Clinical implications of airway obstruction with normal or low FEV1 in childhood and adolescence.

BACKGROUND: Airway obstruction is defined by spirometry as a low forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) ratio. This impaired ratio may originate from a low FEV1 (classic) or a normal FEV1 in combination with a large FVC (dysanaptic). The clinical implications of dysanaptic obstruction during childhood and adolescence in the general population remain unclear. AIMS: To investigate the association between airway obstruction with a low or normal FEV1 in childhood and adolescence, and asthma, wheezing and bronchial hyperresponsiveness (BHR). METHODS: In the BAMSE (Barn/Child, Allergy, Milieu, Stockholm, Epidemiology; Sweden) and PIAMA (Prevention and Incidence of Asthma and Mite Allergy; the Netherlands) birth cohorts, obstruction (FEV1:FVC ratio less than the lower limit of normal, LLN) at ages 8, 12 (PIAMA only) or 16 years was classified as classic (FEV1

Exploring proteomic plasma biomarkers in eosinophilic and neutrophilic asthma.

BACKGROUND: Few biomarkers identify eosinophilic and neutrophilic asthma beyond cell concentrations in blood or sputum. Finding novel biomarkers for asthma endotypes could give insight about disease mechanisms and guide tailored treatment. Our aim was to investigate clinical characteristics and inflammation-related plasma proteins in relation to blood eosinophil and neutrophil concentrations in subjects with and without asthma. METHODS: We included 24-26-year-old subjects (n = 2063) from the Swedish population-based cohort BAMSE. Subjects with asthma (n = 239) and without asthma (n = 1824) were subdivided based on blood eosinophil and neutrophil concentrations (cut-offs 0.3 × 109 /L and 5.0 × 109 /L, respectively). We measured the levels of 92 plasma proteins using Olink Proseek Multiplex Inflammation Panel Assay. Group statistics tests were used to analyse the data, as well as adjusted multiple logistic regression models. RESULTS: Among subjects with asthma, 21.8% had eosinophilic asthma and 20.5% neutrophilic asthma. Eosinophilic asthma, but not neutrophilic asthma, was associated with a distinct clinical phenotype with, for example, higher proportions of eczema and sensitization. Most plasma proteins that associated with high eosinophil and/or neutrophil blood concentrations in subjects with asthma showed similar associations in subjects without asthma. However, out of these proteins, MMP10 levels were associated with eosinophilic asthma and were significantly higher as compared to controls with high eosinophilic concentration, while CCL4 levels associated with high neutrophil concentration only in subjects with asthma. CONCLUSIONS: Eosinophilic asthma was associated with a clear clinical phenotype. With our definitions, we identified MMP10 as a possible plasma biomarker for eosinophilic asthma and CCL4 was linked to neutrophilic asthma. These proteins should be evaluated further in clinical settings and using sputum granulocytes to define the asthma endotypes.

Changes in lifestyle, adiposity, and cardiometabolic markers among young adults in Sweden during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic has impacted on public health in several ways. The aim of the study was to investigate changes in lifestyle, adiposity, and cardiometabolic markers among young adults in Sweden during the COVID-19 pandemic and their determinants. METHODS: The study included 1 004 participants from the population-based birth cohort BAMSE. Anthropometrics, body composition (bioelectric impedance analyses), pulse, and blood pressure were measured before (December 2016-May 2019; mean age 22.6 years) and during (October 2020-June 2021; mean age 25.7 years) the COVID-19 pandemic. Lifestyle changes during the pandemic were assessed through a questionnaire. RESULTS: All measures of adiposity (weight, BMI, body fat percentage, trunk fat percentage) and cardiometabolic markers (blood pressure, pulse) increased during the study period (e.g., body fat percentage by a median of + 0.8% in females, p < 0.001, and + 1.5% in males, p < 0.001). Male sex, non-Scandinavian ethnicity, BMI status (underweight and obesity), and changes in lifestyle factors, e.g., decreased physical activity during the pandemic, were associated with higher increase in BMI and/or adiposity. CONCLUSION: Lifestyle factors, adiposity and cardiometabolic markers may have been adversely affected among young adults in Sweden during the COVID-19 pandemic compared with the preceding years. Targeted public health measures to reduce obesity and improve healthy lifestyle are important to prevent future non-communicable diseases.

SARS-CoV-2-specific B- and T-cell immunity in a population-based study of young Swedish adults.

