-48% decrease in SIDS mortality.

Do immunisations reduce the risk for SIDS? A meta-analysis

BACKGROUND

There are claims that immunisations cause sudden infant death syndrome (SIDS), but some studies have found either no association or that they are associated with a reduced risk of SIDS.

AIMS

To conduct a meta-analysis examining the relationship between immunisation and SIDS.

METHODS

Nine case-controls studies were identified examining this association, of which four adjusted for potential confounders.

RESULTS

The summary odds ratio (OR) in the univariate analysis suggested that immunisations were protective, but the presence of heterogeneity makes it difficult to combine these studies. The summary OR for the studies reporting multivariate ORs was 0.54 (95% CI=0.39-0.76) with no evidence of heterogeneity.

CONCLUSIONS

Immunisations are associated with a halving of the risk of SIDS. There are biological reasons why this association may be causal, but other factors, such as the healthy vaccinee effect, may be important. Immunisations should be part of the SIDS prevention campaigns.

Determinants of developmental delay in infants aged 12 months

The aim of this study was to determine which demographic, maternal, obstetric and postnatal variables were associated with achievement of developmental milestones at the age of 12 months in term infants. Mothers and babies were enrolled in the Auckland Birthweight Collaborative Study shortly after birth. All infants were full term (gestation >or= 37 weeks). Approximately half of the sample were small for gestational age (SGA = birthweight <or= 10th percentile), and half were appropriate for gestational age (AGA = birthweight > 10th percentile). A maternal interview was conducted soon after birth. Phase 2 of the study occurred 12 months later when mothers were sent a postal questionnaire requesting information about the child's health and development during the first year of life using the Denver Prescreening Developmental Questionnaire. Seven hundred and forty-four (85.4%) European mothers returned the postal questionnaire. SGA children were not at increased risk of developmental delay at 12 months of age. In a sample representative of New Zealand European children, after adjustment for the effects of potential confounders, maternal smoking during pregnancy (OR = 2.1 [95% CI 1.1, 4.0]), maternal smoking during the first year of life (OR = 1.9 [95% CI 1.0, 3.8]) and low levels of satisfaction with parenting (OR = 2.4 [95% CI 1.1, 5.2]) were associated with significantly increased risk of developmental delay. In the subgroup of SGA children, maternal smoking during pregnancy (OR = 2.9 [95% CI 1.4, 6.2]), high levels of stress associated with parenting (OR = 2.2 [95% CI 1.2, 4.0]), and low levels of satisfaction with parenting (OR = 4.3 [95% CI 1.3, 13.5]) were significantly associated with developmental delay after adjustment for the effects of potential confounders. In conclusion, maternal and postnatal factors were better predictors of developmental delay than demographic variables.

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.

Do risk factors differ between explained sudden unexpected death in infancy and sudden infant death syndrome?

BACKGROUND

In Germany, 2910 infants died in 2004; for many infants the reason was clear, especially prematurity or congenital abnormalities. However, 394 babies die every year suddenly and unexpectedly. The cause may be immediately clear, but is often not obvious.

AIMS

(1) To describe the causes of explained sudden unexpected death in infancy (SUDI) and (2) to compare risk factors for sudden infant death syndrome (SIDS) and explained SUDI.

METHODS

A 3-year population-based case-control study in Germany, 1998-2001.

RESULTS

455 deaths, of which 51 (11.2%) were explained. Most of these deaths were due to respiratory or generalised infections. The risk factors for SIDS and explained SUDI were remarkably similar except for sleep position and breast feeding. Prone sleeping position is a major risk factor for SIDS (adjusted odds ratio (OR) 7.16, 95% confidence interval (CI) 3.85 to 13.31) but not for explained SUDI (adjusted OR 1.71, 95% CI 0.25 to 11.57). Not being breast fed in the first 2 weeks of life is a risk factor for SIDS (adjusted OR 2.37, 95% CI 1.46 to 3.84) but not for explained SUDI (adjusted OR 0.39, 95% CI 0.08 to 1.83).

CONCLUSIONS

Prone sleeping position is a unique risk factor for SIDS. Socioeconomic disadvantage and maternal smoking are risk factors for both SIDS and explained SUDI, and provide an opportunity for targeted intervention.

