Maternal stress during pregnancy is associated with moderate to severe depression in 11-year-old children

AIM

Maternal stress during pregnancy has been associated with negative outcomes in children. We examined the risk factors for symptoms of depression in 11-year-old children, including the interaction between birthweight and other variables.

METHODS

We collected maternal, obstetric and demographic information from birth through to the age of 11. Approximately, half of the 609 children were born small-for-gestational-age (SGA). Information collected at 3.5 and 7 years of age included intelligence testing and parent-reported behavioural and emotional development. At 11 years of age, the children completed the Center for Epidemiological Studies Depression Scale for Children. Multivariable logistic regression analysis examined the relationship between self-reported symptoms of moderate to severe depression at the age of 11 and explanatory variables.

RESULTS

Symptoms of moderate to severe depression were related to increasing maternal stress during pregnancy, young maternal age, lower intelligence test scores at 7-years-old and being bullied at school in the previous 6 months. There was also a significant interaction between maternal stress in pregnancy and symptoms of depression in 11-year-old children born SGA.

CONCLUSION

Increasing maternal stress during pregnancy was associated with increased risk of symptoms of moderate to severe depression in 11-year-old children, especially those who were born SGA.

Fast-food consumption and body mass index in children and adolescents: an international cross-sectional study

OBJECTIVE

To investigate whether reported fast-food consumption over the previous year is associated with higher childhood or adolescent body mass index (BMI).

DESIGN

Secondary analysis from a multicentre, multicountry cross-sectional study (International Study of Asthma and Allergies in Children (ISAAC) Phase Three).

SUBJECTS AND METHODS

Parents/guardians of children aged 6-7 completed questionnaires which included questions about their children's asthma and allergies, fast-food consumption, height and weight. Adolescents aged 13-14 completed the same questionnaire. The questionnaire asked "In the past 12 months, how often on average did you (your child) eat fast-food/burgers?" The responses were infrequent (never/only occasionally), frequent (once/twice a week) or very frequent (three or more times per week). A general linear mixed model was used to determine the association between BMI and fast-food consumption, adjusting for Gross National Income per capita by country, measurement type (whether heights/weights were reported or measured), age and sex.

RESULTS

72,900 children (17 countries) and 199,135 adolescents (36 countries) provided data. Frequent and very frequent fast-food consumption was reported in 23% and 4% of children, and 39% and 13% of adolescents, respectively. Children in the frequent and very frequent groups had a BMI that was 0.15 and 0.22 kg/m(2) higher than those in the infrequent group (p<0.001). Male adolescents in the frequent and very frequent groups had a BMI that was 0.14 and 0.28 kg/m(2) lower than those in the infrequent group (p<0.001). Female adolescents in the frequent and very frequent groups had a BMI that was 0.19 kg/m(2) lower than those in the infrequent group (p<0.001).

CONCLUSIONS

Reported fast-food consumption is high in childhood and increases in adolescence. Compared with infrequent fast-food consumption, frequent and very frequent consumption is associated with a higher BMI in children. Owing to residual confounding, reverse causation and likely misreporting, the reverse association observed in adolescents should be interpreted with caution.

Associations between acetaminophen use during pregnancy and ADHD symptoms measured at ages 7 and 11 years

Objective

Our aim was to replicate and extend the recently found association between acetaminophen use during pregnancy and ADHD symptoms in school-age children.

Methods

Participants were members of the Auckland Birthweight Collaborative Study, a longitudinal study of 871 infants of European descent sampled disproportionately for small for gestational age. Drug use during pregnancy (acetaminophen, aspirin, antacids, and antibiotics) were analysed in relation to behavioural difficulties and ADHD symptoms measured by parent report at age 7 and both parent- and child-report at 11 years of age. The analyses included multiple covariates including birthweight, socioeconomic status and antenatal maternal perceived stress.

Results

Acetaminophen was used by 49.8% of the study mothers during pregnancy. We found significantly higher total difficulty scores (Strengths and Difficulty Questionnaire parent report at age 7 and child report at age 11) if acetaminophen was used during pregnancy, but there were no significant differences associated with any of the other drugs. Children of mothers who used acetaminophen during pregnancy were also at increased risk of ADHD at 7 and 11 years of age (Conners’ Parent Rating Scale-Revised).

Conclusions

These findings strengthen the contention that acetaminophen exposure in pregnancy increases the risk of ADHD-like behaviours. Our study also supports earlier claims that findings are specific to acetaminophen.

Risk factors for migraine and tension-type headache in 11 year old children

BACKGROUND

Though migraine and tension type headache are both commonly diagnosed in childhood, little is known about their determinants when diagnosed prior to puberty onset. Our aim was to determine psychosocial- and health-related risk factors of migraine and tension-type headache in 11 year old children.

METHODS

871 New Zealand European children were enrolled in a longitudinal study at birth and data were collected at birth, 1, 3.5, 7, and 11 years of age. Primary headache was determined at age 11 years based on the International Headache Society. Perinatal factors assessed were small for gestational age status, sex, maternal smoking during pregnancy, maternal perceived stress, and maternal school leaving age. Childhood factors assessed were sleep duration, percent body fat, television watching, parent and self-reported total problem behaviour, being bullied, and depression.

RESULTS

Prevalence of migraine and tension-type headache was 10.5% and 18.6%, respectively. Both migraine and TTH were significantly associated with self-reported problem behaviour in univariable logistic regression analyses. Additionally, migraine was associated with reduced sleep duration, and both sleep and behaviour problems remained significant after multivariable analyses. TTH was also significantly associated with antenatal maternal smoking, higher body fat, and being bullied. For TTH, problem behaviour measured at ages 3.5 and 11 years both remained significant after multivariable analysis. Being born small for gestational age was not associated with either headache group.

CONCLUSIONS

Although they share some commonality, migraine and tension-type headache are separate entities in childhood with different developmental characteristics. The association between primary headache and problem behaviour requires further investigation.

Learning from child death review in the USA, England, Australia, and New Zealand

Despite pronounced reductions in child mortality in industrialised countries, variations exist within and between countries. Many child deaths are preventable, and much could be done to further reduce mortality. For the family, their community, and professionals caring for them, every child's death is a tragedy. Systematic review of all child deaths is grounded in respect for the rights of children and their families, and aimed towards the prevention of future child deaths. In a Series of three papers, we discuss child death in high-income countries in the context of evolving child death review processes. This paper outlines the background to and development of child death review in the USA, England, Australia, and New Zealand. We consider the purpose, process, and outputs of child death review, and discuss how these factors can contribute to a greater understanding of children's deaths and to knowledge for the prevention of future child deaths.

