Australian Infants Research Articles

Predictors of Early Introduction of Core and Discretionary Foods in Australian Infants-Results from HSHK Birth Cohort Study.

Early introduction of complementary foods can have a detrimental impact on children’s long-term health. This study examined the timing and determinants of early introduction of core and discretionary foods among infants in Sydney, Australia. Mothers (n = 1035) from an ongoing population-based birth cohort study were interviewed at 8, 17, 34 and 52 weeks postpartum. The outcome was ‘age at which particular core and discretionary food items were first introduced’. Multivariable logistic regression models were used to investigate family and infant-related determinants of early introduction of core (<17 weeks of age) and discretionary foods (<52 weeks of age). Of the 934 mother-infant dyads interviewed, 12% (n = 113) of infants were introduced core foods before 17 weeks of age (median: 22). Mothers working part-time (adjusted odds ratio (OR): 3.42, 95% confidence interval (CI): 1.54–7.62) and those exclusively formula-feeding their babies at four-weeks postpartum (adjusted OR 3.26, 95% CI: 1.99–5.33) were most likely to introduce core foods early. Ninety-five percent (n = 858) of infants were introduced discretionary foods before 52 weeks of age (median: 28). Low socio-economic status was significantly associated with early introduction of discretionary foods (adjusted OR: 3.72, 95% CI: 1.17–11.78). Compliance with infant feeding guidelines related to core foods was better; however, discretionary foods were introduced early in most infants.

Whole-Cell Pertussis Vaccination and Decreased Risk of IgE-Mediated Food Allergy: A Nested Case-Control Study

Rates of food allergy have increased markedly in Australia and other high- income countries in recent years. On the basis of ecological observations, and the known immunologic characteristics of whole-cell pertussis (wP) compared with acellular pertussis (aP) vaccines, we hypothesized that wP vaccination in infancy protects against the development of food allergy. To determine whether infants who receive wP in infancy were less likely to develop IgE-mediated food allergy than those who received aP. Retrospective cohort-nested case-control study of Australian children born in the period 1997 to 1999, the period of transition from using wP-containing to aP-containing vaccines. Children diagnosed with IgE-mediated food allergy were individually matched to 10 controls by date of birth, socioeconomic decile, and jurisdiction of birth. The odds ratio of vaccination with wP versus aP among cases and matched controls was calculated using conditional logistic regression. The odds ratio of receiving the first dose as wP (rather than aP) among cases of food allergy compared with controls was 0.77 (95% CI, 0.62-0.95). The results of secondary analyses (any dose as wP vs aP-only, and wP-only vs aP-only) were broadly similar. Australian infants who received wP vaccines were less likely to be diagnosed with food allergy in childhood than contemporaneous children who received aP vaccines. If a protective effect is confirmed in a randomized controlled trial, wP or mixed wP and aP vaccination schedules could form part of an effective strategy for combating the rise in food allergies.

Intravenous fat induces changes in PUFA and their bioactive metabolites: Comparison between Japanese and Australian preterm infants

ObjectiveOxylipins are biologically active signaling molecules that initiate and resolve inflammation; they are synthesized by oxidation of polyunsaturated fatty acids (PUFAs) and reflect PUFA intake and status. The PUFA intake in preterm infants differs between countries because of the type of lipid emulsions used and the PUFA content of breast milk. We compared total blood PUFA, free PUFA and their oxylipin levels in dried whole blood samples from preterm infants born in Australia and Japan. MethodsWe enrolled 30 and 14 preterm infants born less than 31 weeks’ gestation, from Adelaide and Japan respectively. Blood samples were obtained from cord blood, and on postnatal days 4, 7, 14 and 28. Total PUFAs were measured using gas chromatography, while free fatty acids and oxylipins were screened using ultra high-performance liquid chromatography mass spectroscopy. ResultsDifferences in the levels of blood PUFA between the centres were found which were in line with the timing and type of lipid emulsion administration. Significant differences in longitudinal levels were seen more often in free PUFA and their oxylipins than in total blood PUFA. This was particularly true for AA and DHA. In contrast, differences in the levels could be seen in total blood EPA, as well as in free EPA and its oxylipins. Further, levels of many free PUFA and their oxylipins were higher in Japanese infants than in Australian infants. ConclusionDifferences in total and free fatty acids and unesterified oxylipins, were observed during the first weeks of life and between preterm infants born in Australia and Japan, which were likely a reflection of the type of lipid emulsion and timing of administration. The clinical significance of these changes remains to be explored.

