Early growth and adult respiratory function in men and women followed from the fetal period to adulthood

Physical activity and body mass related to catch-up lung function growth in childhood: a population-based accelerated cohort study

OBJECTIVE

The existence of catch-up lung function growth and its predictors is uncertain. We aimed to identify lung function trajectories and their predictors in a population-based birth cohort.

METHODS

We applied group-based trajectory modelling to z-scores of forced expiratory volume in 1 second (zFEV1) and z-scores of forced vital capacity (zFVC) from 1151 children assessed at around 4, 7, 9, 10, 11, 14 and 18 years. Multinomial logistic regression models were used to test whether potential prenatal and postnatal predictors were associated with lung function trajectories.

RESULTS

We identified four lung function trajectories: a low (19% and 19% of the sample for zFEV1 and zFVC, respectively), normal (62% and 63%), and high trajectory (16% and 13%) running in parallel, and a catch-up trajectory (2% and 5%) with catch-up occurring between 4 and 10 years. Fewer child allergic diseases and higher body mass index z-score (zBMI) at 4 years were associated with the high and normal compared with the low trajectories, both for zFEV1 and zFVC. Increased children's physical activity during early childhood and higher zBMI at 4 years were associated with the catch-up compared with the low zFEV1 trajectory (relative risk ratios: 1.59 per physical activity category (1.03-2.46) and 1.47 per zBMI (0.97-2.23), respectively). No predictors were identified for zFVC catch-up growth.

CONCLUSION

We found three parallel-running and one catch-up zFEV1 and zFVC trajectories, and identified physical activity and body mass at 4 years as predictors of zFEV1 but not zFVC catch-up growth.

Associations between birth weight and lung function in a Japanese adult population: The tohoku medical megabank community-based cohort study

BACKGROUND

Birth weight, as a measure of intrauterine growth, is commonly used in epidemiological studies and is reported to be associated with adult lung function. However, findings regarding this association in previous studies have been inconsistent. Furthermore, no studies have reported associations stratified by age or smoking status, or adjusted for eosinophil count or other parameters related to type 2 airway inflammation.

METHODS

This cross-sectional study included 2632 men and 7237 women aged ≥20 years living in Miyagi Prefecture, Japan. Lung function was assessed based on spirometry. Birth weight data were obtained through a questionnaire survey. Analysis of covariance was used to evaluate the associations between birth weight and lung function, adjusting for potential confounders. Stratified analyses by age and smoking status were also conducted, together with a sub-analysis for low birth-weight participants.

RESULTS

Birth weight was positively associated with forced expiratory volume in 1 s (FEV1) for both sexes and with vital capacity in women, after adjusting for height, age, smoking status, and parameters related to type 2 airway inflammation. The stratified analysis for smoking status revealed associations in never-smokers and ex-smokers. When stratified by age, the associations were confirmed in middle-aged participants. The effect of smoking status on the FEV1 of low birth-weight participants was not significant.

CONCLUSIONS

Our analysis of a large, Japanese adult population showed that birth weight was independently and positively associated with adult lung function, even after adjustment for age, height, smoking status, and parameters related to type 2 airway inflammation.

Long-term implications of fetal growth restriction

Fetal growth restriction (FGR), or intrauterine growth restriction (IUGR), is a complication of pregnancy where the fetus does not achieve its genetic growth potential. FGR is characterized by a pathological retardation of intrauterine growth velocity in the curve of intrauterine growth. However, the FGR definition is still debated, and there is a lack of a uniform definition in the literature. True IUGR, compared to constitutional smallness, is a pathological condition in which the placenta fails to deliver an adequate supply of oxygen and nutrients to the developing fetus. Infants with IUGR, compared to appropriately grown gestational age infants, have a significantly higher risk of mortality and neonatal complications with long-term consequences. Several studies have demonstrated how suboptimal fetal growth leads to long-lasting physiological alterations for the developing fetus as well as for the newborn and adult in the future. The long-term effects of fetal growth retardation may be adaptations to poor oxygen and nutrient supply that are effective in the fetal period but deleterious in the long term through structural or functional alterations. Epidemiologic studies showed that FGR could be a contributing factor for adult chronic diseases including cardiovascular disease, metabolic syndrome, diabetes, respiratory diseases and impaired lung function, and chronic kidney disease. In this review we discussed pathophysiologic mechanisms of FGR-related complications and potential preventive measures for FGR.

Perinatal origins of bronchopulmonary dysplasia-deciphering normal and impaired lung development cell by cell

Bronchopulmonary dysplasia (BPD) is a multifactorial disease occurring as a consequence of premature birth, as well as antenatal and postnatal injury to the developing lung. BPD morbidity and severity depend on a complex interplay between prenatal and postnatal inflammation, mechanical ventilation, and oxygen therapy as well as associated prematurity-related complications. These initial hits result in ill-explored aberrant immune and reparative response, activation of pro-fibrotic and anti-angiogenic factors, which further perpetuate the injury. Histologically, the disease presents primarily by impaired lung development and an arrest in lung microvascular maturation. Consequently, BPD leads to respiratory complications beyond the neonatal period and may result in premature aging of the lung. While the numerous prenatal and postnatal stimuli contributing to BPD pathogenesis are relatively well known, the specific cell populations driving the injury, as well as underlying mechanisms are still not well understood. Recently, an effort to gain a more detailed insight into the cellular composition of the developing lung and its progenitor populations has unfold. Here, we provide an overview of the current knowledge regarding perinatal origin of BPD and discuss underlying mechanisms, as well as novel approaches to study the perturbed lung development.

The Association of Self-Reported Birthweight with Lung Function and Respiratory Diseases: Results from a Multi-Centre, Multi-Case Control Study in Italy

Early life conditions are associated with lung function and the development of respiratory and non-respiratory illnesses. The relationship with birthweight (BW), however, is conflicting. We examined associations of self-reported BW with lung function and the development of respiratory and also non-respiratory diseases within the GEIRD (Gene-Environment Interaction in Respiratory Diseases) project, an Italian multi-centre, multi-case control study involving cases of COPD, asthma, allergic rhinitis and controls. Multinomial logistic regression was performed with case/control status as response variable; BW as main determinant; and adjusting for sex, age and smoking status. Of the 2287 participants reporting BW, 6.4% (n = 147) had low BW (<2500 g), and this proportion was greater in women than men (7.8% vs. 5.1%; p = 0.006). Both men and women with low BW were shorter than those with normal BW (mean ± SD: 160.2 ± 5.5 vs. 162.6 ± 6.5 cm in women, p = 0.009; 172.4 ± 6.1 vs. 174.8 ± 7.2 cm in men, p < 0.001). Although FEV1 and FVC were reduced in individuals with low BW, this was explained by associations with sex and height. In multivariable analysis, BW was not associated with respiratory diseases in adulthood. However, those with low BW had a higher risk of self-reported hospitalisation for lung disease before the age of two (10.3% vs. 4.1%; p < 0.001), severe respiratory infection before the age of five (16.9% vs. 8.8%; p = 0.001) and hypertension in adulthood (29.9% vs. 23.7%; p = 0.001); however, they had a lower risk of arrhythmia (2.7% vs. 5.8%; p = 0.027).

Neonatal nutritional risk and pulmonary function

INTRODUCTION

The neonatal period is a critical initial stage of postnatal lung development and maturation. This study aimed to investigate the effects of the nutritional status on pulmonary function in late preterm and full-term neonates.

METHODS

A total of 172 newborns were included in the study. Nutritional risk screening, weight measurement, assessment of albumin and caloric intake, and a pulmonary function examination were conducted on the 7th day after birth.

RESULTS

There was a significant correlation between the nutritional risk and changes in body weight. Tidal volume (VT), minute ventilation (MV), VT per kg body weight (VT/kg), and MV per kg body weight (MV/kg) in the low nutritional risk group were significantly higher than those in the medium nutritional risk group (all P < .05). Albumin and caloric intake in the low nutritional risk group were significantly higher than those in the medium nutritional risk group (both P < .01). VT, VT/kg, MV, and MV/kg in the weight loss group were lower than those in the no weight loss group (all P < .05).