BACKGROUND: Young adults are now considered major spreaders of coronavirus disease 2019 (COVID-19) disease. Although most young individuals experience mild to moderate disease, there are concerns of long-term adverse health effects. The impact of COVID-19 disease and to which extent population-level immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exists in young adults remain unclear. OBJECTIVE: We conducted a population-based study on humoral and cellular immunity to SARS-CoV-2 and explored COVID-19 disease characteristics in young adults. METHODS: We invited participants from the Swedish BAMSE (Barn [Children], Allergy Milieu, Stockholm, Epidemiology) birth cohort (age 24-27 years) to take part in a COVID-19 follow-up. From 980 participants (October 2020 to June 2021), we here present data on SARS-CoV-2 receptor-binding domain-specific IgM, IgA, and IgG titers measured by ELISA and on symptoms and epidemiologic factors associated with seropositivity. Further, SARS-CoV-2-specific memory B- and T-cell responses were detected for a subpopulation (n = 108) by ELISpot and FluoroSpot. RESULTS: A total of 28.4% of subjects were seropositive, of whom 18.4% were IgM single positive. One in 7 seropositive subjects was asymptomatic. Seropositivity was associated with use of public transport, but not with sex, asthma, rhinitis, IgE sensitization, smoking, or body mass index. In a subset of representative samples, 20.7% and 35.0% had detectable SARS-CoV-2 specific B- and T-cell responses, respectively. B- and T-cell memory responses were clearly associated with seropositivity, but T-cell responses were also detected in 17.2% of seronegative subjects. CONCLUSIONS: Assessment of IgM and T-cell responses may improve population-based estimations of SARS-CoV-2 infection. The pronounced surge of both symptomatic and asymptomatic infections among young adults indicates that the large-scale vaccination campaign should be continued.

Fruit, vegetable and dietary antioxidant intake in school age, respiratory health up to young adulthood.

BACKGROUND: Dietary antioxidants may protect the lung against oxidative damage and prevent chronic respiratory disease. We aimed to investigate fruit, vegetable and antioxidant intake (measured as total antioxidant capacity, TAC) at age 8 years in relation to asthma and lung function up to 24 years. METHODS: In this study of 2506 participants from a Swedish birth cohort, diet was assessed using food frequency questionnaires. Information on asthma was collected by questionnaires, and lung function was measured by spirometry at ages 8, 16 and 24 years. Generalized estimating equations and mixed effect models were used to assess overall, age- and sex-specific associations. RESULTS: After adjustment for confounders, a higher fruit intake at age 8 years was associated with a tendency to reduced odds of prevalent asthma (T3 vs. T1, OR 0.78; 95% CI 0.60-1.01, p-trend .083), with reduced odds of incident asthma and increased odds of remittent asthma (≥median, OR 0.76; 95% CI 0.58-0.99 and OR 1.60; 95% CI 1.05-2.42, respectively) up to 24 years. Comparable, but non-significant, odds ratios were observed in analyses of long-term fruit intake (mean intake at ages 8 and 16 years). In contrast, no association was observed with vegetable intake. A higher dietary TAC (T3 vs. T1) at 8 years was associated with reduced odds of prevalent asthma (OR 0.73; 95% CI 0.58-0.93, p-trend .010) and improved lung function development (FEV1 -z +0.11; 95% CI 0.01-0.21, p-trend .036 and FVC-z +0.09; 95% CI -0.01-0.20, p-trend .072) up to 24 years. Associations were more pronounced among males, and regarding asthma, participants sensitized to aeroallergens. CONCLUSIONS: Antioxidant intake in school age may improve asthma and lung function up to young adulthood. Although our results should be interpreted with caution, they emphasize the importance of following current dietary guidelines regarding consumption of antioxidant-rich foods as part of a balanced diet.

Non-adherence and sub-optimal treatment with asthma medications in young adults: a population-based cohort study.

