Body mass index may modify asthma prevalence among low-birth-weight children

What is the impact of birth weight corrected for gestational age on later onset asthma: a meta-analysis

Background

Asthma is a common multifactorial disease affecting millions worldwide. The Barker hypothesis postulates an association between later onset disease risk and energy exposure in utero. Birth weight corrected for gestational age is better for measuring the infant size, which reflects energy exposure in utero. Findings on asthma and birth weight corrected for gestational age have been inconclusive. We conducted a meta-analysis to further clarify the relationship between birth weight corrected for gestational age and later onset asthma.

Methods

A systematic literature search of the PubMed, Web of Science, MEDLINE, and Scopus databases up to January 2021 was conducted. The subject terms were used as follows: “asthma”, “allerg*”, “respiratory”, “birth weight”, “gestational age”, “birth outcomes”, “intrauterine growth retardation”, and “fetal growth restriction”.

Results

We included 12 articles with data from a total of 6,713,596 people. Compared with non-SGA infants, infants small for gestation age (SGA) were not associated with an increased risk of asthma (OR = 1.07; 95% CI 0.94–1.21). However, in the subgroup analysis, we found an increased risk of later onset asthma among SGA in studies conducted in Asia, with a large sample size, and defined asthma through medical records rather than questionnaires. Large for gestational age (LGA) was not associated with an increased risk of asthma when non-LGA or appropriated for gestational age (AGA) infants were used as the reference (OR = 1.02; 95% CI 0.90–1.16; OR = 1.01; 95% CI 0.88–1.15).

Conclusion

These results indicated that neither SGA nor LGA was associated with an increased risk of asthma. However, considering the limitations of the research, these results should be interpreted with caution.

Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective

An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia.

Methods

We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development.

Results

Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73–5.82) for the family history of asthma, 3.50 (95% CI: 2.62–4.67) for the family history of atopy, 3.57 (95% CI: 3.03–4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47–2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12–6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23–1.38), cigarette smoke exposure (1.44, 95% CI: 1.30–1.60), cigarette smoking (1.66, 95% CI: 1.44–1.90), body mass index (BMI)–related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO₂, PM10, and O₃; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32).

Conclusions

The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00273-x.

Adverse childhood experiences and risk factors associated with asthma among children in the United States: the intersection of sex and race/ethnicity

OBJECTIVE

The objectives of this cross-sectional study were to examine: 1) the association between adverse childhood experiences (ACEs) and asthma among children, and 2) the interaction between sex and race/ethnicity on asthma.

METHODS

Data for this study were obtained from the 2017-2018 National Survey of Children's Health. Binary logistic regression was conducted on an analytic sample of 49,000 children ages 0-17 years with asthma as the outcome variable and ACEs as the main explanatory variable.

RESULTS

Based on parent reports, we found that 11.5% of children had asthma and about 42% had at least one ACE, with 9.7% having ≥3 ACEs. Controlling for other factors, children with ≥3 ACEs had 1.45 times higher odds of having asthma when compared to children with no ACEs. Non-Hispanic Black males and females were more likely to have asthma when compared to non-Hispanic White males.

CONCLUSIONS

The findings of this study demonstrate an association between ACEs and asthma with children exposed to ≥3 ACEs more likely to have asthma underscoring the importance of cumulative effect of ACEs on asthma. Our study also revealed an interaction between sex and race/ethnicity on asthma among children. Additional studies are needed to understand the mechanisms through which ACEs is associated with asthma among children.

Preterm birth is associated with higher prevalence of wheeze and asthma in a selected population of Japanese children aged three years

BACKGROUND

The present cross-sectional study investigated the associations between low birthweight (LBW), high birthweight, preterm birth (PTB), postterm birth, small for gestational age (SGA), and large for gestational age (LGA) and the prevalence of wheeze and asthma in Japanese children aged three years (age range, 33-54 months; mean age, 38.7 months).

METHODS

Study subjects were 6364 children. A questionnaire was used to collect all data. Wheeze and asthma were defined according to the criteria of the International Study of Asthma and Allergies in Childhood.