Recommendations for sudden infant death syndrome prevention: a discussion document

This article reviews the evidence for the current UK Department of Health recommendations for prevention of sudden infant death syndrome (SIDS) and suggests other factors that should be considered. The wording of the Department of Health recommendations for SIDS prevention has changed over the past 6 years, but the specific recommendations are largely consistent with the scientific evidence. The emphasis on thermal and illness factors and immunisation could be reduced. Bed sharing and sharing the parental bedroom should be given more emphasis. Two major recommendations need to be discussed in greater detail: (1) breast feeding and (2) pacifier use. Meta-analyses or reviews looking at each risk factor or a combination of risk factors are required. Further, it is recommended that a committee is established that reviews the recommendations and publishes the evidence that leads to these recommendations, as is done by the American Academy of Pediatrics Taskforce on Sudden Infant Death Syndrome.

Sudden infant death syndrome: No increased risk after immunisation

BACKGROUND

Although previous studies have shown either no association between immunisation and SIDS or even a decreased risk of SIDS, adverse effects, including death, from immunisations continue to cause concern, especially when a new vaccine is introduced.

METHODS

A large case control study with immunisation data on 307 SIDS cases and 971 controls.

RESULTS

SIDS cases were immunised less frequently and later than controls. Furthermore there was no increased risk of SIDS in the 14 days following immunisation. There was no evidence to suggest the recently introduced hexavalent vaccines were associated with an increased risk of SIDS.

CONCLUSIONS

This study provides further support that immunisations may reduce the risk of SIDS.

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

OBJECTIVE

To test the hypothesis that infants with sudden infant death syndrome (SIDS) found face down (FD) would have SIDS risk factors different from those found in other positions (non-face-down position, NFD).

STUDY DESIGN

We used the New Zealand Cot Death Study data, a 3-year, nationwide (1987 to 1990), case-control study. Odds ratios (univariate and multivariate) for FD (n = 154) and NFD SIDS (n = 239) were estimated separately, and statistical differences between the two groups were assessed.

RESULTS

Of 12 risk factors for SIDS, there were 8 with a statistically significant difference between FD and NFD infants. After adjustment for the potential confounders, younger infant age, Maori ethnicity, low birth weight, prone sleep position, use of a sheepskin, and pillow use were all associated with a greater risk of SIDS in the FD than the NFD group. Sleeping during the nighttime, maternal smoking, and bed-sharing were associated with a risk of SIDS only in the NFD group. Pacifier use was associated with a decreased risk for SIDS only in the NFD group, whereas being found with the head covered was associated with a decreased risk for SIDS for the FD group.

CONCLUSIONS

Infants with SIDS in the FD position appear to be a distinct subgroup of SIDS. These differences in risk factors provide clues to mechanisms of death in both SIDS subtypes.

Should pacifiers be recommended to prevent sudden infant death syndrome?

OBJECTIVES

Our aim was to review the evidence for a reduction in the risk of sudden infant death syndrome (SIDS) with pacifier ("dummy" or "soother") use, to discuss possible mechanisms for the reduction in SIDS risk, and to review other possible health effects of pacifiers.

RESULTS

There is a remarkably consistent reduction of SIDS with pacifier use. The mechanism by which pacifiers might reduce the risk of SIDS is unknown, but several mechanisms have been postulated. Pacifiers might reduce breastfeeding duration, but the studies are conflicting.

CONCLUSIONS

It seems appropriate to stop discouraging the use of pacifiers. Whether it is appropriate to recommend pacifier use in infants is open to debate.

Smoking and the sudden infant death syndrome

The aims of this review are (a) to critically examine the epidemiologic evidence for a possible association between smoking and the sudden infant death syndrome (SIDS), (b) to review the pathology and postulated physiological mechanism(s) by which smoking might be causally related to SIDS, and (c) to provide recommendations for SIDS prevention in relation to tobacco smoking. Over 60 studies have examined the relation between maternal smoking during pregnancy and risk of SIDS. With regard to prone-sleep-position intervention programs, the pooled relative risk associated with maternal smoking was RR = 2.86 (95% CI = 2.77, 2.95) before and RR = 3.93 (95% CI = 3.78, 4.08) after. Epidemiologically, to distinguish the effect of active maternal smoking during pregnancy from involuntary tobacco smoking by the infants of smoking mothers is difficult. Clear evidence for environmental tobacco smoke exposure can be obtained by examining the risk of SIDS from paternal smoking when the mother is a non-smoker. Seven such studies have been carried out. The pooled unadjusted RR was 1.49 (95% CI = 1.25, 1.77). Consideration of the pathological and physiological effects of tobacco suggests that the predominant effect from maternal smoking comes from the in utero exposure of the fetus to tobacco smoke. Assuming a causal association between smoking and SIDS, about one-third of SIDS deaths might have been prevented if all fetuses had not been exposed to maternal smoking in utero.