CONCLUSIONS

Changes in neonatal weight mainly affect lung volume (VT, VT/kg, MV, and MV/kg), suggesting that an improvement in the neonatal nutritional status is important for the development of lung volume.

Perspectives: on Precision Nutrition Research in Heart, Lung, and Blood Diseases and Sleep Disorders

The release of the 2020-2030 Strategic Plan for NIH Nutrition Research (SPNR) and its emphasis on precision nutrition has provided an opportunity to identify future nutrition research that addresses individual variability in response to diet and nutrition across the life span-including those relevant to the Strategic Vision of the National Heart, Lung, and Blood Institute (NHLBI). The SPNR and the NHLBI's Strategic Vision were developed with extensive input from the extramural research community, and both have 4 overarching strategic goals within which are embedded several objectives for research. For the SPNR, these include 1) spur discovery science and normal biological functions (e.g., role of the microbiome in health and disease), 2) population science to understand individual differences (e.g., biomarkers including 'omics that predict disease status), 3) emerging scientific areas of investigation and their application (e.g., data science, artificial intelligence), and 4) cross-cutting themes (e.g., training the scientific workforce and minority health and health disparities). These strategic goals and objectives serve as blueprints for research and training. Nutrition remains important in the prevention and treatment of heart, lung, blood, and sleep (HLBS) disorders and diseases, and the NHLBI has played a pivotal role in supporting nutrition research. In this paper, we report important gaps in the scientific literature related to precision nutrition in HLBS diseases. Research opportunities that could stimulate precision nutrition and their alignment with the SPNR and the NHLBI Strategic Vision Objectives are provided. These opportunities include 1) exploring individual differences in response to varying dietary patterns and nutrients; 2) investigating genetic/epigenetic, biological (e.g., microbiome, biomarkers), social, psychosocial, and environmental underpinnings of individual variability in diet; 3) elucidating the role of circadian rhythm and chrononutrition; and 4) applying implementation science research methods in precision nutrition interventions relevant to HLBS diseases.

Low length/weight growth trajectories of early-term infants during the first year: evidence from a longitudinal study in China

OBJECTIVE

To identify common length, weight and body mass index (BMI) growth trajectories of term infants during infancy, and to determine their association with early-term infants.

DESIGN

Prospective longitudinal study.

SETTING

Wuhan, China.

PATIENTS

A total of 4308 term infants (born at 37-41 weeks of gestation) were included. All term infants were single live birth with no defects and birth weight ≥2500 g, and their mothers were permanent residents of Wuhan for more than 2 years. After excluding 887 infants, a total of 3421 term infants (1028 early-term infants born at 37-38 weeks of gestation and 2393 full-term infants born at 39-41 weeks of gestation) entered the statistical analysis stage.

MAIN OUTCOME MEASURES

Patterns of length, weight and BMI growth trajectories by using group-based trajectory modelling.

RESULTS

Three distinct physical growth trajectories were identified as follows: length: low stable (1056, 30.9%), moderate stable (1887, 55.2%) and high increasing (477, 13.9%); weight: low stable (1031, 30.1%), moderate stable (1884, 55.1%) and high increasing (505, 14.8%); BMI: low stable (689, 20.1%), moderate stable (2167, 63.4%) and high increasing (564, 16.5%). Compared with the full-term infants, early-term infants were more likely to remain at low-stable trajectory in length (OR: 1.40; 95% CI: 1.19 to 1.66) and weight (OR:1.29; 95% CI: 1.09 to 1.53). These associations were still statistically significant after adjusting potential confounders and were more evident among girls in the stratified analysis. There was no statistical association between BMI trajectory patterns and gestational age categories.

CONCLUSION

Our results suggested the heterogeneity of term infants existed in length, weight and BMI growth trajectories of early childhood. Compared with full-term birth, early-term birth was related to low length and weight trajectories rather than BMI trajectory. Further research is needed to evaluate the duration of these low trajectories and their possible long-term health effects.

Can birth weight predict offspring's lung function in adult age? Evidence from two Swedish birth cohorts

BACKGROUND

Associations between birth weight (BW) and adult lung function have been inconsistent and limited to early adulthood. We aimed to study this association in two population-based cohorts and explore if BW, adjusted for gestational age, predicts adult lung function. We also tested adult lung function impairment according to the mis-match hypothesis-small babies growing big as adults.

METHODS

We included 3495 individuals (aged 46.4 ± 5.4 years) from the Malmo Preventive Project (MPP), Sweden, born between 1921 and 1949, and 1401 young to middle-aged individuals (aged 28.6 ± 6.7 years) from the Malmo Offspring Study (MOS) with complete data on BW and gestational age. Adult lung function (forced vital capacity [FVC], forced expiratory volume in one second [FEV1] and the FEV1/FVC-ratio) were analysed as level of impairment (z-score), using multiple linear and logistic regressions.

RESULTS

BW (z-score) did not predict adult lung function in MPP, whereas BW was a significant (p = 0.003) predictor of FEV1 following full adjustment in MOS. For every additional unit increase in BW, children were 0.77 (95% CI 0.65-0.92) times less likely to have impaired adult lung function (FEV1). Moreover, adults born with lower BW (< 3510 g) showed improved lung function (FEV1 and FEV1/FVC in MOS and MPP, respectively) if they achieved higher adult body weight.

CONCLUSIONS

Adults born with lower birth weight, adjusted for gestational age, are more likely to have impaired lung function, seen in a younger birth cohort. Postnatal growth pattern may, however, compensate for low birth weight and contribute to better adult lung function.

Genetic correlation and causal relationships between cardio-metabolic traits and lung function impairment

BACKGROUND

Associations of low lung function with features of poor cardio-metabolic health have been reported. It is, however, unclear whether these co-morbidities reflect causal associations, shared genetic heritability or are confounded by environmental factors.

METHODS

We performed three analyses: (1) cardio-metabolic health to lung function association tests in Northern Finland Birth cohort 1966, (2) cross-trait linkage disequilibrium score regression (LDSC) to compare genetic backgrounds and (3) Mendelian randomisation (MR) analysis to assess the causal effect of cardio-metabolic traits and disease on lung function, and vice versa (bidirectional MR). Genetic associations were obtained from the UK Biobank data or published large-scale genome-wide association studies (N > 82,000).

RESULTS

We observed a negative genetic correlation between lung function and cardio-metabolic traits and diseases. In Mendelian Randomisation analysis (MR), we found associations between type 2 diabetes (T2D) instruments and forced vital capacity (FVC) as well as FEV1/FVC. Body mass index (BMI) instruments were associated to all lung function traits and C-reactive protein (CRP) instruments to FVC. These genetic associations provide evidence for a causal effect of cardio-metabolic traits on lung function. Multivariable MR suggested independence of these causal effects from other tested cardio-metabolic traits and diseases. Analysis of lung function specific SNPs revealed a potential causal effect of FEV1/FVC on blood pressure.

CONCLUSIONS

The present study overcomes many limitations of observational studies by using Mendelian Randomisation. We provide evidence for an independent causal effect of T2D, CRP and BMI on lung function with some of the T2D effect on lung function being attributed to inflammatory mechanisms. Furthermore, this analysis suggests a potential causal effect of FEV1/FVC on blood pressure. Our detailed analysis of the interplay between cardio-metabolic traits and impaired lung function provides the opportunity to improve the quality of existing intervention strategies.

The different phenotypes of COPD

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with significant morbidity and mortality. To improve the health status and reduce symptom burden, it is important to identify a group of patients with similar characteristics and prognosis, called clinical phenotypes. Herein we shall review the different phenotypes of COPD.

SOURCES OF DATA

Keywords (COPD, phenotype, acute exacerbation) search was conducted in PubMed, Google Scholar.

AREAS OF AGREEMENT

Those with raised blood eosinophil counts respond better to steroid therapy at stable state and exacerbation.