The ORVAC trial protocol: a phase IV, double-blind, randomised, placebo-controlled clinical trial of a third scheduled dose of Rotarix rotavirus vaccine in Australian Indigenous infants to improve protection against gastroenteritis

IntroductionRotavirus vaccines were introduced into the Australian National Immunisation Program in 2007. Despite this, Northern Territory Indigenous children continue to be hospitalised with rotavirus at a rate more than 20...

Vitamin K deficiency bleeding in Australian infants 1993–2017: an Australian Paediatric Surveillance Unit study

ObjectiveTo undertake surveillance of vitamin K deficiency bleeding (VKDB) in Australia from 1993 to 2017, during a time of change to national recommendations and available vitamin K formulations.MethodsPaediatricians reported cases...

Developmental outcomes following prenatal exposure to methamphetamine: A Western Australian perspective.

To describe neurodevelopmental outcomes among a cohort of Western Australian infants exposed to maternal methamphetamine use during pregnancy and to determine whether the Ages and Stages Questionnaire is a reliable screening tool for this population. Methamphetamine-using women were approached for participation when referred to the state-wide perinatal specialist drug and alcohol service for pregnancy care. Drug use during pregnancy was self-reported in each trimester using a standardised questionnaire. Ages and Stages Questionnaires were completed by infant care givers at 4 and 12 months, and development was formally assessed at 12 months using the Griffiths Mental Development Scales. Griffiths results for term-born infants in our cohort were compared to a Western Australian historical cohort of 443 healthy 1-2-year-olds. A total of 112 methamphetamine-using pregnant women participated in the study, who gave birth to 110 live-born infants. Ages and Stages Questionnaires were completed for 89 (81%) and 78 (71%) of the infants at 4 and 12 months, respectively. The Ages and Stages assessment identified 30 infants (33.7%) as having a potential developmental delay at 4 months and 29 infants (38.7%) as having a potential developmental delay at 12 months. Griffiths assessments were performed on 64 (58%) of the infants, with a mean general quotient of 92.7. This was significantly lower in term-born babies compared to the historical cohort (who had a median general quotient of 113.0). There was a weak correlation between 12-month Ages and Stages scores and Griffiths general quotients (r = 0.322) and no correlation between 4-month Ages and Stages Questionnaire scores and later Griffiths results. Infants born to women reporting methamphetamine use during pregnancy are at increased risk of developmental delay and may warrant enhanced developmental follow-up. However, they are a challenging group to follow due to complex psychosocial factors. Ages and Stages Questionnaires at 4 and 12 months were not helpful in screening for infants who had a developmental delay at 12 months.

Renal dysfunction is already evident within the first month of life in Australian Indigenous infants born preterm

Antecedents of the high rates of chronic kidney disease in Australian Indigenous peoples may originate early in life. Fourteen percent of Australian Indigenous infants are born preterm (under 37 weeks gestation) and, therefore, at risk. Here, our observational cohort study sought to determine the impact of preterm birth on renal function in Australian Indigenous and non-Indigenous infants. Renal function was assessed between 4-29 days postnatally in 60 Indigenous and 42 non-Indigenous infants born at 24-36 weeks gestation. Indigenous ethnicity was associated with impaired renal function, with significantly higher serum creatinine (geometric mean ratio (GMR) 1.15 [1.06, 1.25]), fractional excretion of sodium (GMR 1.21 [1.04, 1.39]), and urine albumin (GMR 1.57 [1.05, 2.34]), β-2 microglobulin (GMR 1.82 [1.11, 2.98]) and cystatin C (GMR 3.27 [1.54, 6.95]) when controlling for gestational/postnatal age, sex and birth weight Z-score. Renal injury, as indicated by high urine neutrophil gelatinase-associated lipocalin levels, was associated with maternal smoking and postnatal antibiotic exposure. Indigenous infants appeared to be most susceptible to the adverse impact of antibiotics. These findings show that preterm Australian Indigenous infants are highly vulnerable to renal dysfunction. Preterm birth may contribute to their increased risk of chronic kidney disease. Thus, we recommended that renal function should be closely monitored life-long in Indigenous children born preterm.