Are the risk factors for SIDS different for preterm and term infants?

BACKGROUND

Mortality from SIDS has declined since the recommendation that infants are not placed prone to sleep. SIDS mortality is higher in infants born preterm than those born at term.

AIM

To determine if risk factors for SIDS are any different for preterm and term infants.

METHODS

Mortality data over time were used to determine whether the reduction in SIDS mortality rates had occurred equally in term and preterm infants. Data from two New Zealand studies (a case-control study and a case-cohort study) were used to determine if any differences existed in risk factors for SIDS between term and preterm infants before and after the SIDS prevention campaign.

RESULTS

SIDS mortality appears to have decreased by similar proportions in term and preterm infants. Risk factors for SIDS were similar in preterm and term infants, except for parity where there was a significant interaction. Increasing parity was a risk factor for SIDS in term infants but not preterm infants.

CONCLUSION

SIDS rates have decreased at comparable rates in term and preterm infants, but preterm birth still remains a risk factor for SIDS. The magnitude of the odds ratios associated with modifiable risk factors were similar for both groups. There may however be a difference in risk associated with parity between term and preterm infants. The messages for risk factors for SIDS are applicable to mothers of preterm as well as term infants.

Neuroactive steroids and inhibitory neurotransmission: mechanisms of action and physiological relevance

Dysfunction of GABA(A) receptor-mediated inhibition is implicated in a number of neurological and psychiatric conditions including epilepsy and affective disorders. Some of these conditions have been associated with abnormal levels of certain endogenously occurring neurosteroids, which potently and selectively enhance the function of the brain's major inhibitory receptor, the GABA(A) receptor. Consistent with their ability to enhance neuronal inhibition, such steroids exhibit in animals and humans anxiolytic, anticonvulsant and anesthetic actions. Neurosteroids, exemplified by the potent progesterone metabolite, 5alpha-pregnan-3alpha-ol-20-one can be synthesized de novo in the CNS both in neurones and glia in levels sufficient to modulate GABA(A) receptor function. Neurosteroid levels are not static, but are subject to dynamic fluctuations, for example during stress, or the later stages of pregnancy. These observations suggest that these endogenous modulators may refine the function of the brain's major inhibitory receptor and thus, play an important physiological and pathophysiological role. However, given the ubiquitous expression of GABA(A) receptors throughout the mammalian CNS, changes in neurosteroid levels should be widely experienced, causing a generalized enhancement of neuronal inhibition. Such a non-specific action would seem incompatible with a physiological role. However, neurosteroid action is both brain region and neurone selective. This specificity results from a variety of molecular mechanisms including receptor subunit composition, local steroid metabolism and phosphorylation. This paper will evaluate the relative contribution these mechanisms play in defining the interaction of neurosteroids with synaptic and extra-synaptic GABA(A) receptors.

Maternal stress, social support and preschool children's intelligence

BACKGROUND

Despite some research suggesting maternal stress may be associated with cognitive impairment in preschool children, there has been little direct investigation of the association between maternal stress, social support and children's intelligence.

AIM

To determine whether maternal stress and social support during pregnancy and during the child's early years of life are associated with the intelligence test performance of preschool children.

STUDY DESIGN

Five hundred and fifty European mothers and children enrolled in the Auckland Birthweight Collaborative Study at birth were interviewed when the child was 3 1/2 years of age.

SUBJECTS

All children were full term gestation and approximately half the sample were small for gestational age at birth (SGA = birthweight < or = 10th percentile).

OUTCOME MEASURE

The cognitive ability of children aged 3 1/2 years was assessed using the Stanford Binet Intelligence Scale 4th Edition.

RESULTS

In the total sample, maternal stress and lack of social support during pregnancy were significantly associated with lower intelligence test scores of children. In the group of SGA children, maternal stress post pregnancy was significantly associated with lower intelligence test scores in children. There is evidence that for some children the presence of good social support for mothers may reduce the negative effects of maternal stress on children's cognitive development.

CONCLUSION

Maternal stress and lack of social support appear to be associated with lower intelligence test scores of preschool children. Social support may attenuate some of the negative effects of maternal stress on intelligence in children born small for gestational age.

