Exposure to violence, chronic stress, nasal DNA methylation, and atopic asthma in children

BACKGROUND

Exposure to violence (ETV) or chronic stress may influence asthma through unclear mechanisms.

METHODS

Epigenome-wide association study (EWAS) of ETV or chronic stress measures and DNA methylation in nasal epithelium from 487 Puerto Ricans aged 9-20 years who participated in the Epigenetic Variation and Childhood Asthma in Puerto Ricans study [EVA-PR]). We assessed four measures of ETV and chronic stress in children (ETV scale, gun violence, and perceived stress) and their mothers (perceived stress). Each EWAS was conducted using linear regression, with CpGs as dependent variables and the stress/violence measure as a predictor, adjusting for age, sex, the top five principal components, and SVA latent factors. We then selected the top 100 CpGs (by p value) associated with each stress/violence measure in EVA-PR and conducted a meta-analysis of the selected CpGs and atopic asthma using data from EVA-PR and two additional cohorts (Project Viva and PIAMA).

RESULTS

Three CpGs (in SNN, PTPRN2, and LINC01164) were associated with maternal perceived stress or gun violence (p = 1.28-3.36 × 10^-7 ), but not with atopic asthma, in EVA-PR. In a meta-analysis of three cohorts, which included the top CpGs associated with stress/violence measures in EVA-PR, 12 CpGs (in STARD3NL, SLC35F4, TSR3, CDC42SE2, KLHL25, PLCB1, BUD13, OR2B3, GALR1, TMEM196, TEAD4, and ANAPC13) were associated with atopic asthma at FDR-p < .05.

CONCLUSIONS

Pending confirmation in longitudinal studies, our findings suggest that nasal epithelial methylation markers associated with measures of ETV and chronic stress may be linked to atopic asthma in children and adolescents.

A genome-wide study of DNA methylation in white blood cells and asthma in Latino children and youth

Latinos are heavily affected with childhood asthma. Little is known about epigenetic mechanisms of asthma in Latino youth. We conducted a meta-analysis of two epigenome-wide association studies (EWAS) of asthma, using DNA from white blood cells (WBCs) from 1,136 Latino children and youth aged 6 to 20 years. Genes near the top CpG sites in this EWAS were examined in a pathway enrichment analysis, and we then assessed whether our results replicated those from publicly available data from three independent EWAS conducted in non-Latino populations. We found that DNA methylation profiles differed between subjects with and without asthma. After adjustment for covariates and multiple testing, two CpGs were differentially methylated at a false discovery rate (FDR)-adjusted P < 0.1, and 193 CpG sites were differentially methylated at FDR-adjusted P < 0.2. The two top CpGs are near genes relevant to inflammatory signalling, including CAMK1D (Calcium/Calmodulin Dependent Protein Kinase ID) and TIGIT (T Cell Immunoreceptor With Ig And ITIM Domains). Moreover, 25 genomic regions were differentially methylated between subjects with and without asthma, at Šidák-corrected P < 0.10. An enrichment analysis then identified the TGF-beta pathway as most relevant to asthma in our analysis, and we replicated some of the top signals from publicly available EWAS datasets in non-Hispanic populations. In conclusion, we have identified novel epigenetic markers of asthma in WBCs from Latino children and youth, while also replicating previous results from studies conducted in non-Latinos.

Testosterone-to-estradiol ratio and lung function in a prospective study of Puerto Rican youth

BACKGROUND

Age- and sex-related differences in asthma may be due to changes in sex hormone levels.

OBJECTIVE

To evaluate whether a change in free testosterone or free testosterone-to-estradiol ratio is associated with changes in lung function and eosinophils in the Puerto Rican youth.

METHODS

We tested for the association between the change in sex hormone levels and change in lung function or change in eosinophils in a prospective study of 317 children (with and without asthma) followed up from ages 6 to 14 years to ages 10 to 20 years (146 females, 171 males) in San Juan, Puerto Rico. Serum levels of testosterone, estradiol, sex hormone-binding globulin, and progesterone were measured at 2 study visits, approximately 4.9 years apart. Using testosterone and sex hormone-binding globulin levels, we derived free testosterone and the free testosterone-to-estradiol ratio. Multivariable linear regression was used for the analysis of change in lung function and eosinophils, conducted separately by sex.

