Spatiotemporal hierarchical Bayesian analysis to identify factors associated with COVID-19 in suburban areas in Colombia.

Introduction: The pandemic had a profound impact on the provision of health services in Cúcuta, Colombia where the neighbourhood-level risk of Covid-19 has not been investigated. Identifying the sociodemographic and environmental risk factors of Covid-19 in large cities is key to better estimate its morbidity risk and support health strategies targeting specific suburban areas. This study aims to identify the risk factors associated with the risk of Covid-19 in Cúcuta considering inter -spatial and temporal variations of the disease in the city's neighbourhoods between 2020 and 2022. Methods: Age-adjusted rate of Covid-19 were calculated in each Cúcuta neighbourhood and each quarter between 2020 and 2022. A hierarchical spatial Bayesian model was used to estimate the risk of Covid-19 adjusting for socioenvironmental factors per neighbourhood across the study period. Two spatiotemporal specifications were compared (a nonparametric temporal trend; with and without space-time interaction). The posterior mean of the spatial and spatiotemporal effects was used to map the Covid-19 risk. Results: There were 65,949 Covid-19 cases in the study period with a varying standardized Covid-19 rate that peaked in October-December 2020 and April-June 2021. Both models identified an association of the poverty and stringency indexes, education level and PM10 with Covid-19 although the best fit model with a space-time interaction estimated a strong association with the number of high-traffic roads only. The highest risk of Covid-19 was found in neighbourhoods in west, central, and east Cúcuta. Conclusions: The number of high-traffic roads is the most important risk factor of Covid-19 infection in Cucuta. This indicator of mobility and connectivity overrules other socioenvironmental factors when Bayesian models include a space-time interaction. Bayesian spatial models are important tools to identify significant determinants of Covid-19 and identifying at-risk neighbourhoods in large cities. Further research is needed to establish causal links between these factors and Covid-19.

Using the health beliefs model to explore children's attitudes and beliefs on air pollution.

OBJECTIVES: Traffic-related air pollution (TRAP) negatively impacts children's health. Self-protective measures are available, but population uptake is variable. It is essential to understand human beliefs and behaviours related to air pollution in order to understand the lack of self-protection in communities. As a prelude to undertaking a comprehensive assessment of children's attitudes and beliefs on the health effects of TRAP exposure, we sought to develop and validate an appropriate instrument. STUDY DESIGN: This study used exploratory sequential mixed methods. METHODS: This instrument, based on the constructs of the health belief model (HBM), aimed to determine factors predicting wearing a mask to protect against TRAP exposure. An initial literature-based questionnaire was modified using in-depth interviews, focus group discussions, and a quantitative survey pilot. This study included 121 school students and nine professional experts in Vietnam. The questionnaire was tested for content validity, agreement, test-retest reliability, and internal consistency. RESULTS: The concordance of questionnaire items between two repeated assessments ranged from 47.2% to 78.3%, intraclass correlation coefficients ranged from 0.16 to 0.87 and Cronbach's internal reliability coefficient for the instrument was 0.60. CONCLUSION: The self-administered instrument, based on the HBM, is suitable to understand health attitudes and beliefs related to self-protective behaviours to reduce TRAP exposure.

Pediatric lung function testing during a pandemic: An international perspective.

The COVID pandemic has passed its first peak for now in many countries while some are still on the rise, with some facing a second wave of cases. Precautions and infection control measures for both pediatric and adult pulmonary function testing (PFT) have been a topic of debate during the pandemic. Many centers had to close their PFT laboratories during the initial periods of the pandemic and are reopening as the numbers of new cases are decreasing. This review aims to summarize different practices of PFT laboratory management in different countries, including patient appointments, personal protective equipment, testing room requirements and telemedicine during and immediately following the COVID pandemic.

Harmonizing analytical chemistry and clinical epidemiology for human biomonitoring studies. A case-study of plastic product chemicals in urine.

There is an interdisciplinary interface between analytical chemistry and epidemiology studies with respect to the design, execution, and analysis of environmental epidemiology cohorts and studies. Extracting meaningful results linking chemical exposure to human health outcomes begins at study design and spans the entire workflow. Here we discuss analytical experimental design from an exposure science perspective, and propose a reporting checklist for the design of human biomonitoring studies. We explain key analytical chemistry concepts of blanks and limits of reporting and present a case series of plastic product chemical exposure in prenatal urine specimens from the Barwon Infant Study.

Effect of omega-3 fatty acids supplementation during pregnancy on lung function in preschoolers: a clinical trial.