No evidence for copy number and methylation variation in H19 and KCNQ10T1 imprinting control regions in children born small for gestational age

Background

There is a substantial genetic component for birthweight variation, and although there are known associations between fetal genotype and birthweight, the role of common epigenetic variation in influencing the risk for small for gestational age (SGA) is unknown. The two imprinting control regions (ICRs) located on chromosome 11p15.5, involved in the overgrowth disorder Beckwith-Wiedemann syndrome (BWS) and the growth restriction disorder Silver-Russell syndrome (SRS), are prime epigenetic candidates for regulating fetal growth. We investigated whether common variation in copy number in the BWS/SRS 11p15 region or altered methylation levels at IGF2/H19 ICR or KCNQ10T1 ICR was associated with SGA.

Methods

We used a methylation-specific multiplex-ligation-dependent probe amplification assay to analyse copy number variation in the 11p15 region and methylation of IGF2/H19 and KCNQ10T1 ICRs in blood samples from 153 children (including 80 SGA), as well as bisulfite pyrosequencing to measure methylation at IGF2 differentially methylated region (DMR)0 and H19 DMR.

Results

No copy number variants were detected in the analyzed cohort. Children born SGA had 2.7% lower methylation at the IGF2 DMR0. No methylation differences were detected at the H19 or KCNQ10T1 DMRs.

Conclusions

We confirm that a small hypomethylation of the IGF2 DMR0 is detected in peripheral blood leucocytes of children born SGA at term. Copy number variation within the 11p15 BWS/SRS region is not an important cause of non-syndromic SGA at term.

The Midland and North of England Stillbirth Study (MiNESS)

Background

The United Kingdom has one of the highest rates of stillbirth in Europe, resulting in approximately 4,000 stillbirths every year. Potentially modifiable risk factors for late stillbirths are maternal age, obesity and smoking, but the population attributable risk associated with these risk factors is small.

Recently the Auckland Stillbirth Study reported that maternal sleep position was associated with late stillbirth. Women who did not sleep on their left side on the night before the death of the baby had double the risk compared with sleeping on other positions. The population attributable risk was 37%. This novel observation needs to be replicated or refuted.

Methods/Design

Case control study of late singleton stillbirths without congenital abnormality. Controls are women with an ongoing singleton pregnancy, who are randomly selected from participating maternity units booking list of pregnant women, they are allocated a gestation for interview based on the distribution of gestations of stillbirths from the previous 4 years for the unit. The number of controls selected is proportional to the number of stillbirths that occurred at the hospital over the previous 4 years.

Data collection: Interviewer administered questionnaire and data extracted from medical records. Sample size: 415 cases and 830 controls. This takes into account a 30% non-participation rate, and will detect an OR of 1.5 with a significance level of 0.05 and power of 80% for variables with a prevalence of 57%, such as non-left sleeping position.

Statistical analysis: Mantel-Haenszel odds ratios and unconditional logistic regression to adjust for potential confounders.

Discussion

The hypotheses to be tested here are important, biologically plausible and amenable to a public health intervention. Although this case–control study cannot prove causation, there is a striking parallel with research relating to sudden infant death syndrome, where case–control studies identified prone sleeping position as a major modifiable risk factor. Subsequently mothers were advised to sleep babies prone (“Back to Sleep” campaign), which resulted in a dramatic drop in SIDS. This study will provide robust evidence to help determine whether such a public health intervention should be considered.

Trial registration number

NCT02025530

Early supplementation with Lactobacillus rhamnosus HN001 reduces eczema prevalence to 6 years: does it also reduce atopic sensitization?

BACKGROUND

The role of probiotics in prevention of allergic disease is still not clear; efficacy may depend on the timing, dose, duration, and specific probiotic used. Using a double-blind randomized placebo-controlled trial (Australian New Zealand Clinical Trials Registry: ACTRN12607000518460), we have shown that in a high-risk birth cohort, maternal supplementation from 35 weeks gestation until 6 months if breastfeeding and infant supplementation from birth until 2 years with Lactobacillus rhamnosus HN001 (HN001) (6 × 10(9) cfu/day) halved the cumulative prevalence of eczema at 2 and 4 years. Bifidobacterium animalis subsp lactis HN019 (HN019) (9 × 10(9) cfu/day) had no significant effect.

OBJECTIVE

To determine whether differences in effects of HN001 and HN019 on eczema persist to age 6 years, and to investigate effects on sensitization.

METHODS

Standard procedures were used to assess eczema (The UK Working Party's Criteria), eczema severity (SCORAD), atopic sensitization [skin prick tests (SPT), total and specific IgE] and standard questions used for asthma, wheeze, and rhinoconjunctivitis.

RESULTS

HN001 was associated with significantly lower cumulative prevalence of eczema (HR = 0.56, 95% CI 0.39-0.80), SCORAD ≥ 10 (HR = 0.69, 0.49-0.98) and SPT sensitization (HR = 0.69, 95% CI 0.48-0.99). The point prevalence of eczema (RR = 0.66, 95% CI 0.44-1.00), SCORAD ≥ 10 (RR = 0.62, 95% CI 0.38-1.01) and SPT sensitization (RR = 0.72, 95% CI 0.53-1.00) were also reduced among children taking HN001. HN019 had no significant effect on any outcome.

CONCLUSION AND CLINICAL RELEVANCE

This study provides evidence for the efficacy of the probiotic L. rhamnosus HN001 in preventing the development of eczema and possibly also atopic sensitization in high risk infants to age 6 years. The absence of a similar effect for HN019 indicates that benefits may be species specific.

Birthweight and the risk of atopic diseases: the ISAAC Phase III study

BACKGROUND

The association between birthweight and asthma, eczema and rhinoconjunctivitisis conflicting.

AIMS

To examine the association between birthweight and symptoms of asthma, eczema and rhinoconjunctivitis.

METHODS

Parents or guardians of children aged 6–7 yr completed written questionnaires about symptoms of asthma, rhinoconjunctivitis and eczema, and several risk factors, including birthweight.