AREAS OF CONTROVERSY

There is no universally accepted blood eosinophil cut-off value that will indicate favourable response to corticosteroids and potentially for future biologic therapy.

GROWING POINTS

There is an urgent need for further therapeutic options for COPD patients with non-eosinophilic inflammation.

AREAS TIMELY FOR DEVELOPING RESEARCH

Well-designed COPD trials with identification of phenotypes for more personalization of the treatment of COPD.

Early life exposures and risk of adult respiratory disease during 50 years of follow-up

Adult health is influenced by factors during fetal life affecting organ development and birth weight. We aimed to study such factors in relation to adult respiratory disease (ARD) risk. The Helsingborg Birth Cohort, Sweden, contributed baseline data collected by medical staff through clinical examination and questionnaires on maternal and birth characteristics 1964-1967. Register linkages were performed with completions of data on ARD by ICD 8-10 classifications (1969-2016), and/or ARD-related drug usage (2005-2016) enabling a 50-year follow-up time. Cox proportional hazard regression analyses were made to adjust for potential confounders, adjusted hazard ratio (aHR). A total of 3675 mothers and their offspring were included. Female offspring showed higher frequency of ARD than males, aHR 1.5 (95% CI 1.3-1.8). Maternal use of sedatives during second trimester, aHR 2.2 (95% CI 1.4-3.4), and maternal smoking during most of pregnancy, aHR 1.2 (95% CI 1.0-1.4), were associated with offspring ARD. Stratified by sex, large-for-gestational-age, aHR 1.4 (95% CI 1.0-1.9), was significantly associated with ARD in female offspring along with maternal sedative use during second trimester and maternal smoking during most of pregnancy. Maternal sedative use during second trimester or all trimesters were the only significant risk factors for male offspring. In conclusion, maternal sedative use in second trimester was independently associated with subsequent respiratory disease in adult offspring irrespective of sex.

Early childhood growth is associated with lung function at 7 years: a prospective population-based study

Previous studies have related early postnatal growth with later lung function but their interpretation is limited by the methods used to assess a child's growth. We aimed to assess the association of early childhood growth, measured by body mass index (BMI) trajectories up to 4 years, with lung function at 7 years.We included 1257 children from the Spanish Infancia y Medio Ambiente population-based birth cohort. Early childhood growth was classified into five categories based on BMI trajectories up to 4 years previously identified using latent class growth analysis. These trajectories differed in birth size ("lower", "average", "higher") and in BMI gain velocity ("slower", "accelerated"). We related these trajectories to lung function (forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), FEV₁/FVC and forced expiratory flow at 25%-75% of FVC (FEF_25-75%)) at 7 years, using multivariable mixed regression.Compared to children with average birth size and slower BMI gain (reference), children with higher birth size and accelerated BMI gain had a higher FVC % pred (3.3%, 95% CI 1.0%-5.6%) and a lower FEV₁/FVC % pred (-1.5%, 95% CI -2.9%--0.1%) at 7 years. Similar associations were observed for children with lower birth size and accelerated BMI gain. Children with lower birth size and slower BMI gain had lower FVC % pred at 7 years. No association was found for FEF_25-75%Independently of birth size, children with accelerated BMI gain in early childhood had higher lung function at 7 years but showed airflow limitation. Children with lower birth size and slower BMI gain in early childhood had lower lung function at 7 years.

Perinatal biomarkers implying 'Developmental Origins of Health and Disease' consequences in intrauterine growth restriction

The intrauterine-growth-restricted (IUGR) state, particularly the asymmetric one, has been associated with 'Developmental Origins of Health and Disease' (DOHaD) consequences later in life. Several environmental factors, acting during the phase of foetal developmental plasticity interact with genotypic variation, 'programme' tissue function and change the capacity of the organism to cope with its environment. They may be responsible for chronic illness risk in adulthood. Detection of possible future DOHaD consequences at a very early age, by applying relevant biomarkers, is of utmost importance. This review focuses on biomarkers possibly predicting consequences from bone, psychoneural system and lung. Although no concrete biomarker has been identified for bone disorders in adulthood, reduced brain-derived neurotrophic factor (BDNF) concentrations in cord blood and BDNF DNA methylation might predict schizophrenia and possibly depression, bipolar disorder and autism. High surfactant protein D (SP-D) concentrations in cord blood of IUGR foetuses/neonates could point to structural lung immaturity, resulting to asthma and chronic obstructive pulmonary disease in adult life.

Sex-specific differences in the association between birth weight and lung volume in Japanese young adults

BACKGROUND

Fetal growth disturbances may influence adult lung function and can lead to pulmonary diseases in adulthood. Although the results of previous studies are controversial, low birth weight seems to be associated with poor adult lung function. This study aimed to assess previously unknown information about the sex-specific association between birth weight and adult lung volume in the Japanese population.

METHODS

We evaluated pulmonary parameters in 200 consenting young medical students (age, 20-29 years) with a never smoking history at Kochi University. Subjects whose lung function was not sufficiently examined or those with evidence of current or previous respiratory diseases were excluded (n=7). All students underwent spirometry, and their weight records at birth or 3 years of age were obtained from their maternal and child handbooks. Associations between the spirometric parameters and birth/3-year weights were statistically analyzed.

RESULTS

We evaluated 91 male and 102 female students. Their mean age was 23.3 years. Assessment revealed that birth weight significantly correlated with the percent predicted value of forced vital capacity (%FVC; r_s=0.17, p=0.018) but not with the forced expiratory volume in 1 s/FVC ratio. Sex-specific analysis revealed significant correlations between birth weight and %FVC in males (r_s=0.22, p=0.041) but not in females. Body weight at the age of 3 years also significantly correlated with %FVC only in males (r_s=0.32, p=0.021).

CONCLUSIONS

Birth weight is significantly associated with pulmonary function in Japanese young adults. The associations are especially significant in males.

Early-life undernutrition reprograms CD4+ T-cell glycolysis and epigenetics to facilitate asthma

BACKGROUND

Exposure to early-life undernutrition is closely related to higher risks of adverse immunologic outcomes in adulthood. Although it has been suggested that asthma has its origins in early life, its underlying mechanisms remain largely unknown.

OBJECTIVE

We characterized the effects of early-life undernutrition on T lymphocytes, which play a pivotal role in immune diseases, and we investigated whether this contributes to susceptibility to asthma in adulthood.

METHODS

Pregnant mice were fed a protein restriction diet (PRD) to establish an early-life undernutrition model. Naive CD4⁺ T cells (CD4⁺CD62L^hiCD44^-) from offspring were used throughout the study. T_H2 differentiation was examined by using fluorescence-activated cell sorting and ELISA under T_H2-polarized conditions in vitro and through ovalbumin-induced experimental asthma in vivo. T-cell metabolism was measured with a Seahorse XF96 Analyzer. DNA methylation levels were measured by using bisulfite sequencing.

RESULTS

PRD CD4⁺ T cells displayed increased activation and proliferation and were prone to differentiate into T_H2 cells both in vitro and in vivo, leading to susceptibility to experimental asthma. Mechanistically, early-life undernutrition upregulated mechanistic target of rapamycin 1-dependent glycolysis and induced conserved noncoding DNA sequence 1 DNA hypomethylation in the T_H2 cytokine locus of CD4⁺ T cells. Glycolysis blockades undermined increased T_H2 skewing and alleviated experimental asthma in PRD mice.

CONCLUSION

Early-life undernutrition induced mechanistic target of rapamycin 1-dependent glycolysis upregulation and T_H2 cytokine locus hypomethylation in CD4⁺ T cells, resulting in increased T-cell activation, proliferation, and T_H2 skewing and further susceptibility to experimental asthma.

