Effects of tobacco smoking and abstinence on middle latency auditory evoked potentials

Smoking and risk of sleep-related issues: a systematic review and meta-analysis of prospective studies

OBJECTIVES

Smoking has many deleterious consequences on health, one of which can be sleep-related issues. Therefore, a meta-analysis was performed with the aim of pooling results from studies on the relationship between smoking and sleep-related issues.

METHODS

The present study follows PRISMA guidelines. Databases were searched by both researchers to find the articles. The review was done up to December 2018. In order to analyze the results of the screened articles, statistical indexes were converted to logarithms and the studies were combined with each other. Finally, several analyses were conducted with respect to various subgroups. In the subgroup analysis, the pool index of the studies was determined and the degree of heterogeneity in each subgroup was presented. Meta-regression was also used.

RESULTS

Smoking is associated with a risk of developing sleep-related issues. Risk ratio (1.47; 1.20-1.79) for smokers was higher than for non-smokers. Egger's test and Begg's test indicated publication bias.

CONCLUSIONS

Smoking is associated with sleep-related issues. Informing smokers about the effects of smoking on sleep issues can be effective in reducing and preventing its consequences.

Sleep correlates of substance use in community-dwelling Ethiopian adults

PURPOSE

The relationship between sleep disturbances and substance use can have harmful effects. Evidence shows widespread use of substances, including khat, in the Ethiopian population. However, to the best of our knowledge, no study has investigated the sleep correlates of substance use in community-dwelling Ethiopian adults.

MATERIALS AND METHODS

A cross-sectional study using simple random sampling was performed on community-dwelling adults (n = 371, age = 25.5 ± 5.7 years, body mass index = 22.0 ± 2.2 kg/m²) in Mizan-Aman, Ethiopia. Dichotomized sleep measures (sleep quality and sleep latency) assessed by the Pittsburgh Sleep Quality Index (PSQI) were used in association analysis using binary logistic regression with substance use (khat, smoking, and alcohol).

RESULT

Sleep latency was associated with khat chewing (adjusted odds ratio (AOR) = 2.8, 95% confidence interval (CI) 1.7-4.4) and tobacco smoking (AOR = 2.1, 95% CI 1.4-3.0). Sleep quality was associated with khat chewing (AOR = 3.1, 95% CI 1.8-5.2), tobacco smoking (AOR = 1.7, 95% CI 1.2-2.5), and alcohol intake (AOR = 1.9, 95% CI 1.1-3.1).

CONCLUSION

Sleep correlates of substance use were found in community-dwelling Ethiopians. These findings may aid in the development of targeted strategies to manage substance use-related sleep disturbances.

The interaction between anxiety sensitivity and cigarette smoking level in relation to sleep onset latency among adolescent cigarette smokers

Cigarette smoking during adolescence is linked to a number of sleep disturbances and has been consistently linked to sleep onset latency among adults. However, little research has examined factors that may influence the relation between cigarette smoking level and sleep onset latency among adolescents. One factor that may be particularly important in this regard is anxiety sensitivity (AS). The current study examined whether cigarette smoking level interacted with AS in its association with sleep onset latency among 94 adolescent (Mage = 15.72) cigarette smokers. As hypothesized, AS interacted with smoking level to relate to sleep onset latency, even after controlling for age and gender. This relation was specific to sleep onset latency as opposed to other types of sleep disturbances, and that adolescents who smoked at higher levels tended to go to sleep later and wake up later than adolescents who smoked at relatively lower levels.

Auditory middle latency responses in chronic smokers compared to nonsmokers: differential effects of stimulus and age

PURPOSE

Effects of clicks and tonebursts on early and late auditory middle latency response (AMLR) components were evaluated in young and older cigarette smokers and nonsmokers.

METHOD

Participants ( n = 49) were categorized by smoking and age into 4 groups: (a) older smokers, (b) older nonsmokers, (c) young smokers, and (d) young nonsmokers. Monaural, 2-channel AMLRs were acquired from Fz and Cz electrodes with 3 stimuli (clicks, 500 Hz, and 3000 Hz).

RESULTS

Group differences included significantly higher V-Na amplitude in young adults and shorter Pb latency in older nonsmokers. Young smokers had a significantly higher Nb-Pb amplitude and shorter Nb latency than other groups. Toneburst stimuli yielded significantly longer V, Na, and Pa latencies compared to clicks. Pb latency was shorter at Fz than at Cz. Relative amplitudes were significantly higher at Fz than at Cz overall; Pa-Nb and Nb-Pb were significantly lower for 3000 Hz than for 500 Hz and clicks.