RESULTS

There were 162,324 children from 60 centres in 26 countries. Low birthweight(<2.5 kg) was associated with an increased risk of symptoms of asthma (current wheeze odds ratio = 1.20; 95% confidence interval = 1.12–1.30). Low birthweight was associated with a lower risk of eczema ever. Low birthweight was not associated with rhinoconjunctivitis. Large babies (birthweight ≥4.5 kg) were not associated with any of these outcomes.

CONCLUSIONS

This study has confirmed that low birthweight is a risk factor for symptoms of asthma, but not for rhinoconjunctivitis. The findings for eczema are equivocal.

A triple risk model for unexplained late stillbirth

BACKGROUND

The triple risk model for sudden infant death syndrome (SIDS) has been useful in understanding its pathogenesis. Risk factors for late stillbirth are well established, especially relating to maternal and fetal wellbeing.

DISCUSSION

We propose a similar triple risk model for unexplained late stillbirth. The model proposed by us results from the interplay of three groups of factors: (1) maternal factors (such as maternal age, obesity, smoking), (2) fetal and placental factors (such as intrauterine growth retardation, placental insufficiency), and (3) a stressor (such as venocaval compression from maternal supine sleep position, sleep disordered breathing). We argue that the risk factors within each group in themselves may be insufficient to cause the death, but when they interrelate may produce a lethal combination.

SUMMARY

Unexplained late stillbirth occurs when a fetus who is somehow vulnerable dies as a result of encountering a stressor and/or maternal condition in a combination which is lethal for them.

Vitamin D during pregnancy and infancy and infant serum 25-hydroxyvitamin D concentration

OBJECTIVE

To determine the vitamin D dose necessary to achieve serum 25-hydroxyvitamin D (25(OH)D) concentration ≥ 20 ng/mL during infancy.

METHODS

A randomized, double-blind, placebo-controlled trial in New Zealand. Pregnant mothers, from 27 weeks' gestation to birth, and then their infants, from birth to age 6 months, were randomly assigned to 1 of 3 mother/infant groups: placebo/placebo, vitamin D3 1000/400 IU, or vitamin D3 2000/800 IU. Serum 25(OH)D and calcium concentrations were measured at enrollment, 36 weeks' gestation, in cord blood, and in infants at 2, 4, and 6 months of age.

RESULTS

Two-hundred-and-sixty pregnant women were randomized. At enrollment, the proportions with serum 25(OH)D ≥ 20 ng/mL for placebo, lower-dose, and higher-dose groups were 54%, 64%, and 55%, respectively. The proportion with 25(OH)D ≥ 20 ng/mL was larger in both intervention groups at 36 weeks' gestation (50%, 91%, 89%, P < .001). In comparison with placebo, the proportion of infants with 25(OH)D ≥ 20 ng/mL was larger in both intervention groups to age 4 months: cord blood (22%, 72%, 71%, P < .001), 2 months (50%, 82%, 92%, P < .001), and 4 months (66%, 87%, 87%, P = .004), but only in the higher-dose group at age 6 months (74%, 82%, 89%, P = .07; higher dose versus placebo P = .03, lower dose versus placebo P = .21).

CONCLUSIONS

Daily vitamin D supplementation during pregnancy and then infancy with 1000/400 IU or 2000/800 IU increases the proportion of infants with 25(OH)D ≥ 20 ng/mL, with the higher dose sustaining this increase for longer.

Antibiotic treatment during infancy and increased body mass index in boys: an international cross-sectional study

OBJECTIVE

To investigate whether antibiotic exposure during the first year of life is associated with increased childhood body mass index (BMI).

DESIGN

Secondary analysis from a multi-centre, multi-country, cross-sectional study (The International Study of Asthma and Allergies in Childhood Phase Three).

SUBJECTS

A total of 74 946 children from 31 centres in 18 countries contributed data on antibiotic use in the first 12 months of life and current BMI.

METHODS

Parents/guardians of children aged 5-8 years completed questionnaires that included questions about their children's current height and weight, and whether in the child's first 12 months of life, they had received any antibiotics, paracetamol, were breastfed or the mother/female guardian smoked cigarettes, and whether the child had wheezed in the past 12 months. A general linear mixed model was used to determine the association of antibiotic exposure with BMI, adjusting for age, sex, centre, BMI measurement type (self-reported or measured), maternal smoking, breastfeeding, paracetamol use, gross national income and current wheeze.

RESULTS

There was a significant interaction between sex and early-life antibiotic exposure. Early-life antibiotic exposure was associated with increased childhood BMI in boys (+0.107 kg m(-2), P<0.0001), but not in girls (-0.008 kg m(-2), P=0.75) after controlling for age, centre and BMI measurement type. The association remained in boys (+0.104 kg m(-2), P<0.0007), after adjustment for maternal smoking, breastfeeding, paracetamol use and current wheeze. There was no interaction between age, maternal smoking, breastfeeding, paracetamol use, gross national income and current wheeze in the association between early antibiotic exposure and BMI.

CONCLUSIONS

Exposure to antibiotics during the first 12 months of life is associated with a small increase in BMI in boys aged 5-8 years in this large international cross-sectional survey. By inference this provides additional support for the importance of gut microbiota in modulating the risk of obesity, with a sex-specific effect.

The worldwide association between television viewing and obesity in children and adolescents: cross sectional study

Background

Studies exploring the effect of television viewing on obesity throughout childhood are conflicting. Most studies have been confined to single high-income countries. Our aim was to examine the association between television viewing habits and Body Mass Index (BMI) in adolescents and children in a multicentre worldwide sample.

Methods

In the International Study of Asthma and Allergies in Children Phase Three, adolescents aged between 12 and 15 years completed questionnaires which included questions on television viewing habits, height and weight. Parents/guardians of children aged between 5 and 8 years completed the same questionnaire on behalf of their children. The questionnaire asked “During a normal week, how many hours a day (24 hours) do you (does your child) watch television?” Responses were categorised as; “short” (<1 hour), “moderate” (1 to ≤3 hours), “long” (3 to ≤5 hours) and “prolonged” (>5 hours).

Findings

207,672 adolescents from 37 countries and 77,003 children from 18 countries provided data. Daily television viewing in excess of one hour was reported in 89% of adolescents and 79% of children. Compared with adolescents in the short viewing group, those in the moderate, long and prolonged groups had BMIs that were 0.14 kg/m², 0.21 kg/m², 0.30 kg/m² and 0.08 kg/m², 0.16 kg/m² and 0.17 kg/m² larger for females and males respectively (both P<0.001). Compared with children in the short viewing group, those in the moderate, long and prolonged groups had BMIs that were 0.24 kg/m², 0.34 kg/m², 0.36 kg/m² and 0.19 kg/m², 0.32 kg/m² and 0.36 kg/m² larger for females and males respectively (both P<0.001).

