Gender differences in respiratory symptoms in 19-year-old adults born preterm

OBJECTIVE: To study the prevalence of respiratory and atopic symptoms in (young) adults born prematurely, differences between those who did and did not develop Bronchopulmonary Disease (BPD) at neonatal age and differences in respiratory health between males and females. METHODS: DESIGN: Prospective cohort study. SETTING: Nation wide follow-up study, The Netherlands. PARTICIPANTS: 690 adults (19 year old) born with a gestational age below 32 completed weeks and/or with a birth weight less than 1500 g. Controls were Dutch participants of the European Community Respiratory Health Survey (ECRHS). MAIN OUTCOME MEASURES: Presence of wheeze, shortness of breath, asthma, hay fever and eczema using the ECRHS-questionnaire RESULTS: The prevalence of doctor-diagnosed asthma was significantly higher in the ex-preterms than in the general population, whereas eczema and hay fever were significant lower. Women reported more symptoms than men. Preterm women vs controls: asthma 13% vs 5% (p < 0.001); hay fever 8% vs 20% (p < 0.001); eczema 10% vs 42% (p < 0.001). Preterm men vs controls: asthma 9% vs 4% (p = 0.007); hay fever 8% vs 17% (p = 0.005); eczema 9% vs 31% (p < 0.001) Preterm women reported more wheeze and shortness of breath during exercise (sob) than controls: wheeze 30% vs 22% (p = 0.009); sob 27% vs 16% (p < 0.001); 19-year-old women with BPD reported a higher prevalence of doctor diagnosed asthma compared to controls (24% vs 5% p < 0.001) and shortness of breath during exercise (43% vs 16% p = 0.008). The prevalence of reported symptoms by men with BPD were comparable with the controls. CONCLUSION: Our large follow-up study shows a higher prevalence of asthma, wheeze and shortness of breath in the prematurely born young adults. 19-year-old women reported more respiratory symptoms than men. Compared to the general population atopic diseases as hay fever and eczema were reported less often

Lung Volume, Breathing Pattern and Ventilation Inhomogeneity in Preterm and Term Infants

BACKGROUND: Morphological changes in preterm infants with bronchopulmonary dysplasia (BPD) have functional consequences on lung volume, ventilation inhomogeneity and respiratory mechanics. Although some studies have shown lower lung volumes and increased ventilation inhomogeneity in BPD infants, conflicting results exist possibly due to differences in sedation and measurement techniques. METHODOLOGY/PRINCIPAL FINDINGS: We studied 127 infants with BPD, 58 preterm infants without BPD and 239 healthy term-born infants, at a matched post-conceptional age of 44 weeks during quiet natural sleep according to ATS/ERS standards. Lung function parameters measured were functional residual capacity (FRC) and ventilation inhomogeneity by multiple breath washout as well as tidal breathing parameters. Preterm infants with BPD had only marginally lower FRC (21.4 mL/kg) than preterm infants without BPD (23.4 mL/kg) and term-born infants (22.6 mL/kg), though there was no trend with disease severity. They also showed higher respiratory rates and lower ratios of time to peak expiratory flow and expiratory time (t(PTEF)/t(E)) than healthy preterm and term controls. These changes were related to disease severity. No differences were found for ventilation inhomogeneity. CONCLUSIONS: Our results suggest that preterm infants with BPD have a high capacity to maintain functional lung volume during natural sleep. The alterations in breathing pattern with disease severity may reflect presence of adaptive mechanisms to cope with the disease process

Long-term health-related and economic consequences of short-term outcomes in evaluation of perinatal interventions