RESULTS

The prevalence values of wheeze and asthma were 19.5% and 7.7%, respectively. Of the 6364 subjects, 8.8% were classified as LBW (<2500g), 90.4% as normal birthweight, 0.8% as high birthweight (≥4000g), 4.8% as PTB (<37 weeks), 94.8% as term birth, 0.4% as postterm birth (≥42 weeks), 7.8% as SGA (<10th percentile), 82.5% as appropriate for gestational age, and 9.7% as LGA (>90th percentile). Compared with term birth, PTB was independently positively associated with wheeze and asthma: the adjusted ORs (95% CI) were 1.47 (1.11-1.92) and 1.52 (1.02-2.20), respectively. An independent positive association was shown between PTB and wheeze only in boys; the interaction between PTB and sex was significant. Such an interaction between PTB and sex was not seen for asthma. No evident associations were observed between LBW, high birthweight, postterm birth, SGA, or LGA and wheeze or asthma.

CONCLUSIONS

This is the first study in Japan to show that PTB, but not LBW or SGA, was significantly positively associated with childhood wheeze and asthma.

Neurocognitive and Health Correlates of Overweight and Obesity among Ten-Year-Old Children Born Extremely Preterm

OBJECTIVE

To assess the relationship between overweight (body mass index [BMI] percentile ≥85 and <95) and obesity (BMI ≥95 percentile) and developmental and health outcomes at 10 years of age in a cohort of individuals born extremely preterm.

STUDY DESIGN

This was an observational cohort study of children born extremely preterm and then assessed at age 10 years for neurocognitive function and parent-reported behavior and health outcomes. Participants included 871 children aged 10 years. To describe the strength of association between overweight or obesity and outcomes, we used logistic regression models adjusting for confounders. Neurocognitive function, academic achievement, parent-reported health outcome surveys, and height and weight were measured.

RESULTS

BMI category at 10 years of age was not associated with differences in intelligence, language, or academic achievement. Parents of children with obesity were more likely to report their child had asthma (OR 2.2; 95% CI 1.4-3.5), fair/poor general health (OR 3.2; 95% CI 1.4-7.5), and decreased physical function (OR 1.7; 95% CI 1.1-2.9) but less likely to have physician diagnosed attention-deficit/hyperactivity disorder (OR 0.5; 95% CI 0.3-0.97) or an individualized education plan (OR 0.6; 95% CI 0.4-0.99).

CONCLUSION

Among children born extremely preterm, an elevated BMI, compared with normal or low BMI, is not associated with a difference in neurocognitive function. However, asthma, fair/poor general health, and decreased physical function were more prevalent among study participants with obesity, and attention-deficit/hyperactivity disorder and individualized education plan were less prevalent.

Evaluation of the associations between childhood asthma and prenatal and perinatal factors

OBJECTIVE

To identify prenatal and perinatal risk factors for childhood asthma.

METHODS

A retrospective case-control study was undertaken among children aged 7-14 years in Tehran, Iran, between March 2009 and November 2014. Data for children with asthma (Iranian nationality, non-smoking parents, and middle-class socioeconomic status) were compared with those for an equal number of age- and sex-matched non-asthmatic children. Prenatal and perinatal risk factors were evaluated via complete data sheets of maternal pregnancy and delivery. Forward logistic regression analysis was performed.

RESULTS

Both groups contained 134 children. Risk of asthma was shown to be associated with maternal history of asthma (adjusted odds ratio [aOR] 11.62, 95% confidence interval 1.38-96.93; P=0.024), vaginal bleeding during pregnancy (aOR 3.76, 95% CI 1.86-7.57; P<0.001), antibiotics during pregnancy (aOR 3.19, 95% CI 1.52-6.67; P=0.002), and maternal age 30 years or older (aOR 2.54, 95% CI 1.30-4.95; P=0.006). Breastfeeding was protective against childhood asthma (aOR 0.29, 95% CI 0.151-0.575; P<0.001).

CONCLUSION

History of maternal asthma was the most influential factor on development of childhood asthma, followed by vaginal bleeding during pregnancy, antibiotic exposure in utero, and older maternal age.

Asthma as a disruption in iron homeostasis

Over several decades, asthma has evolved from being recognized as a single disease to include a diverse group of phenotypes with dissimilar natural histories, pathophysiologies, responses to treatment, and distinctive molecular pathways. With the application of Occam's razor to asthma, it is proposed that there is one cause underlying the numerous phenotypes of this disease and that the responsible molecular pathway is a deficiency of iron in the lung tissues. This deficiency can be either absolute (e.g. asthma in the neonate and during both pregnancy and menstruation) or functional (e.g. asthma associated with infections, smoking, and obesity). Comparable associations between asthma co-morbidity (e.g. eczema, urticaria, restless leg syndrome, and pulmonary hypertension) with iron deficiency support such a shared mechanistic pathway. Therapies directed at asthma demonstrate a capacity to impact iron homeostasis, further strengthening the relationship. Finally, pathophysiologic events producing asthma, including inflammation, increases in Th2 cells, and muscle contraction, can correlate with iron availability. Recognition of a potential association between asthma and an absolute and/or functional iron deficiency suggests specific therapeutic interventions including inhaled iron.