Interpretation

Increased television viewing hours were positively associated with BMI in both adolescents and children with an apparent dose response effect. These findings extend the evidence that television viewing contributes to increased BMI in childhood.

Time trends, ethnicity and risk factors for eczema in New Zealand children: ISAAC Phase Three

BACKGROUND

Eczema is a common chronic disease which has significant morbidity and costs for children and their families. Phase One (1993) of the International Study of Asthma and Allergies in Childhood (ISAAC) found a high prevalence of symptoms of eczema in New Zealand.

OBJECTIVE

In Phase Three (2001-3) we aimed to answer these three questions: Is the prevalence of eczema changing over time?; Are there ethnic differences in prevalence?; and What are the risk factors for eczema?

METHODS

Five New Zealand centres participated in ISAAC Phases One and Three using the same methodology. Questionnaires about ethnicity, symptoms of eczema and environmental factors were completed by parents of 6-7 year olds (children) and self-completed by 13-14 year olds (adolescents). Prevalence and change per year were calculated by centre, ethnicity and gender. Prevalence differences between centres and associations with environmental factors were examined using logistic regression.

RESULTS

There was little change in prevalence over time for the children, and a decrease in prevalence for the adolescents. Prevalence was higher among Māori and even higher among Pacific participants than among European children. Positive associations with current eczema symptoms were found for both age groups for truck traffic in the street of residence, and current paracetamol consumption, and for children only, antibiotics or paracetamol in the 1st year of life. Inverse associations were found with residence in New Zealand less than 5 years, consumption of milk, seafood, and eggs, and presence of a dog in the home.

CONCLUSION

Eczema remains a significant problem, particularly for young Māori and Pacific New Zealanders in whom less recognition of eczema and poorer access to effective, sustained eczema management may be contributing factors. Reverse causation may explain all the environmental findings apart from truck traffic which is increasing in New Zealand.

The association between BMI, vigorous physical activity and television viewing and the risk of symptoms of asthma, rhinoconjunctivitis and eczema in children and adolescents: ISAAC Phase Three

BACKGROUND

Several studies have observed an association between obesity and asthma, but whether or not there is an association with rhinoconjunctivitis or eczema is unclear.

AIMS

To examine the relationship between body mass index categories (underweight, overweight and obesity), vigorous physical activity and television viewing and the risk of symptoms of asthma, rhinoconjunctivitis and eczema.

METHODS

As part of International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three, parents or guardians of children aged 6-7 years completed written questionnaires about symptoms of asthma, rhinoconjunctivitis and eczema, and several potential risk factors, such as vigorous physical activity and television viewing, and other information such as the child's height and weight. Adolescents aged 13-14 years self-completed the questionnaires on these symptoms and potential risk factors and reported their own height and weight. For 28% of children and 24% of adolescents, the height and weight was objectively measured.

RESULTS

A total of 76 164 children aged 6-7 years (from 29 centres and 17 countries) and 201 370 adolescents aged 13-14 years (from 73 centres and 35 countries) provided data meeting the inclusion criteria. There were associations between overweight and obesity, but not underweight, and symptoms of asthma and eczema but not rhinoconjunctivitis. Vigorous physical activity was positively associated with symptoms of asthma, rhinoconjunctivitis and eczema in adolescents, but not children. Viewing television for five or more hours/day was associated with an increased risk of symptoms of asthma, rhinoconjunctivitis and eczema in adolescents and symptoms of asthma in children.

CONCLUSIONS AND CLINICAL RELEVANCE

This study has confirmed the association between overweight and obesity and symptoms of asthma. It has extended these observations to include significant associations with symptoms of eczema, but not rhinoconjunctivitis. There are complex relationships between obesity, vigorous physical activity and sedentary behaviour and the symptoms of asthma, rhinoconjunctivitis and eczema in children.

Bed sharing when parents do not smoke: is there a risk of SIDS? An individual level analysis of five major case-control studies

OBJECTIVE

To resolve uncertainty as to the risk of Sudden Infant Death Syndrome (SIDS) associated with sleeping in bed with your baby if neither parent smokes and the baby is breastfed.

DESIGN

Bed sharing was defined as sleeping with a baby in the parents' bed; room sharing as baby sleeping in the parents' room. Frequency of bed sharing during last sleep was compared between babies who died of SIDS and living control infants. Five large SIDS case-control datasets were combined. Missing data were imputed. Random effects logistic regression controlled for confounding factors.

SETTING

Home sleeping arrangements of infants in 19 studies across the UK, Europe and Australasia.

PARTICIPANTS

1472 SIDS cases, and 4679 controls. Each study effectively included all cases, by standard criteria. Controls were randomly selected normal infants of similar age, time and place.

RESULTS

In the combined dataset, 22.2% of cases and 9.6% of controls were bed sharing, adjusted OR (AOR) for all ages 2.7; 95% CI (1.4 to 5.3). Bed sharing risk decreased with increasing infant age. When neither parent smoked, and the baby was less than 3 months, breastfed and had no other risk factors, the AOR for bed sharing versus room sharing was 5.1 (2.3 to 11.4) and estimated absolute risk for these room sharing infants was very low (0.08 (0.05 to 0.14)/1000 live-births). This increased to 0.23 (0.11 to 0.43)/1000 when bed sharing. Smoking and alcohol use greatly increased bed sharing risk.

CONCLUSIONS

Bed sharing for sleep when the parents do not smoke or take alcohol or drugs increases the risk of SIDS. Risks associated with bed sharing are greatly increased when combined with parental smoking, maternal alcohol consumption and/or drug use. A substantial reduction of SIDS rates could be achieved if parents avoided bed sharing.

Dietary patterns of children at 3.5 and 7 years of age: a New Zealand birth cohort study

AIM

To describe the dietary patterns of children at 3.5 and 7 years born small for gestational age (SGA) and appropriate for gestational age (AGA) and the association of dietary patterns with socio-demographic and obstetric factors.

METHODS

Children from a New Zealand birth cohort study were followed up at 3.5 (n = 550) and 7 (n = 591) years. Dietary information was collected using a Food Frequency Questionnaire.