RESULTS

In girls, each quartile increment in the free testosterone-to-estradiol ratio was associated with a 2.03% increment in percent predicted forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) between study visits. In males, each quartile increment in the free testosterone-to-estradiol ratio was associated with a 3.27% increment in percent predicted FEV₁ and a 1.81% increment in percent predicted FEV₁/FVC between study visits. In girls with asthma, an increased free testosterone-to-estradiol ratio was significantly associated with decreased eosinophils between visits (P=0.03).

CONCLUSION

In Puerto Rican youth, increased free testosterone-to-estradiol ratio over time was associated with an increased FEV₁/FVC in both sexes, and with an increased FEV₁ in males.

A genome-wide association study of severe asthma exacerbations in Latino children and adolescents

Severe asthma exacerbations are a major cause of school absences and healthcare costs in children, particularly those in high-risk racial/ethnic groups.To identify susceptibility genes for severe asthma exacerbations in Latino children and adolescents, we conducted a meta-analysis of genome-wide association studies (GWAS) in 4010 Latino youth with asthma in four independent cohorts, including 1693 Puerto Ricans, 1019 Costa Ricans, 640 Mexicans, 256 Brazilians and 402 members of other Latino subgroups. We then conducted methylation quantitative trait locus, expression quantitative trait locus and expression quantitative trait methylation analyses to assess whether the top single nucleotide polymorphism (SNP) in the meta-analysis is linked to DNA methylation and gene expression in nasal (airway) epithelium in separate cohorts of Puerto Rican and Dutch children and adolescents.In the meta-analysis of GWAS, an SNP in FLJ22447 (rs2253681) was significantly associated with 1.55 increased odds of severe asthma exacerbation (95% CI 1.34-1.79, p=6.3×10-9). This SNP was significantly associated with DNA methylation of a CpG site (cg25024579) at the FLJ22447 locus, which was in turn associated with increased expression of KCNJ2-AS1 in nasal airway epithelium from Puerto Rican children and adolescents (β=0.10, p=2.18×10-7).SNP rs2253681 was significantly associated with both DNA methylation of a cis-CpG in FLJ22447 and severe asthma exacerbations in Latino youth. This may be partly explained by changes in airway epithelial expression of a gene recently implicated in atopic asthma in Puerto Rican children and adolescents (KCNJ2-AS1).

Serum insulin-like growth factor-1, asthma, and lung function among British adults

BACKGROUND

Insulin-like growth factor-1 (IGF-1) plays a key role in the pathogenesis of metabolic syndrome, which is in turn associated with asthma. Whether IGF-1 contributes to asthma causation or asthma severity is largely unknown.

OBJECTIVE

To evaluate the relation between serum IGF-1 and asthma, asthma outcomes, and lung function in adults.

METHODS

Cross-sectional study of 297,590 adults (aged 40-69 years) who participated in the United Kingdom Biobank, had no diagnosis of diabetes, and were not on insulin. Multivariable logistic or linear regression was used to analyze serum IGF-1 and physician-diagnosed asthma, current wheezing, asthma hospitalizations, and lung function measures (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], and FEV1 to FVC ratio).

RESULTS

Serum IGF-1 levels above the lowest quartile (Q1) were significantly associated with lower odds of asthma (adjusted odds ratio for fourth quartile [Q4] vs Q1 = 0.88; 95% confidence interval [CI], 0.85-0.91). Among the participants with asthma, IGF-1 levels above Q1 were significantly associated with lower odds of current wheezing (adjusted odds ratio for Q4 vs Q1 = 0.89; 95% CI, 0.83-0.96), but not with asthma hospitalizations. Serum IGF-1 was significantly and positively associated with FEV1 (b = 20.9 mL; 95% CI, 19.1-22.7) and FVC (b = 25.6 mL; 95% CI, 23.4-27.7), regardless of an asthma diagnosis; these associations were significant in men and women, with larger estimated effects in men.