Effect of foetal and infant growth and body composition on respiratory outcomes in preterm-born children

Body composition and growth outcomes of preterm-born subjects have been studied by many researchers. In general, preterm-born children have lower height and weight especially in infancy. Despite showing potential for catch-up growth, they continue to lag behind their term counterparts in adolescence and adulthood. The various methods of studying body composition and the differing gestations and ages at which it is assessed may go some way to explaining the inconsistent results observed in different studies. In addition, there is a paucity of data on the effects of foetal and infant growth and of body composition on later respiratory outcomes. In largely term-born subjects, foetal growth and growth trajectories appear to have differential effects on later respiratory outcomes. Early weight gain in infancy appears to be associated with increased respiratory symptoms in childhood but catch-up growth in infancy appears to be associated with possible improved lung function status.

The effect of early growth patterns and lung function on the development of childhood asthma: a population based study

BACKGROUND

Infant weight gain is associated with lower lung function and a higher risk of childhood asthma. Detailed individual childhood growth patterns might be better predictors of childhood respiratory morbidity than the difference between two weight and height measurements. We assessed the associations of early childhood growth patterns with lung function and asthma at the age of 10 years and whether the child's current body mass index (BMI) influenced any association.

METHODS

We derived peak height and weight growth velocity, BMI at adiposity peak, and age at adiposity peak from longitudinally measured weight and height data in the first 3 years of life of 4435 children enrolled in a population-based prospective cohort study. At 10 years of age, spirometry was performed and current asthma was assessed by questionnaire. Spirometry outcomes included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), FEV₁/FVC ratio, and forced expiratory flow after exhaling 75% of vital capacity (FEF₇₅).

RESULTS

Greater peak weight velocity was associated with higher FVC but lower FEV₁/FVC and FEF₇₅. Greater BMI at adiposity peak was associated with higher FVC and FEV₁ but lower FEV₁/FVC and FEF₇₅. Greater age at adiposity peak was associated with higher FVC, FEV₁, FEV₁/FVC and FEF₇₅, particularly in children with a small size at birth, and lower odds of current asthma in boys. The child's current BMI only explained the associations of peak weight velocity and BMI at adiposity peak with FVC and FEV₁. Peak height velocity was not consistently associated with impaired lung function or asthma.

CONCLUSION

Peak weight velocity and BMI at adiposity peak were associated with reduced airway patency in relation to lung volume, whereas age at adiposity peak was associated with higher lung function parameters and lower risk of asthma at 10 years, particularly in boys.

Nutrition and Lung Growth

Experimental evidence from animal models and epidemiology studies has demonstrated that nutrition affects lung development and may have a lifelong impact on respiratory health. Chronic restriction of nutrients and/or oxygen during pregnancy causes structural changes in the airways and parenchyma that may result in abnormal lung function, which is tracked throughout life. Inadequate nutritional management in very premature infants hampers lung growth and may be a contributing factor in the pathogenesis of bronchopulmonary dysplasia. Recent evidence seems to indicate that infant and childhood malnutrition does not determine lung function impairment even in the presence of reduced lung size due to delayed body growth. This review will focus on the effects of malnutrition occurring at critical time periods such as pregnancy, early life, and childhood, on lung growth and long-term lung function.

Clinical characterization of children with resistant airflow obstruction, a multicenter study

OBJECTIVE

To characterize a cohort of children with airflow limitation resistant to bronchodilator (BD) therapy.

METHODS

Pulmonary function tests performed in children 6-17 years of age at 15 centers in a clinical research consortium were screened for resistant airflow limitation, defined as a post-BD FEV₁ and/or an FEV₁/FVC less than the lower limits of normal. Demographic and clinical data were analyzed for associations with pulmonary function.

RESULTS

582 children were identified. Median age was 13 years (IQR: 11, 16), 60% were males; 62% were Caucasian, 28% were African-American; 19% were obese; 32% were born prematurely and 21% exposed to second hand smoke. Pulmonary diagnoses included asthma (93%), prior significant pneumonia (28%), and bronchiectasis (5%). 65% reported allergic rhinitis, and 11% chronic sinusitis. Subjects without a history of asthma had significantly lower post-BD FEV₁% predicted (p = 0.008). Subjects without allergic rhinitis had lower post-BD FEV₁% predicted (p = 0.003). Children with allergic rhinitis, male sex, obesity and Black race had better pulmonary function post-BD. There was lower pulmonary function in children after age 11 years without a history of allergic rhinitis, as compared to those with a history of allergic rhinitis.

CONCLUSIONS

The most prevalent diagnosis in children with BD-resistant airflow limitation is asthma. Allergic rhinitis and premature birth are common co-morbidities. Children without a history of asthma, as well as those with asthma but no allergic rhinitis, had lower pulmonary function. Children with BD-resistant airflow limitation may represent a sub-group of children with persistent obstruction and high risk for life-long airway disease.

Early determinants of metabolically healthy obesity in young adults: study of the Northern Finland Birth Cohort 1966

BACKGROUND

A body of literature suggests a metabolically healthy phenotype in individuals with obesity. Despite important clinical implications, the early origins of metabolically healthy obesity (MHO) have received little attention.

OBJECTIVE

To assess the prevalence of MHO among the Northern Finland Birth Cohort 1966 (NFBC1966) at 31 years of age, examine its determinants in early life taking into account the sex specificity.

METHODS

We studied 3205 term-born cohort participants with data available for cardio-metabolic health outcomes at 31 years, and longitudinal height and weight data. After stratifying the population by sex, adult BMI and a strict definition of metabolic health (i.e., no risk factors meaning metabolic health), we obtained six groups. Repeated childhood height and weight measures were used to model early growth and early adiposity phenotypes. We employed marginal means adjusted for mother and child covariates including socio-economic status, birth weight and gestational-age, to compare differences between the groups.

RESULTS

The prevalence of adult MHO was 6% in men and 13.5% in women. Differences in adult metabolic status were linked to alterations in BMI and age at adiposity peak in infancy (p < 0.0003 in men and p = 0.027 in women), and BMI and age at adiposity rebound (AR) (p < 0.0001 irrespective of sex). Compared to MHO, metabolically unhealthy obese (MUO) women were five and a half months younger at AR (p = 0.007) with a higher BMI while MUO men were four months older (p = 0.036) with no difference in BMI at AR.

CONCLUSION

At the time of AR, MHO women appeared to be older than their MUO counterparts while MHO men were younger. These original results support potential risk factors at the time of adiposity rebound linked to metabolic health in adulthood. These variations by sex warrant independent replication.

Birth Weight and Lung Function in Adulthood: A Systematic Review and Meta-analysis

RATIONALE

There is evidence suggesting that birth weight may influence lung function in adulthood, but it is unclear whether it might differentially affect restrictive (FVC) and obstructive (FEV₁/FVC) patterns.

OBJECTIVES

To summarize evidence available on the association of birth weight, weight at 1 year, and weight gain in the first year of life with FVC and FEV₁/FVC in adulthood.

METHODS

We performed a systematic review of the literature by searching MEDLINE, EMBASE, and Web of Science through January 2015. Data were combined using inverse-variance weighted meta-analysis with random effects models and between-study heterogeneity evaluated. We conducted a priori subgroup or sensitivity analyses by age, country wealth, ethnicity, sex, and smoking. We evaluated risk of bias using the Newcastle Ottawa Scale and reporting bias using funnel plots.

RESULTS

Eighteen articles were included in the review and 13 in the meta-analyses. Most studies were from high-income countries, and all had a low risk of bias. We found strong evidence of an association of birth weight with adult FVC, a 59.4 ml higher FVC in adulthood per kilogram increase in birth weight (95% confidence interval, 43.3-75.5), with no evidence of heterogeneity. Evidence of an association of birth weight with FEV₁/FVC was weaker and showed some inconsistency across studies. Only one study investigated weight at 1 year, and another one reported weight gain in the first year.

CONCLUSIONS

Our meta-analyses show strong and consistent evidence of an association of birth weight with adult FVC, a measure of restrictive impairment, with much weaker evidence for airflow obstruction.

Early life insults as determinants of chronic obstructive pulmonary disease in adult life

Background

Early life events may predispose to the development of chronic lung disease in adulthood.

