Short and long-term effects of cigarette smoking independently influence exhaled nitric oxide concentration in asthma

McSharry, Charles; McKay, I C; Chaudhuri, Rekha; Livingston, Eric W.; Fraser, Iona; Thomson, Neil C.

doi:10.1016/j.jaci.2005.03.025

Cited by 67 publications

(62 citation statements)

References 48 publications

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“…Like the studies of MCSHARRY et al [32] and MALINOVSCHI et al subjects aged ,21 yrs and, therefore, would not have reached the same conclusions as the present study regarding FeNO levels in young smokers compared with nonsmokers [1][2][3][4]6]. One possible explanation for the current findings regarding the lack of a difference in FeNO levels in young smokers compared with nonsmokers is related to the known association of increasing age in children (but not adults) with increasing FeNO [40][41][42].…”

Section: Discussioncontrasting

confidence: 87%

“…Recent studies by MCSHARRY et al [32] and MALINOVSCHI et al [10] did not observe a similar age-related decline in FeNO levels in healthy nonasthmatic smokers. The current authors believe that the present results were different from the results of the other two other studies because they had smaller sample sizes and did not include subjects ,21 yrs of age.…”

Section: Discussionmentioning

confidence: 81%

“…Prior studies of FeNO in nonsmoking adults indicated that there was no association of age with FeNO levels [31]. In a recent study, MCSHARRY et al [32] identified an association of decreasing FeNO levels with age in asthmatic smokers. Whether smoking results in age-related declines in FeNO in otherwise healthy subjects has not been determined.…”

mentioning

confidence: 98%

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Smoking is associated with an age-related decline in exhaled nitric oxide

Sundy

Hauswirth²,

Mervin-Blake³

et al. 2007

European Respiratory Journal

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Age-related declines in forced expiratory volume in one second are accelerated in smokers. Smoking is associated with decreased exhaled nitric oxide fraction (FeNO). The aim of the present study was to determine the impact of age on FeNO in otherwise healthy smokers and nonsmokers.FeNO and serum cotinine levels were measured in 994 healthy subjects aged 18-40 yrs. American Thoracic Society questionnaire data on smoking habits was used to validate serum cotinine levels as a surrogate marker for categorisation of smokers and nonsmokers in the cohort.Serum cotinine levels were a good discriminator of smokers (n599) and nonsmokers (n5895). FeNO levels were significantly lower in otherwise healthy smokers compared with nonsmokers. There was an inverse correlation of serum cotinine levels with FeNO. No correlation of age with FeNO was found in nonsmokers but an inverse correlation of FeNO with age in smokers was found. FeNO was significantly lower in smokers aged 21-40 yrs compared with nonsmokers aged 21-40 yrs, but was not lower in smokers aged 18-20 yrs compared with nonsmokers of the same age.Smoking was associated with decreased exhaled nitric oxide. The greatest smoking-related declines in exhaled nitric oxide occurred in older subjects. This suggests that smoking is associated with age-related declines in exhaled nitric oxide and justifies future mechanistic studies that address the impact of exhaled nitric oxide decline on lung function.

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Section: Discussioncontrasting

confidence: 87%

Section: Discussionmentioning

confidence: 81%

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Smoking is associated with an age-related decline in exhaled nitric oxide

Sundy

Hauswirth²,

Mervin-Blake³

et al. 2007

European Respiratory Journal

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“…Males had higher concentrations of eNO than females, as has been noted by others (Franklin et al, 2004). Those exposed to environmental tobacco smoke at home had lower eNO and higher eCO concentrations than those unexposed, again consistent with prior studies (Deveci et al, 2004;McSharry et al, 2005). Although univariate analyses demonstrated lower concentrations eNO and eCO in association with controller medication use, this was not the case in the final multivariate models at a 0.05 level of statistical significance, possibly because of the fact that only five subjects used controllers (data not presented).…”

Section: Discussionsupporting

confidence: 87%

“…When the eCO-iCO analyses were restricted to days that iCO was below the 50th percentile (0.57 ppm), the association between eCO and iCO was no longer significant (P ¼ 0.25). Four subjects had mean eCO concentrations 45 ppm, high enough to suggest that they were actually smokers (Deveci et al, 2004;McSharry et al, 2005). Excluding from analyses these four individuals slightly reduced the estimated effect of iNO on eNO by 15% and of iCO on eCO by 2%.…”

Section: Indoor Outdoor and Exhaled Monoxide Relationshipsmentioning

confidence: 96%

Bias and confounding in longitudinal measures of exhaled monoxides

Dorevitch

Demirtaş

Scheff

et al. 2007

J Expo Sci Environ Epidemiol

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The measurement of exhaled nitric oxide and carbon monoxide concentrations is an emerging method of monitoring airway inflammation longitudinally in community-based studies. Inhaled concentrations of these monoxides influence exhaled concentrations. Little is known about the degree to which inhaled concentrations distort temporal trends in, or estimated effects of air pollutants on, exhaled monoxides. We sought to evaluate whether estimated effects of air pollutants on exhaled monoxides are distorted by trends in indoor and outdoor monoxides, and to characterize determinants of exhaled monoxide concentrations among residents of public housing. In a panel study, 42 residents of public housing provided over 1000 exhaled breath samples. Samples from all subjects were analyzed for nitric oxide; samples from 27 of these subjects were also analyzed for carbon monoxide. The effects of indoor and outdoor monoxide concentrations on exhaled concentrations were quantified. Confounding of associations between particulate matter concentrations and exhaled nitric oxide concentrations was explored. Determinants of exhaled monoxide concentrations among public housing residents are similar to those of other populations. Exhaled monoxide concentrations are more strongly associated with indoor than with outdoor monoxide concentrations. Approximately half of the variability in exhaled monoxide concentrations over time can be explained by changes in indoor monoxide concentrations. Indoor monoxide concentrations can markedly distort both temporal trends in exhaled concentrations as well as estimated effects of particulate matter on exhaled monoxides. Prior estimated effects of particulate matter on exhaled nitric oxide concentrations may have been confounded by nitric concentrations indoors at the time of exhaled air collection. To prevent distortions of longitudinal trends in airway inflammation and estimated health effects of air pollutants, inspiratory scrubber use is necessary but not sufficient to remove the confounding effect of indoor monoxides, and analyses should adjust exhaled monoxide concentrations for concentrations indoors.

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