Lung function: population epidemiology and concordance in Australian children aged 11-12 years and their parents

Clustering of asthma and related comorbidities and their association with maternal health during pregnancy: evidence from an Australian birth cohort

Background

The population-based classification of asthma severity is varied and needs further classification. This study identified clusters of asthma and related comorbidities of Australian children aged 12–13 years; determined health outcome differences among clusters; and investigated the associations between maternal asthma and other health conditions during pregnancy and the children’s clustered groups.

Methods

Participants were 1777 children in the birth cohort of the Longitudinal Study of Australian Children (LSAC) who participated in the Health CheckPoint survey and the LSAC 7th Wave. A latent class analysis (LCA) was conducted to identify clusters of children afflicted with eight diseases, such as asthma (ever diagnosed or current), wheezing, eczema, sleep problem/snoring/breathing problem, general health status, having any health condition and food allergy. Multinomial logistic regression was used to investigate the association between maternal asthma or other health conditions and LCA clusters.

Results

The study identified four clusters: (i) had asthma – currently healthy (11.0%), (ii) never asthmatic & healthy (64.9%), (iii) early-onset asthmatic or allergic (10.7%), and (iv) asthmatic unhealthy (13.4%). The asthmatic unhealthy cluster was in poor health in terms of health-related quality of life, general wellbeing and lung functions compared to other clusters. Children whose mothers had asthma during pregnancy were 3.31 times (OR 3.31, 95% CI: 2.06–5.30) more likely to be in the asthmatic unhealthy cluster than children whose mothers were non-asthmatic during pregnancy.

Conclusion

Using LCA analysis, this study improved a classification strategy for children with asthma and related morbidities to identify the most vulnerable groups within a population-based sample.

Oral health: Epidemiology and concordance in Australian children and parents

INTRODUCTION

Studying parent-child pair health provides the opportunity to identify risk factors and opportunities for oral health prevention and intervention focusing on the family context. The aim of this study was to describe the oral health of children aged 11-12 years and their parents in a national sample of parent-child dyads in Australia.

METHODS

The Child Health CheckPoint is a study of 11 to 12-year-old children and one parent nested within the Longitudinal Study of Australian Children, a nationally representative cohort study. In 2015-16, the study collected two-dimensional photographic intra-oral images and was scored using visual assessments of the teeth, oral hygiene and malocclusion.

RESULTS

Of the 1874 CheckPoint families, 1396 biological parent-child pairs had at least one oral health measure recorded. Over two-thirds of children had moderate to severe gingival inflammation (69.7%, 95%CI 64.7-74.9). Parents had a lower proportion of poor oral hygiene (2.1%, 95% CI 1.4-3.0) than children (13.0%, 95% CI 11.3-14.9). High concordance was seen in the Modified Gingival Index correlation coefficient 0.49 (95%CI 0.44-0.53).

CONCLUSION

The high concordance in gingival health between child-parent pairs supports the familial and behavioural links established in previous studies. Children had poorer oral hygiene but fewer visible dental caries lesions than their parents. As dental caries is a chronic and cumulative disease, preventive interventions targeting children's oral hygiene are needed.

Which factors can influence the number of forced expiratory manoeuvres on spirometry in schoolchildren?

INTRODUCTION

Spirometry is of great value for understanding respiratory function and management of lung diseases. Adaptations in the exam were made to meet paediatric population since the forced expiratory manoeuvres (FEM) present in the exam require effort and cooperation; therefore, its use should be reconsidered.

OBJECTIVE

To analyse factors that may influence the number of FEM required for successful spirometry in schoolchildren.

METHOD

Healthy children aged between 6 and 12 years were tested. FEM were conducted according to the American Thoracic Society/European Respiratory Society guideline. The children were divided into three groups according to the number of attempts: G3M if child completed the test in three FEM; G4M if child completed in four attempts FEM; and G5/8M if child completed the test in five to eight FEM. Factors that potentially influenced the number of FEM included: age; impulse oscillometry parameters; slow vital capacity; respiratory muscle strength; orofacial motor function, school performance, physical activity level and quality of life. The Kolmogorov-Smirnov test was performed, followed by the Chi-Square, repeated measures ANOVA and Kruskal-Wallis tests; thereafter, a multinomial logistic regression was applied.

RESULTS

One hundred and forty-nine schoolchildren (80 girls) with mean age of 9.13 years (±1.98) were included, age was related to the required number of FEM (F = 3.38(2), P = .03) and children with poor school performance had a 2.84-fold greater chance of completing the exam in more than five attempts.

CONCLUSION

Age and school performance influenced the number of FEM required for a successful spirometry in schoolchildren.

No obvious impact of caesarean delivery on childhood allergic outcomes: findings from Australian cohorts

BACKGROUND AND OBJECTIVE

As caesarean delivery and childhood allergy continue to rise, their inter-relationships may change. We examined whether caesarean delivery predicts allergic disease and impaired lung function in two contemporary harmonised population-based cohorts.

METHODS

Parent-reported asthma and eczema data were drawn from two prospective Australian infant cohorts, HealthNuts (n=5276, born 2006-2010) and the Longitudinal Study of Australian Children (LSAC, n=5107, born 2003-2004) at age 6-7 years, and spirometric lung function from LSAC's Child Health CheckPoint (n=1756) at age 11-12 years. Logistic regression estimated associations between delivery mode and current asthma and eczema at 6-7 years, and linear regression examined lung function at 11-12 years. Models were adjusted for potential confounding factors.

