Prenatal vitamin D supplementation to prevent childhood asthma: 15-year results from the Vitamin D Antenatal Asthma Reduction Trial (VDAART).

This article provides an overview of the findings obtained from the Vitamin D Antenatal Asthma Reduction Trial (VDAART) spanning a period of 15 years. The review covers various aspects, including the trial's rationale, study design, and initial intent-to-treat analyses, as well as an explanation of why those analyses did not achieve statistical significance. Additionally, the article delves into the post hoc results obtained from stratified intent-to-treat analyses based on maternal vitamin D baseline levels and genotype-stratified analyses. These results demonstrate a statistically significant reduction in asthma among offspring aged 3 and 6 years when comparing vitamin D supplementation (4400 IU/d) to the standard prenatal multivitamin with vitamin D (400 IU/d). Furthermore, these post hoc analyses found that vitamin D supplementation led to a decrease in total serum IgE levels and improved lung function in children compared to those whose mothers received a placebo alongside the standard prenatal multivitamin with vitamin D. Last, the article concludes with recommendations regarding the optimal dosing of vitamin D for pregnant women to prevent childhood asthma as well as suggestions for future trials in this field.

Preschool impulse oscillometry predicts active asthma and impaired lung function at school age.

BACKGROUND: Asthmatic symptoms often start during early childhood. Impulse oscillometry (IOS) is feasible in preschool children who may be unable to reliably perform spirometry measurements. OBJECTIVE: We sought to evaluate the use of IOS in a multicenter, multiethnic high-risk asthma cohort titled the Vitamin D Antenatal Asthma Reduction Trial. METHODS: The trial recruited pregnant women whose children were followed from birth to age 8 years. Lung function was assessed with IOS at ages 4, 5, and 6 years and spirometry at ages 5, 6, 7, and 8 years. Asthma status, respiratory symptoms, and medication use were assessed with repeated questionnaires from birth to age 8 years. RESULTS: In total, 220 children were included in this secondary analysis. Recent respiratory symptoms and short-acting ß2-agonist use were associated with increased respiratory resistance at 5 Hz at age 4 years (ß = 2.6; 95% CI, 1.0 to 4.4; P = .002 and ß = 3.4; 95% CI, 0.7 to 6.2; P = .015, respectively). Increased respiratory resistance at 5 Hz at age 4 years was also associated with decreased lung function from ages 5 to 8 years (ß = -0.3; 95% CI, -0.5 to -0.1; P < .001 for FEV1 at 8 years) and active asthma at age 8 years (ß = 2.0; 95% CI, 0.2 to 3.8; P = .029). CONCLUSIONS: Increased respiratory resistance in preschool IOS is associated with frequent respiratory symptoms as well as school-age asthma and lung function impairment. Our findings suggest that IOS may serve as a potential objective measure for early identification of children who are at high risk of respiratory morbidity.

Blood stored in EDTA tubes provides accurate peanut basophil activation test results for 48 hours.

BACKGROUND: The peanut basophil activation test (BAT) has demonstrated excellent diagnostic accuracy with heparinized blood, but its clinical utility is limited by the short stability of samples stored in this anticoagulant. OBJECTIVE: Using EDTA anticoagulated blood, these investigations determined if Peanut BAT sample stability can be extended to 2 days, the minimum stability requirement for diagnostic tests currently offered through American reference laboratories. METHODS: Peanut non-allergic control (NAC), peanut IgE sensitized (PS), and peanut allergic (PA) children aged 6 months through 17 years were recruited from members of Kaiser Permanente Southern California. EDTA anti-coagulated blood samples were collected from participants, shipped to a centralized laboratory, and stored at 4oC for peanut BAT testing 1 and 2 days later. RESULTS: Peanut BAT results for 23 unblinded participants were used to establish sample rejection and interpretation criteria that were subsequently validated in a prospective double-blind study involving 112 additional children (39-NAC, 36-PS, 37-PA). Of 105 blinded blood samples tested on each study day, 88 (84%) day-1 and 90 (86%) day-2 peanut BAT results were considered interpretable, with diagnostic accuracies of 95.5% and 94.4%, respectively. Moreover, all interpretable PA results were considered positive (100% sensitivity). CONCLUSION: Using EDTA anti-coagulated blood samples collected remotely, 1 and 2 days before testing, study results highlight the favorable diagnostic performance characteristics of the peanut BAT and provide further evidence that the test could be readily operationalized for clinical use by interested commercial reference laboratories.