<p>Abstract</p> <p>Background</p> <p>Many perinatal interventions are performed to improve long-term neonatal outcome. To evaluate the long-term effect of a perinatal intervention follow-up of the child after discharge from the hospital is necessary because serious sequelae from perinatal complications frequently manifest themselves only after several years. However, long-term follow-up is time-consuming, is not in the awareness of obstetricians, is expensive and falls outside the funding-period of most obstetric studies. Consequently, short-term outcomes are often reported instead of the primary long-term end-point. With this project, we will assess the current state of affairs concerning follow-up after obstetric RCTs and we will develop multivariable prediction models for different long-term health outcomes. Furthermore, we would like to encourage other researchers participating in follow-up studies after large obstetric trials (> 350 women) to inform us about their studies so that we can include their follow-up study in our systematic review. We would invite these researchers also to join our effort and to collaborate with us on the external validation of our prediction models.</p> <p>Methods/Design</p> <p>A systematic review of neonatal follow-up after obstetric studies will be performed. All reviews of the Cochrane Pregnancy and Childbirth group will be assessed for reviews on interventions that aimed to improve neonatal outcome. Reviews on interventions primary looking at other aspects than neonatal outcome such as labour progress will also be included when these interventions can change the outcome of the neonate on the short or long-term. Our review will be limited to RCTs with more than 350 women. Information that will be extracted from these RCTs will address whether, how and for how long follow-up has been performed. However, in many cases long-term follow-up of the infants will not be feasible. An alternative solution to limited follow-up could be to develop prediction models to estimate long-term health outcomes of the newborn based on specific perinatal outcomes and other covariates. For the development of multivariable prediction models for several health outcomes, we will use data available from a Dutch cohort study of preterm (< 32 weeks) and/or small for gestational age infants (< 1500 g). These infants were born in The Netherlands in 1983 and followed until they reached the age of 19.</p> <p>Discussion</p> <p>The systematic review will provide insight in the extent and methods used for follow-up assessments after obstetric RCTs in the past. The prediction models can be used by future studies to extrapolate short-term outcomes to a long-term horizon or to indicate for which neonates long-term follow-up is required, as their outcomes (either absence or presence of sequelae) cannot be adequately predicted from short-term outcomes and clinical background characteristics.</p

Development of lung function in very low birth weight infants with or without bronchopulmonary dysplasia: Longitudinal assessment during the first 15 months of corrected age

<p>Abstract</p> <p>Background</p> <p>Very low birth weight (VLBW) infants (< 1,500 g) with bronchopulmonary dysplasia (BPD) develop lung damage caused by mechanical ventilation and maturational arrest. We compared functional lung development after discharge from hospital between VLBW infants with and without BPD.</p> <p>Methods</p> <p>Comprehensive lung function assessment was performed at about 50, 70, and 100 weeks of postmenstrual age in 55 sedated VLBW infants (29 with former BPD [O₂supplementation was given at 36 weeks of gestational age] and 26 VLBW infants without BPD [controls]). Mean gestational age (26 vs. 29 weeks), birth weight (815 g vs. 1,125 g), and the proportion of infants requiring mechanical ventilation for ≥7 d (55% vs. 8%), differed significantly between BPD infants and controls.</p> <p>Results</p> <p>Both body weight and length, determined over time, were persistently lower in former BPD infants compared to controls, but no significant between-group differences were noted in respiratory rate, respiratory or airway resistance, functional residual capacity as determined by body plethysmography (FRC_pleth), maximal expiratory flow at the FRC (V'max _FRC), or blood gas (pO₂, pCO₂) levels. Tidal volume, minute ventilation, respiratory compliance, and FRC determined by SF6 multiple breath washout (representing the lung volume in actual communication with the airways) were significantly lower in former BPD infants compared to controls. However, these differences became non-significant after normalization to body weight.</p> <p>Conclusions</p> <p>Although somatic growth and the development of some lung functional parameters lag in former BPD infants, the lung function of such infants appears to develop in line with that of non-BPD infants when a body weight correction is applied. Longitudinal lung function testing of preterm infants after discharge from hospital may help to identify former BPD infants at risk of incomplete recovery of respiratory function; such infants are at risk of later respiratory problems.</p

Children with smoking parents have a higher airway resistance measured by the interruption technique

