Vitamin D deficiency at 16 to 20 weeks' gestation is associated with impaired lung function and asthma at 6 years of age

Rationale: Vitamin D deficiency is associated with chronic lung disease. We have previously shown in an in vivo mouse model that maternal vitamin D deficiency is associated with alterations in early life lung structure and function. However, there are limited data to support a relationship between maternal vitamin D deficiency during the early stages of lung development and postnatal lung function in human populations. Objectives: To assess the association between maternal vitamin D deficiency, postnatal lung function, and asthmatic status in a longitudinal birth cohort. Methods: Serum was collected at 16 to 20 weeks' gestation at the time of recruitment in a community-based prospective birth cohort for measurement of vitamin D (25[OH]D). Lung function was assessed by spirometry according to American Thoracic Society guidelines in children at 6 and 14 years of age. Demographic and clinical history data were collected by questionnaire at recruitment and at the follow-up visits. Measurements and Main Results: FVC Z-scores in both sexes (ß, 0.007 [95% confidence interval (CI), 0.001-0.013]; P = 0.02) and FEV1 Z-scores in girls (ß, 0.007 [95% CI, 0.001-0.013]; P = 0.02) were positively associated with maternal serum 25(OH)D at 6 years of age. These associations were mostly absent at 14 years of age. Maternal vitamin D deficiency was positively associated with asthma at 6 years of age but only in boys (odds ratio, 3.03 [95% CI, 1.02-9.02]; P = 0.04). Conclusions: This study supports the notion that vitamin D deficiency during lung development may impact on postnatal lung growth and increase the risk of developing lung disease

Early life exposure to coal mine fire smoke emissions and altered lung function in young children

Background and objective Long‐term respiratory risks following exposure to relatively short periods of poor air quality early in life are unknown. We aimed to evaluate the association between exposure to a 6‐week episode of air pollution from a coal mine fire in children aged <2 years, and their lung function 3 years after the fire. Methods We conducted a prospective cohort study. Individual exposure to 24‐h average and peak concentrations of particulate matter with an aerodynamic diameter <2.5 μm in diameter (PM2.5) during the fire were estimated using dispersion and chemical transport modelling. Lung function was measured using the forced oscillation technique (FOT), generating standardized Z‐scores for resistance and reactance at a frequency of 5 Hz (Rrs5 and Xrs5), and area under the reactance curve (AX). We used linear regression models to assess the associations between PM2.5 exposure and lung function, adjusted for potential confounders. Results Of the 203 infants originally recruited, 84 aged 4.3 ± 0.5 years completed FOT testing. Median (interquartile range, IQR) for average and peak PM2.5 were 7.9 (6.8–16.8) and 103.4 (60.6–150.7) μg/m3, respectively. The mean ± SD Z‐scores for Rrs5, Xrs5 and AX were 0.56 ± 0.80, –0.76 ± 0.88 and 0.72 ± 0.92, respectively. After adjustment for potential confounders including maternal smoking during pregnancy, a 10 μg/m3 increase in average PM2.5 was significantly associated with worsening AX (β‐coefficient: 0.260; 95% CI: 0.019, 0.502), while the association between a 100‐μg/m3 increase in peak PM2.5 and AX was borderline (0.166; 95% CI: −0.002, 0.334). Conclusion Infant exposure to coal mine fire emissions could be associated with long‐term impairment of lung reactance

Associations between respiratory and vascular function in early childhood

Background and objective The link between respiratory and vascular health is well documented in adult populations. Impaired lung function is consistently associated with thicker arteries and higher incidence of cardiovascular disease. However, there are limited data on this relationship in young children and the studies that exist have focussed on populations at high risk of cardiorespiratory morbidity. We determined if an association exists between respiratory and cardiovascular function in young children and, if so, whether it is confounded by known cardiorespiratory risk factors. Methods Respiratory and vascular data from a prospective cohort study established to evaluate the health implications 3 years after coal mine fire smoke exposure in children aged 3–5 years were used. Respiratory function was measured using the forced oscillation technique and included resistance at 5 Hz (R5), reactance at 5 Hz (X5) and area under the reactance curve (AX). Vascular health was measured by carotid intima-media thickness (ultrasound) and pulse wave velocity (arterial tonometry). Regression analyses were used to examine the relationship between the respiratory Z-scores and cardiovascular measures. Subsequent analyses were adjusted for potential confounding by maternal smoking during pregnancy, maternal education and exposure to fine particulate matter <2.5 μm in aerodynamic diameter (PM2.5). Results Peripheral lung function (X5 and AX), but not respiratory system resistance (R5), was associated with vascular function. Adjustment for maternal smoking, maternal education and early life exposure to PM2.5 had minimal effect on these associations. Conclusion These observations suggest that peripheral lung stiffness is associated with vascular stiffness and that this relationship is established early in life

Rationale, design and methods for the 22 year follow-up of the Western Australian Pregnancy Cohort (Raine) Study

Background: Young adulthood is a critical life period for health and health behaviours. Related measurements collected before and after birth, and during childhood and adolescence can provide a life-course analysis of important factors that contribute to health and behaviour in young adulthood. The Western Australian Pregnancy Cohort (Raine) Study has collected a large number of such measurements during the fetal, perinatal, infancy, childhood and adolescence periods and plans to relate them to common health issues and behaviours in young adults, including spinal pain, asthma, sleep disorders, physical activity and sedentary behaviour and, work absenteeism and presenteeism. The aim of this paper is to describe the rationale, design and methods of the 22 year follow-up of the Raine Study cohort. Methods/Design: The Raine Study is a prospective cohort study. Participants still active in the cohort (n = 2,086) were contacted around the time of their 22nd birthday and invited to participate in the 22 year follow-up. Each was asked to complete a questionnaire, attend a research facility for physical assessment and an overnight sleep study, wear activity monitors for a week, and to maintain a sleep and activity diary over this week. The questionnaire was broad and included questions related to sociodemographics, medical history, quality of life, psychological factors, lifestyle factors, spinal pain, respiratory, sleep, activity and work factors. Physical assessments included anthropometry, blood pressure, back muscle endurance, tissue sensitivity, lung function, airway reactivity, allergic status, 3D facial photographs, cognitive function, and overnight polysomnography. Discussion: Describing the prevalence of these health issues and behaviours in young adulthood will enable better recognition of the issues and planning of health care resources. Providing a detailed description of the phenotype of these issues will provide valuable information to help educate health professionals of the needs of young adults. Understanding the life-course risk factors of health issues and behaviours in young adulthood will have important health planning implications, supporting the development of targeted interventions to improve current health status and reduce the onset and development of further ill-health across adulthood