Advancing assessment of asthma control with a composite tool: The Asthma Impairment and Risk Questionnaire.

BACKGROUND: National and international asthma guidelines and reports do not include control tools that combine impairment assessment with exacerbation history in one instrument. OBJECTIVE: To analyze the performance of the composite Asthma Impairment and Risk Questionnaire (AIRQ) in assessing both domains of control and predicting exacerbation risk compared with the Global Initiative for Asthma (GINA) 4-question symptom control tool (GINA SCT), Asthma Control Test (ACT), and physician expert opinion (EO) informed by GINA SCT responses and appraisal of GINA-identified risk factors for poor asthma outcomes. METHODS: Multivariable logistic regressions evaluated AIRQ and GINA SCT as predictors of ACT. McNemar's test compared the proportion of patients categorized at baseline as completely or well-controlled by each assessment but with current impairment or previous-year and subsequent-year exacerbations. RESULTS: The analysis included 1064 patients aged 12 years or older; mean (SD) age 43.8 years (19.3); 70% female; 79% White; and 6% Hispanic or Latino. AIRQ and GINA SCT were highly predictive of ACT well-controlled vs not well-controlled and very poorly controlled (receiver operator characteristic area under curve AIRQ = 0.90, GINA SCT = 0.86, P = .03 AIRQ vs GINA SCT) and ACT very poorly controlled vs well-controlled and not well-controlled asthma (receiver operator characteristic area under curve AIRQ = 0.91, GINA SCT = 0.87, P = .01 AIRQ vs GINA SCT). AIRQ rated fewer patients as having completely or well-controlled asthma who had current impairment (P < .01) or with previous-year and subsequent-year exacerbations (P < .001) than did GINA SCT, ACT, and EO. CONCLUSION: AIRQ performs better in assessing both domains of current control and predicting exacerbation risk than do control tools and EO informed by GINA SCT and risk factors for poor asthma outcomes.

Assessing meaningful change in the Asthma Impairment and Risk Questionnaire.

BACKGROUND: The Asthma Impairment and Risk Questionnaire (AIRQ) is a 10-item, yes/no, equally weighted control tool. Lower scores indicate better control. Moreover, 7 impairment items reflect previous 2-week symptoms, and 3 risk items assess previous 12-month exacerbations. The Follow-up AIRQ for use between annual assessments has a 3-month recall period for exacerbation items. OBJECTIVE: To evaluate the responsiveness of the AIRQ over time and identify a minimal important difference (MID). METHODS: The AIRQ longitudinal study data were analyzed from patients with asthma aged 12 years and older. Anchor-based methods assessed differences in AIRQ scores relative to Patient Global Impression of Change, the accepted MIDs for St. George's Respiratory Questionnaire and Asthma Control Test, and exacerbation occurrence over 12 months. Baseline and 12-month data reflected 12-month recall AIRQ scores; Follow-up AIRQ scores were used for 3-, 6-, and 9-month analyses. RESULTS: A total of 1070 patients were included. The Patient Global Impression of Change rating of "much improved" was associated with AIRQ mean score changes from baseline to months 3, 6, 9, and 12 of -2.0, -1.9, -1.9, and -1.8, respectively. The mean AIRQ score change among patients who met the St. George's Respiratory Questionnaire MID (≥4-point decrease) was -1.8 at 6 and 12 months. The AIRQ mean scores decreased from baseline by -2.2 to -2.5 points at months 3, 6, 9, and 12 for patients who met the Asthma Control Test MID (≥ 3-point increase). A 2-point higher baseline AIRQ score was associated with a 1.7 odds ratio of 12-month exacerbation occurrence (95% CI, 1.53-1.89). CONCLUSION: A change score of 2 is recommended as the AIRQ MID.

Maternal vitamin D status modifies the effects of early life tobacco exposure on child lung function.