OBJECTIVE: Pharmacological treatment plays a key role in the management of asthma, but medication adherence is generally low. Our aim was to assess factors associated with dispensing patterns of, and adherence to, asthma medication in young adults with asthma. METHODS: The study included young adults (age 22-24 years) from the Swedish population-based birth cohort BAMSE (n = 3,064) with linkage to register data on dispensed asthma medications and recorded diagnosis. Dispensing information was collected in January 2014-June 2019 (the study period) to cover the period of questionnaire data. Adherence to asthma medication was defined as refilling a prescription within 18 months. RESULTS: In total, 234 individuals (7.6%) had asthma (doctor's diagnosis of asthma in combination with respiratory symptoms) and had been dispensed at least one prescription of asthma medication during the study period. Among them, 77% were dispensed a controller medication. The mean number of prescriptions dispensed per individual was higher in males than females (11.0 vs. 7.2; p < 0.01). The proportion of asthmatics with only a short-acting ß2-agonist (SABA) dispensed was 22%, of which 33% were classified as having uncontrolled asthma. Adherence to controller medication was 60% and higher among those with an asthma diagnosis from specialized care than those diagnosed in primary care (RR 1.32 95% CI 1.03-1.69). Sex, socioeconomic status, and non-allergic comorbidity did not affect adherence. CONCLUSION: Young adults with asthma had few prescriptions of asthma medication dispensed, indicating sub-optimal treatment. A considerable proportion was dispensed only SABA. Furthermore, adherence to controller medication was relatively low.

Predictors of electronic cigarette use and its association with respiratory health and obesity in young adulthood in Sweden; findings from the population-based birth cohort BAMSE.

Despite the growing popularity of electronic cigarettes (e-cigarettes) over the last decade, few epidemiological studies have examined the influence on respiratory health in young adulthood. The aim of this study was to identify factors associated with e-cigarette use in young adulthood in Sweden, and to examine associations between e-cigarette use and lung function, respiratory symptoms, and obesity. This cross-sectional study included 3055 young adults from Sweden and used questionnaire and clinical data obtained at age 22-25 years. The prevalence of current e-cigarette use was 3.9% (n = 120). Few participants reported daily (0.4%) or exclusive (0.8%) use of e-cigarettes. In a multivariable adjusted logistic regression model, e-cigarette use was significantly associated with male gender (OR:3.2; 95% CI:1.5-6.7) and cigarette smoking (OR:14.7; 95% CI:5.5-39.0 for daily smoking). Prevalence of cough (15.0% vs. 8.5%) and mucus production (22.3% vs. 14.8%) was significantly higher among e-cigarette users compared to non-users, while no difference in lung function was observed. In addition, the prevalence of overweight/obesity was higher among e-cigarette users compared to non-users (36.7% vs. 22.3% with BMI≥25 kg/m2). In conclusion, cigarette smokers and males used e-cigarette more often compared to females and non-cigarette smokers. Attention should be given to respiratory symptoms among e-cigarette users, although our results may be explained by the concurrent use of conventional cigarettes, as the group of exclusive e-cigarette users were too small to allow firm conclusions.

COVID-19 among young adults in Sweden: self-reported long-term symptoms and associated factors.

AIMS: The main aim of the study was to describe self-reported symptoms of COVID-19 and examine if long-term symptoms are associated with lifestyle factors or common chronic diseases among Swedish young adults. A secondary aim was to compare the prevalence of smoking and snuff use before and during the COVID-19 pandemic. METHODS: The study population includes 1644 participants aged 23-26 years from the Swedish population-based birth cohort BAMSE. From August to November 2020, the participants answered a web questionnaire on COVID-19 symptoms, lifestyle and health. Information on tobacco use was compared against the previous study follow-up in 2016-2019. RESULTS: The prevalence of suspected COVID-19 symptoms was 45.3% (n=742), and 80 of these (10.8%) reported long-term symptoms (⩾4 weeks). There was no significant difference in sociodemographic or lifestyle factors in relation to the duration of suspected COVID-19 symptoms. Rhinitis, migraine and lower self-rated health before the pandemic was more common among participants with long-term symptoms. In addition, there was a tendency for higher prevalences of asthma, chronic bronchitis and depression in this group. The prevalence of smoking decreased from 18.9% before the pandemic to 14.7% during the pandemic, while snuff use increased from 12.7% to 22.4% (P<0.001). CONCLUSIONS: Almost half of Swedish young adults have had symptoms of suspected COVID-19 from February up to August 2020. Among these, one out of 10 have had long-term symptoms for at least 4 weeks. Long-term symptoms of suspected COVID-19 were associated with several common chronic conditions. Smoking may have decreased during the pandemic, while snuff use may have increased.

Low-level exposure to polycyclic aromatic hydrocarbons is associated with reduced lung function among Swedish young adults.