Aim

To provide an update on current knowledge of early nongenetic origins of COPD.

Materials and methods

Systematic literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

A total of 16 studies, comprising 69,365 individuals, met the predefined criteria and were included in the present review. Studies have shown that in utero tobacco exposure, low birth weight, preterm birth, and respiratory diseases, primarily asthma and pneumonia, in early childhood are associated with lung function impairment later in childhood, and by that predispose to subsequent development of COPD, although the causal association between childhood respiratory diseases and COPD has been questioned in one study. Environmental tobacco exposure has also been shown to have negative impact on lung function in childhood possibly leading to COPD in adulthood, although it is at present not possible to clearly distinguish between the impact of active and the environmental tobacco exposure on subsequent development of COPD.

Conclusion

Tobacco exposure in utero and early life is a risk factor for subsequent development of COPD. Furthermore, low birth weight, lower respiratory tract infections and asthma, including wheezy bronchitis, in childhood also seem to be important determinants for later development of COPD. Early life insults may, therefore, be crucial to COPD development.

Foetal growth restriction in mice modifies postnatal airway responsiveness in an age and sex-dependent manner

Epidemiological studies demonstrate an association between intrauterine growth restriction (IUGR) and asthma; however the underlying mechanism is unknown. We investigated the impact of maternal hypoxia-induced IUGR on airway responsiveness in male and female mice during juvenility and adulthood. Pregnant BALB/c mice were housed under hypoxic conditions for gestational days 11-17.5 and then returned to normoxic conditions for the remainder of pregnancy. A control group was housed under normoxic conditions throughout pregnancy. Offspring were studied at 2 weeks (juveniles) and 8 weeks (adults), where lung volume was assessed by plethysmography, airway responsiveness to methacholine determined by the forced oscillation technique and lungs fixed for morphometry. IUGR offspring were lighter at birth, exhibited "catch-up growth" by 2 weeks, but were again lighter in adulthood. IUGR males were "hyper-responsive" at 2 weeks and "hypo-responsive" as adults, in contrast with IUGR females who were hyper-responsive in adulthood. IUGR males had increased inner and total wall thickness at 2 weeks which resolved by adulthood, while airways in IUGR females were structurally normal throughout life. There were no differences in lung volume between Control and IUGR offspring at any age. Our data demonstrate changes in airway responsiveness as a result of IUGR that could influence susceptibility to asthma development and contribute to sexual dimorphism in asthma prevalence which switches from a male dominated disease in early life to a female dominated disease in adulthood.

The role of respiratory tract infections and the microbiome in the development of asthma: A narrative review

Asthma is a common disease in childhood, and might predispose for chronic obstructive respiratory morbidity in adolescence and adulthood. Various early-life risk factors might influence the risk of wheezing, asthma, and lower lung function in childhood. Cohort studies demonstrated that lower respiratory tract infections in the first years of life are associated with an increased risk of wheezing and asthma, while the association with lung function is less clear. Additionally, the gut and airway microbiome might influence the risk of wheezing and asthma. The interaction between respiratory tract infections and the microbiome complicates studies of their associations with wheezing, asthma, and lung function. Furthermore, the causality behind these observations is still unclear, and several other factors such as genetic susceptibility and the immune system might be of importance. This review is focused on the association of early-life respiratory tract infections and the microbiome with wheezing, asthma, and lung function, it is possible influencing factors and perspectives for future studies.

Altitude and COPD prevalence: analysis of the PREPOCOL-PLATINO-BOLD-EPI-SCAN study

BACKGROUND

COPD prevalence is highly variable and geographical altitude has been linked to it, yet with conflicting results. We aimed to investigate this association, considering well known risk factors.

METHODS

A pooled analysis of individual data from the PREPOCOL-PLATINO-BOLD-EPI-SCAN studies was used to disentangle the population effect of geographical altitude on COPD prevalence. Post-bronchodilator FEV1/FVC below the lower limit of normal defined airflow limitation consistent with COPD. High altitude was defined as >1500 m above sea level. Undiagnosed COPD was considered when participants had airflow limitation but did not report a prior diagnosis of COPD.

RESULTS

Among 30,874 participants aged 56.1 ± 11.3 years from 44 sites worldwide, 55.8% were women, 49.6% never-smokers, and 12.9% (3978 subjects) were residing above 1500 m. COPD prevalence was significantly lower in participants living at high altitude with a prevalence of 8.5% compared to 9.9%, respectively (p < 0.005). However, known risk factors were significantly less frequent at high altitude. Hence, in the adjusted multivariate analysis, altitude itself had no significant influence on COPD prevalence. Living at high altitude, however, was associated with a significantly increased risk of undiagnosed COPD. Furthermore, subjects with airflow limitation living at high altitude reported significantly less respiratory symptoms compared to subjects residing at lower altitude.

CONCLUSION

Living at high altitude is not associated with a difference in COPD prevalence after accounting for individual risk factors. However, high altitude itself was associated with an increased risk of undiagnosed COPD.

Structural and functional ventilatory impairment in infants with severe bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most frequent serious complication in preterm infants. We aimed to describe lung structure and ventilatory function of preterm infants with severe BPD and explored the association between early postnatal growth and these outcomes.

METHODS

We included preterm infants born ≤32 weeks gestational age (GA) with severe BPD. Lung structure was assessed on chest CT with the PRAGMA-BPD scoring system and ventilatory function by polysomnography (PSG) at 6 months corrected age. Postnatal growth was assessed by weight measured at birth, and at 2 and 6 months corrected age.

RESULTS

We included 49 infants (median [IQR] GA of 25.7 [24.6-26.3] weeks and mean [SD] birth weight of 760 [210] g). A 95.5% of the chest CT scans showed architectural distortion of the lung, and an oxygen desaturation index (ODI) >5 was found in 74% of the infants. An increase in GA of 1 week was associated with higher total and normal lung volume (β coefficient [95% CI]: 1.86 [0.15, 3.57] and 2.03 [0.41, 3.65]), less hypoattenuation (-4.3 [-7.70, -0.90]%) and lower ODI (-36.7 [-64.2, -9.10]%). Higher weight at 6 months was independently associated with higher total and normal lung volume, and with less severe desaturations. Increased weight gain between 2 and 6 months of corrected age was associated with less severe desaturations during sleep (β coefficient [95% CI]: 2.09 [0.49, 3.70]).

CONCLUSION

Most preterm infants with severe BPD have structural lung abnormalities and impaired ventilatory function early in life, partly explained by birth characteristics and infant growth.

Are preterm-born survivors at risk of long-term respiratory disease?

BACKGROUND

To evaluate the long-term impact of preterm birth on respiratory function in female patients born preterm, we undertook spirometric examinations twice, as they reached the age of puberty, then follow-up examinations of part of the same cohort in adulthood. We sought evidence that preterm birth is correlated with poorer spirometric results into adulthood.

METHODS

A total of 70 girls (aged 12.2 ± 1.5 years in 1997) who had been born preterm (at 34.7 ± 1.86 weeks, none having experienced bronchopulmonary dysplasia) took part in spriometric examinations in 1997 and again in 1998. Of those, after a gap of 17 years, a group of 12 were successfully recontacted and participated in the 2015 examination as adults (then aged 27.6 ± 2.6 years, born at 34.5 ± 1.92 weeks). We compared spirometric results across the adolescent and adult examinations, and compared the adult results with an adult reference group.

RESULTS

The percentage values of FEV1 (forced expiratory volume in 1 s), FVC (forced vital capacity) and MVV (maximal voluntary ventilation) showed significant improvement between the two examinations in the early adolescent period. In adulthood, FEV1%pred (percentage predicted forced expiratory volume in 1 s) showed no statistically significant difference. The mean values of both FVC and FVC%pred (percentage predicted forced vital capacity) for the preterm-born group were lower than for the reference group, but this was not statistically significant. The preterm-born group showed lower values of such parameters as forced expiratory flow at 25-75% of FVC, MEF25 (maximal expiratory flow at 25% of forced vital capacity) and FEV1/FVC as compared with the reference group, but again without statistical significance.