BACKGROUND: Prior studies suggest that vitamin D may modify the effects of environmental exposures; however, none have investigated gestational vitamin D and cumulative tobacco smoke exposure (TSE) throughout pregnancy and early life. OBJECTIVES: This study investigated the effects of early life TSE on child lung function and the modulatory effects of gestational vitamin D on this association. METHODS: The VDAART (Vitamin D Antenatal Asthma Reduction Trial) recruited nonsmoking pregnant women and followed the mother-child pairs to age 6 years. TSE was assessed with questionnaires and plasma cotinine measurements in the mothers (10-18 and 32-38 gestational weeks) and children (1, 3, and 6 years). Cumulative TSE was calculated from the repeated cotinine measurements. 25-hydroxyvitamin D (25[OH]D) levels were measured at 10-18 and 32-38 gestational weeks. Lung function was assessed at 6 years with spirometry and impulse oscillometry. RESULTS: Of the 476 mother-child pairs, 205 (43%) had increased cotinine levels at ≥1 time point. Cumulative TSE was associated with decreased FEV1 (ß = -0.043 L, P = .018) and increased respiratory resistance at 5 Hz (R5; ß = 0.060 kPa/L/s, P = .002). This association persisted in subjects with insufficient (<30 ng/mL) 25(OH)D levels throughout pregnancy (ß = 0.077 kPa/L/s, P = .016 for R5) but not among those with sufficient levels throughout pregnancy. CONCLUSIONS: Cumulative TSE from pregnancy to childhood is associated with dose- and duration-dependent decreases in child lung function at 6 years even in the absence of reported maternal smoking. Gestational vitamin D may modulate this effect and have therapeutic potential for minimizing the adverse effect of TSE on lung throughout early life. RANDOMIZED TRIAL: Maternal Vitamin D Supplementation to Prevent Childhood Asthma (VDAART); clinicaltrials.gov identifier: NCT00920621.

Six-Year Follow-up of a Trial of Antenatal Vitamin D for Asthma Reduction.

BACKGROUND: We previously reported the results of a trial of prenatal vitamin D supplementation to prevent asthma and recurrent wheeze in young children, which suggested that supplementation provided a protective effect at the age of 3 years. We followed the children through the age of 6 years to determine the course of asthma and recurrent wheeze. METHODS: In this follow-up study, investigators and participants remained unaware of the treatment assignments through the children's sixth birthday. We aimed to determine whether, when maternal levels of 25-hydroxyvitamin D were taken into account, children born to mothers who had received 4400 IU of vitamin D3 per day during pregnancy (vitamin D group) would have a lower incidence of asthma and recurrent wheeze at the age of 6 years than would those born to mothers who had received 400 IU of vitamin D3 per day (control group). Time-to-event methods were used to compare the treatment groups with respect to time to the onset of asthma or recurrent wheeze. Multivariate methods were used to compare longitudinal measures of lung function between the treatment groups. RESULTS: There was no effect of maternal vitamin D supplementation on asthma and recurrent wheeze in either an intention-to-treat analysis or an analysis with stratification according to the maternal 25-hydroxyvitamin D level during pregnancy. There was no effect of prenatal vitamin D supplementation on most of the prespecified secondary outcomes. We found no effects of prenatal supplementation on spirometric indexes. Although there was a very small effect on airway resistance as measured by impulse oscillometry, this finding was of uncertain significance. CONCLUSIONS: Vitamin D supplementation during the prenatal period alone did not influence the 6-year incidence of asthma and recurrent wheeze among children who were at risk for asthma. (Funded by the National Heart, Lung, and Blood Institute; VDAART ClinicalTrials.gov number, NCT00920621.).

Dupilumab leads to better-controlled asthma and quality of life in children: the VOYAGE study.

BACKGROUND: Dupilumab has shown long-term treatment benefits in children with uncontrolled asthma. We assessed in more detail the impact of dupilumab on asthma control and health-related quality of life (HRQoL) in children and their caregivers. METHODS: Children aged 6-11 years with uncontrolled moderate-to-severe type 2 asthma (baseline blood eosinophils ≥150 cells·µL-1 or fractional exhaled nitric oxide ≥20 ppb; n=350) were treated with dupilumab or placebo for 52 weeks in the VOYAGE study. Primary outcomes of these analyses were asthma control (change from baseline in Asthma Control Questionnaire 7 Interviewer-Administered (ACQ-7-IA) and achieving a clinically meaningful response of ≥0.5 points); proportion of patients achieving well-controlled asthma or better (ACQ-7-IA ≤0.75 points); effect on patients' (Standardised Paediatric Asthma Quality of Life Questionnaire Interviewer-Administered (PAQLQ(S)-IA)) and caregivers' (Paediatric Asthma Caregiver's Quality of Life Questionnaire (PACQLQ)) HRQoL; and allergic rhinitis-related QoL. RESULTS: Dupilumab versus placebo significantly improved children's ACQ-7-IA scores by week 4 with sustained improvements through week 52 (least squares mean difference at week 52: -0.44, 95% CI -0.59- -0.30; p<0.0001); a higher proportion achieved a clinically meaningful response (week 52: 86% versus 75%; p=0.0051). At weeks 24 and 52, more children who received dupilumab achieved well-controlled asthma (ACQ-7-IA ≤0.75 points: 61% versus 43%; p=0.0001 and 70% versus 46%; p<0.0001, respectively). Significant improvements in PAQLQ(S)-IA and PACQLQ scores were observed by week 52. CONCLUSIONS: In children aged 6-11 years with moderate-to-severe type 2 asthma, dupilumab treatment was associated with rapid, sustained improvements in asthma control. HRQoL was significantly improved for children and their caregivers.

Early-life fecal metabolomics of food allergy.

BACKGROUND: Intestinal microenvironmental perturbations may increase food allergy risk. We hypothesize that children with clinical food allergy, those with food sensitization, and healthy children can be differentiated by intestinal metabolites in the first years of life. METHODS: In this ancillary analysis of the Vitamin D Antenatal Asthma Reduction Trial (VDAART), we performed untargeted metabolomic profiling in 824 stool samples collected at ages 3-6 months, 1 year and 3 years. Subjects included 23 with clinical food allergy at age 3 and/or 6 years, 151 with food sensitization but no clinical food allergy, and 220 controls. We identified modules of correlated, functionally related metabolites and sought associations of metabolite modules and individual metabolites with food allergy/sensitization using regression models. RESULTS: Several modules of functionally related intestinal metabolites were reduced among subjects with food allergy, including bile acids at ages 3-6 months and 1 year, amino acids at age 3-6 months, steroid hormones at 1 year, and sphingolipids at age 3 years. One module primarily containing diacylglycerols was increased in those with food allergy at age 3-6 months. Fecal caffeine metabolites at age 3-6 months, likely derived from breast milk, were increased in those with food allergy and/or sensitization (beta = 5.9, 95% CI 1.0-10.8, p = .02) and were inversely correlated with fecal bile acids and bilirubin metabolites, though maternal plasma caffeine levels were not associated with food allergy and/or sensitization. CONCLUSIONS: Several classes of bioactive fecal metabolites are associated with food allergy and/or sensitization including bile acids, steroid hormones, sphingolipids, and caffeine metabolites.

The maternal prenatal and offspring early-life gut microbiome of childhood asthma phenotypes.

BACKGROUND: The infant fecal microbiome is known to impact subsequent asthma risk, but the environmental exposures impacting this association, the role of the maternal microbiome, and how the microbiome impacts different childhood asthma phenotypes are unknown. METHODS: Our objective was to identify associations between features of the prenatal and early-life fecal microbiomes and child asthma phenotypes. We analyzed fecal 16 s rRNA microbiome profiling and fecal metabolomic profiling from stool samples collected from mothers during the third trimester of pregnancy (n = 120) and offspring at ages 3-6 months (n = 265), 1 (n = 436) and 3 years (n = 506) in a total of 657 mother-child pairs participating in the Vitamin D Antenatal Asthma Reduction Trial. We used clinical data from birth to age 6 years to characterize subjects with asthma as having early, transient or active asthma phenotypes. In addition to identifying specific genera that were robustly associated with asthma phenotypes in multiple covariate-adjusted models, we clustered subjects by their longitudinal microbiome composition and sought associations between fecal metabolites and relevant microbiome and clinical features. RESULTS: Seven maternal and two infant fecal microbial taxa were robustly associated with at least one asthma phenotype, and a longitudinal gut microenvironment profile was associated with early asthma (Fisher exact test p = .03). Though mode of delivery was not directly associated with asthma, we found substantial evidence for a pathway whereby cesarean section reduces fecal Bacteroides and microbial sphingolipids, increasing susceptibility to early asthma. CONCLUSION: Overall, our results suggest that the early-life, including prenatal, fecal microbiome modifies risk of asthma, especially asthma with onset by age 3 years.

The Asthma Impairment and Risk Questionnaire enhances the assessment of asthma control.

BACKGROUND: Asthma control is often overestimated in routine practice, and despite advances in the understanding of immunopathology and the availability of new precision therapies, the burden of disease remains unacceptably high. OBJECTIVE: To compare the performance of the Asthma Impairment and Risk Questionnaire (AIRQ) with patient and physician assessments and the Asthma Control Test (ACT) in identifying asthma control. METHODS: Baseline data from a longitudinal study of the AIRQ were analyzed. Patients with asthma in the United States aged 12 years and older followed in 24 specialty practices and 1 specialty-affiliated primary care clinic were enrolled between May and November 2019. At entry, participants completed AIRQ and ACT, and participants and physicians completed 5-point Likert scale assessments of control. RESULTS: A total of 1112 participants were enrolled (mean [SD] age = 43.9 [19.3] years, 70% of the female sex, 78% White). Overall, 62% of participants rated themselves as well- or completely controlled, and 54% were rated comparably by physicians. The ACT classified 49% of participants as well-controlled, with 35% similarly categorized by AIRQ. Previous-year exacerbations were experienced by 32% of participants who self-rated as well- or completely controlled, 30% who were rated as well- or completely controlled by physicians, and 29% assessed as well-controlled by ACT, but only 15% of those classified as well-controlled by AIRQ. CONCLUSION: The burden of asthma is substantial in patients cared for by asthma specialists, and asthma control is overestimated by patients, physicians, and the symptom-based ACT. The AIRQ assesses risk in addition to symptom control and may serve to improve asthma control determination by assessing previous exacerbations.

Association of the gut microbiome and metabolome with wheeze frequency in childhood asthma.

BACKGROUND: While the microbiome has an established role in asthma development, less is known about its contribution to morbidity in children with asthma. OBJECTIVE: In this ancillary study of the Vitamin D Antenatal Asthma Reduction Trial (VDAART), we analyzed the gut microbiome and metabolome of wheeze frequency in children with asthma. METHODS: Bacterial 16S ribosomal RNA microbiome and untargeted metabolomic profiling were performed on fecal samples collected from 3-year-old children with parent-reported physician-diagnosed asthma. We analyzed wheeze frequency by calculating the proportion of quarterly questionnaires administered between ages 3 and 5 years in which parents reported the child had wheezed (wheeze proportion). Taxa and metabolites associated with wheeze were analyzed by identifying log fold changes with respect to wheeze frequency and correlation/linear regression analyses, respectively. Microbe-metabolite and microbe-microbe correlation networks were compared between subjects with high and low wheeze proportion. RESULTS: Specific taxa, including the genus Veillonella and histidine pathway metabolites, were enriched in subjects with high wheeze proportion. Among wheeze-associated taxa, Veillonella and Oscillospiraceae UCG-005, which was inversely associated with wheeze, were correlated with the greatest number of fecal metabolites. Microbial networks were similar between subjects with low versus high wheeze frequency. CONCLUSION: Gut microbiome features are associated with wheeze frequency in children with asthma, suggesting an impact of the gut microbiome on morbidity in childhood asthma.

Impact of cannabis knowledge and attitudes on real-world practice.

BACKGROUND: Increased cannabis consumption worldwide challenges allergists because of an upsurge in cannabis allergy and need to discuss cannabis with patients. OBJECTIVE: To determine the knowledge, attitudes, and practices regarding cannabis among allergists and their approach to recognizing and diagnosing suspected cannabis allergy. METHODS: The International Allergist Canna Knowledge, Attitudes, and Practices Survey was completed by members from 3 International Allergy Societies. Survey questions included the following: 13 on cannabis attitudes, 7 on cannabis knowledge, and 4 on real-world allergy practices. Knowledge level was dichotomized and Statistical Package for the Social Sciences TwoStep Cluster Analysis grouped participants by attitudes. Multivariate analysis determined the relationship of knowledge and attitude to practice delivery. RESULTS: Of 570 eligible surveys started, 445 (78.1%) were completed. Participants were 49.7% of female sex, 65.9% aged 24 to 56 years, approximately 70% in practice for more than or equal to 10 years, and 29.2% practicing in an area where cannabis use is illegal. Of the respondents, 43.1% reported consulting on patients with suspected cannabis allergy and 54.7% had undertaken skin prick testing, in vitro cannabis testing, or both. Statistically significant differences were found between the 3 societies for most variables analyzed. Analysis of attitudes revealed 3 clusters named Traditional, Progressive, and Unsure. Those with more progressive attitudes toward cannabis and who had more knowledge were more comfortable speaking to patients about cannabis and more often asked patients on how often and how they used cannabis (all P < .001). CONCLUSION: Varying knowledge and attitudes toward cannabis affecting comfort communicating with patients about cannabis were found in members of 3 allergy societies supporting the need for more cannabis research and education.

Evaluating construct validity of the Asthma Impairment and Risk Questionnaire using a 3-month exacerbation recall.

BACKGROUND: Recurrent assessment of asthma control is essential to evaluating disease stability and intervention impacts. An assessment that can be administered between annual clinic visits is needed. The Asthma Impairment and Risk Questionnaire (AIRQ) is a cross-sectionally validated, 10-item, yes or no, composite control tool evaluating previous 2-week symptoms and previous 12-month exacerbations. OBJECTIVE: To evaluate the construct validity of the AIRQ using a 3-month recall period for exacerbation-based risk questions and retaining the 2-week recall for symptom-based impairment items. METHODS: At baseline, patients completed the AIRQ with 12-month recall exacerbation items, Asthma Control Test (ACT), St. George's Respiratory Questionnaire (SGRQ), and global self-assessments of asthma risk, control, and symptom severity. Patient-reported exacerbations were captured monthly. The AIRQ with 3-month recall exacerbation items, ACT, and global self-assessments was administered at months 3, 6, and 9, and SGRQ at month 6. RESULTS: A total of 1112 patients aged 12 years or older were enrolled (mean [SD] age, 43.9 [19.5] years). The AIRQ and each administration of the AIRQ with 3-month recall exacerbation items classified asthma control similarly to an ACT plus exacerbation validation standard. For both AIRQ versions, SGRQ scores were higher with worsening asthma control (P < .001). At months 3, 6, and 9, worse AIRQ control levels were associated with higher proportions of patients with 1 or more and 2 or more exacerbations in the previous 3 months and patient global self-assessments indicating greater asthma morbidity (all P < .001). CONCLUSION: The AIRQ using exacerbation risk items with a 3-month recall period exhibits construct validity for classifying current asthma control and can be administered between annual AIRQ assessments.

Factors Associated with Persistence of Severe Asthma from Late Adolescence to Early Adulthood.

RATIONALE: Asthma severity in children generally starts mild but may progress and stay severe for unknown reasons. OBJECTIVES: Identify factors in childhood that predict persistence of severe asthma in late adolescence and early adulthood. METHODS: The Childhood Asthma Management Program is the largest and longest asthma trial in 1041 children aged 5-12 years with mild to moderate asthma. We evaluated 682 participants from the program with analyzable data in late adolescence (age 17-19) and early adulthood (age 21-23). MEASUREMENTS: Severe asthma was defined using criteria from the American Thoracic Society and the National Asthma Education and Prevention Program to best capture severe asthma. Logistic regression with stepwise elimination was used to analyze clinical features, biomarkers, and lung function predictive of persistence of severe asthma. MAIN RESULTS: In late adolescence and early adulthood 12% and 19% of the patents had severe asthma, respectively; only 6% were severe at both time periods. For every 5% decrease in post bronchodilator FEV1/FVC in childhood, the odds of persistence of severe asthma increased 2.36-fold (95% CI: 1.70-3.28; p <0.0001), for participants with maternal smoking during pregnancy odds of persistence of severe asthma increased 3.17-fold (95% CI: 1.18-8.53, p=0.02). Reduced growth lung function trajectory was significantly associated with persistence of severe asthma compared to normal growth. CONCLUSIONS: Lung function and maternal smoking during pregnancy were significant predictors of severe asthma from late adolescence to early adulthood. Interventions to preserve lung function early may prevent disease progression.

Effect of early and late prenatal vitamin D and maternal asthma status on offspring asthma or recurrent wheeze.

BACKGROUND: Childhood asthma developmental programming is complex. Maternal asthma is a strong risk factor for childhood asthma, whereas vitamin D (VD) has emerged as a modifiable prenatal exposure. OBJECTIVE: Our aim was to examine the combined effect of early and late prenatal VD status in during pregnancies in women with and without asthma on childhood asthma or recurrent wheeze development. METHODS: We conducted a cohort study using prospectively collected data from the Vitamin D Antenatal Asthma Reduction Trial, a randomized, double-blinded, placebo-controlled VD supplementation trial in pregnant women at high risk of offspring asthma (N = 806 mother-offspring pairs). 25-Hydroxyvitamin-D (25(OH)D) level was measured in early and late pregnancy. Our main exposure was an ordered variable representing early and late prenatal VD sufficiency (25(OH)D level ≥ 30 ng/mL) status during pregnancy in women with and without asthma. The primary outcome was offspring with asthma or recurrent wheeze by age 3 years. We also examined the effect of prenatal VD level on early life asthma or recurrent wheeze progression to active asthma at age 6 years. RESULTS: Among mothers with asthma versus among mothers with early and late prenatal VD insufficiency, those with early or late VD sufficiency (adjusted odds ratio = 0.56; 95% CI = 0.31-1.00) or early and late VD sufficiency (adjusted odds ratio = 0.36; 95% CI = 0.15-0.81) had a lower risk of offspring with asthma or recurrent wheeze by age 3 years (Pfor trend = .008). This protective trend was reiterated in asthma or recurrent wheeze progression to active asthma from age 3 to 6 years (Pfor trend = .04). CONCLUSION: This study implies a protective role for VD sufficiency throughout pregnancy, particularly in attenuating the risk conferred by maternal asthma on childhood asthma or recurrent wheeze development.