RATIONALE: Prenatal omega-3 fatty acids improve alveolarization, diminish inflammation, and improve pulmonary growth, but it is unclear whether these outcomes translate into improved postnatal lung function. OBJECTIVE: We assessed the effect of prenatal supplementation with docosahexaenoic acid (DHA) on offspring lung function through 60 months of age. METHODS: We included a cohort of 772 Mexican preschoolers whose mothers participated in a clinical trial (NCT00646360) of supplementation with DHA or a placebo from week 18-22 of gestation through delivery. MEASUREMENTS: The children were followed after birth and anthropometric measurements and forced oscillation tests were performed at 36, 48, and 60 months of age. The effect of DHA was tested using a longitudinal mixed effect models. RESULTS: Overall, mean (Standard Deviation) of the measurements of respiratory system resistance and respiratory system reactance at 6, 8, and 10 Hz during follow up period were 11.3 (2.4), 11.1 (2.4), 10.3 (2.2) and -5.2 (1.6), -4.8 (1.7), -4.6 (1.6), respectively. There were no significant differences in pulmonary function by treatment group. DHA did not affect the average lung function or the trajectories through 60 months. CONCLUSIONS: Prenatal DHA supplementation did not influence pulmonary function in this cohort of Mexican preschoolers.

Childhood atopy and mental health: a prospective, longitudinal investigation.

BACKGROUND: Prior studies have suggested a relationship between atopy and mental health, although methodological barriers have limited the generalizability of these findings. The objective of this study was to investigate the relationship between early-life atopy and vulnerability to mental health problems among youth in the community. METHOD: Data were drawn from the Raine Study (N = 2868), a population-based birth cohort study in Western Australia. Logistic regression and generalized estimating equations were used to examine the relationship between atopy at ages 1-5 years [using parent report and objective biological confirmation (sera IgE)], and the range of internalizing and externalizing mental health problems at ages 5-17 years. RESULTS: Atopy appears to be associated with increased vulnerability to affective and anxiety problems, compared to youth without atopy. These associations remained significant after adjusting for a range of potential confounders. No relationship was evident between atopy and attention deficit hyperactivity disorder or externalizing problems. CONCLUSIONS: Findings are the first linking atopy (measured by both parent report and objective verification) with increased vulnerability to affective and anxiety problems. Therefore, replication is required. If replicated, future research aimed at understanding the possible biological and/or social and environmental pathways underlying these links is needed. Such information could shed light on shared pathways that could lead to more effective treatments for both atopy and internalizing mental health problems.

Parental pre-pregnancy BMI is a dominant early-life risk factor influencing BMI of offspring in adulthood.

OBJECTIVE: We examined parental and early-life variables in order to identify risk factors for adulthood overweight and obesity in offspring. We report here on the longitudinal prevalence of overweight and obesity in Australian children born between 1989 and 1991 and followed from birth to age 22. METHODS: Data were analysed on 1355 participants from the Western Australian Pregnancy Cohort (Raine) Study, with anthropometry collected during pregnancy, at birth, one year and at three yearly intervals thereafter. Multivariate analyses and cross-sectional logistic regression quantified the timing and contribution of early-life risk factors for overweight and obesity in young-adulthood. RESULTS: At five years of age 12.6% of children were overweight and 5.2% were obese. By early adulthood, the prevalence of obesity had increased to 12.8%, whilst overweight remained relatively stable at 14.2% (range from early childhood to adulthood 11-16%). Parental pre-pregnancy body mass index (BMI) was the strongest determinant of adult offspring BMI. Although rapid first year weight gain was associated with increased offspring BMI, the impact of first year weight-gain diminished over childhood, whilst the impact of parental BMI increased over time. CONCLUSIONS: Parental pre-pregnancy BMI and rapid early-life weight gain predispose offspring to obesity in adulthood.

Cross-sectional biomonitoring study of pesticide exposures in Queensland, Australia, using pooled urine samples.

A range of pesticides are available in Australia for use in agricultural and domestic settings to control pests, including organophosphate and pyrethroid insecticides, herbicides, and insect repellents, such as N,N-diethyl-meta-toluamide (DEET). The aim of this study was to provide a cost-effective preliminary assessment of background exposure to a range of pesticides among a convenience sample of Australian residents. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n = 24 pools of 100 specimens). Concentrations of urinary pesticide biomarkers were quantified using solid-phase extraction coupled with isotope dilution high-performance liquid chromatography-tandem mass spectrometry. Geometric mean biomarker concentrations ranged from <0.1 to 36.8 ng/mL for organophosphate insecticides, <0.1 to 5.5 ng/mL for pyrethroid insecticides, and <0.1 to 8.51 ng/mL for all other biomarkers with the exception of the DEET metabolite 3-diethylcarbamoyl benzoic acid (4.23 to 850 ng/mL). We observed no association between age and concentration for most biomarkers measured but noted a "U-shaped" trend for five organophosphate metabolites, with the highest concentrations observed in the youngest and oldest age strata, perhaps related to age-specific differences in behavior or physiology. The fact that concentrations of specific and non-specific metabolites of the organophosphate insecticide chlorpyrifos were higher than reported in USA and Canada may relate to differences in registered applications among countries. Additional biomonitoring programs of the general population and focusing on vulnerable populations would improve the exposure assessment and the monitoring of temporal exposure trends as usage patterns of pesticide products in Australia change over time.

Rapid, automated online SPE-LC-QTRAP-MS/MS method for the simultaneous analysis of 14 phthalate metabolites and 5 bisphenol analogues in human urine.

Phthalates and bisphenol A (BPA) have received special attention in recent years due to their frequent use in consumer products and potential for adverse effects on human health. BPA is being replaced with a number of alternatives, including bisphenol S, bisphenol B, bisphenol F and bisphenol AF. These bisphenol analogues have similar potential for adverse health effects, but studies on human exposure are limited. Accurate measurement of multiple contaminants is important for estimating exposure. This paper describes a sensitive and automated method for the simultaneous determination of 14 phthalate metabolites, BPA and four bisphenol analogues in urine using online solid phase extraction coupled with high-performance liquid chromatography/tandem mass spectrometry using a hybrid triple-quadrupole linear ion trap mass spectrometer (LC-QTRAP-MS/MS), requiring very little sample volume (50µL). Quantification was performed under selected reaction monitoring (SRM) mode with negative electrospray ionization. The use of SRM combined with an enhanced product ion scan within the same analysis was examined. Unequivocal identification was provided by the acquisition of three SRM transitions per compound and isotope dilution. The analytical performance of the method was evaluated in synthetic and human urine. Linearity of response over three orders of magnitude was demonstrated for all of the compounds (R(2)>0.99), with method detection limits of 0.01-0.5ng/mL and limits of reporting of 0.07-3.1ng/mL. Accuracy ranged from 93% to 113% and inter- and intra-day precision were <22%. Finally, the validated method has been successfully applied to a cohort of pregnant women to measure biomarker concentrations of phthalates and bisphenols, with median concentrations ranging from 0.3ng/mL (bisphenol S) to 18.5ng/mL (monoethyl phthalate).

Relationship between cytokine expression patterns and clinical outcomes: two population-based birth cohorts.

BACKGROUND: Models that incorporate patterns of multiple cytokine responses to allergens, rather than individual cytokine production, may better predict sensitization and asthma. OBJECTIVE: To characterize the patterns of peripheral blood mononuclear cells' (PBMCs) cytokine responses to house dust mite (HDM) allergens among children from two population-based birth cohorts using machine learning techniques. METHODS: PBMCs collected at 8 years of age from the UK Manchester Asthma and Allergy Study (n = 268) and at 14 years of age from the Australian Raine Study (n = 1374) were cultured with HDM extract (10 µg/ml). Cytokine expression (IL-13, IL-5, IFN-γ, and IL10) was measured in the supernatant. Cytokine patterns were identified using a Gaussian mixture model clustering, and classification stability was assessed by bootstrapping. RESULTS: A six-class model indicated complex latent structure of cytokine expression. Based on the characteristics of each class, we designated them as follows: 'Nonresponders' (n = 905, 55%); 'IL-10 responders' (n = 49, 3%); 'IFN-γ and IL-13 medium responders' (n = 56, 3.4%); 'IL-13 medium responders' (n = 351, 21.4%); 'IL-5 and IL-13 medium responders' (n = 77, 4.7%); and 'IL-13 and IL-5 high responders' (n = 204, 12.4%). 'IL-13 and IL-5 high responders' were at much higher risk of HDM sensitization and asthma compared to all other classes, with 88% of children assigned to this class being sensitized and 28.5% having asthma. CONCLUSION: Using model-based clustering, we identified several distinct patterns of cytokine response to HDM and observed interplay between cytokine expression level, cytokine patterns (especially IL-13 and IL-5), and clinical outcomes. 'IL-13 and IL-5 high responders' class was strongly associated with HDM sensitization. However, among HDM-sensitized children, one-third showed no PBMC response to HDM, and the majority of HDM-sensitized children did not have asthma or wheeze. Our findings suggest that positive HDM 'allergy tests' and asthma are associated with a broad range of immunophenotypes, which may have important implications for the use of cytokine-targeted treatment approaches.