CONCLUSION

In a large study of British adults, higher serum IGF-1 levels were associated with lower odds of asthma and current wheezing and higher FEV1 and FVC. Our findings suggest potential beneficial effects of circulating IGF-1 on asthma and asthma outcomes in adults.

Exposure to violence, chronic stress, nasal DNA methylation, and atopic asthma in children

Background

Exposure to violence (ETV) or stress may cause asthma through unclear mechanisms.

Methods

Epigenome-wide association study (EWAS) of DNA methylation in nasal epithelium and four ETV or chronic stress measures in 487 Puerto Ricans aged 9-20 years who participated in the Epigenetic Variation and Childhood Asthma in Puerto Ricans study [EVA-PR]). We assessed measures of ETV or chronic stress in children (ETV scale, gun violence, and perceived stress) and their mothers (perceived stress). Each EWAS was conducted using linear regression, with CpGs as dependent variables and the stress/violence measure as a predictor, adjusting for age, sex, the top five principal components, and SVA latent factors. We then selected the top 100 CpGs (by P-value) associated with each stress/violence measure in EVA-PR and conducted a meta-analysis of the selected CpGs and atopic asthma using data from EVA-PR and two additional cohorts (Project Viva and PIAMA).

Results

In the EWAS of stress/violence in EVA-PR, gun violence was associated with methylation of cg18961589 in LINC01164 (β=0.03, P =1.28×10 ^-7 ), and maternal stress was associated with methylation of cg03402351 in SNN (β=0.04, P =1.69×10 ^-7 ) and cg19064846 in PTPRN2 (β=0.03, P =3.36×10 ^-7 ). In a meta-analysis of three cohorts, which included the top CpGs associated with stress/violence in EVA-PR, CpGs in STARD3NL, SLC35F4, TSR3, CDC42SE2, KLHL25, PLCB1, BUD13, OR2B3, GALR1, TMEM196, TEAD4 and ANAPC13 were associated with atopic asthma at FDR- P < 0.05.

Conclusions

ETV and chronic stress may increase the risk of atopic asthma through DNA methylation in airway epithelium, though this needs confirmation in future longitudinal studies.

Indoor endotoxin, proximity to a major roadway, and severe asthma exacerbations among children in Puerto Rico

BACKGROUND

Few studies have examined concurrent exposure to household endotoxin and traffic-related air pollution in relation to childhood asthma, yet both factors are associated with asthma outcomes.

OBJECTIVE

To examine whether proximity to a major roadway (a traffic-related air pollution proxy) modifies the estimated effects of indoor endotoxin on asthma outcomes in children.

METHODS

Cross-sectional study of 200 children with asthma (ages, 6-14 years) living in Puerto Rico. Residential distance to a major roadway was calculated as the distance from the participant's residential US census block centroid to the nearest major road. The outcomes of interest were severe asthma exacerbations, missed school days for asthma, atopy, lung function, and bronchodilator response (BDR). Logistic, linear, or negative binomial regression was used for the multivariable analysis.

RESULTS

In the multivariable analysis, there was an interaction between indoor endotoxin and residential distance to a roadway on severe asthma exacerbations (P = .02) and BDR (P = .07). In an analysis stratified by distance to a roadway, each log₁₀-unit increase in endotoxin was associated with 4.21 times increased odds of severe asthma exacerbations among children living within 499 m (the lower 3 quartiles of residential distance) to a road (95% confidence interval, 1.5-12.0). Among subjects living further than 499 m away from a roadway, each log₁₀-unit increase in endotoxin was associated with reduced odds of severe asthma exacerbations (odds ratio, 0.03; 95% confidence interval, 0.001-0.67). Similar but less substantial findings were observed for BDR.

CONCLUSION

Our findings suggest that residential proximity to a major road modifies the estimated effect of endotoxin on severe asthma exacerbations in children.