Low gestational vitamin D level and childhood asthma are related to impaired lung function in high-risk children.

BACKGROUND: Lung function impairment in early life often persists into adulthood. Therefore, identifying risk factors for low childhood lung function is crucial. OBJECTIVE: We examined the effect of 25-hydroxyvitamin D (25[OH]D) level and childhood asthma phenotype on childhood lung function in the Vitamin D Antenatal Asthma Reduction Trial (VDAART). METHODS: The 25(OH)D level was measured at set time points in mothers during pregnancy and in children during early life. On the basis of parental reports, children were categorized into 3 clinical phenotypes: asymptomatic/infrequent wheeze, early transient wheeze, and asthma at age 6 years. Lung function was assessed with impulse oscillometry at ages 4, 5, and 6 years and with spirometry at ages 5 and 6 years. RESULTS: A total of 570 mother-child pairs were included in this post hoc analysis. Mean gestational 25(OH)D-level quartiles were negatively associated with child respiratory resistance at 5 Hz (R5) from age 4 to 6 years (ß, -0.021 kPa/L/s; 95% CI, -0.035 to -0.007; P = .003) and positively associated with FEV1 (ß, 0.018 L; 95% CI, 0.005-0.031; P = .008) and forced vital capacity (ß, 0.022 L; 95% CI, 0.009-0.036; P = .002) from age 5 to 6 years. Children with asthma at age 6 years had lower lung function from age 4 to 6 years than the asymptomatic/infrequent wheeze group (ß, 0.065 kPa/L/s; 95% CI, 0.028 to 0.102; P < .001 for R5 and ß, -0.063 L; 95% CI, -0.099 to -0.028; P < .001 for FEV1). CONCLUSIONS: Low gestational 25(OH)D level and childhood asthma are important risk factors for decreased lung function in early childhood.

Cannabis attitudes and patterns of use among followers of the Allergy & Asthma Network.

BACKGROUND: Cannabis use in patients with allergy/asthma, a high-risk group for adverse effects to cannabis, is unknown. OBJECTIVE: To determine the patterns of use and attitudes toward cannabis in patients with allergy/asthma. METHODS: An anonymous online survey on cannabis attitudes and use was conducted through the Adult Allergy & Asthma Network. The Asthma Control Test assessed asthma burden. Cluster analyses determined group phenotypes and factor analyses condensed cannabis subjective effects into similar response patterns. RESULTS: A total of 88 of 489 respondents (18.0%) currently use cannabis with most at the age of less than 50 years old, of female sex, and of White race. Of the noncannabis users (N = 401), 2.5% reported cannabis allergy. Cluster analysis revealed that a liberal attitude toward cannabis was associated with current cannabis use (P < .001). Among current cannabis users, 40.9% of their physicians inquired on cannabis use; only 37.5% of users wanted to discuss cannabis. In addition, 65.9% used cannabis for medical or medical/recreational purposes. Cannabinoids used were tetrahydrocannabinol (33.0%), cannabidiol (19.3%), or both (47.7%). Smoked and vaped cannabis were reported by 53.4% and 35.2%, respectively. Furthermore, 51 cannabis users (58.0%) reported current asthma with 39.2% uncontrolled; of these, 50% smoked cannabis. Compared with current participants with asthma not using cannabis, those currently using cannabis experienced similar levels of asthma control, quality of life, and frequency of asthma exacerbations. Positive effects were endorsed more than negative effects to cannabis (P < .001). Moreover, 19.3% of cannabis users reported coughing that was associated with smoking cannabis (P < .001). CONCLUSION: Cannabis was used by less than 20% of the respondents with positive effects more frequent than negative effects. Half of cannabis users with uncontrolled asthma smoke cannabis, but only a minority of the physicians inquire about its use.

Generalizability of an Automatic Explanation Method for Machine Learning Prediction Results on Asthma-Related Hospital Visits in Patients With Asthma: Quantitative Analysis.