Environmental risk factors related to the incidence of wheeze and asthma in adolescence

BACKGROUND

Asthma is common among adolescents, but there are few population-based studies on the risk factors for incident asthma and wheeze at this age group.

OBJECTIVE

To study risk factors for incident asthma and wheeze in adolescence.

METHOD

Within the Obstructive Lung Disease In Northern Sweden (OLIN) studies, a cohort of 3430 school children (age 7-8 year) was recruited in 1996. In the present study, this cohort was followed from age 12-19 year. At baseline (age 12 year), 3151 participated and skin prick tests (SPT) were performed. The cohort was resurveyed annually, and risk factors for the cumulative incidence of asthma and wheeze from age 12-19 year were analysed using multivariate Cox regression.

RESULTS

Female sex (wheeze: HR 1.4 95%CI 1.2-1.6; asthma: HR 1.8 95%CI 1.2-2.5) and a positive SPT to cat, dog or horse at baseline (wheeze: HR 1.6 95%CI 1.2-2.1; asthma: HR 2.3 95%CI 1.4-4.0) were significantly associated with the cumulative incidence of wheeze and asthma. Increasing numbers of siblings were inversely related to the incidence of wheeze (HR 0.9 95%CI 0.8-0.97) and asthma (HR 0.8 95%CI 0.7-0.97). Parental asthma was related to the incidence of asthma (HR 1.8 95%CI 1.2-2.6) while ever smoking (HR 2.0 95%CI 1.6-2.4) and house dampness (HR 1.3 95%CI 1.1-1.6) were risk factors for the incidence of wheeze. Maternal ETS exposure increased the risk of incident asthma in non-sensitized subjects (HR 1.9 95%CI 1.0-3.7).

CONCLUSION AND CLINICAL RELEVANCE

Several environmental risk factors related to the incidence of asthma and wheeze in adolescence were identified and may be possible targets for intervention and prevention.

Respiratory consequences of late preterm birth

In developed countries most preterm births occur between 34 and 37 weeks' gestation. Deliveries during this 'late preterm' period are increasing and, since even mild prematurity is now recognised to be associated with adverse health outcomes, this presents healthcare challenges. Respiratory problems associated with late preterm birth include neonatal respiratory distress, severe RSV infection and childhood wheezing. Late preterm birth prematurely interrupts in utero lung development and is associated with maternal and early life factors which adversely affect the developing respiratory system. This review considers 1) mechanisms underlying the association between late preterm birth and impaired respiratory development, 2) respiratory morbidity associated with late preterm birth, particularly long-term outcomes, and 3) interventions which might protect respiratory development by addressing risk factors affecting the late preterm population, including maternal smoking, early life growth restriction and vulnerability to viral infection.

Birth weight and childhood wheezing disorders: a systematic review and meta-analysis

BACKGROUND

Previous observational studies have claimed that birth weight and childhood wheezing disorders are associated although the results remained inconsistent. One systematic review and two systematic reviews that included meta-analyses reported inconsistent results. We aimed to conduct a systematic review and meta-analysis to investigate this.

METHODS

An online search of published papers linking childhood asthma and wheezing disorders with birth weight up to February 2014 was carried out using EMBASE and Medline medical research databases. Summary ORs were estimated using random-effects models. Subgroup meta-analyses were performed to assess the robustness of risk associations and between-study heterogeneity.

RESULTS

A total of 37 studies comprising 1,71, 737 participants were included in our meta-analysis. The unadjusted summary ORs for risk of childhood wheezing disorders associated with low birth weight (<2.5 kg) were 1.60 (95% CI 1.39 to 1.85, p<0.001) and 1.37 (95% CI 1.05 to 1.79, p=0.02) when compared with ≥2.5 and 2.5-4.0 kg birthweight groups, respectively. The overall summary OR for high birth weight (>4 kg) as compared to the 2.5-4.0 kg birthweight group was 1.02 (95% CI 0.99 to 1.04, p=0.13). There was substantial heterogeneity in the unadjusted low birth weight risk estimates which was not accounted for by predefined study characteristics. There was no significant heterogeneity in the high birth weight risk estimates. There was some evidence of funnel plot asymmetry and small study effects in the low birth weight (2.5 vs ≥2.5 kg and <2.5 vs 2.5-4 kg) OR estimates.