CONCLUSIONS

(1) A somewhat below-norm level of respiratory parameters among preterm-born girls entering pubescence may attest to continued negative impact on their respiratory system. (2) A significant improvement in their spirometric results 1 year later may indicate that pubescence helps compensate for the earlier negative effect of preterm birth. (3) No significant differences were seen in lung function in preterm-born adults as compared with a reference group of adults, although the preterm-born group did exhibit lower values of all parameters studied and more frequent obstructive disorders.

Age, Sexual Dimorphism, and Disease Associations in the Developing Human Fetal Lung Transcriptome

The fetal origins of disease hypothesis suggests that variations in the course of prenatal lung development may affect life-long pulmonary function growth, decline, and pathobiology. Many studies support the existence of differences in the developing lung trajectory in males and females, and sex-specific differences in the prevalence of chronic lung diseases, such as asthma and bronchopulmonary dysplasia. The objectives of this study were to investigate the early developing fetal lung for transcriptomic correlates of postconception age (maturity) and sex, and their associations with chronic lung diseases. We analyzed whole-lung transcriptome profiles of 61 females and 78 males at 54-127 days postconception (dpc) from nonsmoking mothers using unsupervised principal component analysis and supervised linear regression models. We identified dominant transcriptomic correlates for postconception age and sex with corresponding gene sets that were enriched for developing lung structural and functional ontologies. We observed that the transcriptomic sex difference was not a uniform global time shift/lag, rather, lungs of males appear to be more mature than those of females before 96 dpc, and females appear to be more mature than males after 96 dpc. The age correlate gene set was consistently enriched for asthma and bronchopulmonary dysplasia genes, but the sex correlate gene sets were not. Despite sex differences in the developing fetal lung transcriptome, postconception age appears to be more dominant than sex in the effect of early fetal lung developments on disease risk during this early pseudoglandular phase of development.

Increased heterogeneity of airway calibre in adult rats after hypoxia-induced intrauterine growth restriction

BACKGROUND AND OBJECTIVE

Intrauterine growth restriction (IUGR) is associated with asthma development. We hypothesized that IUGR disrupts airway development leading to postnatal structural abnormalities of the airway that predispose to disease. This study therefore examined structural changes to the airway and lung in a rat model of maternal hypoxia-induced IUGR.

METHODS

Pregnant rats were housed under hypoxic conditions (11.5% O₂ ) from gestational days (GDs) 13 to 20 (pseudoglandular-canalicular stages, i.e. period of airway development) and then returned to normoxic conditions (21% O₂ ). A control group of pregnant rats was housed under normoxic conditions throughout pregnancy. Weights of male offspring were recorded at birth and 7 weeks of age (adulthood), at which point lungs were fixed for morphometry and stereology (n = 6/group), or bronchoalveolar lavage fluid (BALF) was collected for cell counts (n = 6/group).

RESULTS

IUGR offspring were lighter at birth compared with control, but not at 7 weeks. While there was no difference in mean airway dimensions or lung volume, there was greater anatomical variation in airway lumen area in the IUGR group. A mathematical model of the human lung was used to show that greater heterogeneity in lumen area in IUGR-affected individuals increases bronchoconstriction during simulated bronchial challenge. More macrophages were identified in the BALF of IUGR offspring.

CONCLUSION

The rat model demonstrates that IUGR leads to a more heterogeneous distribution of airway lumen calibre in adulthood with potential implications for bronchoconstriction in human subjects. Together with increased lung macrophages, these findings support a phenotypic shift after IUGR that may impact disease susceptibility.

Reduced Forced Vital Capacity in an African Population. Prevalence and Risk Factors

RATIONALE

Black Africans have reduced FVC compared with white persons, but the prevalence and determinants of reduced values are not well understood.

OBJECTIVES

To evaluate the prevalence and factors leading to reduced FVC in a Nigerian population and to examine current theories regarding the determinants of this difference.

METHODS

We studied the ventilatory function of 883 adults aged 40 years or older participating in the Burden of Obstructive Lung Disease Study in Ile-Ife, Nigeria. Respondents completed pre- and post-bronchodilator spirometry test and provided information on their smoking history, respiratory symptoms, risk factors, and diagnoses, including anthropometric details. We used standard categories to define body mass index as either underweight, normal, overweight, or obese. We defined reduced FVC as a post-bronchodilator FVC below the lower limit of normal using National Health and Nutrition Examination Survey (NHANES) equations, Global Lung Function Initiative 2012 equations, and local reference equations based on nonsmoking study participants without a respiratory diagnosis. We fit multivariate linear regression models to FVC as a continuous measure, adjusting for age, sex, height, and other confounders.

RESULTS

The prevalence of reduced FVC was 70.4% for men and 72.8% for women when using NHANES values for white Americans, 17.8% for men and 14.4% for women using NHANES equations for African Americans, and 15.5% for men and 20.5% for women using the Global Lung Function Initiative 2012 equations. Using the equations derived from nonsmoking respondents in the survey without a respiratory diagnosis, the prevalence of reduced FVC was less than 4% for both men and women. FVC was lower in participants who had less than 7 years of education (FVC, -96 ml; 95% confidence interval [CI], -172 to -19), were underweight (FVC, -269 ml; 95% CI, -464 to -73), were overweight (FVC, -132 ml; 95% CI, -219 to -46), and were obese (FVC, -222 ml; 95% CI, -332 to -112).

CONCLUSIONS

There is a wide variation in the prevalence of reduced FVC based on the reference standard used. This variation is not satisfactorily explained by factors thought to affect FVC within individual populations. However, the prevalence strongly associates with both education level and body mass index in this population, regardless of the specific standard used.

Chronic respiratory disease - the acceptable epidemic?

Chronic obstructive pulmonary disease (COPD) is a major cause of disability and death in the UK but is an even greater problem in low income countries. It is assumed by many to be almost entirely attributed to smoking. However, smoking alone cannot account for the distribution of the disease in the world and there is accumulating evidence that the disease is overwhelmingly a disease of poverty. The size of the problem and the failure of current hypotheses to explain the distribution of chronic lung disease make the lack of funding in this area surprising. The failure of science funders to respond to the analysis of the Cooksey report, which pointed out the extreme discrepancy between the size of the problem and the paucity of research funding, represents a serious failure in science policy. The lack of urgency in the face of such a large burden of illness suggests a degree of complacency in the face of a disease that is overwhelmingly a disease of the poor.

Gender Differences in the Association of Individual and Contextual Exposures with Lung Function in a Rural Canadian Population

INTRODUCTION

To investigate the association of individual and contextual exposures with lung function by gender in rural-dwelling Canadians.

METHODS

A cross-sectional mail survey obtained completed questionnaires on exposures from 8263 individuals; a sub-sample of 1609 individuals (762 men, 847 women) additionally participated in clinical lung function testing. The three dependent variables were forced expired volume in one second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC ratio. Independent variables included smoking, waist circumference, body mass index, indoor household exposures (secondhand smoke, dampness, mold, musty odor), occupational exposures (grain dust, pesticides, livestock, farm residence), and socioeconomic status. The primary analysis was multiple linear regression, conducted separately for each outcome. The potential modifying influence of gender was tested in multivariable models using product terms between gender and each independent variable.

RESULTS

High-risk waist circumference was related to reduced FVC and FEV₁ for both genders, but the effect was more pronounced in men. Greater pack-years smoking was associated with lower lung function values. Exposure to household smoke was related to reduced FEV₁, and exposure to livestock, with increased FEV₁. Lower income adequacy was associated with reduced FVC and FEV₁.

CONCLUSION

High-risk waist circumference was more strongly associated with reduced lung function in men than women. Longitudinal research combined with rigorous exposure assessment is needed to clarify how sex and gender interact to impact lung function in rural populations.