Fetal homologue of infant crying

Four behavioural states are recognised in the human fetus and are comparable to those of the neonate: 1F (quiet sleep), 2F (active state), 3F (quiet awake), and 4F (active awake). State 5, or crying, is not considered to have a fetal correlate. In a study assessing the effects of exposure to tobacco and cocaine during pregnancy on fetal response and habituation to vibroacoustic stimulation, what appears to be the fetal homologue of crying was observed. These behaviours were seen on ultrasound, and have been captured on video recordings and include: an initial exhalation movement associated with mouth opening and tongue depression, followed by a series of three augmented breaths, the last breath ending in an inspiratory pause followed by an expiration and settling. This is the first report/video documenting these behaviours and suggests the possibility of a state 5F.

Risk factors for atopic dermatitis in New Zealand children at 3.5 years of age

BACKGROUND

The prevalence of atopic dermatitis (AD) is increasing in Western societies. The hygiene hypothesis proposes that this is due to reduced exposure to environmental allergens and infections during early life.

OBJECTIVES

To examine factors associated with a diagnosis of AD at 3.5 years of age, especially those factors implicated by the hygiene hypothesis.

METHODS

The Auckland Birthweight Collaborative study is a case-control study of risk factors for small for gestational age babies. Cases were born at term with birthweight < or = 10th centile; controls were appropriate for gestational age, with birthweight > 10th centile. The infants were assessed at birth, 1 year and 3.5 years of age. Data were collected by parental interview and examination of the child. AD was defined as the presence of an itchy rash in the past 12 months with three or more of the following: history of flexural involvement; history of generally dry skin; history of atopic disease in parents or siblings; and visible flexural dermatitis as per photographic protocol. Statistical analyses took into account the disproportionate sampling of the study population.

RESULTS

Analysis was restricted to European subjects. Eight hundred and seventy-one children were enrolled at birth, 744 (85.4%) participated at 1 year, and 550 (63.2%) at 3.5 years. AD was diagnosed in 87 (15.8%) children seen at 3.5 years. The prevalence of AD did not differ by birthweight. AD at 3.5 years was associated with raised serum IgE > 200 kU L(-1), and wheezing, asthma, rash or eczema at 1 year. In multivariate analysis, adjusted for parental atopy and breastfeeding, AD at 3.5 years was associated with atopic disease in the parents: maternal atopy only, adjusted odds ratio (OR) 3.83, 95% confidence interval (CI) 1.20-12.23; paternal atopy only, adjusted OR 3.59, 95% CI 1.09-11.75; both parents atopic, adjusted OR 6.12, 95% CI 2.02-18.50. There was a higher risk of AD with longer duration of breastfeeding: < 6 months, adjusted OR 6.13, 95% CI 1.45-25.86; > or = 6 months, adjusted OR 9.70, 95% CI 2.47-38.15 compared with never breastfed. These findings remained significant after adjusting for environmental factors and a personal history of atopy. AD at 3.5 years was associated with owning a cat at 3.5 years (adjusted OR 0.45, 95% CI 0.21-0.97) but not with owning a dog at 3.5 years, pets at 1 year, nor with older siblings. Furthermore, AD at 3.5 years was not associated with gender, socioeconomic status, maternal smoking, parity, damp, mould, immunizations, body mass index or antibiotic use in first year of life.

CONCLUSIONS

A personal and a parental history of atopic disease are risk factors for AD at 3.5 years. Duration of breastfeeding was associated with an increased risk of AD. No association was found with those factors implicated by the hygiene hypothesis. This study suggests that breastfeeding should not be recommended for the prevention of AD.

Breastfeeding and intelligence of preschool children

AIM

To investigate whether breastfeeding during infancy is a determinant of intelligence at 3.5 y.

METHODS

Five hundred and fifty European children enrolled at birth in the Auckland Birthweight Collaborative Study were assessed at 3.5 y of age. Approximately half were small for gestational age (SGA < or =10th percentile) at birth and half were appropriate for gestational age (AGA >10th percentile). Duration of breastfeeding was recorded at maternal interview, and the intelligence of children was assessed using the Stanford Binet Intelligence Scale. Regression analysis was used to calculate estimates of difference in intelligence scores between breastfeeding groups for the total sample and the group of SGA children. Analyses of the total sample were weighted to account for the disproportionate sampling of SGA children.

RESULTS

Breastfeeding was not significantly related to intelligence scores in the total sample despite a trend for longer periods of breastfeeding to be associated with higher intelligence scores. However, in the SGA group, breastfeeding was significantly related to IQ at 3.5 y. Small for gestational age children who were breastfed for longer than 12 mo had adjusted scores 6.0 points higher than those who were not breastfed (p=0.06).