Pesticide metabolite concentrations in Queensland pre-schoolers – Exposure trends related to age and sex using urinary biomarkers

This study aimed to assess pesticide concentration and composition trends associated with age and sex in Australian infants and toddlers. Individual urine samples (n = 400) were collected in 2014/5 from Queensland infants and toddlers aged 0–5 y and composited into 20 pools of 20 individual samples by age (of 5 strata) and sex. Nineteen biomarkers including organophosphate and pyrethroid pesticide metabolites, herbicides and metabolites, and an insect repellent, DEET, were measured. In total, seven organophosphate pesticide metabolites, three pyrethroid metabolites and one herbicide metabolite were detectable in >50% of the sample pools. A significant increase of concentrations of dimethyl phosphate, dimethyl dithiophosphate, diethyl thiophosphate (DETP), 3,5,6-trichloro-2-pyridinol (TCPY), 4-nitrophenol and 3-phenoxybenzoic acid with age was observed (with the p value of <0.0001 to 0.034). This suggested that exposure increases following weaning or as a result of increased dietary intake and mobility/activity. Significant age trends remained after adjustment for body weight and urine flow for DETP and TCPY (p = 0.029 and 0.016 respectively). The level of estimated “worst-case scenario” daily intake of chlorpyrifos from these pooled samples ranged from 0.40 to 1.8 μg/kg-day, which was below the Australian Acceptable Daily Intake guideline (3 μg/kg-day). This study presents the first dataset of age trends in concentrations of these pesticides for infants and toddlers and contributed to new understanding of exposure pathways and potential risks.

High incidence of respiratory disease in Australian infants despite low rate of maternal cigarette smoking.

The burden of wheezing illnesses in Australian infants has not been documented since the success of initiatives to reduce maternal cigarette smoking. We aimed to determine the incidence of wheeze and related health-care utilisation during the first year of life among a contemporary Australian birth cohort. A birth cohort of 1074 infants was assembled between 2010 and 2013. Parents completed questionnaires periodically. Several non-exclusive infant respiratory disease phenotypes were defined, including any wheeze, wheeze with shortness of breath and recurrent wheeze. Skin prick testing was performed to determine atopic wheeze. Health-care utilisation for respiratory disease was determined from questionnaires and hospital medical records. Retention to 1 year was 840/1074 (83%). The incidence of any wheeze was 51.8% (95% confidence interval (CI) 48.3-55.2%), wheeze with shortness of breath 20.6% (95% CI 17.9-23.5), recurrent wheeze 19.4% (95% CI 16.8-22.2) and atopic wheeze 6% (95% CI 4.6-7.8). Respiratory illness resulted in primary health-care utilisation in 82.2% (95% CI 79.3-84.8) of participants and hospital presentation in 8.8% (95% CI 7.2-10.6). Maternal smoking during pregnancy was uncommon (15.7%) and was not associated with wheeze or health resource utilisation. Male gender, familial atopy and asthma and smaller household size were associated with a higher incidence of wheeze. The incidence of wheezing illness among Australian infants remains high despite relatively low rates of maternal smoking during pregnancy. The majority of the health-care burden is borne by primary health-care services. Further research is required to inform novel prevention strategies.

Maternal fetal programming of birthweight among Australian Aboriginal infants: a population-based data linkage study

