American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Jan 1997
Multicenter StudyCigarette smoking: a risk factor for idiopathic pulmonary fibrosis.
We conducted a multicenter case-control study of clinically and histologically diagnosed idiopathic pulmonary fibrosis (IPF), a chronic diffuse interstitial lung disease of unknown cause. The study included 248 cases, and 491 control subjects identified through random-digit dialing, matched to cases in sex, age, and geographic region. Telephone interviews were conducted with both cases and controls to collect information on potential risk factors for IPF, including smoking and household, occupational, and environmental exposures. ⋯ Risk was significantly elevated for former smokers (OR = 1.9; 95% CI: 1.3 to 2.9) and for smokers with 21 to 40 pack-yr (OR = 2.3; 95% CI: 1.3 to 3.8). A history of smoking is associated with an increased risk for the development of IPF. Although there was no clear exposure-response pattern with cumulative consumption of cigarettes, there was a trend for time since cessation of smoking, with the highest risk for those who had most recently quit.
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Am. J. Respir. Crit. Care Med. · Jan 1997
Effects of menopause and nasal occlusion on breathing during sleep.
Prevalence of sleep-disordered breathing (SDB) is reported to increase in menopausal women. We examined response to a nocturnal respiratory challenge (nasal occlusion) during overnight polysomnography in 31 women (45 to 55 yr). Thirteen were premenopausal, four perimenopausal, and 14 postmenopausal by history and hormonal assay. ⋯ Responders and nonresponders were not distinguished by age, menopausal status, nor several cephalometric or anthropometric variables. Body mass index (31.1 +/- 8.5 versus 24.3 +/- 3.4, p < 0.003), neck circumference (34.0 +/- 2.5 versus 32.5 +/- 1.7 cm, p < 0.05), and mandibular-hyoid distance (18.5 +/- 3.8 versus 14.5 +/- 5.7 mm, p < 0.05) were greater in responders. These findings suggest hormonal factors may be less important than weight and facial morphology in midlife development of SDB in women.
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Am. J. Respir. Crit. Care Med. · Jan 1997
Chronic, episodic, reversible airway obstruction after viral bronchiolitis in rats.
Viral bronchiolitis in human infants has been associated with persistent airway abnormalities, but not proven as a cause. Previously we observed some adult rats had airway obstruction and hyperresponsiveness following bronchiolitis at an early age. The purpose of this study was to determine, via serial measurements of lung mechanics, whether the postbronchiolitis airway obstruction was episodic or continuous, and to determine the magnitude and duration of glucocorticoid effects. ⋯ The virus group had higher lung resistance (p = 0.03) and lower dynamic compliance (p = 0.005) than control rats, with airway obstruction occurring in an episodic pattern. Dexamethasone treatment had a transient effect in postbronchiolitis rats; lung resistance normalized in Week 15 (p = 0.006), then returned to pretreatment levels by Weeks 16-18. We conclude that viral bronchiolitis in rats can result in a chronic syndrome of intermittent, reversible airway obstruction which has multiple parallels with human asthma over a prolonged time period.
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Am. J. Respir. Crit. Care Med. · Jan 1997
Comparative StudyRacial differences in sleep-disordered breathing in African-Americans and Caucasians.
In this case-control family study of sleep-disordered breathing (SDB), we describe the distributions of SDB and SDB risk factors in African-Americans and Caucasians. A total of 225 African-Americans and 622 Caucasians, ages 2 to 86 yr, recruited as members of families with an individual with known sleep apnea (85 index families) or as members of neighborhood control families (63 families) were studied with an overnight home sleep-study, questionnaires, and physical measurements. A subsample underwent cephalometry. ⋯ In subjects < or = 25 yr, RDI level and IAA prevalence were higher in African-Americans (odds ratio, adjusted for obesity, sex, proband sampling, and familial clustering, 1.88, 1.03 to 3.52, 95% CI). In this age group, racial differences also were observed in the relationship between RDI and age (p < 0.001 for the RDI-age interaction). This suggests that young African-Americans may be at increased risk for sleep apnea.