CONCLUSIONS

Our results suggest that low birth (<2.5 kg) is an independent risk factor for wheezing disorders during childhood and adolescence although there was substantial heterogeneity among the risk estimates. However, we found no significant association of high birth weight with wheezing disorders.

Epigenetics of hyper-responsiveness to allergen challenge following intrauterine growth retardation rat

Background

Epidemiological studies have revealed that intrauterine growth retardation (IUGR) or low birth weight is linked to the later development of asthma. Epigenetic regulatory mechanisms play an important role in the fetal origins of adult disease. However, little is known regarding the correlation between epigenetic regulation and the development of asthma following IUGR.

Methods

An IUGR and ovalbumin (OVA)-sensitization/challenge rat model was used to study whether epigenetic mechanisms play a role in the development of asthma following IUGR.

Results

Maternal nutrient restriction increased histone acetylation levels of the endothelin-1 (ET-1) gene promoter in lung tissue of offspring, but did not cause significant alterations of DNA methylation. The effect was maintained until 10 weeks after birth. Furthermore, these epigenetic changes may have induced IUGR individuals to be highly sensitive to OVA challenge later in life, resulting in more significant changes related to asthma.

Conclusions

These findings suggest that epigenetic mechanisms might be closely associated with the development of asthma following IUGR, providing further insight for improved prevention of asthma induced by environmental factors.

Effect of low birth weight on childhood asthma: a meta-analysis

Background

Low birth weight is strongly correlated with an increased risk of adult diseases. Additionally, low birth weight might be a risk factor for asthma later in life.

Methods

A systematic literature search of the PubMed database from 1966 to November 2013 was conducted. The criteria for inclusion of papers were as follows: case–control or cohort studies; the odds ratio (OR) or risk ratio (RR) estimates with the corresponding 95% confidence intervals (CIs) were presented, or there were sufficient data for calculation; and studies were published in English up to October 2013. Random-effect and fixed-effect meta-analyses, meta-regression, and cumulative meta-analysis were conducted.

Results

Thirteen cohort studies and 1,105,703 subjects were included. The overall pooled RRs (95% CIs) of asthma risk for low birth weight were 1.162 (fixed-effects model, 95% CI, 1.128–1.197) and 1.152 (random-effects model, 95% CI, 1.082–1.222). In stratified analyses, the effect of low birth weight on childhood asthma was strong, particularly in studies conducted in Europe, those with a small sample size, and those published recently. A meta-regression analysis did not find significant determinants.

Conclusions

This meta-analysis shows that low birth weight significantly increases the risk of childhood asthma.

Mechanisms of obesity in asthma

PURPOSE OF REVIEW

Obesity and asthma are chronic conditions affecting millions of people worldwide. The two conditions also appear to be linked with an increased risk of asthma in people who are obese. The purpose of this review is to describe mechanism(s) that may explain the association between asthma and obesity.

RECENT FINDINGS

Current evidence suggests that the association between asthma and obesity is linked by two major phenotypes and three important pathways of obesity-related asthma: one phenotype with primary (often atopic) asthma that is aggravated by obesity and a second phenotype with late-onset nonatopic asthma, which predominantly affects women and primarily seems to be associated with neutrophilic inflammation. Proposed pathways include the mechanical effects of obesity (fewer deep inspirations leading to increased airway hyperresponsiveness), an inflammatory pathway driven by obesity-related cytokines (adipokines), and finally environment and lifestyle changes that have led to an increasing prevalence of obesity over the past 50 years (including exposures in utero, physical activity, and diet) may also result in asthma in predisposed individuals. How these environmental changes influence the occurrence and expression of asthma may depend on the age of exposure and on interactions with genetic susceptibilities.

SUMMARY

Future research should be directed to shed light on the associations between obesity and asthma phenotypes, modern lifestyles and environmental exposures and genetic susceptibilities.

VIDEO ABSTRACT

http://links.lww.com/COAI/A6.

Low birth weight and environmental tobacco smoke increases the risk of wheezing in adolescents: a retrospective cohort study

Background

Low birth weight (LBW) and environmental tobacco smoke (ETS) exposure are each associated with wheezing in children. This study was designed to examine the combined association of LBW and ETS with wheezing.