Risk factors for atopic and nonatopic asthma in Puerto Rican children

BACKGROUND

Little is known about the risk factors for atopic and nonatopic asthma among children in Puerto Rico. We aimed to identify modifiable risk factors for atopic and nonatopic asthma in this vulnerable population.

METHODS

Case-control study of children with (n = 305) and without (n = 327) asthma in San Juan (Puerto Rico). Asthma was defined as physician-diagnosed asthma and wheeze in the previous year. Atopic asthma (n = 210) was defined as asthma and greater than or equal to one positive IgE to aero-allergens. Nonatopic asthma (n = 95) was defined as asthma and no positive IgE to the allergens tested. Logistic regression was used for the multivariable analysis of atopic and nonatopic asthma.

RESULTS

In a multivariable analysis, body mass index (BMI) z score, prematurity, parental asthma, lifetime exposure to gun violence, and having a bird in the child's home were associated with increased odds of atopic asthma, while each one-point increment in a dietary score (range: -2 [least healthy diet] to +2 [healthiest diet]) was associated with 37% reduced odds of atopic asthma (95% confidence interval [CI] = 0.48-0.81; P < .01). In a separate multivariable analysis, parental asthma, early-life second-hand smoke (SHS) exposure, and daycare attendance in the first year of life were significantly associated with increased odds of nonatopic asthma, while each one-point increment in the dietary score was associated with 42% reduced odds of nonatopic asthma (95% CI = 0.45-0.76; P < .01).

CONCLUSIONS

We have identified potentially modifiable risk factors for atopic asthma (eg, BMI and gun violence), nonatopic asthma (eg, early-life SHS and daycare attendance), or both (eg, an unhealthy diet) in Puerto Rican children.

Serum free testosterone and asthma, asthma hospitalisations and lung function in British adults

OBJECTIVE

We examined the relation between serum-free testosterone and asthma, wheeze, asthma hospitalisations and lung function in older adults.

DESIGN

Cross-sectional study.

SETTING

UK.

PARTICIPANTS

256 419 adults aged 40 to 69 years, recruited from 2006 to 2010.

MAIN OUTCOME MEASURES

Multivariable logistic or linear regression was used for the analysis of free testosterone and physician-diagnosed asthma, current wheeze, asthma hospitalisations and lung function measures, which was adjusted for serum estradiol, smoking status and other covariates.

RESULTS

Free testosterone levels above the lowest quartile (Q1) were significantly associated with lower odds of asthma in both women (adjusted OR (aOR) for Q4 (the highest quartile) versus Q1=0.67, 95% CI=0.64 to 0.71) and men (aOR for Q4 versus Q1=0.87, 95% CI=0.82 to 0.91). Among subjects with asthma, free testosterone levels above Q1 were significantly associated with lower odds of current wheeze in women (aOR range=0.78 to 0.87), and free testosterone levels in Q4 were associated with lower odds of current wheeze in men (aOR for Q4 versus Q1=0.86, 95% CI=0.77 to 0.95). Among women with asthma, free testosterone levels in Q4 were also associated with lower odds of ≥1 asthma hospitalisation. Among men, free testosterone was positively associated with FEV₁ and FVC. Among women, free testosterone was negatively and weakly associated with FVC.

CONCLUSION

In a large study of British adults, elevated free testosterone levels are associated with lower odds of asthma and current wheeze in women and men, lower odds of asthma hospitalisations in women, and higher FEV₁ and FVC in men. DISSEMINATION TO PARTICIPANTS, AND RELATED PATIENT AND PUBLIC COMMUNITIES: The results of the study will be linked to the UK Biobank website.

Effect of Vitamin D3 Supplementation on Severe Asthma Exacerbations in Children With Asthma and Low Vitamin D Levels: The VDKA Randomized Clinical Trial

IMPORTANCE

Severe asthma exacerbations cause significant morbidity and costs. Whether vitamin D3 supplementation reduces severe childhood asthma exacerbations is unclear.

OBJECTIVE

To determine whether vitamin D3 supplementation improves the time to a severe exacerbation in children with asthma and low vitamin D levels.

