Publications

OBJECTIVES

The aim of this study was to investigate whether exposure to a range of relatively low concentrations of aged secondhand smoke (SHS), similar to those encountered commonly in the community, would impair endothelial function in a concentration-dependent manner.

BACKGROUND

Exposure to SHS impairs endothelial function in humans. The concentration-dependent relationship for aged SHS effects on endothelial function after an exposure of short duration is unknown.

METHODS

Thirty-three healthy nonsmokers were exposed to 1 of 2 low levels of aged SHS or to conditioned filtered air for 30 min. The primary end point was change in maximal percent brachial artery flow-mediated dilation after exposure.

RESULTS

In a linear regression model for each increase in SHS exposure by 100 μg/m(3) respirable suspended particles, the absolute maximal percent brachial artery flow-mediated dilation was reduced by 0.67%. We did not find evidence of a threshold for the effect of SHS on flow-mediated dilation.

CONCLUSIONS

Short-term exposure to real-world levels of aged SHS for 30 min resulted in a concentration-dependent decrease in endothelial function as measured by flow-mediated dilation.

BACKGROUND

A combination of prednisone, azathioprine, and N-acetylcysteine (NAC) has been widely used as a treatment for idiopathic pulmonary fibrosis. The safety and efficacy of this three-drug regimen is unknown.

METHODS

In this randomized, double-blind, placebo-controlled trial, we assigned patients with idiopathic pulmonary fibrosis who had mild-to-moderate lung-function impairment to one of three groups -- receiving a combination of prednisone, azathioprine, and NAC (combination therapy), NAC alone, or placebo -- in a 1:1:1 ratio. The primary outcome was the change in longitudinal measurements of forced vital capacity during a 60-week treatment period.

RESULTS

When approximately 50% of data had been collected (with 77 patients in the combination-therapy group and 78 in the placebo group), a planned interim analysis revealed that patients in the combination-therapy group, as compared with the placebo group, had an increased rate of death (8 vs. 1, P=0.01) and hospitalization (23 vs. 7, P<0.001). These observations, coupled with no evidence of physiological or clinical benefit for combination therapy, prompted the independent data and safety monitoring board to recommend termination of the combination-therapy group at a mean follow-up of 32 weeks. Data from the ongoing comparison of the NAC-only group and the placebo group are not reported here.

CONCLUSIONS

Increased risks of death and hospitalization were observed in patients with idiopathic pulmonary fibrosis who were treated with a combination of prednisone, azathioprine, and NAC, as compared with placebo. These findings provide evidence against the use of this combination in such patients. (Funded by the National Heart, Lung, and Blood Institute and the Cowlin Family Fund; ClinicalTrials.gov number, NCT00650091.).

BACKGROUND

Genetic variants that contribute to asthma susceptibility might be present at varying frequencies in different populations, which is an important consideration and advantage for performing genetic association studies in admixed populations.

OBJECTIVE

We sought to identify asthma-associated loci in African American subjects.

METHODS

We compared local African and European ancestry estimated from dense single nucleotide polymorphism genotype data in African American adults with asthma and nonasthmatic control subjects. Allelic tests of association were performed within the candidate regions identified, correcting for local European admixture.

RESULTS

We identified a significant ancestry association peak on chromosome 6q. Allelic tests for association within this region identified a single nucleotide polymorphism (rs1361549) on 6q14.1 that was associated with asthma exclusively in African American subjects with local European admixture (odds ratio, 2.2). The risk allele is common in Europe (42% in the HapMap population of Utah residents with Northern and Western European ancestry from the Centre d'Etude du Polymorphisme Humain collection) but absent in West Africa (0% in the HapMap population of Yorubans in Ibadan, Nigeria), suggesting the allele is present in African American subjects because of recent European admixture. We replicated our findings in Puerto Rican subjects and similarly found that the signal of association is largely specific to subjects who are heterozygous for African and non-African ancestry at 6q14.1. However, we found no evidence for association in European American or Puerto Rican subjects in the absence of local African ancestry, suggesting that the association with asthma at rs1361549 is due to an environmental or genetic interaction.

CONCLUSION

We identified a novel asthma-associated locus that is relevant to admixed populations with African ancestry and highlight the importance of considering local ancestry in genetic association studies of admixed populations.