Linking bronchopulmonary dysplasia to adult chronic lung diseases: role of WNT signaling

Bronchopulmonary dysplasia (BPD) is one of the most common chronic lung diseases in infants caused by pre- and/or postnatal lung injury. BPD is characterized by arrested alveolarization and vascularization due to extracellular matrix remodeling, inflammation, and impaired growth factor signaling. WNT signaling is a critical pathway for normal lung development, and its altered signaling has been shown to be involved in the onset and progression of incurable chronic lung diseases in adulthood, such as chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis (IPF). In this review, we summarize the impact of WNT signaling on different stages of lung development and its potential contribution to developmental lung diseases, especially BPD, and chronic lung diseases in adulthood.

Physical activity and lung function decline in adults with asthma: The HUNT Study

BACKGROUND AND OBJECTIVE

People with asthma may seek advice about physical activity. However, the benefits of leisure time physical activity on lung function are unclear. We investigated the association between leisure time physical activity and lung function decline in adults with asthma.

METHODS

In a population-based cohort study in Norway, we used multiple linear regressions to estimate the annual mean decline in lung function (and 95% CI) in 1329 people with asthma over a mean follow-up of 11.6 years. The durations of light and hard physical activity per week in the last year were collected by questionnaire. Inactive participants did not report any light or hard activity, while active participants reported light or hard activity.

RESULTS

The mean decline in forced expiratory volume in 1 s (FEV₁ ) was 37 mL/year among inactive participants and 32 mL/year in active participants (difference: -5 mL/year (95% CI: -13 to 3)). The mean decline in forced vital capacity (FVC) was 33 mL/year among inactive participants and 31 mL/year in active participants (difference: -2 mL/year (95% CI: -11 to 7)). The mean decline in FEV₁ /FVC ratio was 0.36%/year among inactive participants and 0.22%/year in active participants (difference: -0.14%/year (95% CI: -0.27 to -0.01)). The mean decline in peak expiratory flow (PEF) was 14 mL/year among the inactive participants and 10 mL/year in active participants (difference: -4 mL/year (95% CI: -9 to 1)).

CONCLUSION

We observed slightly less decline in lung function in physically active than inactive participants with asthma, particularly for FEV₁ , FEV₁ /FVC ratio and PEF.

Intrauterine growth restriction predicts lower lung function at school age in children born very preterm

OBJECTIVE

Children born preterm have lower lung function compared with term-born children. Intrauterine growth restriction (IUGR) may predispose individuals to chronic obstructive pulmonary disease. The purpose of this observational study was to investigate the role of IUGR as predictor of lung function at school age in children born very preterm. We further studied the difference in lung function between term-born and preterm-born children with distinct morbidities.

DESIGN

Preterm-born children and age-matched and sex-matched term-born comparison groups (88 of each) were studied at the mean age of 11 years. Spirometry and diffusing capacity of the lung for carbon monoxide (DLCO) were recorded. All preterm-born subjects with IUGR (n=23), defined as birth weight less than -2 SD, were compared with preterm-born subjects without IUGR (n=65).

RESULTS

In the preterm-born children exposed to IUGR, the forced expiratory volume in 1 s (FEV1) was 5.7 (95% CI -10.2 to -1.3) and DLCO 9.2 percentage points lower (95% CI -15.7 to -2.7) than in the preterm-born children with appropriate in utero growth (expressed as percentage of predicted values). The effect of IUGR in decreasing FEV1 and DLCO remained significant after adjustment for bronchopulmonary dysplasia (BPD). Further study indicated that after adjustment with IUGR and BPD, prematurity explained reduction in FEV1 but not in DLCO.

CONCLUSIONS

In children born very preterm, IUGR is an independent risk factor for a lower lung function in school age. We propose that IUGR and BPD are the major early factors predisposing the children born very preterm to lower lung function.

FGR in the setting of preterm sterile intra-uterine milieu is associated with a decrease in RDS

OBJECTIVE

To determine if fetal growth restriction (FGR) in the setting of sterile intra-uterine milieu would be associated with a decrease in respiratory distress syndrome (RDS) of preterm-neonates.

METHODS

The relationship between FGR and neonatal RDS was examined in 92 singleton preterm-neonates (gestational age [GA]: 24.5-33.4 weeks) born to mothers with sterile intra-uterine milieu, which consisted of both sterile amniotic fluid (AF), and inflammation-free placenta. Sterile AF was defined in the absence of both infection and inflammation in AF. AF inflammation was defined in the presence of AF MMP-8 ≥23 ng/ml. FGR was defined in the presence of birth-weight (BW) below the 5th percentile for GA.

RESULTS

FGR was present in 32% and RDS was found in 46% of patients. RDS was less common (24% vs. 56%; P < 0.01) and umbilical arterial pH at birth ≤7.15 was more common (33% vs. 13%; P < 0.05) in preterm-neonates with FGR than in those without FGR. There is a stepwise increase in RDS with increasing BW (i.e., below the 5th percentile, the 5th ∼10th percentile, and above the 10th percentile for GA) (P < 0.01, linear by linear association). Logistic regression analysis demonstrated that FGR was a better independent predictor of a decrease in RDS (OR = 0.049, 95%CI 0.009-0.259, P < 0.0005) than advanced GA at delivery (OR = 0.584, 95%CI 0.423-0.806, P < 0.005) after adjusting for other confounding variables.

CONCLUSION

FGR in the setting of sterile intra-uterine milieu is associated with a decrease in RDS of preterm-neonates. This observation suggests that chronic intra-uterine hypoxic stress related to FGR may be beneficial to fetal lung maturation. Pediatr Pulmonol. 2016;51:812-819. © 2015 Wiley Periodicals, Inc.

Growth Deficiency in Cystic Fibrosis Is Observable at Birth and Predictive of Early Pulmonary Function

INTRODUCTION

Cystic fibrosis (CF) is a complex disease that includes both pulmonary and gastrointestinal challenges, resulting in decreased weight. Pulmonary symptoms of CF are extremely variable. Greater body mass at an early age is associated with improved pulmonary function, but it is unknown at what age weight becomes predictive of pulmonary disease severity. The purpose of this study was to investigate the relationship between birth weight and pulmonary function in CF.

METHODS

Birth weight and pulmonary data were obtained. Linear regressions were used to examine the relationship between these two variables. A one-tailed t-test was used to compare birth weights between CF patients and the national average.

RESULTS

Birth weight was significantly lower in babies with CF and correlated with pulmonary disease at ages 6 and 10 years but not with age at which Pseudomonas aeruginosa colonization was observed.

DISCUSSION

These data suggest that CF growth deficiency has prenatal origins. Early nutritional intervention for babies with CF and a low birth weight is warranted to maximize pulmonary potential.

[DOHaD: long-term impact of perinatal diseases (IUGR and prematurity)]

The first epidemiological studies showing a link between low birth weight and chronic diseases in adults did not distinguish the origins of low birth weight. A low birth weight may be the result of a premature birth. It can also be caused by an intrauterine growth restriction (IUGR). A child can be both preterm and IUGR. It is clear now that prematurity is an independent risk factor for programming chronic adult diseases. However, unlike adults born IUGR, adults born prematurely do not have an increased risk to develop metabolic syndrome (dyslipidemia or obesity). An increased risk of neurodevelopmental and psychiatric morbidity and hypertension is found after a premature birth. Mechanisms of chronic diseases programming are multiple: they involve both the cause of prematurity and IUGR such as infection / inflammation or placental insufficiency, but also consequences for therapeutic or nutritional strategies needed to support these children. This chapter describes the possible prevention of perinatal programming of noncommunicable diseases.

Peak weight velocity in infancy is negatively associated with lung function in adolescence

BACKGROUND

Rapid weight gain during infancy increases childhood asthma risk, which might be related to impaired lung function. This study investigated associations between peak weight velocity (PWV) during the first two years of life and spirometric lung function indices at 15 years of age.

