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Lower hypoxic ventilatory response in smokers compared to non-smokers during abstinence from cigarettes

View Article: PubMed Central - PubMed

ABSTRACT

Background: Carotid body O2-chemosensitivity determines the hypoxic ventilatory response (HVR) as part of crucial regulatory reflex within oxygen homeostasis. Nicotine has been suggested to attenuate HVR in neonates of smoking mothers. However, whether smoking affects HVR in adulthood has remained unclear and probably blurred by acute ventilatory stimulation through cigarette smoke. We hypothesized that HVR is substantially reduced in smokers when studied after an overnight abstinence from cigarettes i.e. after nicotine elimination.

Methods: We therefore determined the isocapnic HVR of 23 healthy male smokers (age 33.9 ± 2.0 years, BMI 24.2 ± 0.5 kg m−2, mean ± SEM) with a smoking history of >8 years after 12 h of abstinence and compared it to that of 23 healthy male non-smokers matched for age and BMI.

Results: Smokers and non-smokers were comparable with regard to factors known to affect isocapnic HVR such as plasma levels of glucose and thiols as well as intracellular levels of glutathione in blood mononuclear cells. As a new finding, abstinent smokers had a significantly lower isocapnic HVR (0.024 ± 0.002 vs. 0.037 ± 0.003 l min−1 %−1BMI−1, P = 0.002) compared to non-smokers. However, upon re-exposure to cigarettes the smokers’ HVR increased immediately to the non-smokers’ level.

Conclusions: This is the first report of a substantial HVR reduction in abstinent adult smokers which appears to be masked by daily smoking routine and may therefore have been previously overlooked. A low HVR may be suggested as a novel link between smoking and aggravated hypoxemia during sleep especially in relevant clinical conditions such as COPD.

Electronic supplementary material: The online version of this article (doi:10.1186/s12890-016-0323-0) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

Hypoxic ventilatory response before and after re-exposure to cigarette smoke. Individual (small symbols) and mean ± S.E.M. (big symbols) values of HVR before and after smoking of one cigarette in a subgroup (n = 14) of 12-h-abstinent smokers. The increase in HVR through smoking was highly significant (Wilcoxon-test)
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Fig2: Hypoxic ventilatory response before and after re-exposure to cigarette smoke. Individual (small symbols) and mean ± S.E.M. (big symbols) values of HVR before and after smoking of one cigarette in a subgroup (n = 14) of 12-h-abstinent smokers. The increase in HVR through smoking was highly significant (Wilcoxon-test)

Mentions: All statistical analyses were performed by SPSS (Version 22.0, IBM, Munich, Germany). The main outcome measure HVR as well as secondary variables were compared between SM and NSM by the two-tailed student’s t-test for unpaired samples after testing for normal distribution. Changes in HVR within the group of SM through acute smoking were analyzed by the Wilcoxon-test. All values are presented in figures and tables as means ± SEM, individual values are additionally given in the Figs. 1 and 2. The level of statistical significance was set at P < 0.05.Fig. 1


Lower hypoxic ventilatory response in smokers compared to non-smokers during abstinence from cigarettes
Hypoxic ventilatory response before and after re-exposure to cigarette smoke. Individual (small symbols) and mean ± S.E.M. (big symbols) values of HVR before and after smoking of one cigarette in a subgroup (n = 14) of 12-h-abstinent smokers. The increase in HVR through smoking was highly significant (Wilcoxon-test)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5121951&req=5

Fig2: Hypoxic ventilatory response before and after re-exposure to cigarette smoke. Individual (small symbols) and mean ± S.E.M. (big symbols) values of HVR before and after smoking of one cigarette in a subgroup (n = 14) of 12-h-abstinent smokers. The increase in HVR through smoking was highly significant (Wilcoxon-test)
Mentions: All statistical analyses were performed by SPSS (Version 22.0, IBM, Munich, Germany). The main outcome measure HVR as well as secondary variables were compared between SM and NSM by the two-tailed student’s t-test for unpaired samples after testing for normal distribution. Changes in HVR within the group of SM through acute smoking were analyzed by the Wilcoxon-test. All values are presented in figures and tables as means ± SEM, individual values are additionally given in the Figs. 1 and 2. The level of statistical significance was set at P < 0.05.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Carotid body O2-chemosensitivity determines the hypoxic ventilatory response (HVR) as part of crucial regulatory reflex within oxygen homeostasis. Nicotine has been suggested to attenuate HVR in neonates of smoking mothers. However, whether smoking affects HVR in adulthood has remained unclear and probably blurred by acute ventilatory stimulation through cigarette smoke. We hypothesized that HVR is substantially reduced in smokers when studied after an overnight abstinence from cigarettes i.e. after nicotine elimination.

Methods: We therefore determined the isocapnic HVR of 23 healthy male smokers (age 33.9&thinsp;&plusmn;&thinsp;2.0&nbsp;years, BMI 24.2&thinsp;&plusmn;&thinsp;0.5&nbsp;kg&nbsp;m&minus;2, mean&thinsp;&plusmn;&thinsp;SEM) with a smoking history of &gt;8&nbsp;years after 12&nbsp;h of abstinence and compared it to that of 23 healthy male non-smokers matched for age and BMI.

Results: Smokers and non-smokers were comparable with regard to factors known to affect isocapnic HVR such as plasma levels of glucose and thiols as well as intracellular levels of glutathione in blood mononuclear cells. As a new finding, abstinent smokers had a significantly lower isocapnic HVR (0.024&thinsp;&plusmn;&thinsp;0.002 vs. 0.037&thinsp;&plusmn;&thinsp;0.003&nbsp;l&nbsp;min&minus;1 %&minus;1BMI&minus;1, P&thinsp;=&thinsp;0.002) compared to non-smokers. However, upon re-exposure to cigarettes the smokers&rsquo; HVR increased immediately to the non-smokers&rsquo; level.

Conclusions: This is the first report of a substantial HVR reduction in abstinent adult smokers which appears to be masked by daily smoking routine and may therefore have been previously overlooked. A low HVR may be suggested as a novel link between smoking and aggravated hypoxemia during sleep especially in relevant clinical conditions such as COPD.

Electronic supplementary material: The online version of this article (doi:10.1186/s12890-016-0323-0) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus