COVID-19 vaccine uptake among young adults: Influence of asthma and sociodemographic factors.

Background: Asthma was initially described as a risk factor for severe coronavirus disease 2019 (COVID-19), but the uptake of COVID-19 vaccine among young adults with asthma is not well studied. Objective: The aims were to assess COVID-19 vaccine uptake among young adults in general and to explore potential determinants including sociodemographic factors and asthma. Methods: Participants from the population-based birth cohort BAMSE (Barn/Child, Allergy, Milieu, Stockholm, Epidemiology) were included: 4,064 in the study population, 3,064 in a follow-up at age 24 years, and 2,049 in a COVID-19 follow-up (mean age, 26.5 years). Asthma and asthma-associated characteristics were assessed through questionnaires and clinical data. Data on all COVID-19 vaccines registered between January 1, 2021, and February 15, 2023, were extracted from the National Vaccination Register. Results: In the study population (n = 4,064), 53.9% had ≥3 COVID-19 vaccine doses registered. In the 24-year follow-up population (n = 3,064), vaccine uptake differed in relation to education (P < .001). Among the participants with university/college education, 65.7% had an uptake of ≥3 doses of vaccine, compared to 54.1% among the participants with elementary school/high school education. Participants with asthma had decreased odds of receiving ≥3 doses (adjusted odds ratio = 0.62; 95% confidence interval, 0.41-0.92) and ≥2 compared to peers without asthma. Those with uncontrolled disease also had decreased odds of receiving ≥3 doses (adjusted odds ratio = 0.30; 95% confidence interval, 0.13-0.66) and ≥2 compared to participants with controlled asthma. Conclusions: COVID-19 vaccine uptake among young adults is lower in individuals from households with lower socioeconomic status and among those with asthma, including uncontrolled asthma.

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

Infantile atopic dermatitis - increasing severity predicts negative impacts on maternal and infant sleep: a mixed methods study.

BACKGROUND: While the impacts of atopic dermatitis (AD) on maternal and child sleep outcomes have been previously explored, less is known about the associations between infantile AD and sleep quality and quantity. OBJECTIVE: To describe the perceived causes of AD-associated maternal sleep disturbances and the association between AD severity and infant sleep outcomes. METHODS: Mothers with infants aged < 19 months old with a diagnosis of AD were recruited from social media and medical clinics in Winnipeg, Canada between October 2021 and May 2022. Infant AD severity was classified using maternal-reported data on the Patient-Oriented Scoring Atopic Dermatitis tool (PO-SCORAD). Quantitative data were collected via a series of questionnaires with a subset of mothers subsequently completing semi-structured interviews. Quantitative and qualitative data were integrated in the discussion. RESULTS: Mothers of infants with moderate/severe AD (6/12) were more likely to report their infant suffering from a higher degree of sleeplessness (i.e., ≥ 5 on a scale of 0-10) over the past 48 h compared to mothers of infants with mild AD (0/18). This was supported by qualitative findings where mothers described how their infant's sleep quality and quantity worsened with AD severity. Additionally, 7/32 mothers reported that their child's AD, regardless of severity, disturbed their sleep. Maternal sleep loss was most commonly attributed to infant itching (6/7), followed by worry (4/7). CONCLUSION: Infantile AD severity was associated with worse sleep outcomes for both mothers and infants. We propose that maternal and infantile sleep quality and quantity can be improved by reducing AD severity through adherence to topical treatments.

Lung function in young adulthood in relation to moderate-to-late preterm birth.

Background: Moderate-to-late preterm birth (32 to <37 weeks of gestation) has been associated with impaired lung function in adolescence, but data in adulthood and physiological phenotyping beyond spirometry are scarce. We aimed to investigate lung function development from adolescence into young adulthood and to provide physiological phenotyping in individuals born moderate-to-late preterm. Methods: Lung function data from individuals born moderate-to-late preterm (n=110) and term (37 to <42 weeks of gestation, n=1895) in the Swedish birth cohort BAMSE were used for analysis and included dynamic spirometry, fractional exhaled nitric oxide and multiple breath nitrogen wash-out. Data from 16- and 24-year follow-ups were analysed using regression models stratified on sex and adjusted for smoking. Data-driven latent class analysis was used to phenotype moderate-to-late preterm individuals at 24 years, and groups were related to background factors. Results: Males born moderate-to-late preterm had lower forced expiratory volume in 1 s (FEV1) at 24 years of age (-0.28 z-score, p=0.045), compared to males born term. In females, no difference was seen at 24 years, partly explained by a significant catch up in FEV1 between 16 and 24 years (0.18 z-score, p=0.01). Lung function phenotypes described as "asthma-like", "dysanapsis-like" and "preterm reference" were identified within the preterm group. Maternal overweight in early pregnancy was associated with "asthma-like" group membership (OR 3.59, p=0.02). Conclusion: Our results show impaired FEV1 at peak lung function in males born moderate-to-late preterm, while females born moderate-to-late preterm had significant catch up between the ages of 16 and 24 years. Several phenotypes of lung function impairment exist in individuals born moderate-to-late preterm.

Infantile atopic dermatitis and maternal-infant bonding: a mixed methods study.

BACKGROUND: Childhood atopic dermatitis can have a negative effect on caregivers' quality of life and stress levels due to the burdensome nature of its treatment. Given that the condition often emerges in infancy, atopic dermatitis-related stress also carries the potential to negatively affect the developing mother-infant bond. While it is plausible that atopic dermatitis has a negative impact on maternal-infant bonding, these relationships have not been studied directly. In light of this gap, the current study investigated the association between infantile atopic dermatitis and the maternal-infant bond using a mixed-method design. METHODS: Mothers of infants (< 19 months) with atopic dermatitis were recruited from social media and medical clinics between October 2021 and May 2022. Mothers with infants unaffected by inflammatory skin conditions were also recruited to serve as a control group. Participants were asked to complete questionnaires related to their demographics, child's health, and mother-infant bond. Multiple linear regression analyses were used to assess bonding quality among cases and controls. A subset of cases were also asked to participate in semi-structured interviews focused on infantile atopic dermatitis and the maternal-infant bond. RESULTS: The final sample consisted of 32 cases and 65 controls. Scores on the impaired bonding and risk of abuse subscales did not significantly differ between cases and controls. However, mothers of infants with atopic dermatitis did report lower levels of caregiving anxiety (b = - 1.47, p < 0.01) and pathological anger/rejection (b = - 1.74, p = 0.02) relative to controls. Qualitative findings suggest that the topical therapies required to manage atopic dermatitis may strengthen the bond between some mothers and infants. CONCLUSION: Findings suggest that atopic dermatitis does not have a negative impact on maternal-infant bonding and may actually improve bonds in some cases. In light of this finding, clinicians may leverage the potentially positive impact of atopic dermatitis-related caregiving on the maternal-infant bond to encourage caregivers to remain adherent to their child's topical treatments.

Assessing tobacco use in Swedish young adults from self-report and urinary cotinine: a validation study using the BAMSE birth cohort.

OBJECTIVES: Studies on health effects of tobacco often rely on self-reported exposure data, which is subjective and can lead to misclassification. The aim of this study was to describe the prevalence of cigarette smoking, snus and e-cigarette use, as well as to validate self-reported tobacco use among young adults in Sweden. METHOD: Participants of a population-based Swedish cohort (n=3052), aged 22-25 years, assessed their tobacco use in a web questionnaire. Urinary cotinine was analysed in a subsample of the study population (n=998). The agreement between self-reported tobacco use and urinary cotinine was assessed using Cohen's Kappa coefficient (κ) at a cut-off level of 50 ng/mL. RESULTS: Patterns of tobacco use differed between men and women. Among men, 20.0% reported daily snus use, 5.8% daily cigarette smoking and 5.6% any e-cigarette use. In contrast, 3.2% of the women reported daily snus use, 9.0% daily cigarette smoking and 2.4% any e-cigarette use. Among the tobacco use categories, daily snus users had the highest levels of cotinine. Of reported non-tobacco users, 3.5% had cotinine levels above the cut-off, compared with 68.0% among both occasional cigarette smokers and snus users, 67.5% among all e-cigarette users and 94.7% and 97.8% among daily cigarette smokers and snus users, respectively. Agreement between self-reported tobacco use and urinary cotinine was classified as strong for daily use of cigarettes (κ=0.824) and snus (κ=0.861), while moderate to weak for occasional smoking (κ=0.618), occasional snus use (κ=0.573) and any e-cigarette use (κ=0.576). CONCLUSIONS: We found high validity of self-reported tobacco use in our study population, particularly for daily tobacco use. Further, we found that daily snus users were exposed to high levels of cotinine. Together with previous findings, our results indicate good validity of self-reported tobacco use among young adults.

Post COVID-19 symptoms are common, also among young adults in the general population.

Post coronavirus disease-19 (post COVID-19) is mainly studied in clinical populations and less is known about post COVID-19 in a young general population. The aim of the study is to investigate the prevalence and symptoms of post COVID-19 and its potential risk factors in young adults. Participants from the Swedish population-based birth cohort BAMSE were included (n = 2022, mean age 26.5 years). Post COVID-19 was assessed through a questionnaire and defined as symptoms after confirmed COVID-19 (registry-based or self-reported positive test) lasting for ≥ 2 months. In total, 681 participants had had confirmed COVID-19. Among them, 112 (16.5%) fulfilled the definition of post COVID-19 (17.8% in females, 14.5% in males, p = 0.26). The most common post COVID-19 symptoms were altered smell and taste (68.8%), dyspnea (33.7%) and fatigue (30.4%). Overall, no major risk factors for post COVID-19 were identified except for being bedbound during COVID-19. However, asthma and rhinitis were associated with the post COVID-19 symptom dyspnea, migraine with altered smell and taste, and lower self-rated health with fatigue. In conclusion, post COVID-19 symptoms are common, also among young adults in the general population. Although not life-threatening, it could have a considerable impact on public health due to the high prevalence and long-term symptoms.

Dietary fibre in relation to lung function and respiratory symptoms from childhood to adulthood.

Background: Epidemiological studies suggest beneficial associations between dietary fibre intake, lung function and chronic respiratory symptoms in adults. Our aim was to investigate the association between dietary fibre intake in childhood and respiratory health up to adulthood. Methods: The individual fibre intake of 1956 participants from the Swedish population-based birth cohort BAMSE was estimated from 98- and 107-item food frequency questionnaires at ages 8 and 16 years, respectively. At 8, 16 and 24 years, lung function was measured by spirometry. Respiratory symptoms (cough, mucus production, breathing difficulties/wheeze) were assessed by questionnaires, and airway inflammation by exhaled nitric oxide fraction (FENO) (≥25 ppb) at 24 years. Longitudinal associations with lung function were analysed by mixed-effects linear regression; associations with respiratory symptoms and airway inflammation were analysed by logistic regression, adjusting for potential confounders. Results: There were no associations between fibre intake at 8 years, as total and from different sources, spirometry measurements and respiratory symptoms at 24 years. Higher fruit fibre intake tended to be inversely associated with airway inflammation at 24 years (OR 0.70, 95% CI 0.48-1.00), which became non-significant after exclusion of participants with food-related allergic symptoms (OR 0.74, 95% CI 0.49-1.10). No associations between fibre intake at 8 and 16 years as an updated lagged exposure and spirometry measurements up to 24 years were observed. Conclusion: In this longitudinal study, we observed no consistent association between dietary fibre intake in childhood and lung function or respiratory symptoms up to adulthood. Further research on dietary fibre in relation to respiratory health across the life course is needed.

Ambient air pollution exposure linked to long COVID among young adults: a nested survey in a population-based cohort in Sweden.

Background: Post COVID-19 conditions, also known as long COVID, are of public health concern, but little is known about their underlying risk factors. We aimed to investigate associations of air pollution exposure with long COVID among Swedish young adults. Methods: We used data from the BAMSE (Children, Allergy, Environment, Stockholm, Epidemiology [in Swedish]) cohort. From October 2021 to February 2022 participants answered a web-questionnaire focusing on persistent symptoms following acute SARS-CoV-2 infection. Long COVID was defined as symptoms after confirmed infection with SARS-CoV-2 lasting for two months or longer. Ambient air pollution levels (particulate matter ≤2.5 µm [PM2.5], ≤10 µm [PM10], black carbon [BC] and nitrogen oxides [NOx]) at individual-level addresses were estimated using dispersion modelling. Findings: A total of 753 participants with SARS-CoV-2 infection were included of whom 116 (15.4%) reported having long COVID. The most common symptoms were altered smell/taste (n = 80, 10.6%), dyspnea (n = 36, 4.8%) and fatigue (n = 34, 4.5%). Median annual PM2.5 exposure in 2019 (pre-pandemic) was 6.39 (interquartile range [IQR] 6.06-6.71) µg/m3. Adjusted Odds Ratios (95% confidence intervals) of PM2.5 per IQR increase were 1.28 (1.02-1.60) for long COVID, 1.65 (1.09-2.50) for dyspnea symptoms and 1.29 (0.97-1.70) for altered smell/taste. Positive associations were found for the other air pollutants and remained consistent across sensitivity analyses. Associations tended to be stronger among participants with asthma, and those having had COVID during 2020 (versus 2021). Interpretation: Ambient long-term PM2.5 exposure may affect the risk of long COVID in young adults, supporting efforts for continuously improving air quality. Funding: The study received funding from the Swedish Research Council (grant no. 2020-01886, 2022-06340), the Swedish Research Council for Health, Working life and Welfare (FORTE grant no. 2017-01146), the Swedish Heart-Lung Foundation, Karolinska Institute (no. 2022-01807) and Region Stockholm (ALF project for cohort and database maintenance).

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.

Obese asthma phenotypes display distinct plasma biomarker profiles.

BACKGROUND: Obese asthma is a complex phenotype and further characterization of the pathophysiology is needed. This study aimed to explore inflammation-related plasma biomarkers in lean and overweight/obese asthmatics. METHODS: We elucidated levels of inflammation-related plasma proteins in obese asthma phenotypes in the population-based cohort BAMSE (Swedish: Children, Allergy, Milieu, Stockholm, Epidemiology) using data from 2069 24-26-year-olds. Subjects were divided into lean asthma (n = 166), lean controls (n = 1440), overweight/obese asthma (n = 73) and overweight/obese controls (n = 390). Protein levels (n = 92) were analysed using the Olink Proseek Multiplex Inflammation panel. RESULTS: Of the 92 included proteins, 41 were associated with lean and/or overweight/obese asthma. The majority of proteins associated with overweight/obese asthma also associated with overweight/obesity among non-asthmatics. Beta-nerve growth factor (BetaNGF), interleukin 10 (IL-10), and matrix metalloproteinase 10 (MMP10) were associated only with lean asthma while C-C motif chemokine 20 (CCL20), fibroblast growth factor 19 (FGF19), interleukin 5 (IL-5), leukemia inhibitory factor (LIF), tumor necrosis factor ligand superfamily member 9 (TNFRSF9), and urokinase-type plasminogen activator (uPA) were associated only with overweight/obese asthma. Overweight/obesity modified the association between asthma and 3 of the proteins: fibroblast growth factor 21 (FGF21), interleukin 4 (IL-4), and urokinase-type plasminogen activator (uPA). In the overweight/obese group, interleukin-6 (IL-6) was associated with non-allergic asthma but not allergic asthma. CONCLUSION: These data indicate distinct plasma protein phenotypes in lean and overweight/obese asthmatics which, in turn, can impact upon therapeutic approaches.

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.

Dietary fibre in relation to asthma, allergic rhinitis and sensitization from childhood up to adulthood.

Background: Dietary fibre may reduce the risk of allergy. Our aim was to investigate the association between fibre intake in childhood, asthma, allergic rhinitis and IgE sensitization up to adulthood. Methods: The individual fibre intake of 2285 participants from the Swedish population-based birth cohort BAMSE was estimated between 98- and 107-item food frequency questionnaires at ages 8 and 16 years, respectively. At 8, 16 and 24 years, asthma and allergic rhinitis symptoms were assessed by questionnaires, and sensitization to common allergens by serum IgE. Longitudinal associations were analysed by generalized estimating equations, adjusting for potential confounders. Results: An inverse overall association was indicated between fibre intake at 8 years and allergic rhinitis symptoms up to 24 years (OR per 5 g/d 0.86; 95% CI 0.77-0.96), particularly in combination with airborne (0.74; 0.62-0.89) and food (0.69; 0.54-0.88) allergen sensitization. Higher fibre intake was also associated with specific allergen sensitization, for example, birch (0.77; 0.67-0.88) and soy (0.68; 0.53-0.87). No association was observed with asthma. Regarding sources, fruit (0.79; 0.67-0.94) and other (potatoes, chips/popcorn, legumes, and nuts, 0.71; 0.50-0.99), but not cereal or vegetable fibre were associated with allergic rhinitis. In additional analyses, including long-term fibre intake at 8 and 16 years, excluding participants with food-related allergic symptoms to examine reverse causation, as well as adjusting for antioxidant intake, associations were attenuated and became non-significant. Conclusion: Higher fibre intake in mid-childhood may be inversely associated with allergic rhinitis and sensitization to specific allergens up to adulthood. However, avoidance of food triggers of allergic symptoms in allergic rhinitis patients may contribute to the protective associations.

Lung function in young adulthood: differences between males and females with asthma.

Background: There are phenotypic differences in asthma in males and females. Differences in lung function between the sexes at the peak lung function level in young adulthood are so far not directly addressed. The aim of the present study was to assess lung function in early adulthood in males and females depending on asthma onset and remission. Methods: Participants were included from the population-based birth cohort BAMSE and classified as having: never asthma, childhood asthma in remission, adolescent onset asthma or persistent asthma. Pre- and post-bronchodilator lung function (in Z-score) and lung clearance index (LCI) were measured at age 24 years. Lung function was compared stratified for sex between the never asthma and asthma groups univariately and in multiple linear regression analyses adjusted for maternal and paternal asthma, maternal smoking during pregnancy, secondary smoking, daily smoking, early respiratory syncytial virus infection, traffic pollution, childhood allergic sensitisation, and body mass index at age 24 years. Results: All asthma phenotypes were associated with a lower forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) post-bronchodilation at 24 years. This was most pronounced in males with persistent asthma compared to males with never asthma (regression coefficient: -0.503; 95% CI: -0.708- -0.298). Childhood asthma (in remission or persistent) was associated with a lower FEV1. After adjustment, the associations remained significant for males. For females, the significant associations with lower FEV1 and FEV1/FVC remained only for subjects with asthma in remission. Persistent asthma was associated with higher LCI in females. Conclusions: In females, in contrast to males, the association between asthma and lower lung function was attenuated after adjustment for known risk factors.

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.

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.