BACKGROUND: Exposure to polycyclic aromatic hydrocarbons (PAHs) has been linked to adverse pulmonary effects. However, the impact of low-level environmental PAH exposure on lung function in early adulthood remains uncertain. OBJECTIVES: To evaluate the associations between urinary PAH metabolites and lung function parameters in young adults. METHODS: Urinary metabolites of pyrene, phenanthrene, and fluorene were analysed in 1000 young adults from Sweden (age 22-25 years) using LC-MS/MS. Lung function and eosinophilic airway inflammation were measured by spirometry and exhaled nitric oxide fraction (FeNO), respectively. Linear regression analysis was used to evaluate associations between PAH metabolites and the outcomes. RESULTS: Median urinary concentrations of 1-OH-pyrene, ∑OH-phenanthrene, and ∑OH-fluorene were 0.066, 0.36, 0.22 µg/L, respectively. We found inverse associations of ∑OH-phenanthrene and ∑OH-fluorene with FEV1 and FVC, as well as between 1-OH-pyrene and FEV1/FVC ratio (adjusted P < 0.05; all participants). An increase of 1% in ∑OH-fluorene was associated with a decrease of 73 mL in FEV1 and 59 mL in FVC. In addition, ∑OH-phenanthrene concentrations were, in a dose-response manner, inversely associated with FEV1 (B from -109 to -48 compared with the lowest quartile of ∑OH-phenanthrene; p trend 0.004) and FVC (B from -159 to -102 compared with lowest quartile; p-trend <0.001). Similar dose-response associations were also observed between ∑OH-fluorene and FEV1 and FVC, as well as between 1-OH-pyrene and FEV1/FVC (p-trend <0.05). There was no association between PAH exposure and FeNO, nor was there an interaction with smoking, sex, or asthma. CONCLUSION: Low-level PAH exposure was, in a dose-response manner, associated with reduced lung function in young adults. Our findings have public health implications due to i) the widespread occurrence of PAHs in the environment and ii) the clinical relevance of lung function in predicting all-cause and cardiovascular disease mortality.

Dietary antioxidant intake in school age and lung function development up to adolescence.

Dietary antioxidant intake has been hypothesised to influence lung function. The association between total antioxidant capacity (TAC) of the diet at age 8 years and lung function development up to 16 years in 2307 participants from the Swedish population-based birth cohort BAMSE (Children, Allergy, Milieu, Stockholm, Epidemiology) was investigated.Information on TAC was obtained from a food frequency questionnaire at 8 years. Lung function was measured by spirometry at 8 and 16 years, impulse oscillometry (IOS) and exhaled nitric oxide fraction (F eNO) at 16 years. Low lung function was defined as forced expiratory volume in 1 s (FEV1) z-score below the 25th percentile. Longitudinal associations between TAC and lung function were analysed by mixed effect models adjusted for potential confounders. Stratification by asthma at 8 years was performed to examine effect modification.The median TAC intake was 10 067 µmol Trolox equivalents (TE)·g-1, with males having a lower mean compared to females (9963 versus 10 819 µmol TE·g-1). In analyses of lung function change between 8 and 16 years, there were no statistically significant associations between TAC in tertiles and spirometry results for the total study population. Among children with asthma at 8 years (prevalence 7%), higher TAC was associated with higher mean FEV1 (0.46 sd, 95% CI 0.11-0.80) and decreased odds of low lung function at 16 years (OR 0.28, 95% CI 0.12-0.65). There were no associations between TAC and forced vital capacity or IOS/F eNO results.High dietary antioxidant intake in school age may be associated with improved lung function development from school age to adolescence among children with asthma.

Maternal body mass index, gestational weight gain, and the risk of overweight and obesity across childhood: An individual participant data meta-analysis.