Low birthweight, which is common among Australian Aboriginal infants, has been found to persist across generations because of shared genetic and environmental factors and possibly fetal programming. Fetal programming refers to the response of a fetus to hostile uterine conditions with lifelong effects and possibly, in turn, providing a poorer uterine environment for future offspring. Fetal programming might have a greater effect in populations that have undergone rapid lifestyle transitions-for example, Indigenous populations. Disentangling causal effects is difficult, but family-based approaches could provide insights. We explored whether poor maternal fetal growth caused low birthweight in Aboriginal infants. In this data linkage study, we used linked administrative health records of 12 865 singleton Aboriginal infants born in Western Australia between 1980 and 2010 and their relatives (including siblings born in 2011). Electronic birth records included all births since 1980 with at least 20 weeks completed gestation or a birthweight of 400 g. We compared parental-offspring birthweight associations using three approaches-a regression analysis of the complete sample, adjusting for confounding variables; a comparison of the maternal-offspring and paternal-offspring associations; and a within-cousin group comparison. We used binary and continuous measures of birthweight. We categorised infants and their parents as small for gestational age (SGA) if their birthweight was below the first decile of birthweights for all singleton livebirths of the same sex and gestational age in Australia between 1998 and 2007. The relative risk (RR) of SGA birth was higher for infants with SGA mothers than for those with non-SGA mothers (RR 1·65, 95% CI 1·49 to 1·83), after adjusting for grandmaternal parity. After additional adjustment for maternal height, the risk remained higher for those with non-SGA mothers (RR 1·51, 1·36 to 1·68). The maternal birthweight Z score coefficient was 0·17 (95% CI 0·14 to 0·20), compared with 0·13 (0·10 to 0·16) for paternal birthweight, a difference of 0·03 (-0·01 to 0·08). In the cousin analysis, the maternal-offspring association was fully attenuated (0·00, 95% CI -0·05 to 0·06). Conditions in the current pregnancy were strongly associated with offspring birthweight Z score. Smoking was associated with a mean decrease of 0·39 (95% CI -0·45 to -0·34) in offspring birthweight Z score, drug misuse with a decrease of 0·31 (-0·43 to -0·20), and diabetes with an increase of 0·58 (0·39 to 0·77). We found little support for maternal fetal programming causing low offspring birthweight. The similar maternal and paternal influence on birthweight and our cousin analysis suggested transmission of genetic and environmental factors could explain much of the maternal-offspring birthweight association. Compared with other risk factors in the current pregnancy, fetal programming appears to have little or no role in the high numbers of infants with low birthweight among Aboriginal populations. National Health and Medical Research Council of Australia and Bellberry Ltd.

Shedding Light on Vitamin D Status and Its Complexities during Pregnancy, Infancy and Childhood: An Australian Perspective.

Ensuring that the entire Australian population is Vitamin D sufficient is challenging, given the wide range of latitudes spanned by the country, its multicultural population and highly urbanised lifestyle of the majority of its population. Specific issues related to the unique aspects of vitamin D metabolism during pregnancy and infancy further complicate how best to develop a universally safe and effective public health policy to ensure vitamin D adequacy for all. Furthermore, as Australia is considered a “sunny country”, it does not yet have a national vitamin D food supplementation policy. Rickets remains very uncommon in Australian infants and children, however it has been recognised for decades that infants of newly arrived immigrants remain particularly at risk. Yet vitamin D deficiency rickets is entirely preventable, with the caveat that when rickets occurs in the absence of preexisting risk factors and/or is poorly responsive to adequate treatment, consideration needs to be given to genetic forms of rickets.

Low birth weight and maternal incarceration in pregnancy: A longitudinal linked data study of Western Australian infants

RationaleImproved birth weight outcomes have been reported for infants of mothers imprisoned during pregnancy relative to similarly disadvantaged mothers, however, findings are equivocal and evidence is lacking from jurisdictions outside the United States. ObjectiveTo investigate whether maternal imprisonment during pregnancy is a determinant of low birth weight (<2500 g) for Indigenous and non-Indigenous infants in Western Australia. MethodsA longitudinal sample of 41,910 singleton infants born in Western Australia (October 1985-December 2013), was identified with linked administrative data and examined by five mutually exclusive categories of maternal corrections history; (i) imprisonment in pregnancy, (ii) imprisonment before pregnancy, (iii) first imprisonment after birth, (iv) community-based corrections record without imprisonment at any time, and (v) no corrections record at any time. Univariate and multivariate Poisson regression was performed to determine key risk factors for low birth weight. Prevalence of risk factors were calculated by maternal corrections history. ResultsAfter adjusting for other significant pregnancy risks, maternal imprisonment before (Indigenous RR 2.02, 95%CI 1.84–2.22, p<.001; non-Indigenous RR 2.48, 95%CI 1.98–3.12, p<.001) or during (Indigenous RR 1.96, 95%CI 1.68–2.29, p<.001; non-Indigenous RR 2.12, 95%CI 1.48–3.03, p<.001) pregnancy remained strong determinants of low birth weight, and carried greater risk than imprisonment after birth (Indigenous RR 1.58, 95%CI 1.44–1.74, p<.001; non-Indigenous RR 1.75, 95%CI 1.51–2.04, p<.001) or community-based corrections orders (Indigenous RR 1.32, 95%CI 1.21–1.43, p<.001; non-Indigenous RR 1.40, 95%CI 1.05–1.88, p<.001), relative to no corrections record. Pregnancy risk factors more prevalent amongst infants whose mothers were imprisoned before or during pregnancy included substance-use related service contacts, hospitalisation for injury, mental health service contacts, and having a sibling in contact with the child protection system. ConclusionWestern Australian infants with mothers imprisoned before or during pregnancy experience elevated risk of low birth weight and exposure to maternal substance use, injury and mental distress in pregnancy.