DESIGN, SETTING, AND PARTICIPANTS

The Vitamin D to Prevent Severe Asthma Exacerbations (VDKA) Study was a randomized, double-blind, placebo-controlled clinical trial of vitamin D3 supplementation to improve the time to severe exacerbations in high-risk children with asthma aged 6 to 16 years taking low-dose inhaled corticosteroids and with serum 25-hydroxyvitamin D levels less than 30 ng/mL. Participants were recruited from 7 US centers. Enrollment started in February 2016, with a goal of 400 participants; the trial was terminated early (March 2019) due to futility, and follow-up ended in September 2019.

INTERVENTIONS

Participants were randomized to vitamin D3, 4000 IU/d (n = 96), or placebo (n = 96) for 48 weeks and maintained with fluticasone propionate, 176 μg/d (6-11 years old), or 220 μg/d (12-16 years old).

MAIN OUTCOMES AND MEASURES

The primary outcome was the time to a severe asthma exacerbation. Secondary outcomes included the time to a viral-induced severe exacerbation, the proportion of participants in whom the dose of inhaled corticosteroid was reduced halfway through the trial, and the cumulative fluticasone dose during the trial.

RESULTS

Among 192 randomized participants (mean age, 9.8 years; 77 girls [40%]), 180 (93.8%) completed the trial. A total of 36 participants (37.5%) in the vitamin D3 group and 33 (34.4%) in the placebo group had 1 or more severe exacerbations. Compared with placebo, vitamin D3 supplementation did not significantly improve the time to a severe exacerbation: the mean time to exacerbation was 240 days in the vitamin D3 group vs 253 days in the placebo group (mean group difference, -13.1 days [95% CI, -42.6 to 16.4]; adjusted hazard ratio, 1.13 [95% CI, 0.69 to 1.85]; P = .63). Vitamin D3 supplementation, compared with placebo, likewise did not significantly improve the time to a viral-induced severe exacerbation, the proportion of participants whose dose of inhaled corticosteroid was reduced, or the cumulative fluticasone dose during the trial. Serious adverse events were similar in both groups (vitamin D3 group, n = 11; placebo group, n = 9).

CONCLUSIONS AND RELEVANCE

Among children with persistent asthma and low vitamin D levels, vitamin D3 supplementation, compared with placebo, did not significantly improve the time to a severe asthma exacerbation. The findings do not support the use of vitamin D3 supplementation to prevent severe asthma exacerbations in this group of patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02687815.

[Significance of microRNA 216a, 324-5p and 29a expression in peripheral blood in patients with acute pancreatitis and their correlation with liver injury]

Objective: To investigate the significance of microRNA (miR)-216a, miR-324-5p, miR-29a expression in peripheral blood in patients with acute pancreatitis (AP) and their correlation with liver injury. Methods: It was a case-control study design. To select 130 AP patients admitted from June 2017 to May 2019 in the First People's Hospital of Shangqiu, and the patients were divided into mild AP group (MAP group) and moderately severe AP group (SAP group) according to the disease severity, or 54 patients in the liver injury group (20 were MAP and 34 were SAP) and 76 in the non-liver injury group(all were MAP) according to liver injury. And another 40 healthy volunteers were selected as the healthy group. The expressions of miR-216a, miR-324-5p and miR-29a in peripheral blood of MAP group, SAP group, healthy group and liver injury group, non-liver injury group were compared, and the correlation between the miRNA levels and clinical indexes was analyzed. The predictive value of miRNA levels in peripheral blood for AP complicated with liver injury was analyzed by receiver operating characteristic (ROC) curve. Results: The levels of miR-216a and miR-29a in MAP group and SAP group were higher than those in healthy group, and the level of miR-324-5p was lower than that in healthy group (all P<0.01). The levels of miR-216a and miR-29a in SAP group were higher than those in MAP group, and the level of miR-324-5p was lower than that in healthy group (all P<0.01). Balthazar CT Score, acute physiology and chronic health evaluations (APACHE Ⅱ) score, C-reactive protein level, length of hospital stay were positively correlated with the levels of miR-216a and miR-29a in peripheral blood (all P<0.05), and negatively correlated with the levels of miR-324-5p (P<0.05). The levels of miR-216a and miR-29a in the peripheral blood in the liver injury group were higher than those in the non-liver injury group, and they were higher inSAP patients than those in MAP patients in the liver injury group (all P<0.05). The level of miR-324-5p in the peripheral blood in the liver injury group was lower than that in the non-liver injury group, and it was lower in SAP patients than that in MAP patientsin the liver injury group (all P<0.05). The area under ROC curve of miR-216a, miR-324-5p, and miR-29a in peripheral blood to predicate the AP complicated with liver damage was 0.694, 0.750 and 0.814, respectively. Conclusions: The levels of miR-216a and miR-29a increase in peripheral blood and the level of miR-324-5p decreases in patients with AP, and they are closely related to Balthazar CT score, APACHEⅡ score, C-reactive protein and length of hospital stay. The levels of miR-216a, miR-324-5p, miR-29a has certain predictive value for AP with liver injury, of which miR-29a has the highest predictive value.