RESULTS

Three dietary patterns were defined in these children ('traditional', 'junk' and 'healthy'). Factors associated with dietary patterns were examined in multivariable analyses. At 3.5 years, 'junk' was associated with maternal smoking in pregnancy, no attendance at antenatal classes, maternal BMI and a younger maternal age. At 3.5 years, 'healthy' was associated with being married when pregnant. At 7 years, 'traditional' was associated with being born SGA, smoking in pregnancy, a younger maternal age and being male.

CONCLUSION

Maternal socio-demographic, obstetric factors and birth size were associated with dietary patterns. The associations were not consistent with each dietary pattern across age groups. To examine the impact of diet in childhood on growth and health outcomes, factors influencing dietary patterns should be assessed at regular intervals throughout childhood.

Reduced genetic influence on childhood obesity in small for gestational age children

Background

Children born small-for-gestational-age (SGA) are at increased risk of developing obesity and metabolic diseases later in life, a risk which is magnified if followed by accelerated postnatal growth. We investigated whether common gene variants associated with adult obesity were associated with increased postnatal growth, as measured by BMI z-score, in children born SGA and appropriate for gestational age (AGA) in the Auckland Birthweight Collaborative.

Methods

A total of 37 candidate SNPs were genotyped on 547 European children (228 SGA and 319 AGA). Repeated measures of BMI (z-score) were used for assessing obesity status, and results were corrected for multiple testing using the false discovery rate.

Results

SGA children had a lower BMI z-score than non-SGA children at assessment age 3.5, 7 and 11 years. We confirmed 27 variants within 14 obesity risk genes to be individually associated with increasing early childhood BMI, predominantly in those born AGA.

Conclusions

Genetic risk variants are less important in influencing early childhood BMI in those born SGA than in those born AGA, suggesting that non-genetic or environmental factors may be more important in influencing childhood BMI in those born SGA.

A postal survey of maternal sleep in late pregnancy

Background

Sleep disturbances in late pregnancy are common. This study aimed to survey sleep problems in third trimester pregnant women and to compare sleep in the pre-pregnancy period with the third trimester.

Methods

Third-trimester women (n=650) were sent a postal survey containing questions relating to sleep experience, including perceived sleep quality, sleep difficulties, night waking, sleep environment, snoring, daytime tiredness and daytime napping. Time periods reported on were before pregnancy and in the last week.

Results

Respondents numbered 244 (38%). Before pregnancy, the mean reported duration of night-time sleep was 8.1 (SD 1.1) hours; in the last week this had decreased to 7.5 (SD 1.8) hours (p<.0001). Only 29% rated their sleep quality in the last week as very good or fairly good, compared with 82% rating their sleep this way before the pregnancy. The main reasons for sleeping difficulties were discomfort (67%) and pain (36%). Snoring increased significantly over the course of the pregnancy, with 37% reporting snoring often or every night in the last week. Those with a pre-pregnancy body mass index of greater than 25 were significantly more likely to snore (p=.01). Only 4% of women had an abnormal Epworth Sleepiness Scale score (i.e. >10) prior to pregnancy, whereas in the last week 33% scored in the abnormal range. Likewise, 5% had regularly napped during the daytime before pregnancy, compared with 41% in the last week.

Conclusions

Sleep problems are common in women in late pregnancy, and increase markedly compared with before pregnancy.

Bioelectrical impedance for measuring percentage body fat in young persons with Down syndrome: validation with dual-energy absorptiometry

AIM

Children with Down syndrome have an increased prevalence of obesity, although there is little work describing body composition in this population. The aims of this study were to accurately measure body fat in children with Down syndrome and to identify which existing algorithm best predicts percentage body fat in this population.

METHODS

Seventy children with Down syndrome had anthropometric, bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) data collected to calculate percentage body fat (PBF). Pearson correlations were carried out to assess the relationships of various methods for measuring body fat and Bland-Altman plots to assess systematic error.

RESULTS

Mean PBF was 30.5% for girls and 22.5% for boys. A total of 38% of girls and 23% of boys were obese according to international criteria. PBF as determined by DXA correlated well with PBF by BIA in both girls and boys (r = 0.91 and 0.89, respectively, p < 0.001).

CONCLUSION

There are high rates of obesity in children with Down syndrome. BIA can be used to accurately determine adiposity in this population. We recommend the use of the Schaeffer algorithm for calculation of PBF in children with Down syndrome.

Hyperglycaemia monitoring and management in stroke care: policy vs. practice

AIM

To evaluate the extent to which hyperglycaemia was monitored and managed among patients admitted to hospital with acute stroke and transient ischaemic attack.

METHODS

We conducted a retrospective cohort study involving a review of the records of 112 patients consecutively admitted with acute stroke or transient ischaemic attack to all three district general hospitals in one Health and Social Care Trust in Northern Ireland from 1 January to 15 April 2008. Glucose results for each of the first 5 days of hospital admission were ascertained. We compared interventions, clinical outcome and discharge planning between patients who experienced glucose ≥ 7.8 mmol/l in the first 5 days, and patients with lower glucose results.

RESULTS

The daily prevalence rate of hyperglycaemia > 7.8 mmol/l across the first 5 days ranged from 24 to 34%. A total of 41 (37%) patients experienced hyperglycaemia on at least one occasion during the first 5 days. A history of diabetes mellitus prompted near patient glucose testing, but, among patients without diagnosed diabetes, glycaemia was under-monitored. Hyperglycaemia was a persisting trend, was under-treated and under-reported to general practitioners. Elevated glucose results failed to influence higher rates of fasting plasma glucose tests and BMI assessment.

CONCLUSIONS

There is a need for greater vigilance in the detection of hyperglycaemia and undiagnosed diabetes mellitus among patients admitted to hospital with stroke or transient ischaemic attack.

SIDS prevention: 3000 lives saved but we can do better

Mortality from sudden infant death syndrome (SIDS) has decreased substantially from the late 1980s. This has been attributed to the change in infant sleep position initially from prone (front) to side and then to predominantly supine (back). We calculate that this has saved over 3000 lives. However, we argue that we could save more infant lives, if more focus was given to the risks observed from parents sleeping in the same bed as their babies.