CONCLUSION

Breastfeeding may be particularly important for the cognitive development of preschool children born small for gestational age.

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

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

Infection, health problems, and health care utilisation, and the risk of sudden infant death syndrome

AIM

To examine whether symptoms suggestive of infection, health problems, and health care utilisation are risk factors for SIDS.

METHODS

Matched case-control study with 333 SIDS infants and 998 control infants matched for region, age, gender, and reference sleep. Information was obtained by parental interview, paediatrician completed questionnaire, and hospital admission data.

RESULTS

No symptoms were associated with SIDS after adjustment for potential confounders. Illness in the last four weeks as reported by the paediatrician did not differ between cases and controls. Developmental problems and special investigations at any stage of life significantly increased the risk of SIDS (adjusted OR = 2.14 and 2.07). Admission to hospital after the first week of life was associated with an increased risk of SIDS (adjusted OR = 1.88).

CONCLUSION

Symptoms of infection and illness are no longer risk factors for SIDS in communities such as Germany where few infants sleep prone. The increased risk of SIDS with developmental problems may indicate that infants which subsequently die of SIDS are abnormal or in some way vulnerable.

Unnatural causes of sudden unexpected deaths initially thought to be sudden infant death syndrome

The aim of this clinicopathological study was to determine the frequency of infant deaths due to unnatural causes among cases of sudden and unexpected infant death. Nine institutes of legal medicine in Germany that took part in the German study on Sudden Infant Death Syndrome (GeSID), representing 35% of the German territory, investigated in a 3-year period (from 1998 to 2001) 339 cases of infant death that were not expected to be due to unnatural causes from the first external examination. All cases were investigated by complete, standardised, post-mortem examination including death scene investigation, autopsy, histology, toxicology and neuropathology. The frequency of unnatural deaths was 5.0% (n=17). The causes of death were head injury (n=7), suffocation (n=5), poisoning (n=2), neglect (n=2) and septicaemia due to aspiration of a foreign body (n=1). Two deaths were unsuspected accidents and 12 were due to infanticide. In 3 cases, it was not possible to differentiate between accidental death and infanticide. A complete postmortem examination including an analysis of the clinical history, death scene investigation, autopsy, histology, toxicology, and neuropathology is mandatory to differentiate sudden and unexpected deaths due to natural causes (e.g. SIDS) and cases of unnatural death.

Effects of maternal cigarette smoking and cocaine use in pregnancy on fetal response to vibroacoustic stimulation and habituation

BACKGROUND

Cigarette smoking and cocaine use in pregnancy are common in the US and both are risk factors for sudden infant death syndrome (SIDS). Although the cause of SIDS is not known, one postulated mechanism involves abnormalities of arousal and arousal regulation. Cigarette smoking and cocaine use may cause deficits of arousal. Many believe arousal deficits occur prenatally.

AIMS

The aim of this study was to assess the effects of cigarette smoke and cocaine exposure during pregnancy on measures of fetal arousal and arousal competency: 1) the fetal response to vibroacoustic stimulation (VAS) and 2) habituation to VAS.

HYPOTHESIS

Maternal cigarette smoking and cocaine use in pregnancy are associated with altered arousal and arousal regulation in the fetus.

METHODS

Three groups of mother-fetal dyads were enrolled: 1) cigarette smokers (n = 54), 2) cocaine users (n = 30), and 3) controls (n = 60). One hundred eight fetuses were tested at 29-31 wk gestation, 119 at 32-35 wk, and 118 at 36+ wk. The fetal response to VAS was assessed using real-time ultrasound and a paradigm of arousal responsiveness. Responders were tested with repeated VAS to assess habituation. Also, the quality of fetal reactivity to repeated stimuli was assessed as a measure of arousal and arousal regulation competence (Behavioral Reactivity Scale).

RESULTS

The control group had a larger proportion of fetuses who were too active to initiate testing ("too active to test") (p = 0.013); the proportion of fetuses too active to test decreased with increasing gestational age. The majority of the fetuses who could be tested responded to the initial VAS, and there were no group differences. The proportion of fetuses that habituated and the rate of habituation did not differ between the groups. Behavioral reactivity did not differ between groups.

CONCLUSIONS

The original hypotheses were not confirmed. However, the chosen assessment paradigms may have lacked sensitivity. The proportion of fetuses that were "too active to test" decreased with gestational age. The control group had a larger proportion of fetuses that were "too active to test" compared with the exposure groups. We speculate that these findings indicate that prenatal exposure to these neuroteratogens may have produced an acceleration of the behavioral response to vibroacoustic stimulation.