Glycated Hemoglobin A1c, Lung Function, and Hospitalizations Among Adults with Asthma

BACKGROUND

Insulin resistance and metabolic dysfunction have been associated with asthma risk and asthma severity.

OBJECTIVE

To examine the association between glycated hemoglobin A_1c (HbA_1c), asthma-related hospitalizations, and lung function measures among adults in the United Kingdom.

METHODS

A cross-sectional study was conducted of 47,606 adults aged 40 to 69 years who participated in the UK Biobank and had asthma but no diagnosis of diabetes mellitus. HbA_1c level was analyzed as a continuous measure and also categorized as normal (<42 mmol/mol) or as consistent with prediabetes/diabetes (≥42 mmol/mol). An asthma-related hospitalization was defined as ever having had a hospitalization with an International Classification of Diseases, Ninth/Tenth Revision, Clinical Modification code of a main diagnosis compatible with asthma (International Classification of Diseases, Ninth Revision, Clinical Modification code 493.x or International Classification of Diseases, Tenth Revision, Clinical Modification codes J45.x and J46.x). Logistic or linear regression was used for the multivariable analysis of asthma hospitalizations and lung function measures (FEV₁, forced vital capacity [FVC], and FEV₁/FVC). All models were adjusted for age, sex, ethnic background, body mass index, average annual household income, current smoking status, pack-years of smoking, fasting time, and C-reactive protein level.

RESULTS

Both HbA_1c level (odds ratio, 1.03; 95% CI, 1.01-1.04) and an HbA_1c level in the prediabetes/diabetes range (odds ratio, 1.68; 95% CI, 1.18-2.41) were associated with 1 or more asthma hospitalizations. Moreover, both HbA_1c level and an HbA_1c level in the prediabetes/diabetes range were significantly and inversely associated with FEV₁ and FVC.

CONCLUSIONS

HbA_1c is linked to asthma-related hospitalizations and small decrements in FEV₁ and FVC among British adults with asthma but no diagnosis of diabetes mellitus.

Annual SO2 exposure, asthma, atopy, and lung function in Puerto Rican children

BACKGROUND

Long-term effects of sulfur dioxide (SO₂ ) exposure on children, a vulnerable population, are largely unknown. Further, how long-term SO₂ affects Puerto Rican children living in the island of Puerto Rico, a group with high asthma prevalence, is unclear. We evaluated the effects of annual average 1-hour daily maximum SO₂ average on asthma, atopy, total immunoglobulin E (IgE), and lung function in Puerto Rican children.

METHODS

A cohort of 678 children (351 with asthma, 327 without asthma) was recruited in Puerto Rico from 2009 to 2010. Annual average 1-hour daily maximum SO₂ exposure was interpolated utilizing publicly available monitoring data. Multivariable logistic and linear regression was used for the analysis of asthma, atopy (defined as an IgE ≥0.35 IU/mL to at least one of five common aero-allergens), total IgE, and lung function measures (forced vital capacity [FVC], forced expiratory volume in 1 second [FEV1], and FEV1/FVC ratio).