BACKGROUND: Asthma exerts a substantial burden on patients and health care systems. To facilitate preventive care for asthma management and improve patient outcomes, we recently developed two machine learning models, one on Intermountain Healthcare data and the other on Kaiser Permanente Southern California (KPSC) data, to forecast asthma-related hospital visits, including emergency department visits and hospitalizations, in the succeeding 12 months among patients with asthma. As is typical for machine learning approaches, these two models do not explain their forecasting results. To address the interpretability issue of black-box models, we designed an automatic method to offer rule format explanations for the forecasting results of any machine learning model on imbalanced tabular data and to suggest customized interventions with no accuracy loss. Our method worked well for explaining the forecasting results of our Intermountain Healthcare model, but its generalizability to other health care systems remains unknown. OBJECTIVE: The objective of this study is to evaluate the generalizability of our automatic explanation method to KPSC for forecasting asthma-related hospital visits. METHODS: Through a secondary analysis of 987,506 data instances from 2012 to 2017 at KPSC, we used our method to explain the forecasting results of our KPSC model and to suggest customized interventions. The patient cohort covered a random sample of 70% of patients with asthma who had a KPSC health plan for any period between 2015 and 2018. RESULTS: Our method explained the forecasting results for 97.57% (2204/2259) of the patients with asthma who were correctly forecasted to undergo asthma-related hospital visits in the succeeding 12 months. CONCLUSIONS: For forecasting asthma-related hospital visits, our automatic explanation method exhibited an acceptable generalizability to KPSC. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/resprot.5039.

Impact of Preeclampsia on the Relationship between Maternal Asthma and Offspring Asthma. An Observation from the VDAART Clinical Trial.

RATIONALE: Maternal asthma and preeclampsia have independently been reported to be associated with increased asthma incidence in children of affected mothers. Maternal asthma is also associated with increased risk of preeclampsia development. However, the joint effect of these maternal conditions on child asthma risk is unknown. OBJECTIVES: To study whether development of preeclampsia among pregnant women with asthma was associated with higher risk of childhood asthma in the VDAART (Vitamin D Antenatal Asthma Reduction Trial). METHODS: A total of 806 pregnant women and their offspring at high risk of asthma or atopy, who were followed from VDAART enrollment (10-18 wk of gestation) through the child's third birthday, were included in this cohort analysis. Preeclampsia status was determined by chart review, obstetrician diagnosis, and adjudication by a panel of obstetricians. Child asthma was the main outcome as determined by parental report of a physician diagnosis, and the risk of child asthma was also examined if accompanied by recurrent wheeze. The main risk variable of interest was a four-level ordered variable defined for each mother, with values without asthma without preeclampsia, without asthma with preeclampsia, with asthma without preeclampsia, and with asthma with preeclampsia during their pregnancy. We examined the trend of outcome proportions across these categories. To account for differences in maternal and child characteristics, we used a Weibull regression model for interval-censored data to compare the incidence of child asthma by age of 3 years across the maternal variable categories. MEASUREMENTS AND MAIN RESULTS: The incidence of asthma in 3-year-old children was 9.90% (44/445), 17.95% (7/39), 22.11% (65/294), and 32.14% (9/28) among those born to mothers without asthma and without preeclampsia, mothers without asthma with preeclampsia, mothers with asthma without preeclampsia, and mothers with asthma with preeclampsia, respectively. The incidences demonstrated an increasing trend in risk of child asthma across the maternal groups (P for trend <0.001). After accounting for potential confounders and using time to report of childhood asthma as analysis outcome, risk of asthma was greater among children born to mothers with asthma without preeclampsia, compared with mothers without asthma without preeclampsia (adjusted hazard ratio, 2.18; 95% confidence interval, 1.46-3.26). This risk was 50% greater for children born to mothers with asthma who developed preeclampsia during pregnancy (adjusted hazard ratio, 2.68; 95% confidence interval, 1.30-5.61). The trend in asthma and recurrent wheeze proportions across the maternal groups' children also indicated a higher risk for children born to mothers with asthma with preeclampsia (adjusted hazard ratio, 4.73; 95% confidence interval, 2.20-10.07; P for trend <0.001). CONCLUSIONS: Preeclampsia is associated with increased risk of early life childhood asthma in children less than 3 years old over and above that associated with maternal asthma alone. The results implicate the interplay between maternal factors as strong predictors of offspring asthma and in utero maternal-fetal immune perturbations and developmental dysregulations associated with preeclampsia.