METHODS

Data from 1842 children participating in the GINIplus German birth cohort who underwent spirometry at age 15 were analysed. PWV was calculated from weight measurements obtained between birth and two years of age. Generalised additive models were fitted after adjustment for potential confounding factors (birth weight, height, and age at lung function testing). Results are presented per interquartile range increase (3.5 kg/year) in PWV.

RESULTS

PWV was negatively associated with pre-bronchodilation flow rates after extensive adjustment for potential confounders including asthma: forced expiratory flow at 50% of forced vital capacity (FEF50 ) decreased by 141 ml/s (95%CI = [-225;-57]), FEF75 by 84 ml/s [-144;-24] and FEF25-75 by 118 ml/s [-192;-44]. FEV1 /FVC was also negatively associated with PWV (-0.750% [-1.273;-0.226]) whereas forced expiratory volume in 1s (FEV1 ) and forced vital capacity (FVC) were not. Similar results were found for measurements post-bronchodilation.

CONCLUSION

Early life weight gain was negatively associated with flow indices in adolescence, suggesting structural changes in peripheral lungs.

Determinants of underdiagnosis of COPD in national and international surveys

BACKGROUND

COPD ranks within the top three causes of mortality in the global burden of disease, yet it remains largely underdiagnosed. We assessed the underdiagnosis of COPD and its determinants in national and international surveys of general populations.

METHODS

We analyzed representative samples of adults aged ≥ 40 years randomly selected from well-defined administrative areas worldwide (44 sites from 27 countries). Postbronchodilator FEV1/FVC < lower limit of normal (LLN) was used to define chronic airflow limitation consistent with COPD. Undiagnosed COPD was considered when participants had postbronchodilator FEV1/FVC < LLN but were not given a diagnosis of COPD.

RESULTS

Among 30,874 participants with a mean age of 56 years, 55.8% were women, and 22.9% were current smokers. Population prevalence of (spirometrically defined) COPD ranged from 3.6% in Barranquilla, Colombia, to 19.0% in Cape Town, South Africa. Only 26.4% reported a previous lung function test, and only 5.0% reported a previous diagnosis of COPD, whereas 9.7% had a postbronchodilator FEV1/FVC < LLN. Overall, 81.4% of (spirometrically defined) COPD cases were undiagnosed, with the highest rate in Ile-Ife, Nigeria (98.3%) and the lowest rate in Lexington, Kentucky (50.0%). In multivariate analysis, a greater probability of underdiagnosis of COPD was associated with male sex, younger age, never and current smoking, lower education, no previous spirometry, and less severe airflow limitation.

CONCLUSIONS

Even with substantial heterogeneity in COPD prevalence, COPD underdiagnosis is universally high. Because effective management strategies are available for COPD, spirometry can help in the diagnosis of COPD at a stage when treatment will lead to better outcomes and improved quality of life.

Respiratory effects of air pollution on children

A substantial proportion of the global burden of disease is directly or indirectly attributable to exposure to air pollution. Exposures occurring during the periods of organogenesis and rapid lung growth during fetal development and early post-natal life are especially damaging. In this State of the Art review, we discuss air toxicants impacting on children's respiratory health, routes of exposure with an emphasis on unique pathways relevant to young children, methods of exposure assessment and their limitations and the adverse health consequences of exposures. Finally, we point out gaps in knowledge and research needs in this area. A greater understanding of the adverse health consequences of exposure to air pollution in early life is required to encourage policy makers to reduce such exposures and improve human health.

Early growth characteristics and the risk of reduced lung function and asthma: A meta-analysis of 25,000 children

BACKGROUND

Children born preterm or with a small size for gestational age are at increased risk for childhood asthma.

OBJECTIVE

We sought to assess the hypothesis that these associations are explained by reduced airway patency.

METHODS

We used individual participant data of 24,938 children from 24 birth cohorts to examine and meta-analyze the associations of gestational age, size for gestational age, and infant weight gain with childhood lung function and asthma (age range, 3.9-19.1 years). Second, we explored whether these lung function outcomes mediated the associations of early growth characteristics with childhood asthma.

RESULTS

Children born with a younger gestational age had a lower FEV1, FEV1/forced vital capacity (FVC) ratio, and forced expiratory volume after exhaling 75% of vital capacity (FEF75), whereas those born with a smaller size for gestational age at birth had a lower FEV1 but higher FEV1/FVC ratio (P < .05). Greater infant weight gain was associated with higher FEV1 but lower FEV1/FVC ratio and FEF75 in childhood (P < .05). All associations were present across the full range and independent of other early-life growth characteristics. Preterm birth, low birth weight, and greater infant weight gain were associated with an increased risk of childhood asthma (pooled odds ratio, 1.34 [95% CI, 1.15-1.57], 1.32 [95% CI, 1.07-1.62], and 1.27 [95% CI, 1.21-1.34], respectively). Mediation analyses suggested that FEV1, FEV1/FVC ratio, and FEF75 might explain 7% (95% CI, 2% to 10%) to 45% (95% CI, 15% to 81%) of the associations between early growth characteristics and asthma.

CONCLUSIONS

Younger gestational age, smaller size for gestational age, and greater infant weight gain were across the full ranges associated with childhood lung function. These associations explain the risk of childhood asthma to a substantial extent.

Birth weight and asthma incidence by asthma phenotype pattern in a racially diverse cohort followed through adolescence

OBJECTIVE

Low birth weight (LBW) has been shown to be an independent risk factor for asthma. We hypothesized that LBW would have its greatest impact on early onset disease.

METHODS

A racially diverse cohort of children born from 1983 to 1985 at two hospitals, one urban and one suburban in the same metropolitan area, and oversampled for babies weighing ≤2500 g, was identified retrospectively when the children were 6 years of age and followed periodically. At the age 17 years study visit, cohort members and their parent/guardians were separately interviewed face-to-face regarding the subject's history of asthma using the standardized ISAAC questionnaire. We measured the cumulative incidence of asthma from birth through adolescence defined by age of diagnosis and persistence/remittance.

RESULTS

Six-hundred and eighty teens (82.6% of the original cohort) were included in the analyses, 387 with LBW and 293 of normal birth weight. The prevalence of physician-diagnosed "Current Asthma" was associated with LBW (p = 0.003 for trend), with patterns stronger in males and whites. LBW was associated most strongly with Late Onset Persistent asthma (current asthma that was diagnosed after 8 years); p for trend 0.032. This trend was again most evident in males and whites. None of the asthma categories classified as "remittent" were statistically associated with LBW.

CONCLUSIONS

LBW was not associated with diagnosed asthma that remitted before age 17 years. LBW was associated with asthma diagnosis in mid-childhood that persisted through adolescence, suggesting that the asthmagenic effects of LBW can become evident post the early years of childhood and persist into adulthood.

Farm environment during infancy and lung function at the age of 31: a prospective birth cohort study in Finland

OBJECTIVES

Farming as an occupation is considered a risk factor for asthma and reduced lung function. By contrast, living on a farm during infancy has been reported to be associated with lower risk of asthma in adulthood. However, little is known about the association between farming environment during infancy and lung function in adulthood. We aimed to study the prospective longitudinal association between farming environment during infancy and lung function in adulthood.

DESIGN

A prospective birth cohort study.

SETTING

Northern Finland.

PARTICIPANTS

5666 participants born in 1966 were followed up at the age of 31 years.

PRIMARY OUTCOME MEASURES

Spirometry at the age of 31 years.

RESULTS

To be born into a farmer's family was associated with higher forced expiratory volume in 1 s (FEV1) (36 mL; 95% CI 6 to 67 mL) and forced vital capacity (FVC) (40 mL; 95% CI 5 to 75 mL) at the age of 31 years. Contact with farm animals during infancy was associated with higher FEV1. No associations were seen with FEV1/FVC (FEV1/FVC ratio). Having dogs in childhood revealed similar associations. There was a suggestive dose-dependent association with the number of animal species during childhood and higher FEV1 and FVC at adulthood, especially among women.

CONCLUSIONS

Farming environment in early life may have a positive impact on lung function in adulthood.