CONCLUSIONS

Responses from young smokers revealed a higher amplitude and shorter latency for later AMLR waves, reflecting an arousal effect of smoking in cortical and subcortical generators. AMLR differences in older adults may be due to age-related neurochemical changes in the central nervous system. Stimulus and electrode differences plus smoking and aging effects can guide neurodiagnostic AMLR protocols, especially in young adult smokers.

Alcohol, nicotine, caffeine, and mental disorders

Alcohol, nicotine, and caffeine are the most widely consumed psychotropic drugs worldwide. They are largely consumed by normal individuals, but their use is even more frequent in psychiatric patients, Thus, patients with schizophrenia tend to abuse all three substances. The interrelationships between depression and alcohol are complex. These drugs can all create dependence, as understood in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Alcohol abuse is clearly deleterious to the brain, provoking acute and chronic mental disorders, ranging from intoxication with impairment of cognition, to delirium tremens, halluosis, and dementia. In contrast, the main health consequences of nicotine, notably cancer and cardiovascular disases, lie outside the realm of psychiatry However, the mes of nicotine dependence and motivation to smoke or quit are of concern to psychiatrists.

Cigarette smoking as a risk factor for auditory problems

Smoking is a public health concern and we are still unsure of its relation with auditory problems.

Aim

To study the effects of cigarette smoking in auditory thresholds, in otoacoustic emissions and in their inhibition by the efferent olivocochlear medial system.

Materials and Methods

144 adults from both genders, between 20 and 31 years of age, smoking and non-smoking individuals were submitted to conventional and high-frequency audiometry, transient stimuli otoacoustic emissions and suppression effect investigation.

Results

smokers presented worse auditory thresholds in the frequencies of 12.500Hz in the right ear and 14,000 kHz in both ears. Regarding the otoacoustic emissions, smokers group presented a lower response level in the frequencies of 1,000Hz in both ears and 4,000Hz in the left ear. Among smokers there were more cases of cochlear dysfunction and tinnitus.

Conclusion

Our results suggest that cigarette smoking has an adverse effect on the auditory system.

Mouse model predicts effects of smoking and varenicline on event-related potentials in humans

BACKGROUND

Nicotine alters auditory event-related potentials (ERPs) in rodents and humans and is an effective treatment for smoking cessation. Less is known about the effects of the partial nicotine agonist varenicline on ERPs.

METHODS

We measured the effects of varenicline and nicotine on the mouse P20 and varenicline and smoking on the human P50 in a paired-click task. Eighteen mice were tested following nicotine, varenicline, and their combination. One hundred and fourteen current smokers enrolled in a placebo-controlled within-subject crossover study to test the effects of varenicline during smoking and abstinence. Thirty-two subjects participated in the ERP study, with half receiving placebo first and half varenicline first (VP).

RESULTS

Nicotine and varenicline enhanced mouse P20 amplitude, while nicotine improved P20 habituation by selectively increasing the first-click response. Similar to mice, abstinence reduced P50 habituation relative to smoking by reducing the first-click response. There was no effect of varenicline on P50 amplitude during abstinence across subjects. However, there was a significant effect of medication order on P50 amplitude during abstinence. Subjects in the PV group displayed reduced P50 during abstinence, which was blocked by varenicline. However, subjects in the VP group did not display abstinence-induced P50 reduction.

CONCLUSIONS

Data suggest that smoking improves sensory processing. Varenicline mimics amplitude changes associated with nicotine and smoking but fails to alter habituation. The effect of medication order suggests a possible carryover effect from the previous arm. This study supports the predictive validity of ERPs in mice as a marker of drug effects in human studies.

Effects of chronic and acute smoking on AMLRs in older and younger listeners

Chronic and acute smoking effects on the auditory middle latency response (AMLR) were studied in older (55-81 years) and younger (19-30 years) normal-hearing listeners. Forty healthy participants were selected for one of four groups: older smokers, older nonsmokers, younger smokers, or younger nonsmokers. Biochemical urine analyses confirmed participant categorization as smoker or nonsmoker. Click-evoked AMLRs were acquired once from nonsmokers and twice (chronic condition, acute condition) from smokers. Waveform latency (V, Na, Pa) and relative amplitude (V-Na, Na-Pa) were examined with two independent variables (age, smoking) using MANOVA. Results (n=40) revealed no chronic effect of smoking in the AMLR from smokers compared to nonsmokers. However, in both older and younger smokers (n=20), Na-Pa amplitude was significantly larger in the acute compared to the chronic smoking condition, indicating an acute smoking effect. There was no interaction of smoking and aging. This is a first study describing long-term, chronic and acute smoking effects on AMLRs in older compared to younger listeners. Results suggest that cigarette smoking is an important variable for AMLR research and clinical practice.