Methods

A retrospective birth cohort analysis linked with a national survey of allergic disorders among 1,018,031 junior high school students in Taiwan (1995–1996) was analyzed. The reported incidence of wheezing (yes or no) and ETS exposure (4 categories: 0, 1–20, 21–40 and greater than or equal to 41 household cigarettes per day) were obtained from validated questionnaires. Multiple logistic regression models were used to assess the associations of interest.

Results

There were 844,003 (83%) subjects analyzed after the exclusion criteria. LBW was associated with an increased risk of reporting ever wheezing (odds ratio [OR] = 1.08, 95% confidence interval [CI] = 1.01–1.16), current wheezing (OR = 1.09, 95% CI = 1.00–1.20) and wheezing with exercise (OR = 1.11, 95% CI = 1.02–1.21) within the smoke-free cohort. Higher ETS exposure correlated to a higher risk of wheezing (ever, current and with exercise). With ETS exposure, adolescents from the lowest birth weight cohorts were more likely to report wheezing (ever, current and with exercise).

Conclusions

ETS and LBW each has been related to increasing public health risk for respiratory symptoms among adolescents. Furthermore, LBW may aggravate the risk among those exposed to ETS. LBW, ETS and associated respiratory impairments may deserve special attention as part of a comprehensive environmental health risk assessment directed toward prevention and intervention.

Neonatal bilirubin levels and childhood asthma in the US Collaborative Perinatal Project, 1959-1965

Evidence shows that asthma originates in early life. Studies have found that phototherapy and/or neonatal jaundice may be associated with asthma. We investigated the association between neonatal bilirubin levels and childhood asthma without phototherapy intervention in the Collaborative Perinatal Project, a multicenter prospective cohort study conducted in the United States from 1959 to 1965. A total of 54,795 livebirths were included, and 40,063 children were followed up until 7 years of age or older. Total serum bilirubin (TSB) levels were examined at 48 hours postpartum in newborns with birthweights of 2,250 g or more. Information on asthma and other diseases through age 7 years was summarized and confirmed by a group of pediatricians and child neurologists. Among 28,807 term infants, the overall prevalence of asthma was 5.26%. Risks of asthma increased with both maximum TSB levels and TSB levels at 48 hours postpartum (P for trend < 0.01). Neonatal maximum TSB levels greater than 15 mg/dL were associated with a 61% increase in the risk of childhood asthma (odds ratio = 1.61, 95% confidence interval: 1.04, 2.08) after adjustment for confounders. In this prospective cohort study of infants born at a time when phototherapy was unavailable, neonatal hyperbilirubinemia was associated with an increased risk of childhood asthma.

Preterm infant linear growth and adiposity gain: trade-offs for later weight status and intelligence quotient

OBJECTIVE

To examine trade-offs between cognitive outcome and overweight/obesity in preterm-born infants at school age and young adulthood in relation to weight gain and linear growth during infancy.

STUDY DESIGN

We studied 945 participants in the Infant Health and Development Program, an 8-center study of preterm (≤37 weeks gestational age), low birth weight (≤2500 g) infants from birth to age 18 years. Adjusting for maternal and child factors in logistic regression, we estimated the odds of overweight/obesity (body mass index [BMI] ≥85th percentile at age 8 or ≥25 kg/m(2) at age 18) and in separate models, low IQ (<85) per z-score changes in infant length and BMI from term to 4 months, from 4 to 12 months, and from 12 to 18 months.

RESULTS

More rapid linear growth from term to 4 months was associated with lower odds of IQ <85 at age 8 years (OR, 0.82; 95% CI, 0.70-0.96), but higher odds of overweight/obesity (OR, 1.27; 95% CI, 1.05-1.53). More rapid BMI gain in all 3 infant time intervals was also associated with higher odds of overweight/obesity, and BMI gain from 4-12 months was associated with lower odds of IQ <85 at age 8. Results at age 18 were similar.

CONCLUSION

In these preterm, low birth weight infants born in the 1980s, faster linear growth soon after term was associated with better cognition, but also with a greater risk of overweight/obesity at age 8 years and 18 years. BMI gain over the entire 18 months after term was associated with later risk of overweight/obesity, with less evidence of a benefit for IQ.

Asthma prevalence and risk factors among children and adolescents living around an industrial area: a cross-sectional study

Background

The exposure to air pollution has negative effects on human health, increasing the risk of respiratory diseases, such as asthma. Few data are yet available on the epidemiology of childhood asthma in some areas of Italy. The aim of the study was to estimate asthma prevalence and related risk factors in children and adolescents residents around the industrial area of Termoli, Molise region, Central-South Italy.