BACKGROUND: Maternal obesity and excessive gestational weight gain may have persistent effects on offspring fat development. However, it remains unclear whether these effects differ by severity of obesity, and whether these effects are restricted to the extremes of maternal body mass index (BMI) and gestational weight gain. We aimed to assess the separate and combined associations of maternal BMI and gestational weight gain with the risk of overweight/obesity throughout childhood, and their population impact. METHODS AND FINDINGS: We conducted an individual participant data meta-analysis of data from 162,129 mothers and their children from 37 pregnancy and birth cohort studies from Europe, North America, and Australia. We assessed the individual and combined associations of maternal pre-pregnancy BMI and gestational weight gain, both in clinical categories and across their full ranges, with the risks of overweight/obesity in early (2.0-5.0 years), mid (5.0-10.0 years) and late childhood (10.0-18.0 years), using multilevel binary logistic regression models with a random intercept at cohort level adjusted for maternal sociodemographic and lifestyle-related characteristics. We observed that higher maternal pre-pregnancy BMI and gestational weight gain both in clinical categories and across their full ranges were associated with higher risks of childhood overweight/obesity, with the strongest effects in late childhood (odds ratios [ORs] for overweight/obesity in early, mid, and late childhood, respectively: OR 1.66 [95% CI: 1.56, 1.78], OR 1.91 [95% CI: 1.85, 1.98], and OR 2.28 [95% CI: 2.08, 2.50] for maternal overweight; OR 2.43 [95% CI: 2.24, 2.64], OR 3.12 [95% CI: 2.98, 3.27], and OR 4.47 [95% CI: 3.99, 5.23] for maternal obesity; and OR 1.39 [95% CI: 1.30, 1.49], OR 1.55 [95% CI: 1.49, 1.60], and OR 1.72 [95% CI: 1.56, 1.91] for excessive gestational weight gain). The proportions of childhood overweight/obesity prevalence attributable to maternal overweight, maternal obesity, and excessive gestational weight gain ranged from 10.2% to 21.6%. Relative to the effect of maternal BMI, excessive gestational weight gain only slightly increased the risk of childhood overweight/obesity within each clinical BMI category (p-values for interactions of maternal BMI with gestational weight gain: p = 0.038, p < 0.001, and p = 0.637 in early, mid, and late childhood, respectively). Limitations of this study include the self-report of maternal BMI and gestational weight gain for some of the cohorts, and the potential of residual confounding. Also, as this study only included participants from Europe, North America, and Australia, results need to be interpreted with caution with respect to other populations. CONCLUSIONS: In this study, higher maternal pre-pregnancy BMI and gestational weight gain were associated with an increased risk of childhood overweight/obesity, with the strongest effects at later ages. The additional effect of gestational weight gain in women who are overweight or obese before pregnancy is small. Given the large population impact, future intervention trials aiming to reduce the prevalence of childhood overweight and obesity should focus on maternal weight status before pregnancy, in addition to weight gain during pregnancy.

Maternal BMI at the start of pregnancy and offspring epigenome-wide DNA methylation: findings from the pregnancy and childhood epigenetics (PACE) consortium.

Pre-pregnancy maternal obesity is associated with adverse offspring outcomes at birth and later in life. Individual studies have shown that epigenetic modifications such as DNA methylation could contribute. Within the Pregnancy and Childhood Epigenetics (PACE) Consortium, we meta-analysed the association between pre-pregnancy maternal BMI and methylation at over 450,000 sites in newborn blood DNA, across 19 cohorts (9,340 mother-newborn pairs). We attempted to infer causality by comparing the effects of maternal versus paternal BMI and incorporating genetic variation. In four additional cohorts (1,817 mother-child pairs), we meta-analysed the association between maternal BMI at the start of pregnancy and blood methylation in adolescents. In newborns, maternal BMI was associated with small (<0.2% per BMI unit (1 kg/m2), P < 1.06 × 10-7) methylation variation at 9,044 sites throughout the genome. Adjustment for estimated cell proportions greatly attenuated the number of significant CpGs to 104, including 86 sites common to the unadjusted model. At 72/86 sites, the direction of the association was the same in newborns and adolescents, suggesting persistence of signals. However, we found evidence for acausal intrauterine effect of maternal BMI on newborn methylation at just 8/86 sites. In conclusion, this well-powered analysis identified robust associations between maternal adiposity and variations in newborn blood DNA methylation, but these small effects may be better explained by genetic or lifestyle factors than a causal intrauterine mechanism. This highlights the need for large-scale collaborative approaches and the application of causal inference techniques in epigenetic epidemiology.

Traffic noise exposure in relation to adverse birth outcomes and body mass between birth and adolescence.

BACKGROUND: There is growing evidence that traffic noise exposure is associated with adiposity among adults but data in children are limited. OBJECTIVE: This longitudinal study examined whether pre- and postnatal noise exposure is associated with body mass index (BMI) between birth and adolescence or with adverse birth outcomes. METHODS: The study was conducted using data from the BAMSE birth cohort, which included 4089 children born in Stockholm County, Sweden. Data on BMI from birth to adolescence were collected via questionnaires, clinical examinations and health care records. A national register provided information on birth outcomes. Road traffic noise levels at the most exposed façade were estimated for all residences of the children during follow-up, as well as of their mothers during pregnancy, and time-weighted average exposure was calculated for different time windows. Maternal occupational noise exposure was obtained from a job-exposure-matrix. Logistic- and quantile regression models were used to estimate associations between noise exposure and health outcomes. RESULTS: We found residential road traffic noise exposure to be associated with increases in BMI from school age to adolescence, but not at earlier ages. In the age groups 8-11 years and 12-16 years the BMI increments were 0.11 kg/m2 per 10 dB Lden (95% CI 0.08-0.13) and 0.20 kg/m2 per 10 dB Lden (95% CI 0.17-0.22), respectively. Maternal noise exposure during pregnancy was generally unrelated to adverse birth outcomes and BMI from birth to adolescence in the children, however, traffic noise exposure was associated with a decreased risk of preterm birth CONCLUSION: Residential road traffic noise exposure was associated with BMI increases from school age to adolescence, but not at earlier ages. Maternal occupational noise exposure or exposure from road traffic during pregnancy were not consistently related to birth outcomes or BMI from birth to adolescence.

Polyunsaturated fatty acids in plasma at 8 years and subsequent allergic disease.

BACKGROUND: Polyunsaturated fatty acids (PUFAs) are hypothesized to modulate the risk of allergic disease. However, evidence from previous studies is inconclusive, and limited longitudinal data exist using circulating biomarkers of PUFA intake and metabolism. OBJECTIVE: We aimed to investigate associations between n-3 and n-6 PUFAs at age 8 years and asthma, rhinitis, and aeroallergen sensitization at age 16 years. METHODS: Proportions of n-3 PUFAs (very long-chain n-3 [VLC n-3; sum of eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid] and α-linolenic acid) and n-6 PUFAs (linoleic acid and arachidonic acid [AA]) in blood samples at age 8 years were measured for 940 children from the prospective Swedish birth cohort BAMSE (Children, Allergy, Milieu, Stockholm, Epidemiology). Allergic disease phenotypes were defined by using questionnaires and IgE measures at the ages of 8 and 16 years. Logistic regression was used to examine potential associations. RESULTS: A higher proportion of total VLC n-3 PUFAs in plasma at age 8 years was associated with a reduced risk of prevalent asthma, rhinitis, and aeroallergen sensitization at age 16 years and with incidence of asthma between 8 and 16 years (adjusted odds ratio, 0.67; 95% CI, 0.47-0.94). AA was associated with a reduced risk of asthma, aeroallergen sensitization, and allergic rhinitis. The findings were most evident for allergic phenotypes of asthma and rhinitis. Additionally, AA was associated with an increased probability of asthma and rhinitis remission between 8 and 16 years of age. CONCLUSION: Higher proportions of certain VLC n-3 and very long-chain n-6 PUFAs in plasma phospholipids at age 8 years were associated with a reduced risk of allergic disease at age 16 years.

Body mass index status and peripheral airway obstruction in school-age children: a population-based cohort study.

BACKGROUND: Few large prospective studies have investigated the impact of body mass index (BMI) on lung function during childhood. METHODS: Using data collected between 2002 and 2013, we analysed associations between BMI status and lung function (assessed by spirometry) from 8 to 16 years, as well as cross-sectional associations with small airway function (impulse oscillometry) at 16 years in the BAMSE cohort (n=2889). At 16 years, cross-sectional associations with local and systemic inflammation were investigated by analysing FENO, blood eosinophils and neutrophils. RESULTS: Overweight and obesity at 8 years were associated with higher FVC, but lower FEV1/FVC ratio at 8 and 16 years. In boys, but not girls, obesity at 8 years was associated with a further reduction in FEV1/FVC between 8 and 16 years. In cross-sectional analyses, overweight and obesity were associated with higher frequency dependence of resistance (R5-20) and larger area under the reactance curve (AX0.5) at 16 years. Increased blood neutrophil counts were seen in overweight and obese girls, but not in boys. No association was found between BMI status and FENO. Persistent, but not transient, overweight/obesity between 8 and 16 years was associated with higher R5-20 and AX0.5 and lower FEV1/FVC (-2.8% (95% CI -4.1 to -1.2) in girls and -2.7% (95% CI -4.4 to -1.1) in boys) at 16 years, compared with persistent normal weight. CONCLUSION: In childhood and adolescence, overweight and obesity, particularly persistent overweight, were associated with evidence of airway obstruction, including the small airways.