Peri-operative adverse respiratory events in children.

Three quarters of all critical incidents and a third of all peri-operative cardiac arrests in paediatric anaesthesia are caused by adverse respiratory events. We screened for risk factors from children's and their families' histories, and assessed the usefulness of common markers of allergic sensitisation of the airway as surrogates for airway inflammation and increased risk for adverse respiratory events. One hundred children aged up to 16 years with two or more risk factors undergoing elective surgery were included in the study. Eosinophil counts, IgE level, specific IgE for D. pteronyssinus, cat epithelia and Gx2 (grass pollen) were measured for each child and adverse respiratory events (bronchospasm, laryngospasm, oxygen desaturation < 95%, severe persistent coughing, airway obstruction and postoperative stridor) were recorded. Twenty-one patients had an adverse respiratory event but allergic markers were poor predictors. Binary logistic regression showed a lack of predictive value of the eosinophil range and adverse respiratory events (p = 0.249). Receiver operating characteristic (ROC) curves for the presence of adverse respiratory events vs level of specific IgE antibody (to Gx2 (AUC 0.614), cat epithelia (0.564) and D. pteronyssinus (0.520)) demonstrated poor predictive values. However, the presence of risk factors was strongly associated with adverse respiratory events (p < 0.001) and a ROC-curve analysis indicated a fair capacity to predict adverse respiratory events (AUC 0.788). There was a significant difference (p = 0.001) between the presence of adverse respiratory events in patients with more than four (p = 0.006), compared with less than four (p = 0.001), risk factors. We conclude that while risk factors taken from the child's (or family) history proved good predictors of adverse respiratory events, immunological markers of allergic sensitisation demonstrated low predictive values. Pre-operative identification of children at high risk for an adverse respiratory event should rely on clinical, rather than immunological, assessment.

Lung function in African infants: a pilot study.

BACKGROUND: The burden of childhood respiratory illness is large in low and middle income countries (LMICs). Infant lung function (ILF) testing may provide useful information about lung growth and susceptibility to respiratory disease. However, ILF has not been widely available in LMICs settings where the greatest burden of childhood respiratory disease occurs. AIM: To implement and evaluate a pilot study of ILF testing in a semi-rural setting in South Africa. METHOD: Infant lung function testing was established at a community hospital in South Africa. All measures were done in unsedated infants during sleep. Measurements, made with the infant quietly breathing through a face mask and bacterial filter, included tidal breathing (TBFVL), exhaled nitric oxide (eNO), and sulphur hexafluoride multiple breath washout (MBW) measures using an ultrasonic flow meter and chemoluminescent NO analyzer. RESULTS: Twenty infants, mean age of 7.7 (SD 2.9) weeks were tested; 8 (40%) were Black African and 12 (60%) were mixed race. Five (25%) infants were preterm. There were 19 (95%) successful TBFVL and NO tests and 18 (90%) successful MBW tests. The mean tidal volume was 30.5 ml (SD 5.9), respiratory rate 50.2 breaths per minute (SD 8.7), and eNO 10.4 ppb (SD 7.3). The mean MBW measures were: functional residual capacity 71 ml (SD 13) and the lung clearance index 7.6 (SD 0.5). The intra-subject coefficient of variations (CV) of lung function measures were similar to published normative data for Caucasian European infants. CONCLUSION: In this study we demonstrate that unsedated infant lung function measures of tidal breathing, MBW, and eNO are feasible in a semi-rural African setting with rates comparable to those reported from high income countries.

Breast feeding and respiratory morbidity in infancy: a birth cohort study

To examine the relation between the duration of breast feeding and morbidity as a result of respiratory illness and infection in the first year of life...

Bisphenol A exposure is not associated with area-level socioeconomic index in Australian children using pooled urine samples.

Bisphenol A (BPA) is used extensively in food-contact materials and has been detected routinely in populations worldwide; this exposure has been linked to a range of negative health outcomes in humans. There is some evidence of an association between BPA and different socioeconomic variables which may be the result of different dietary patterns. The aim of this study was to conduct a preliminary investigation of the association between BPA and socioeconomic status in Australian children using pooled urine specimens and an area-level socioeconomic index. Surplus pathology urine specimens collected from children aged 0-15 years in Queensland, Australia, as samples of convenience (n=469), were pooled by age, sex and area-level socioeconomic index (n=67 pools) and analysed for total BPA using online solid-phase extraction LC-MS/MS. Concentration ranged from 1.08 to 27.4 ng/ml with geometric mean 2.57 ng/ml, and geometric mean exposure was estimated as 70.3 ng/kg d(-1). Neither BPA concentration nor excretion was associated with age or sex, and the authors found no evidence of an association with socioeconomic status. These results suggest that BPA exposure is not associated with socioeconomic status in the Australian population due to relatively homogenous exposures in Australia, or that the socioeconomic gradient is relatively slight in Australia compared with other OECD countries.