A case for not adjusting birthweight customized standards for ethnicity: observations from a unique Australian cohort

Low birthweight is more common in infants of indigenous (Aboriginal and/or Torres Strait Islander) than of White Australian mothers. Controversy exists on whether fetal growth is normally different in different populations. We sought to determine the relationships of birthweight, birthweight percentiles, and smoking with perinatal outcomes in indigenous vs nonindigenous infants to determine whether the White infant growth charts could be applied to indigenous infants. Data were analyzed for indigenous status, maternal age and smoking, and perinatal outcomes in 45,754 singleton liveborn infants of at least 20 weeks gestation or 400 g birthweight delivered in New South Wales, Australia, between June 2010 and July2015. Indigenous infants (n=6372; 14%) had a mean birthweight 67 g lower than nonindigenous infants (P<.0001; with adjustment for infant sex and maternal body mass index). Indigenous mean birthweight percentile was 4.2 units lower (P<.0001). Adjustment for maternal age, smoking, body mass index, and infant sex reduced the difference in birthweight/percentiles to nonsignificance (12 g; P=.07). Disparities exist between indigenous and non-indigenous Australian infants for birthweight, birthweight percentile, and adverse outcome rates. Adjustment for smoking and maternal age removed any significant difference in birthweights and birthweight percentiles for indigenous infants. Our data indicate that birthweight percentiles should not be adjusted for indigenous ethnicity because this normalizes disadvantage; because White and indigenous Australians have diverged for approximately 50,000 years, it is likely that the same conclusions apply to other ethnic groups. The disparities in birthweight percentiles that are associated with smoking will likely perpetuate indigenous disadvantage into the future because low birthweight is linked to the development of chronic noncommunicable disease and poorer educational attainment; similar problems may affect other indigenous populations.

Physiologic closure time of the metopic suture in South Australian infants from 3D CT scans.

This retrospective study aims to investigate the timing of metopic suture fusion in the developing infant in an Australian subpopulation. The study evaluates metopic suture fusion in 258 cranial 3D CT scans of children aged 0-24months over a 5-year period (2011-2016), scanned at Women's and Children's Hospital. The findings suggest that the age range over which physiologic metopic suture fusion occurs is larger than previously reported. The approximate range for physiologic fusion was found to be 3-19months and patients with fusion within this range can be considered normal. Complete suture fusion is expected by 19months. Additionally, results indicate suture fusion prior to 3months is abnormal and diagnostically indicative of metopic synostosis.

Maternal education influences Australian infants' language experience from six months.

Disparities in children's early language skills associated with socioeconomic factors have led to many studies examining children's early language environments, but few as yet in the first year of life. This longitudinal study assessed the home language environments of 50 Australian infants, who varied in maternal education (university education, or not). Full-day audio recordings were collected and analyzed using the LENA system when infants were aged 6-9months and 12-15months. Using the device-specific analysis software, we assessed 12-h projected counts of (1) adult speech input, (2) conversational interactions, and (3) child vocalizations. At both ages, higher maternal education was associated with higher counts of adult words and conversational turns, but not child vocalizations. The study adds to the literature by demonstrating disparities in the infants' language experience within the first year of life, related to mothers' education, with implications for early intervention and parenting supports.