Children exposed to environmental tobacco smoke, during or after pregnancy, are known to have decreased lung function. So far this has been measured using spirometry in schoolchildren and invasive techniques in newborns. The interruption technique (Rint) is a noninvasive technique to measure airway resistance in preschool children. Our aim in this study was to investigate the effect of passive smoke exposure on Rint values in preschool and school-aged children. Rint values were obtained from 557 children in two nursery and two primary schools in the north of the Netherlands. Besides information on parental smoking habits, we collected data on characteristics that might affect airway resistance (respiratory symptoms, atopy, and family history for asthma), using a short questionnaire. Multiple linear regression was used to estimate the associations of these characteristics with Rint, for the whole group as well as for the preschool group separately. Atopy or a positive family history for asthma did not affect Rint values in the total group of 4-12-year-olds. However, as may be expected, height, age, weight, and having respiratory symptoms were associated with Rint. Moreover, Rint was significantly increased if parents smoked three or more cigarettes a day in the presence of their child. This result remained after subgroup analysis in the preschool children (4-6 years old). We conclude that passive smoke exposure is associated with a significantly higher airway resistance in preschool and school-aged children measured by Rint. (C) 2004 Wiley-Liss, Inc

Lung function and exercise capacity in young adults born prematurely

Rationale: Limited information is available about the long-term outcome of lung function and exercise capacity in young adults born prematurely. Objective: To determine long-term effects of prematurity on lung function (volumes, diffusing capacity) and exercise capacity in expreterms compared with healthy peers. Methods: In a prospective cohort study, children born with a gestational age of less than 32 wk and/or a birth weight under 1,500 g were followed up for 19 yr. Participants (n = 42; mean gestational age, 30 wk, and mean birth weight, 1,246 g) and healthy term control subjects (n = 48) were recruited for lung function and exercise tests. Measurements: Spirometry, bodybox (TLCbox), diffusing capacity (DLCO), bicycle ergometer test. Main Results: Preterm birth was associated with lower FEV1 (preterms, 95% predicted, vs. controls, 110% predicted; p <0.001), DL(CO)sb (88% predicted vs. 96% predicted, p = 0.003), and exercise capacity (load, 185 vs. 216 W; p <0.001; anaerobic threshold: mean, 1,546 vs. 1,839 ml/min; p <0.001) compared with control subjects at follow-up. No differences between the groups were found in TLCbox, peak oxygen consumption (Vo(2)), and breathing reserve. No significant differences in lung function and exercise parameters were found between preterms with and without bronchopulmonary dysplasia. Conclusions: Long-term effects of prematurity were airway obstruction and a lower CID diffusing capacity compared with control subjects, although mean lung function parameters were within the normal range. Ex-preterms had a lower exercise level, which could not be explained by impaired lung function or smoking habits, but might be due to impaired physical fitness

Respiratory muscle activity related to flow and lung volume in preterm infants compared with term infants

Infants with chronic lung disease (CLD) have a capacity to maintain functional lung volume despite alterations to their lung mechanics. We hypothesize that they achieve this by altering breathing patterns and dynamic elevation of lung volume, leading to differences in the relationship between respiratory muscle activity, flow and lung volume. Lung function and transcutaneous electromyography of the respiratory muscles (rEMG) were measured in 20 infants with CLD and in 39 healthy age-matched controls during quiet sleep. We compared coefficient of variations (CVs) of rEMG and the temporal relationship of rEMG variables, to flow and lung volume [functional residual capacity (FRC)] between these groups. The time between the start of inspiratory muscle activity and the resulting flow (tria)--in relation to respiratory cycle time--was significantly longer in infants with CLD. Although FRC had similar associations with tria and postinspiratory activity (corrected for respiratory cycle time), the CV of the diaphragmatic rEMG was lower in CLD infants (22.6 versus 31.0%, p = 0.030). The temporal relationship of rEMG to flow and FRC and the loss of adaptive variability provide additional information on coping mechanisms in infants with CLD. This technique could be used for noninvasive bedside monitoring of CLD