Scientific consensus forum to review the evidence underpinning the recommendations of the Australian SIDS and Kids Safe Sleeping Health Promotion Programme--October 2010

This paper summarises a 1-day scientific consensus forum that reviewed the evidence underpinning the Australian SIDS and Kids Safe Sleeping Health Promotion Programme. The focus was on each of the potentially modifiable risk factors for sudden unexpected deaths in infancy, including sudden infant death syndrome (SIDS) and fatal sleeping accidents. In particular infant sleeping position, covering of the face, exposure to cigarette smoke, room sharing, unsafe sleeping environments, bed sharing, immunisation, breastfeeding, pacifier use and Indigenous issues were discussed in depth. The participants recommended that future 'Reducing the Risk' campaign messages should focus on back to sleep, face uncovered, avoidance of cigarette smoke before and after birth, safe sleeping environment, room sharing and sleeping baby in own cot.

Children born small for gestational age are not at special risk for preschool emotion and behaviour problems

Despite the wealth of literature examining long term outcomes of preterm low birthweight children, few studies have directly assessed the developmental impact of being born full term but small for gestational age (SGA). We aim to determine whether (i) being SGA increases preschool behavioural problems and (ii) other risk factors operate differently in SGA and appropriate for gestational age (AGA) controls. 550 New Zealand European mothers and their 3.5 year old children participated in this study. All children were born at full term (>37 weeks' gestation) and approximately half were SGA (≤sex specific 10th percentile for gestation) the remainder were AGA controls. Extensive data were collected at the child's birth, 1 year and 3.5 years. Behavioural problems were measured when children were 3.5 years, using the Strengths and Difficulties Questionnaire (SDQ). Multiple regression analyses were used to examine the associations between risk factors and behavioural problems; statistical weighting was used for analyses of the total study group. There was no significant difference in behavioural problems between SGA and AGA groups. In the total sample the significant predictors of behavioural problems included: mothers' school leaving age; smoking during pregnancy; maternal alcohol use during pregnancy; and absence of the father. Predictors of behavioural problems were found to be the same for SGA and AGA groups. These results do not support the view that SGA is a risk for behavioural preschool difficulties or that SGA children are sensitised to risks known to be associated with such difficulties in the preschool years.

The association between tobacco and the risk of asthma, rhinoconjunctivitis and eczema in children and adolescents: analyses from Phase Three of the ISAAC programme

BACKGROUND

Exposure to parental smoking is associated with wheeze in early childhood, but in 2006 the US Surgeon General stated that the evidence is insufficient to infer a causal relationship between exposure and asthma in childhood and adolescents.

AIMS

To examine the association between maternal and paternal smoking and symptoms of asthma, eczema and rhinoconjunctivitis.

METHODS

Parents or guardians of children aged 6-7 years completed written questionnaires about symptoms of asthma, rhinoconjunctivitis and eczema, and several risk factors, including maternal smoking in the child's first year of life, current maternal smoking (and amount) and paternal smoking. Adolescents aged 13-14 years self completed the questionnaires on these symptoms and whether their parents currently smoked.

RESULTS

In the 6-7-year age group there were 220 407 children from 75 centres in 32 countries. In the 13-14-year age group there were 350 654 adolescents from 118 centres in 53 countries. Maternal and paternal smoking was associated with an increased risk of symptoms of asthma, eczema and rhinoconjunctivitis in both age groups, although the magnitude of the OR is higher for symptoms of asthma than the other outcomes. Maternal smoking is associated with higher ORs than paternal smoking. For asthma symptoms there is a clear dose relationship (1-9 cigarettes/day, OR 1.27; 10-19 cigarettes/day, OR 1.35; and 20+ cigarettes/day, OR 1.56). When maternal smoking in the child's first year of life and current maternal smoking are considered, the main effect is due to maternal smoking in the child's first year of life. There was no interaction between maternal and paternal smoking.

CONCLUSIONS

This study has confirmed the importance of maternal smoking, and the separate and additional effect of paternal smoking. The presence of a dose-response effect relationship with asthma symptoms suggests that the relationship is causal, however for eczema and rhinoconjunctivitis causality is less certain.

Initial evidence that polymorphisms in neurotransmitter-regulating genes contribute to being born small for gestational age

Being born small for gestational age (SGA) is a putative risk factor for the development of later cognitive and psychiatric health problems. While the inter-uterine environment has been shown to play an important role in predicting birth weight, little is known about the genetic factors that might be important. Here we test the hypothesis that neurotransmitter-regulating genes implicated in psychiatric disorders previously shown to be associated with SGA (such as attention-deficit hyperactivity disorder) are themselves predictive of SGA. DNA was collected from 227 SGA and 319 appropriate for gestational age children taking part in the Auckland Birthweight Collaborative Study. Candidate single nucleotide polymorphisms in genes regulating activity within dopamine, serotonin, glutamate and gamma-aminobutyric acid pathways were genotyped. Multiple regression analysis, controlling for potentially confounding factors, supported nominally significant associations between SGA and single nucleotide polymorphisms in COMT, HTR2A, SLC1A1 and SLC6A1. This is the first evidence that genes implicated in psychiatric disorders previously linked to SGA status themselves predict SGA. This highlights the possibility that the link between SGA and psychiatric disorders such as attention-deficit hyperactivity disorder may in part be genetically determined - that SGA marks pre-existing genetic risk for later problems.

Serial developmental assessments in infants with deformational plagiocephaly

AIM

An association between positional plagiocephaly and developmental problems has previously been noted, but whether delays persist over time has not been established. This study aimed to determine developmental outcomes for children with deformational plagiocephaly over 1 year of follow up.

METHODS

This was a longitudinal cohort study of 126 infants with deformational plagiocephaly recruited at an outpatient clinic. Development was assessed with the parent-completed Ages and Stages Questionnaires at recruitment and repeated at follow-up assessments in the home 3, 6 and 12 months later. Questionnaires were scored according to cut-off scores from the Ages and Stages Questionnaires, Third Edition.

RESULTS

Ninety-six percent of children were followed up for the full 12 months. The existence of one or more delays initially was 30%; this rose to 42% at the 3-month follow up then dropped back to 23% by the 12-month follow up. Delays were predominantly in the gross motor domain. Ten percent had > 4 delays in total over the four assessments. Mothers with tertiary education were more likely to have infants showing delays that persisted over time.

CONCLUSIONS

Infants with deformational plagiocephaly exhibited marked delays especially in early infancy. These delays were largely gross motor in type but had reduced to approach the expected level by the time of the 12-month follow up, at a mean age of 17 months.