Does early onset asthma increase childhood obesity risk? A pooled analysis of 16 European cohorts.

The parallel epidemics of childhood asthma and obesity over the past few decades have spurred research into obesity as a risk factor for asthma. However, little is known regarding the role of asthma in obesity incidence. We examined whether early-onset asthma and related phenotypes are associated with the risk of developing obesity in childhood.This study includes 21 130 children born from 1990 to 2008 in Denmark, France, Germany, Greece, Italy, The Netherlands, Spain, Sweden and the UK. We followed non-obese children at 3-4 years of age for incident obesity up to 8 years of age. Physician-diagnosed asthma, wheezing and allergic rhinitis were assessed up to 3-4 years of age.Children with physician-diagnosed asthma had a higher risk for incident obesity than those without asthma (adjusted hazard ratio (aHR) 1.66, 95% CI 1.18-2.33). Children with active asthma (wheeze in the last 12 months and physician-diagnosed asthma) exhibited a higher risk for obesity (aHR 1.98, 95% CI 1.31-3.00) than those without wheeze and asthma. Persistent wheezing was associated with increased risk for incident obesity compared to never wheezers (aHR 1.51, 95% CI 1.08-2.09).Early-onset asthma and wheezing may contribute to an increased risk of developing obesity in later childhood.

Body Mass Index Development and Asthma Throughout Childhood.

Several studies have found an association between overweight and asthma, yet the temporal relationship between their onsets remains unclear. We investigated the development of body mass index (BMI) from birth to adolescence among 2,818 children with and without asthma from a Swedish birth cohort study, the BAMSE (a Swedish acronym for "children, allergy, milieu, Stockholm, epidemiology") Project, during 1994-2013. Measured weight and height were available at 13 time points throughout childhood. Asthma phenotypes (transient, persistent, and late-onset) were defined by timing of onset and remission. Quantile regression was used to analyze percentiles of BMI, and generalized estimating equations were used to analyze the association between asthma phenotypes and the risk of high BMI. Among females, BMI development differed between children with and without asthma, with the highest BMI being seen among females with persistent asthma. The difference existed throughout childhood but increased with age. For example, females with persistent asthma had 2.33 times' (95% confidence interval: 1.21, 4.49) greater odds of having a BMI above the 85th percentile at age ≥15 years than females without asthma. Among males, no clear associations between asthma and BMI were observed. In this study, persistent asthma was associated with high BMI throughout childhood among females, whereas no consistent association was observed among males.

Web-based self-reported height, weight, and body mass index among Swedish adolescents: a validation study.

BACKGROUND: Web-collected height and weight are increasingly used in epidemiological studies; however, the validity has rarely been evaluated. OBJECTIVE: The aim of the study was to validate self-reported height, weight, and corresponding body mass index (BMI) among Swedish adolescents aged approximately 16 years. A secondary aim was to investigate possible prediction factors for validity of self-reported BMI. METHODS: The study included 1698 adolescents from the population-based cohort BAMSE. Height and weight were collected through a Web-based questionnaire and subsequently measured using standard procedures. Differences between reported and measured height, weight, and corresponding BMI were compared by t tests and agreement was evaluated by Pearson correlation and Bland-Altman plots. Multivariable linear regression analysis was used to investigate whether lifestyle and demographic factors predicted validity of self-reported BMI. RESULTS: On average, weight was underestimated by 1.1 kg and height was overestimated by 0.5 cm, leading to an underestimation of BMI by 0.5 kg/m2. Correlation coefficients were .98 for height, .97 for weight, and .94 for BMI, and highly significant. Females underestimated weight to a higher extent than males and overweight and obese participants underestimated weight to a higher extent than normal-weight participants, which resulted in higher underestimation of BMI. Underweight participants, on the contrary, overestimated weight and correspondingly BMI. Overall, a high proportion of participants were classified into the correct BMI category; however, among overweight and obese participants, only 60.2% (139/231) and 46% (20/44) were correctly classified, respectively. In the multivariable prediction model, only gender and BMI status significantly predicted discrepancy between reported and measured BMI. CONCLUSIONS: Web-collected BMI may be used as a valid, quick, and cost-effective alternative to measured BMI among Swedish adolescents. The accuracy of self-reported BMI declines with increasing BMI and self-reported BMI should not be used to estimate the prevalence of overweight or obesity.