A randomized controlled trial of an asthma clinical pathway for children in general practice

AIMS

To evaluate the effect of the implementation of an asthma clinical pathway on asthma in children in general practice.

METHODS

A randomized, controlled trial involving 270 general practitioners. One group of general practitioners implemented the asthma clinical pathway for children (intervention group) and the control group continued with their usual asthma medical care management. The main outcome measures were admissions to hospital for asthma and attendance at the Children's Emergency Department. Compliance with the guidelines was assessed by examining asthma drug prescriptions.

RESULTS

Admissions to hospital for asthma dropped 40% in the intervention group, by 33% in the control group and by 22% in general practitioners not participating in the trial. The differences between the intervention and control and between the intervention and non-participating general practitioners were not statistically significant. The decrease in attendance at the Children's Emergency Department decreased by 25%, 30% and 19%, respectively, but this was not statistically significant. There was a significant decrease in prescriptions for oral relievers, dry powder relievers in the under 6s, mast cell stabilizers and methylxanthines in both control and intervention groups. However, only for oral relievers was there a significant difference between the intervention group and control, with the decrease larger in the intervention group (p < 0.001).

CONCLUSIONS

Admissions to hospital for asthma decreased, as did attendance at the Children's Emergency Department. Prescriptions for asthma medication changed in the direction anticipated with compliance with the asthma clinical pathway. However, we found no evidence within the study that implementation of the asthma clinical pathway by general practitioners resulted in lower morbidity than those general practitioners who did not implement the pathway. Possible explanations are that these general practitioners were already providing care according to the recommendations of the pathway, or that there was contamination of the control group by the intervention, or that the guidelines, although based on currently accepted recommendations, are ineffective.

Placental villitis of unknown origin: epidemiologic associations

OBJECTIVES

This study was undertaken to investigate the incidence and associations of placental villitis of unknown origin or etiology (VUE).

STUDY DESIGN

Five hundred nine placentas from women delivered of small-for-gestational-age infants (SGAP) and 529 placentas from women delivering infants with birth weights appropriate for gestational age (AGAP) were examined prospectively for VUE as part of a population-based case control study of SGA infants at term.

RESULTS

VUE was found in 17.3% of SGAP and 11.7% of AGAP and was an independent risk factor for SGA (adjusted odds ratio 2.35, 95% CI 1.55-3.56). Villitis in conjunction with maternal hypertension increased the risk of SGA substantially (adjusted odds ratio 17.7, 95%CI 3.6-86.9). A study of a wide range of pregnancy-related factors found no significant associations with VUE in AGAP. In contrast, VUE in SGAP had significant associations after multivariate analysis with maternal body mass index, multigravidity, ethnicity, and 1 index of maternal infection.

CONCLUSION

VUE is an independent risk factor for SGA at term. Maternal factors influence this association, possibly by modifying a systemic effect on fetal growth of villous inflammation at commonly occurring defects in the maternal-fetal immune barrier.

Maternal nutritional risk factors for small for gestational age babies in a developed country: a case-control study

AIMS

To assess the effect of maternal diet during pregnancy on the risk of delivering a baby who is small for gestational age (SGA).

METHODS

Case-control study of 844 cases (SGA) and 870 controls (appropriate size for gestational age (AGA)). Only term (37+ completed weeks of gestation) infants were included. Retrospective food frequency questionnaires were completed at birth on the diet at the time of conception and in the last month of pregnancy.

RESULTS

At the time of conception, mothers of AGA infants ate significantly more servings of carbohydrate rich food and fruit, and were more likely to have taken folate and vitamin supplements than mothers of SGA infants. There was some evidence that mothers of AGA infants also ate more servings of dairy products, meat, and fish (0.05 < p < 0.1). However, after adjustment for maternal ethnicity, smoking, height, weight, hypertension, and occupation, fish intake (p = 0.04), carbohydrate-rich foods (p = 0.04), and folate supplementation (p = 0.02) were associated with a reduced risk of SGA. In the last month of pregnancy, only iron supplementation was associated with a reduced risk of SGA (p = 0.05) after adjustment for potential confounders.

CONCLUSIONS

This study suggests that small variations in maternal diets within the normal range during pregnancy in developed countries are associated with differences in birth weight.