The catechol-O-methyltransferase (COMT) Val158Met polymorphism moderates the effect of antenatal stress on childhood behavioural problems: longitudinal evidence across multiple ages

AIM

The functional polymorphism Val158Met in the catechol-O-methyltransferase (COMT) gene was analysed to determine its association with maternal stress and childhood total difficulties.

METHOD

Data were collected at birth from a group of infants who were born small for gestational age and a group who were born at an appropriate size for gestational age and had been enrolled in the Auckland Birthweight Collaborative Study. Children were followed up at the ages of 1 year, 3 years 6 months, 7 years, and 11 years. At the age of 11 years, DNA samples were collected from 546 children (270 females, 276 males): 227 children born small for gestational age and 319 children born at an appropriate size for gestational age. The main independent variable was perceived maternal stress at birth and at 7 and 11 years of age, assessed using the total difficulties scale of the Strength and Difficulties Questionnaire. IQ was assessed at the age of 7 years.

RESULTS

Met/Met homozygotes were at a significantly increased risk of behavioural and emotional problems at the ages of 7 (p=0.002) and 11 years (p=0.003), relative to either heterozygous or homozygous carriers of the Val158Met polymorphism, but only when they were exposed to maternal stress in utero. Met/Met homozygotes had, on average, IQ scores that were four points higher than those of Val/Val homozygotes (p=0.010).

INTERPRETATION

These findings emphasize the potential long-term consequences of prenatal stress for genetically susceptible individuals during neurodevelopment in utero. Our findings add to the general understanding of the aetiology and developmental nature of childhood emotional and behavioural problems.

Antenatal care, identification of suboptimal fetal growth and risk of late stillbirth: findings from the Auckland Stillbirth Study

INTRODUCTION

Stillbirth remains an important public health problem in Australia and New Zealand. The role that antenatal care plays in the prevention of stillbirth in high-income countries is unclear.

METHODS

Cases were women with a singleton, late stillbirth without congenital abnormality, booked to deliver in the Auckland region and born between July 2006 and June 2009. Two controls with ongoing pregnancies were randomly selected at the same gestation at which the stillbirth occurred. Data were collected through interview-administered questionnaires and from antenatal records.

RESULTS

One hundred and fifty five of 215 (72%) cases and 310 of 429 (72%) controls consented to take part in the study. Accessing <50% of recommended antenatal visits was associated with a more than twofold increase in late stillbirth (adjusted odds ratio, aOR, 2.68; 95% CI, 1.04-6.90) compared with accessing the recommended number of visits. Small-for-gestational-age (SGA) babies that had not been identified as SGA prior to birth were significantly more at risk of being stillborn (aOR, 9.46; 95% CI, 1.98-45.13) compared with SGA babies that were identified as such in the antenatal period. No relationship was found between type or model of maternity care provider at booking and late stillbirth risk.

DISCUSSION

This study reinforces the importance of regular antenatal care attendance. Identification of SGA may be one way by which antenatal care reduces stillbirth.

Maternal perception of fetal activity and late stillbirth risk: findings from the Auckland Stillbirth Study

BACKGROUND

  Maternal perception of decreased fetal movements has been associated with adverse pregnancy outcomes, including stillbirth. Little is known about other aspects of perceived fetal activity. The objective of this study was to explore the relationship between maternal perception of fetal activity and late stillbirth (≥28 wk gestation) risk.

METHODS

  Participants were women with a singleton, late stillbirth without congenital abnormality, born between July 2006 and June 2009 in Auckland, New Zealand. Two control women with ongoing pregnancies were randomly selected at the same gestation at which the stillbirth occurred. Detailed demographic and fetal movement data were collected by way of interview in the first few weeks after the stillbirth, or at the equivalent gestation for control women.

RESULTS

  A total of 155/215 (72%) women who experienced a stillbirth and 310/429 (72%) control group women consented to participate in the study. Maternal perception of increased strength and frequency of fetal movements, fetal hiccups, and frequent vigorous fetal activity were all associated with a reduced risk of late stillbirth. In contrast, perception of decreased strength of fetal movement was associated with a more than twofold increased risk of late stillbirth (aOR: 2.37; 95% CI: 1.29-4.35). A single episode of vigorous fetal activity was associated with an almost sevenfold increase in late stillbirth risk (aOR: 6.81; 95% CI: 3.01-15.41) compared with no unusually vigorous activity.

CONCLUSIONS

  Our study suggests that maternal perception of increasing fetal activity throughout the last 3 months of pregnancy is a sign of fetal well-being, whereas perception of reduced fetal movements is associated with increased risk of late stillbirth.

Sudden unexpected infant death in Auckland: a retrospective case review

AIM

To review autopsy reports of all SUDI deaths in the Auckland region, New Zealand, from October 2000 to December 2009.

METHODS

Information on all SUDI cases from 2000 to 2009 was extracted from autopsy and police reports from the National Forensic Pathology Service at Auckland Hospital.

RESULTS

Of the 332 post-mortems in this period, 221 were classified as SUDI. Of these, 83% were Māori or Pacific infants. The median age at death was 11 weeks and 11% occurred in 7- to 28-day-olds. At the time of death, 64% overall were bedsharing; this was more common in 7-28 day olds (92%). Bedsharing infants were significantly younger at death than non-bedsharing infants (p=0.008). Where sleep position was known, 57% were placed in non-supine at the last sleep. There was no evidence of diagnostic shift and the prevalence of bedsharing did not change over the decade.

CONCLUSIONS

Bedsharing was associated with a high proportion of SUDI cases, especially in the youngest infants, and non-supine sleep positions were common. There is a need to enhance SUDI prevention messages and consider innovative ways of promoting safe sleeping environment and supine sleep position in Māori and Pacific communities.

Analysis of MMP2 promoter polymorphisms in childhood obesity

Background

Several lines of evidence suggest a possible functional role of Matrix metalloproteinase -2 (MMP-2) in obesity. The aim of this study was to evaluate the role of MMP-2 promoter polymorphisms in percentage body fat (PBF) as a measure of childhood obesity in a New Zealand population.

Findings

546 samples from the Auckland Birthweight Collaborative (ABC) study were genotyped for the three MMP-2 promoter SNPs -1306 C/T (rs243865), -1575G/A (rs243866) and -790 T/G (rs243864) using the Sequenom genotyping platform. The results demonstrated that an MMP-2 promoter haplotype is associated with PBF in New Zealand 7 year old children.

Conclusion

We have previously determined that environmental factors are associated with differences in PBF in this study group, and now we have demonstrated a possible genetic contribution.