Poor birth outcomes among Aboriginal Western Australians and smoking, alcohol and substance misuse, and assault

IntroductionOn average, Aboriginal neonates in Western Australia (WA) weigh 200g less than non-Aboriginal infants and are 2-3 times more likely to be preterm, stillborn, or die neonatally. They are also more likely to be exposed in utero to maternal behaviour risks like smoking, due to factors such as intergenerational trauma.&#x0D; Objectives and ApproachWe aimed to estimate the proportion of small for gestational age (SGA) births, preterm births, and perinatal deaths of Western Australian Aboriginal infants from 1998-2010 attributable to maternal smoking, alcohol misuse, drug misuse, and assault against the mother. We used linked birth, hospital, mental health, and death records of all Aboriginal singletons and their parents. Using logistic regression with a generalized estimating equation approach, associations between birth outcomes and the four risk factors of interest were estimated after adjusting for maternal age, height and health. Using coefficients from these models, we estimated adjusted population attributable fractions (PAFs).&#x0D; ResultsOf 28,119 births, 16% of infants were SGA, 13% were preterm and 2% died perinatally. 51% of infants were exposed to maternal smoking, alcohol misuse, drug misuse, and/or assault, and 37% [95% CI: 35%, 40%] of SGA births, 16% [95% CI: 14%, 19%] of preterm births and 20% [95% CI: 12%, 28%] of perinatal deaths were attributable to these factors, predominantly smoking. The PAFs for alcohol misuse (for example, for SGA, 3% [95% CI: 2%, 3%]) are likely to be underestimates as it is difficult to identify alcohol misuse using administrative data.&#x0D; Conclusion/ImplicationsWhile smoking rates have dropped considerably, reduction measures have been less successful among Aboriginal women than non-Aboriginal women. Significant improvements in perinatal health are possible with identification and support of effective risk reduction approaches for Aboriginal women, as well as their communities and families.

Using linked data and family studies to understand multigenerational causes of low birthweight among Australian Aboriginal infants

IntroductionLow birthweight is common among Aboriginal infants. Birthweight is correlated across generations due to the transmission of genetic and environmental factors. Another cause may be fetal programming, where a fetus’ response to a hostile environment leads to poor adult health and, in turn, a poor uterine environment for her offspring.&#x0D; Objectives and ApproachIdentifying a causal relationship between maternal birthweight and offspring birthweight is difficult. However, we can gain insights by approaching the question from several different angles, including family studies involving both parents and cousins who share maternal grandparents. Family studies using linked data are possible with data from Western Australia (WA), the only Australian state with a database of family relationships.&#x0D; We used linked birth, hospital, mental health, and family relationship records of 12,865 Aboriginal singletons born 1998 to 2011 in WA whose mother also linked to a WA birth record from 1980 onwards, and their parents’ records.&#x0D; Results17% of births were small for gestational age. Using a linear regression model with a generalised estimating equation approach for offspring birthweight z-score (BWZ), the coefficient for maternal BWZ was 0.17 (95% CI: 0.14, 0.20), compared to 0.13 (95% CI: 0.10, 0.16) for paternal BWZ. The difference in coefficients (0.03 [95% CI: -0.01, 0.08]) provides only limited support for the fetal programming hypothesis. Other associations with offspring BWZ were much larger, including maternal smoking (-0.39 [95% CI: -0.45, -0.34]). After restricting the sample to cousins with shared maternal grandparents (fixed-effects model), the mother-offspring association was fully attenuated (-0.01 [95% CI: -0.07, 0.05]), suggesting transmission of maternal genetic and environmental factors alone can explain the association, though the 95% confidence interval was wide.&#x0D; Conclusion/ImplicationsIf fetal programming is an important cause of low birthweight, Aboriginal people would be disproportionately affected, following generations of low birthweight and chronic disease. However, the family studies indicate fetal programming has a limited role compared to other risk factors in the current pregnancy.

Identifying vulnerable population groups: On-time infant vaccination coverage in Australia