Neonatal nicotine exposure impairs nicotinic enhancement of central auditory processing and auditory learning in adult rats

Children of women who smoke cigarettes during pregnancy display cognitive deficits in the auditory-verbal domain. Clinical studies have implicated developmental exposure to nicotine, the main psychoactive ingredient of tobacco, as a probable cause of subsequent auditory deficits. To test for a causal link, we have developed an animal model to determine how neonatal nicotine exposure affects adult auditory function. In adult control rats, nicotine administered systemically (0.7 mg/kg, s.c.) enhanced the sensitivity to sound of neural responses recorded in primary auditory cortex. The effect was strongest in cortical layers 3 and 4, where there is a dense concentration of nicotinic acetylcholine receptors (nAChRs) that has been hypothesized to regulate thalamocortical inputs. In support of the hypothesis, microinjection into layer 4 of the nonspecific nAChR antagonist mecamylamine (10 microM) strongly reduced sound-evoked responses. In contrast to the effects of acute nicotine and mecamylamine in adult control animals, neither drug was as effective in adult animals that had been treated with 5 days of chronic nicotine exposure (CNE) shortly after birth. Neonatal CNE also impaired performance on an auditory-cued active avoidance task, while having little effect on basic auditory or motor functions. Thus, neonatal CNE impairs nicotinic regulation of cortical function, and auditory learning, in the adult. Our results provide evidence that developmental nicotine exposure is responsible for auditory-cognitive deficits in the offspring of women who smoke during pregnancy, and suggest a potential underlying mechanism, namely diminished function of cortical nAChRs.

Nicotinic acetylcholine receptors in sensory cortex

Acetylcholine release in sensory neocortex contributes to higher-order sensory function, in part by activating nicotinic acetylcholine receptors (nAChRs). Molecular studies have revealed a bewildering array of nAChR subtypes and cellular actions; however, there is some consensus emerging about the major nAChR subtypes and their functions in sensory cortex. This review first describes the systems-level effects of activating nAChRs in visual, somatosensory, and auditory cortex, and then describes, as far as possible, the underlying cellular and synaptic mechanisms. A related goal is to examine if sensory cortex can be considered a model system for cortex in general, because the use of sensory stimuli to activate neural circuits physiologically is helpful for understanding mechanisms of systems-level function and plasticity. A final goal is to highlight the emerging role of nAChRs in developing sensory cortex, and the adverse impact of early nicotine exposure on subsequent sensory-cognitive function.

Effects of tobacco smoking on electroencephalographic, auditory evoked and event related potentials

After overnight abstinence, tobacco smokers smoked an average nicotine yield cigarette and nonsmokers sham smoked an unlit placebo cigarette. EEG alpha(1), delta, and theta frequency amplitudes decreased, whereas alpha(2) and beta frequency amplitude increased. Short, middle (EP) and long latency ERP were also studied in nonsmokers and smokers just after smoking, and after overnight abstinence from tobacco. Short latency potentials were unaffected by tobacco smoking or abstinence. Middle and long-latency potentials were reduced during abstinence and enhanced immediately after tobacco smoking. These findings indicate that compared to nonsmokers smokers have a higher arousal level after smoking than when partially abstinent. Evidence for both normalization from tobacco abstinence as well as stimulation was obtained.

Depressive symptoms and cigarette smoking predict development and persistence of sleep problems in US adolescents

OBJECTIVE

To evaluate factors related to the development and persistence of adolescent sleep problems.

METHODS

In this longitudinal, population-based study, the Teenage Attitudes and Practices Survey was administered by telephone to 7960 adolescents (3921 girls and 4039 boys) 12 to 18 years old in 1989 and at follow-up in 1993. Sleep problems at both time points were assessed using a single item on the Teenage Attitudes and Practices Survey. Those who responded that they "often or sometimes" had trouble going to sleep or staying asleep during the past 12 months were categorized as reporting sleep problems, whereas those who responded "often" were categorized as having frequent sleep problems. Multiple logistic regression analyses were used to identify baseline characteristics predictive of the development and persistence of sleep problems or frequent sleep problems, respectively, from baseline to follow-up.

RESULTS

Of the 4866 adolescents without sleep problems at baseline, 28% developed sleep problems by 1993, and 9% developed frequent sleep problems. Of the 3094 adolescents who reported sleep problems at baseline, 52% reported sleep problems in 1993, and 21% reported frequent sleep problems. Female sex and notable depressive symptoms were associated with the development and persistence of sleep problems and frequent sleep problems at follow-up. Cigarette smoking status showed a dose-response relationship with development of sleep problems and frequent sleep problems, and with persistence of frequent sleep problems at follow-up.

CONCLUSION

The reduction of depressive symptoms and cigarette smoking among adolescents are important factors to consider in prevention and treatment efforts focused on adolescent sleep problems.