Relationship between obesity, ethnicity and risk of late stillbirth: a case control study

Background

In high income countries there has been little improvement in stillbirth rates over the past two decades. Previous studies have indicated an ethnic disparity in the rate of stillbirths. This study aimed to determine whether maternal ethnicity is independently associated with late stillbirth in New Zealand.

Methods

Cases were women with a singleton, late stillbirth (≥28 weeks' gestation) without congenital abnormality, born between July 2006 and June 2009 in Auckland, New Zealand. Two controls with ongoing pregnancies were randomly selected at the same gestation at which the stillbirth occurred. Women were interviewed in the first few weeks following stillbirth, or at the equivalent gestation for controls. Detailed demographic data were recorded. The study was powered to detect an odds ratio of 2, with a power of 80% at the 5% level of significance, given a prevalence of the risk factor of 20%. A multivariable regression model was developed which adjusted for known risk factors for stillbirth, as well as significant risk factors identified in the current study, and adjusted odds ratios and 95% confidence intervals were calculated.

Results

155/215 (72%) cases and 310/429 (72%) controls consented. Pacific ethnicity, overweight and obesity, grandmultiparity, not being married, not being in paid work, social deprivation, exposure to tobacco smoke and use of recreational drugs were associated with an increased risk of late stillbirth in univariable analysis. Maternal overweight and obesity, nulliparity, grandmultiparity, not being married and not being in paid work were independently associated with late stillbirth in multivariable analysis, whereas Pacific ethnicity was no longer significant (adjusted Odds Ratio 0.99; 0.51-1.91).

Conclusions

Pacific ethnicity was not found to be an independent risk factor for late stillbirth in this New Zealand study. The disparity in stillbirth rates between Pacific and European women can be attributed to confounding factors such as maternal obesity and high parity.

Deformational plagiocephaly: a follow-up of head shape, parental concern and neurodevelopment at ages 3 and 4 years

OBJECTIVES

To compare head shape measurements, parental concern about head shape and developmental delays in infancy with measurements obtained at follow-up at ages 3 and 4 years.

DESIGN

Longitudinal cohort study.

SETTING

Initial assessments were conducted at a plagiocephaly clinic; follow-up assessments were conducted in the children's homes.

PARTICIPANTS

129 children with a mean age of 4 years (range 3 years 3 months to 4 years 9 months), all of whom were diagnosed in infancy with deformational plagiocephaly or brachycephaly.

MAIN OUTCOME MEASURES

Head shape measurements of cephalic index and oblique cranial length ratio; level of parental concern about head shape; and delays on parent-completed age-appropriate Ages and Stages Questionnaires.

RESULTS

61% of head shape measurements reverted to the normal range; 4% remained severe at follow-up. Brachycephaly improved more than plagiocephaly. Facial and frontal asymmetry reduced to almost nil. Most had good improvement, but 13% were categorised as having 'poor improvement'. Initially, 85% of parents reported being 'somewhat' or 'very' concerned; this decreased to 13% at follow-up. The percentage of children with ≥1 delay decreased from 41% initially to 11% at follow-up.

CONCLUSIONS

Overall, head shape measurements, parental concern and developmental delays in infancy showed a dramatic improvement when re-measured at 3 and 4 years of age.

A randomized controlled trial of positioning treatments in infants with positional head shape deformities

BACKGROUND

Randomized controlled trials of treatment for deformational plagiocephaly and brachycephaly have been lacking in the literature.

METHODS

Infants (n = 126) presenting to a plagiocephaly clinic were randomized to either positioning strategies or to positioning plus the use of a Safe T Sleep™ positioning wrap. Head shape was measured using a digital photographic technique, and neck function was assessed. They were followed up at home 3, 6 and 12 months later.

RESULTS

There was no difference in head shape outcomes for the two treatment groups after 12 months of follow-up, with 42% of infants having head shapes in the normal range by that time. Eighty per cent of children showed good improvement. Those that had poor improvement were more likely to have both plagiocephaly and brachycephaly and to have presented later to clinic.

CONCLUSIONS

Most infants improved over the 12-month study period, although the use of a sleep positioning wrap did not increase the rate of improvement.

Helping children sleep

Sleep problems in children are very common and affect both the child and parents. The common problems are bedtime resistance, delayed sleep onset and frequent night waking. This review summarises current non-pharmacological practices and intervention options to aid healthy children sleep. Children may benefit from good sleep hygiene practices, which include a consistent routine for bed and consistent bedtime, a quiet darkened and warm bedroom, a consistent wake time and daytime exercise. In more problematic cases children benefit from a sleep programme. Programmes are many and effective, and include extinction or extinction-based procedures, and scheduled awakenings. An extinction programme alone, although highly effective, is difficult for parents to comply with. Modifications of the extinction programme show promise but need further evaluation. Identifying and managing sleep problems in childhood may improve health, including emotional well-being, in adolescence and adulthood.

SIDS: past, present and future

Despite the large reduction in SIDS mortality, which occurred in the early 1990s following the 'Back to Sleep' campaigns, SIDS remains the leading cause of death in the postneonatal age group. This paper describes the position in the 1980s, the contribution of the New Zealand Cot Death Study, what should be recommended and the current research priorities.

CONCLUSION

SIDS is preventable. Application of what we currently know could eliminate SIDS. The challenge is to find ways of implementing our knowledge.

Falling asleep: the determinants of sleep latency

BACKGROUND

Difficulty falling asleep (prolonged sleep latency) is a frequently reported problem in school-aged children.

AIMS

This study aimed to describe the distribution of sleep latency and factors that influence its duration.

METHODS

871 children of European mothers were recruited at birth. 591 (67.9%) children took part in the follow-up at 7 years of age. Sleep and daytime activity were measured objectively by an actigraph worn for 24 h.

RESULTS

Complete sleep data were available for 519 children (87.8%) with a mean age of 7.3 years (SD 0.2). Median sleep latency was 26 minutes (interquartile range 13-42). Higher mean daytime activity counts were associated with a decrease in sleep latency (-1.2 minutes per 102 movement count per minute, p = 0.05). Time spent in sedentary activity was associated with an increase in sleep latency (3.1 minutes per hour of sedentary activity, p = 0.01).

CONCLUSIONS

These findings emphasise the importance of physical activity for children, not only for fitness, cardiovascular health and weight control, but also for promoting good sleep.