Sudden infant death syndrome and unclassified sudden infant deaths: a definitional and diagnostic approach

The definition of sudden infant death syndrome (SIDS) originally appeared in 1969 and was modified 2 decades later. During the following 15 years, an enormous amount of additional information has emerged, justifying additional refinement of the definition of SIDS to incorporate epidemiologic features, risk factors, pathologic features, and ancillary test findings. An expert panel of pediatric and forensic pathologists and pediatricians considered these issues and developed a new general definition of SIDS for administrative and vital statistics purposes. The new definition was then stratified to facilitate research into sudden infant death. Another category, defined as unclassified sudden infant deaths, was introduced for cases that do not meet the criteria for a diagnosis of SIDS and for which alternative diagnoses of natural or unnatural conditions were equivocal. It is anticipated that these new definitions will be modified in the future to accommodate new understanding of SIDS and sudden infant death.

Asthma prevalence in European, Maori, and Pacific children in New Zealand: ISAAC study

The International Study of Asthma and Allergies in Childhood (ISAAC) demonstrated that the highest prevalence of asthma in the world is in English-speaking countries, including New Zealand. In this paper, we compare asthma symptom prevalence in the three major ethnic groups (Maori, Pacific, and European) in the six participating centers in New Zealand. Hospital admission rates for asthma are higher among Maori and Pacific children compared to European children. The working hypothesis was that there were important differences in prevalence of asthma symptoms or diagnosis between ethnic groups which might explain these observed differences in asthma morbidity. In each center in 1992-1993, we sampled approximately 3000 children at each of the age brackets 6-7 years and 13-14 years. There were 37592 participants. Maori children had higher rates of diagnosed asthma and reported asthma symptoms than Pacific children in both age groups (diagnosed asthma in 6-7-year-olds: Maori, 31.7%; Pacific, 21.2%; 95% confidence interval on difference (CID), 7.2, 13.8; P < 0.001; 13-14-year-olds: Maori, 24.7%; Pacific, 19.2%; CID 2.5, 8.5; P < 0.001; recent wheeze in 6-7-year-olds: Maori, 27.6%; Pacific, 22.0%; CID, 2.6, 8.6; P < 0.001; 13-14-year-olds: Maori, 30.8%; Pacific, 21.1%; CID, 4.8, 14.5; P < 0.001;). European children had rates intermediate between those of Maori and Pacific children (6-7-year-olds) or similar to those of Maori children (13-14-year-olds), but had the lowest prevalence of night waking with wheeze in both age groups (e.g., 6-7-year-olds: European, 2.6%; Maori, 5.8%; Pacific, 5.7%; European-Maori CID: -4.2, -2.2, P < 0.001; European-Pacific CID: -4.7, -1.7, P < 0.001; Maori-Pacific CID: -1.7, 1.8, P = 1.0). The pattern of differences closely resembled that in a 1985 Auckland study, despite a 1.5-1.7-fold overall increase in prevalence. In conclusion, there are important differences in asthma prevalence among Maori, Pacific, and European children. These differences are small compared to worldwide variation, but their pattern is stable over time. The higher rate of severe asthma symptoms that Maori and Pacific children report may be one reason for the increased asthma morbidity in these groups. Further studies are needed to determine the reasons for these apparent differences in asthma severity.

What affects the age of first sleeping through the night?

OBJECTIVE

To ascertain the age at which an infant first sleeps regularly through the night and the factors affecting this age.

METHODS

A representative cross sectional sample of 700 infants in south-east England were studied. Information was collected on 511 (73.0%) of the infants by parental interview. Obstetric records were also examined.

RESULTS

Fifty per cent of babies slept through by 8 weeks and 75% by 12 weeks. Multivariate survival analysis used to investigate 61 potential factors found that a heavier birthweight, female gender and co-sleeping less than 2 hours or not at all; younger mothers, school leaving age less than 17 years, stress factors (divorce and no separation from partner for more than a month in the last 12 months); no central heating, and the baby not sharing a room with siblings were associated with an earlier age at which an infant first sleeps through the night.

CONCLUSIONS

Little of the variation between children in age of first sleeping through the night could be explained by these nine factors.

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

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

Does circadian variation in risk factors for sudden infant death syndrome (SIDS) suggest there are two (or more) SIDS subtypes?

Sudden infant death syndrome (SIDS) is known to occur more frequently at night. In two studies it has now been shown that a prone sleep position is more strongly associated with SIDS occurring during the day, whereas night-time deaths are more strongly associated with maternal smoking and illness.

CONCLUSION

This variation, although unexplained, does suggest at least two SIDS subtypes: one related to sleep position and possibly a thermal mechanism, and one related to an uncontrolled inflammatory response to infection predominantly occurring at night. In addition, there are probably other mechanisms that do not show a circadian variation.