Short term variability in urinary bisphenol A in Australian children.

Used frequently in food contact materials, bisphenol A (BPA) has been studied extensively in recent years, and ubiquitous exposure in the general population has been demonstrated worldwide. Characterizing within- and between-individual variability of BPA concentrations is important for characterizing exposure in biomonitoring studies, and this has been investigated previously in adults, but not in children. The aim of this study was to characterize the short-term variability of BPA in spot urine samples in young children. Children aged ≥2-<4 years (n=25) were recruited from an existing cohort in Queensland, Australia, and donated four spot urine samples each over a two day period. Samples were analysed for total BPA using isotope dilution online solid phase extraction-liquid chromatography-tandem mass spectrometry, and concentrations ranged from 0.53 to 74.5 ng/ml, with geometric mean and standard deviation of 2.70 ng/ml and 2.94 ng/ml, respectively. Sex and time of sample collection were not significant predictors of BPA concentration. The between-individual variability was approximately equal to the within-individual variability (ICC=0.51), and this ICC is somewhat higher than previously reported literature values. This may be the result of physiological or behavioural differences between children and adults or of the relatively short exposure window assessed. Using a bootstrapping methodology, a single sample resulted in correct tertile classification approximately 70% of the time. This study suggests that single spot samples obtained from young children provide a reliable characterization of absolute and relative exposure over the short time window studied, but this may not hold true over longer timeframes.

Feasibility of parental collected nasal swabs for virus detection in young children with cystic fibrosis.

BACKGROUND: The detrimental role of viruses has been well described in CF, although the pattern of virus infections has not been investigated in a longitudinal study. The primary aim was to determine the feasibility of fortnightly parent collected swabs in young children with CF. METHODS: Children under three years with CF were recruited. Nasal swabs were collected by parents every fortnight and during periods of symptoms over 12 months. Nasal swabs were posted and virus detected using real-time PCR. RESULTS: Only 27% of the patients completed the study to 10 months, although 98% of the swabs returned were adequate for analysis. Mould was observed growing on 23% of the returned swabs. There was no evidence to demonstrate relationships with symptoms and viruses, prolonged symptoms, prolonged shedding or patterns of virus infections. CONCLUSIONS: This study highlights the need to further investigate the role of viruses in children with CF using a robust method of frequent collection in children for a longitudinal study, with appropriate storage and shipping techniques to avoid mould growth or other potential contaminants.

Age-related trends in urinary excretion of bisphenol A in Australian children and adults: evidence from a pooled sample study using samples of convenience.

Bisphenol A (BPA or 4,4'-(propane-2,2-diyl)diphenol) is a chemical intermediate in the production of polycarbonate and epoxy resins, and is used in a wide range of applications. BPA has attracted significant attention in the past decade due to its frequency of detection in human populations worldwide, and has demonstrated animal toxicity and potential impact on human health, particularly during critical periods of development. The aim of this study was to perform a preliminary assessment of age-related trends in urinary concentration and to estimate daily excretion of BPA in Australian children (aged >0 to <5 yr) and adults (≥15 to <75 yr). This was achieved using 79 samples pooled by age and gender, created from 868 individual samples of convenience collected as part of routine, community-based pathology testing. Total BPA was analyzed using online solid phase extraction (SPE)-liquid chromatography tandem mass spectrometry (LC-MS/MS) and detected in all samples with a range of 0.65-265 ng/ml. No significant differences were observed between males and females. A urine flow model was constructed from published values and was used to provide an estimate of daily excretion per unit body weight for each pooled sample. The daily excretion estimates ranged from 26.2 to 18,200 ng/kg-d for children, and from 20.1 to 165 ng/kg-d for adults. Urinary concentrations and estimated excretion rates were inversely associated with age, and estimated daily excretion in infants and young children was significantly higher than in adults (geometric mean: 107 and 47.0 ng/kg-d, respectively). Higher excretion of BPA in children may be explained by their higher food consumption relative to body weight compared to adults and adolescents, and may also reflect alternative exposure pathways and sources.