RESULTS

Complete case analysis included 3135 HealthNuts and 3654 LSAC children (32.2% and 30.9% born by caesarean, respectively). An association was evident between caesarean delivery and asthma at age 6-7 years in HealthNuts (adjusted OR (aOR) 1.25, 95% CI 1.00 to 1.57) but not in LSAC (aOR 1.05, 95% CI 0.86 to 1.28), while neither study showed clear associations with eczema (HealthNuts: aOR 1.09, 95% CI 0.88 to 1.35; LSAC: aOR 0.89, 95% CI 0.69 to 1.15). Spirometric lung function parameters at age 11-12 years were similar by delivery mode. Associations were not modified by duration of breast feeding, maternal history of asthma/eczema, childcare attendance, number of older siblings or pet exposure.

CONCLUSIONS

In two unselected populations using harmonised protocols, the likely association of caesarean delivery with developing childhood allergy was small.

Telomere length and lung function in a population-based cohort of children and mid-life adults

OBJECTIVE

Telomere length is associated with poorer lung health in older adults, possibly from cumulative risk factor exposure, but data are lacking in pediatric and population-based cohorts. We examined associations of telomere length with lung function in children and mid-life adults.

METHODS

Data were drawn from a population-based cross-sectional study of 11 to 12 year-olds and mid-life adults. Lung function was assessed by spirometric FEV₁ , FVC, FEV ₁ /FVC ratio, and MMEF _25-75 . Telomere length was measured by quantitative polymerase chain reaction from blood and expressed as the amount of telomeric genomic DNA to the beta-globin gene (T/S ratio). Associations of telomere length with spirometric parameters were tested by linear and logistic regression models, adjusting for potential confounders of sex, age, body mass index, socioeconomic position, physical activity, inflammation, asthma, pubertal status, and smoking.

RESULTS

Mean T/S ratio was 1.09 (n = 1206; SD 0.55) in children and 0.81 (n = 1343; SD 0.38) in adults. In adults, for every additional unit in T/S ratio, FEV ₁ /FVC and MMEF _25-75 z-scores were higher (β 0.21 [95% confidence interval, CI; 0.06-0.36] and 0.23 [95% CI; 0.08-0.38], respectively), and the likelihood of being in the lowest quartile for FEV ₁ /FVC and MMEF _25-75 z-scores was lower (odds ratios 0.59 [95% CI, 0.39-0.89] and 0.64 [95% CI, 0.41-0.99], respectively). No evidence of association was seen for adult FEV ₁ or FVC, or any childhood spirometric index after adjustments.

CONCLUSION

Shorter telomere length showed moderate associations with poorer airflow parameters, but not vital capacity (lung volume) in mid-life adults. However, there was no convincing evidence of associations in children.

Population health bio-phenotypes in 11-12 year old children and their midlife parents: Growing Up in Australia's Child Health CheckPoint

In an ambitious undertaking, Growing Up in Australia's Child Health CheckPoint streamlined and implemented wide-ranging population phenotypes and biosamples relevant to non-communicable diseases in nearly 1900 parent-child dyads throughout Australia at child aged 11-12 years. This BMJ Open Special Issue describes the methodology, epidemiology and parent-child concordance of 14 of these phenotypes, spanning cardiovascular, respiratory, bone, kidney, hearing and language, body composition, metabolic profiles, telomere length, sleep, physical activity, snack choice and health-related quality of life. The Special Issue also includes a cohort summary and study methodology paper.

Child Health CheckPoint: cohort summary and methodology of a physical health and biospecimen module for the Longitudinal Study of Australian Children

OBJECTIVES

'Growing Up in Australia: The Longitudinal Study of Australian Children' (LSAC) is Australia's only nationally representative children's longitudinal study, focusing on social, economic, physical and cultural impacts on health, learning, social and cognitive development. LSAC's first decade collected wide-ranging repeated psychosocial and administrative data; here, we describe the Child Health CheckPoint, LSAC's dedicated biophysical module.

DESIGN, SETTING AND PARTICIPANTS

LSAC recruited a cross-sequential sample of 5107 infants aged 0-1 year and a sample of 4983 children aged 4-5 years in 2004, since completing seven biennial visits. CheckPoint was a cross-sectional wave that travelled Australia in 2015-2016 to reach LSAC's younger cohort at ages 11-12 years between LSAC waves 6 and 7. Parent-child pairs participated in comprehensive assessments at 15 Assessment Centres nationwide or, if unable to attend, a shorter home visit.

MEASURES

CheckPoint's intergenerational, multidimensional measures were prioritised to show meaningful variation within normal ranges and capture non-communicable disease (NCD) phenotype precursors. These included anthropometry, physical activity, fitness, time use, vision, hearing, and cardiovascular, respiratory and bone health. Biospecimens included blood, saliva, buccal swabs (also from second parent), urine, hair and toenails. The epidemiology and parent-child concordance of many measures are described in separate papers.

RESULTS

1874 (54% of eligible) parent-child pairs and 1051 second parents participated. Participants' geographical distribution mirrored the broader Australian population; however, mean socioeconomic position and parental education were higher and fewer reported non-English-speaking or Indigenous backgrounds. Application of survey weights partially mitigates that the achieved sample is less population representative than previous waves of LSAC due to non-random attrition. Completeness was uniformly high for phenotypic data (>92% of eligible), biospecimens (74%-97%) and consent (genetic analyses 98%, accessing neonatal blood spots 97%, sharing 96%).

CONCLUSIONS

CheckPoint enriches LSAC to study how NCDs develop at the molecular and phenotypic levels before overt disease emerges, and clarify the underlying dimensionality of health in childhood and mid-adulthood.