IntroductionImmunisation coverage is a good measure of immunisation program effectiveness. Coverage of the 3-dose infant schedule in Australia assessed at age 12 months is &gt;90%. Timeliness is an important goal for population immunity, but on-time coverage of the 2-4-6 month schedule and coverage in specific populations is rarely reported.&#x0D; Objectives and ApproachWe conducted a retrospective population-based cohort study of 1.9 million Australian births, 1996-2012 (approximately 42% of Australia’s population). Individual data from state-held birth and perinatal records were combined with Commonwealth-held immunisation and death records, through probabilistic linkage. We assessed on-time coverage across 13 demographic and perinatal characteristics of diphtheria-tetanus-pertussis vaccines (DTP) defined as vaccination 14 days prior to the scheduled due date, to 30 days afterwards.&#x0D; ResultsOn-time DTP vaccination coverage in non-Aboriginal infants was 88.1% for the 2-month dose, 82.0% for 4-month dose, and 76.7% for 6-month dose; 3-dose coverage was 91.3% when assessed at 12 months. On-time DTP coverage for Aboriginal infants was 77.0%, 66.5%, and 61.0%; 3-dose coverage at 12 months was 79.3%. Appreciable differences in on-time coverage were observed across population subgroups. On-time coverage in non-Aboriginal infants born to mothers with ≥3 previous pregnancies was 62.5% for the 6-month dose (47.9% for Aboriginal infants); up to 23.5% lower than for first-borns. Infants born to mothers who smoked during pregnancy had coverage 8.7-10.3% lower than infants born to non-smoking mothers for the 4- and 6-month dose. A linear relationship was apparent with increasing socio-economic disadvantage and decreasing on-time coverage.&#x0D; Conclusion/ImplicationsOn-time vaccination coverage of the 2-4-6 month schedule is only 50-60% across specific population subgroups representing a significant avoidable public health risk. Australian Aboriginal infants, multiparous mothers, and those who are socio-economically disadvantaged are key groups most likely to benefit from targeted programs addressing vaccine timeliness.

Drinking or Smoking While Breastfeeding and Later Cognition in Children.

Although prenatal alcohol and nicotine exposure are associated with reduced cognition in children, associations between consumption of alcohol during lactation and cognition have not been examined. We aimed to examine whether drinking or smoking while breastfeeding lowers children's cognitive scores. We hypothesized that increased drinking or smoking would be associated with dose-dependent cognitive reductions. Data were sourced from Growing Up in Australia: The Longitudinal Study of Australian Children. Participants were 5107 Australian infants recruited in 2004 and assessed every 2 years. Multivariable linear regression analyses assessed relationships between drinking and smoking habits of breastfeeding mothers and children's Matrix Reasoning, Peabody Picture Vocabulary Test-Third Edition and Who Am I? scores at later waves. Increased or riskier wave 1 maternal alcohol consumption was associated with reductions in Matrix Reasoning scores at age 6 to 7 years in children who had been breastfed (B = -0.11; SE = 0.03; 95% confidence interval: -0.18 to -0.04; P = .01). This relationship was not evident in infants who had never breastfed (B = -0.02; SE = 0.10; 95% confidence interval = -0.20 to 0.17; P = .87). Smoking during lactation was not associated with any outcome variable. Exposing infants to alcohol through breastmilk may cause dose-dependent reductions in their cognitive abilities. This reduction was observed at age 6 to 7 years but was not sustained at age 10 to 11 years. Although the relationship is small, it may be clinically significant when mothers consume alcohol regularly or binge drink. Further analyses will assess relationships between alcohol consumption or tobacco smoking during lactation and academic, developmental, physical, and behavioral outcomes in children.

Duration and Voice Quality of Early Infant Vocalizations.

Infant vocal durations have been studied from a variety of perspectives, including medical, social, and linguistic. The resultant developmental profile across the first 6 months of life, however, is still far from clear. The purpose of this study was to evaluate the durational properties of infant vocalizations from the unique perspective of voice quality. By considering an infant's modal and nonmodal voice qualities, the developmental range of vocalizations produced by infants during the early months of life was captured. Four Australian English-speaking infants were recorded for approximately 1 hr per week during the first 6 months of life. A total of 6,309 vocalizations were perceptually identified and labeled according to voice quality. The duration of each vocalization was subsequently measured. A nonlinear curve was evident for the duration of all vocalizations combined. Duration increased significantly between Months 3 and 5. Modal voice was the only voice quality that displayed a linear increase in duration across the study. All other voice qualities displayed polynomial trends. Based on the current results, the inconsistent pattern of vocal duration development found previously can be reconciled when voice quality properties of vocalizations are taken into account. A nonlinear curve is evident when a broad corpus of infant vocalizations is used, whereas a narrow corpus containing predominantly modal vocalizations displays a linear trend. The results demonstrate the necessity of including nonmodal voice qualities in infant duration experiments so as to not overstate the linear nature of duration increases.