Stress and lack of social support as risk factors for small-for-gestational-age birth

AIM

To determine the contributions of social support and perceived stress to the risk of small-for-gestational-age birth.

METHODS

The investigation was a case-control study of mothers of infants born at 37 or more completed weeks of gestation. Cases weighed less than the sex-specific 10th percentile for gestational age at birth (small for gestational age (SGA), n = 836), and controls (appropriate for gestational age (AGA), n = 870) comprised a random selection of heavier babies.

RESULTS

In univariate analyses measures of informal social support, but not perceived stress or formal social support, were associated with SGA birth. It was found that Asian mothers are less likely to receive support from families and friends. After adjustment for ethnicity, informal social support was not associated with SGA.

CONCLUSIONS

Support appears to reduce the risk of SGA births, but after adjustment for ethnicity this is no longer the case. Stress during pregnancy was not associated with SGA birth.

Snoring in the first year of life

AIM

To describe the prevalence of snoring in infancy and the factors associated with snoring.

METHODS

The investigation comprised a cross-sectional study of 1800 infants. Snoring was ascertained by interviewer-administered questionnaire.

RESULTS

The prevalence of snoring was 15.8% in the first 4 wk of life and 26.1% in the past 2 wk. Snoring in the past 2 wk was associated with increasing age of the infant, male gender, maternal smoking, sleep position, number of respiratory infections and snoring in the first 4 wk of life after adjustment for potential confounders. No associations were found with snoring in the first 4 wk of life.

CONCLUSION

Snoring is common in infancy. The identified risk factors for snoring are probably causally related to snoring. Further studies are needed to establish whether snoring in infancy is associated with current or subsequent morbidity.

The ecological relationship of tobacco smoking to the prevalence of symptoms of asthma and other atopic diseases in children: the International Study of Asthma and Allergies in Childhood (ISAAC)

This study examined the relationship between parental smoking and asthma and other atopic diseases at the ecological level. The prevalence of atopic symptoms in 6-7- and 13-14-year old children was assessed in 91 centres (from 38 countries) and 155 centres (from 56 countries) respectively in the International Study of Asthma and Allergy in Childhood (ISAAC). These symptoms were related to prevalence of tobacco smoking for each country by gender as reported by the World Health Organisation. There was a significant negative association between the prevalence of smoking by men and the prevalence of symptoms of asthma and rhinitis, but not eczema in the 13-14-year age group. There was a significant positive relationship between prevalence of smoking by women and prevalence of wheeze in the last 12 months, but not for any other symptoms in the 13-14-year age group. In the 6-7-year age group, there was a significant negative correlation between prevalence of smoking by men and the prevalence of wheeze causing sleep disturbance and a close to significant negative association at the 5% level with the prevalence of wheeze in the last 12 months and rhinitis. Thus, for the countries that are included in this analysis, countries that have high adult male smoking rates have a lower risk of asthma and rhinitis symptoms in children. It should be stressed that this analysis does not involve information on individual exposures and therefore does not contradict the well-established association of active and passive smoking in individuals with the occurrence of asthma symptoms in the same individuals. Rather, it indicates that this well-established individual-level association does not account for the international differences in asthma prevalence, and that other risk factors for asthma must be responsible for the observed international patterns.

Smoking, nicotine and tar and risk of small for gestational age babies

AIMS

To assess the effect of maternal smoking and environmental tobacco smoke (ETS) on risk of small for gestational age infants (SGA).

METHODS

Case-control study of 844 cases and 870 controls.

RESULTS

Maternal smoking in pregnancy was associated with an increased risk of SGA (adjusted odds ratio (OR)= 2.41; 95% confidence interval (CI) = 1.78, 3.28). We could not detect an increased risk of SGA with paternal smoking, or with other household smokers when the mother was a non-smoker, but did find an increased risk with exposure to ETS in the workplace or while socializing. Infants of mothers who ceased smoking during pregnancy were not at increased risk of SGA, but those who decreased but did not stop remained at risk of SGA. There was no evidence that the concentration of nicotine and tar in the cigarettes influenced the risk of SGA.

CONCLUSIONS

Maternal smoking in pregnancy is a major risk factor for SGA. This study suggests that mothers should be advised to cease smoking completely during pregnancy, and that a reduction in the number of cigarettes smoked or smoking low tar or nicotine concentration cigarettes does not reduce the risk of SGA.