RESULTS

Annual SO₂ exposure (per 1 ppb) was significantly associated with asthma (odds ratio [OR] = 1.42; 95% confidence interval [CI] = 1.05-1.91) and atopy (OR = 1.35; 95% CI = 1.02-1.78). Such exposure was also significantly associated with lower FEV1/FVC in all children (β = -1.42; 95% CI = -2.78 to -0.08) and in children with asthma (β = -2.39; 95% CI= -4.31 to -0.46). Annual SO₂ exposure was not significantly associated with total IgE, FEV1, or FVC.

CONCLUSIONS

Among Puerto Rican children in Puerto Rico, long-term SO₂ exposure is linked to asthma and atopy. In these children, long-term SO₂ exposure is also associated with reduced FEV1/FVC, particularly in those with asthma.

Sex Steroid Hormones and Asthma in a Nationwide Study of U.S. Adults

Rationale: Women have a higher burden of asthma than men. Although sex hormones may explain sex differences in asthma, their role is unclear.Objectives: To examine sex hormone levels and asthma in adults.Methods: Cross-sectional study of serum levels of free testosterone and estradiol and current asthma in 7,615 adults (3,953 men and 3,662 women) aged 18-79 years who participated in the 2013-2014 and 2015-2016 U.S. National Health and Nutrition Examination Survey. Logistic regression was used for the multivariable analysis of sex hormones and current asthma, which was conducted separately in women and men.Measurements and Main Results: Free testosterone levels in the fourth quartile were associated with lower odds of current asthma in women (odds ratio [OR] for the fourth quartile [Q4] vs. Q1, 0.56; 95% confidence interval [CI], 0.39-0.80). Given an interaction between obesity and sex hormones on current asthma, we stratified the analysis by obesity. In this analysis, elevated free testosterone (OR for Q4 vs. Q1, 0.59; 95% CI, 0.37-0.91) and estradiol (OR for Q4 vs. Q1, 0.43; 95% CI, 0.23-0.78) levels were associated with reduced odds of current asthma in obese women, and an elevated serum estradiol was associated with lower odds of current asthma in nonobese men (OR for Q4 vs. Q1, 0.44; 95% CI, 0.21-0.90).Conclusions: Our findings suggest that sex hormones play a role in known sex differences in asthma in adults. Moreover, our results suggest that obesity modifies the effects of sex hormones on asthma in adults.

Serum Cadmium and Lead, Current Wheeze, and Lung Function in a Nationwide Study of Adults in the United States

BACKGROUND

Cadmium and lead are hazardous pollutants.

OBJECTIVE

We examined the relation between serum levels of cadmium and lead and current wheeze, current asthma, and lung function in US adults.

METHODS

A cross-sectional study of 13,888 adults aged 20 to 79 years in 2007-2012 National Health and Nutrition Examination Survey (NHANES) was considered. Multivariable logistic or linear regression was used for the analyses of current wheeze, current asthma, and lung function measures (forced expiratory volume in 1 second [FEV1]% predicted, forced vital capacity [FVC]% predicted, FEV1/FVC% predicted, and fractional exhaled nitric oxide [FeNO]), which were conducted first in all participants, and then separately in never/former smokers and current smokers.

RESULTS

High levels of serum cadmium were significantly associated with current wheeze in all participants and in current smokers (odds ratio for fourth vs first quartile = 2.84, 95% confidence interval = 2.07-3.90, Pfor linear trend < .01), as well as with current asthma in current smokers. Serum lead was not significantly associated with current wheeze or current asthma, regardless of smoking status. Serum cadmium was significantly associated with lower FEV1% predicted, FEV1/FVC% predicted, and FeNO in all participants and in never/former smokers, and serum lead was significantly associated with lower FEV1/FVC% predicted in all participants, with similar findings in never/former smokers and in current smokers.

CONCLUSIONS

Our findings suggest that exposure to cadmium is associated with an increased risk of wheeze and asthma in US adults who currently smoke. Moreover, our results suggest that exposure to cadmium or lead has negative effects on lung function in nonsmoking US adults.