Methods

Prevalence was assessed through the administration of modified ISAAC questionnaires filled out by parents of 89 children and adolescents for the identification of confirmed and probable cases, and by analyzing pediatricians’ databases on drug prescriptions for symptoms control and treatment of assisted population in the study area (n = 1,004), compared to a control area (n = 920) with lower industrialization. The association of asthma with risk factors was evaluated by univariate (Chi-square or Fisher’s Exact test) and regression logistic analysis.

Results

A total of 22 (24.7%) asthmatics were identified, including both confirmed (n = 7; 7.9%) and probable cases (n = 15; 16.8%), most of them (n = 17; 77.3%) resident of Termoli town. All asthma cases were georeferenced based on the residence, however clusters were not found. Using drug prescriptions analysis, a higher prevalence (n = 138; 13.7%) of diagnosed cases was found. Lifetime history of both atopic dermatitis and bronchitis were significantly relateds to asthma cases, as well as an elevated body mass index, whose association is consistent with prevalence data of overweight/obese children living in the study area. Moreover, being resident of the town of Termoli was associated to the occurrence of cases.

Conclusions

Although our data indicated a prevalence concordance with previous national studies in pediatric population, a definitive correlation with environmental industrial factors present in the study area was not established. However, asthma outcome was significantly associated to individuals living in the town of Termoli that, despite the industrial/manufacturing activities, is also subjected to a higher environmental pressure due to the presence of toll road, state highway, railroad, and seaport which may cause air pollution from motor vehicle traffic and increase asthma induction. This study provides hitherto unavailable data on asthma in childhood population living in an industrialized area which was never investigated before, could be part of a systematic review or meta-analysis procedure, might suggest significant findings for larger observational studies, and contribute to complete the frame of disease epidemiology in Italy.

Antenatal steroid exposure and pulmonary outcomes in adolescents born with very low birth weight

OBJECTIVE

To compare asthma history and pulmonary function in adolescents born prematurely with very low birth weight with and without antenatal steroid exposure.

STUDY DESIGN

We studied 188 fourteen-year olds (94 exposed, 84 male). We used parent report to ascertain asthma and asthma-related symptoms and spirometry to assess pulmonary function. Steroid-exposed and -unexposed groups were compared using Mann-Whitney U-tests (continuous variables), χ(2) analysis (categorical variables) and logistic regression (multivariate analyses).

RESULT

The steroid-exposed group had greater prevalence of larger airway obstruction (35% vs 21%), and steroid-exposed adolescents with birth weights <1000 g had 4.5-fold higher odds of larger airway obstruction. Wheezing in the past 12 months was two times as prevalent in steroid-exposed adolescents with birth weights between 1000 and 1500 g.

CONCLUSION

Antenatal steroid exposure does not provide long-term benefits for pulmonary outcomes in adolescents born prematurely with very low birth weight in the era of surfactant therapy.

Lack of relationship between birth conditions and allergic disorders in Japanese children aged 3 years

BACKGROUND

The current cross-sectional study examined the associations between low birth weight (LBW), preterm birth, and small-for-gestational-age (SGA) and the prevalence of wheeze, asthma, and eczema in Japanese children aged 3 years.

METHODS

Study subjects were 2004 children. All data were obtained using a questionnaire. Outcomes were defined according to the criteria of the International Study of Asthma and Allergies in Childhood. Adjustment was made for sex, number of siblings, breastfeeding duration, paternal and maternal educational level, paternal and maternal history of allergic disorders, maternal smoking during pregnancy, secondhand smoke exposure at home, and gestational age at birth.

RESULTS

The prevalence of wheeze, asthma, and eczema in the previous 12 months were 22.1%, 9.0%, and 17.5%, respectively, and 8.4% were classified as LBW (<2500 g), 4.7% as preterm birth (<37 weeks), and 7.1% as SGA (<10th percentile). There were no significant associations between LBW, preterm birth, or SGA and the prevalence of wheeze, asthma, or eczema. A positive relationship between preterm birth and asthma was of borderline significance in children whose mothers had smoked during pregnancy (adjusted OR: 4.71 [95% CI: 0.97-21.39]), but not in those whose mothers had never smoked during pregnancy; the multiplicative interaction between preterm birth and maternal smoking during pregnancy with respect to asthma was significant (p = .04).

CONCLUSIONS

The current study failed to detect significant associations between birth conditions and allergic disorders. Nevertheless, we did find evidence for an interaction between preterm birth and maternal smoking during pregnancy affecting asthma.