Demographic information for the clinical cohorts evaluated in this study.

<p>Definition of abbreviations: N = number of subjects providing DNA samples evaluated in this study; SD = standard deviation; FEV₁ = forced expiratory volume in 1 second (mL); LOCCS = Leukotriene Modifier Or Corticosteroid or Corticosteroid-Salmeterol Trial; LODO = Effectiveness of Low Dose Theophylline as Add On Therapy for the Treatment of Asthma; CLIC = Characterizing the Response to a LT Receptor Antagonist and Inhaled Corticosteroid trial; PACT = Pediatric Asthma Controller Trial.</p><p>Demographic information for the clinical cohorts evaluated in this study.</p

Improvement in lung function related to montelukast treatment, by rs6475448 genotype.

<p>The least-squares (LS) means (adjusted for study, race and gender) and 95% confidence intervals for ΔFEV₁ related to montelukast treatment were generated using R (<a href="http://cran.r-project.org/web/packages/lsmeans/lsmeans.pdf" target="_blank">http://cran.r-project.org/web/packages/lsmeans/lsmeans.pdf</a>), and plotted for each study (panels), by rs6475448 genotypes: homozygous reference (“GG”: LOCCS = 32; LODO = 38; CLIC = 25; PACT = 65), heterozygous (“GA”: LOCCS = 28; LODO = 21; CLIC = 30; PACT = 75) and homozygous variant (“AA”: LOCCS = 9; LODO = 5; CLIC = 5; PACT = 5).</p

Replicated^* GWAS SNPs.

<p>Definition of abbreviations: “SNP” = single nucleotide polymorphism; “Chr.” = chromosome (1–22); “Chr. Location.” = chromosomal position of listed SNP; “β” = effect size estimates (ΔFEV₁, (mL)) for the minor allele.</p><p><b>*</b>Table lists GWA results adjusted for baseline FEV₁, age, race and gender as covariates (additive genetic model), for the SNPs that met criteria for replication in all cohorts (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129385#sec006" target="_blank">Methods</a>) and remained significant after correction for multiple testing. Minor allele frequencies for all SNPs in all cohorts is >5%.</p><p>^<b>‡</b>Combined P value for all cohorts.</p><p>Replicated^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129385#t002fn002" target="_blank">*</a>} GWAS SNPs.</p

Results of the discovery GWAS.

<p>Manhattan plots (<b>A</b> and <b>B</b>) contain −log P values (y-axis) associated with 8-week change in FEV₁ after montelukast treatment, for 532,264 genotyped SNPs organized by chromosome (x-axis), for LOCCS (<b>A</b>) and LODO (<b>B</b>). The threshold for genome-wide significance and suggestive genome-wide significance are indicated as blue and red lines, respectively, in the Manhattan plots. Q-Q plots (<b>C</b> and <b>D</b>) demonstrate the observed −log P values vs. expected −log P values, for SNPs from LOCCS (<b>C</b>) and LODO (<b>D</b>) populations. In all plots, individual SNPs are represented as filled circles.</p

Logistic regression model of risk factors for severe asthma.^*

<p>* OR denotes odds ratio, CI confidence interval.</p><p>^† Older (age 45 years and older) vs. young adult asthma (18–45 year old).</p><p>^‡ OR per each year increase in asthma duration.</p><p>Logistic regression model of risk factors for severe asthma.^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133490#t002fn001" target="_blank">*</a>}</p

Probability of severe asthma as a function of age, and asthma duration.

<p><b>[A]</b> The probability of severe asthma increases as a function of age until the age of 45 years, at which time the probability of severe asthma plateaus. The fitted final logistic regression model, which included variables associated with severe asthma and adjusted for asthma duration, a history of Gastro-esophageal Reflux Disease, and nasal corticosteroids use, was applied to calculate the probability of severe asthma. <b>[B]</b> Individuals were stratified by age groups into older or young adult asthma in order to evaluate the effect of asthma duration on risk of severe asthma in those older or younger than 45 years. Asthma duration has a lesser effect than age on the probability of severe asthma in younger adult asthmatics. In older asthmatics (age 45 years and older), asthma duration has no significant effect on risk of severe asthma.</p

The histogram of age distribution by asthma severity.

<p>This histogram shows the difference in age distribution among severe and nonsevere asthmatics. The distribution of nonsevere asthmatics was skewed to the left reflecting younger age, and severe asthmatics were shifted to older age.</p

The probability of severe asthma as a function of age and stratified by gender.

<p><b>[A]</b> The association between age and the probability of severe asthma by applying a LOWESS (Locally Weighted Scatterplot Smoother) smoother in the overall population. The relationship between age and probability of severe asthma resembles a spline with an inflection point at the age of 45 years. <b>[B]</b> The stratification by gender shows the probability of asthma severity is higher in men than women after age 45.</p

Medication requirement and health care utilization with PS matching and subsequent multivariate adjustment for asthma duration and GERD.^*

<p>* OR denotes odds ratio, ICS inhaled corticosteroids, LABAs long acting beta agonists, ER emergency room, UC urgent care, and OCS oral corticosteroids.</p><p>^† History of previous health care use related to asthma.</p><p>^‡ Health care utilization was self-reported.</p><p>Comparing older asthma vs. young adult asthma groups.</p

Characteristics of patients with asthma, according to age group.^*

<p>* Plus—minus values are means ±SD. BMI denotes body mass index, GERD gastroesophageal reflux disease, FEV1 forced expiratory volume in 1 second, FVC forced vital capacity, PC20 for methacholine the concentration of inhaled methacholine causing a 20% reduction in FEV1, FENO fraction of exhaled nitric oxide, and BAL broncho-alveolar lavage.</p><p>^† P values are for the comparison of older asthma with the young adult asthma group and were calculated with the use t-test for approximately normally distributed clinical characteristics, Pearson's chi-squared test for differences in proportions, and Wilcoxon signed rank test for all other variables.</p><p>Characteristics of patients with asthma, according to age group.^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0133490#t001fn001" target="_blank">*</a>}</p