Effects Of Chronic Cigarette Smoking Research Articles

Structural and functional remodeling of the female Apoe-/- mouse aorta due to chronic cigarette smoke exposure.

Despite a decline in popularity over the past several decades, cigarette smoking remains a leading cause of cardiovascular morbidity and mortality. Yet, the effects of cigarette smoking on vascular structure and function are largely unknown. To evaluate changes in the mechanical properties of the aorta that occur with chronic smoking, we exposed female apolipoprotein E-deficient mice to mainstream cigarette smoke daily for 24 wk, with room air as control. By the time of euthanasia, cigarette-exposed mice had lower body mass but experienced larger systolic/diastolic blood pressure when compared with controls. Smoking was associated with significant wall thickening, reduced axial stretch, and circumferential material softening of the aorta. Although this contributed to maintaining intrinsic tissue stiffness at control levels despite larger pressure loads, the structural stiffness became significantly larger. Furthermore, the aorta from cigarette-exposed mice exhibited decreased ability to store elastic energy and augment diastolic blood flow. Histological analysis revealed a region-dependent increase in the cross-sectional area due to smoking. Increased smooth muscle and extracellular matrix content led to medial thickening in the ascending aorta, whereas collagen deposition increased the thickness of the descending thoracic and abdominal aorta. Atherosclerotic lesions were larger in exposed vessels and featured a necrotic core overlaid by a thinned fibrous cap and macrophage infiltration, consistent with a vulnerable phenotype. Collectively, our data indicate that cigarette smoking decreases the mechanical functionality of the aorta, inflicts morphometric alterations to distinct segments of the aorta, and accelerates the progression of atherosclerosis.NEW & NOTEWORTHY We studied the effects of chronic cigarette smoking on the structure and function of the aorta in a mouse model of nose-only aerosol inhalation. Our data indicated that exposure to cigarette smoke impairs vascular function by reducing the ability of the aorta to store elastic energy and by decreasing aortic distensibility. Combined with a more vulnerable atherosclerotic phenotype, these findings reveal the biomechanical mechanisms that support the development of cardiovascular disease due to cigarette smoking.

GABA concentrations in the anterior cingulate and dorsolateral prefrontal cortices: Associations with chronic cigarette smoking, neurocognition, and decision making.

Chronic cigarette smoking is associated with regional metabolite abnormalities in choline-containing compounds, creatine-containing compounds, glutamate, and N-acetylaspartate. The effects of cigarette smoking on anterior frontal cortical gamma-aminobutyric acid (GABA) concentration are unknown. This study compared chronic smokers (n = 33) and nonsmokers (n = 31) on anterior cingulate cortex (ACC) and right dorsolateral prefrontal cortex (DLPFC) GABA+ (the sum of GABA and coedited macromolecules) concentrations and associations of GABA+ levels in these regions with seven neurocognitive domains of functioning, decision making, and impulsivity measures. Smokers had significantly lower right DLPFC GABA+ concentration than nonsmokers, but groups were equivalent on ACC GABA+ level. Across groups, greater number of days since end of menstrual cycle was related to higher GABA+ level in the ACC but not right DLPFC GABA+ concentration. In exploratory correlation analyses, higher ACC and right DLPFC GABA+ levels were associated with faster processing speed and better auditory-verbal memory, respectively, in the combined group of smokers and nonsmokers; in smokers only, higher ACC GABA+ was related to better decision making and auditory-verbal learning. This study contributes additional novel data on the adverse effects of chronic cigarette smoking on the adult human brain and demonstrated ACC and DLPFC GABA+ concentrations were associated with neurocognition and decision making/impulsivity in active cigarette smokers. Longitudinal studies on the effects of smoking cessation on regional brain GABA levels, with a greater number of female participants, are required to determine if the observed metabolite abnormalities are persistent or normalize with smoking cessation.

Effects of chronic cigarette smoking on myocardial deformation parameters by two-dimensional speckle tracking echocardiography.

Cigarette smoking causes myocardial damage with several mechanisms such as sympathetic nervous system activation, oxidative stress, and endothelial dysfunction. Chronic smokers have an increased risk of morbidity and mortality associated with cardiac events. We aimed to compare the myocardial deformation parameters between chronic smokers and nonsmoker healthy population. Forty-two healthy participants (mean age 33.48±10.00years) without smoking history, 40 participants (mean age 33.98±9.27years) who had been smoking were prospectively included. In addition to conventional echocardiographic measurements, global longitudinal strain (GLS) of left ventricle (LV), GLS of right ventricle (RV), left atrial strain, and strain rate were analyzed. Smokers had lower peak early diastolic velocity (E) and E/a (early diastolic velocity/late diastolic velocity) ratio in mitral inflow (70.0±13.9cm/sec vs 77.1±13.3cm/sec, P=.023; 1.4±0.4 vs 1.7±0.4, P=.011; respectively). Peak early diastolic velocity of mitral valve septal annulus (Em) and Em/Am ratio (peak early diastolic velocity of mitral valve/late diastolic velocity of mitral valve)(11.0±2.1cm/sec vs 12.1±2.4cm/sec, P=.023; 1.2±0.3 vs 1.4±0.4, P=.039; respectively) were lower in smokers. LV GLS and RV GLS were significantly lower in smokers (-17.6%±3.01 vs -19.2%±2.5; P=.013, -18.9%±4.4 vs -21.0%±4.5; P=.039; respectively). Impaired LV and RV deformation were found in chronic smokers in our study. Although there was no statistically significant difference with left ventricular ejection fraction, LVGLS which is the early indicator of LV systolic dysfunction was lower in chronic smokers. The assessment of early harmful effects of smoking on left and right ventricle might be evaluated with speckle tracking echocardiography.

Region-Specific Changes of Insular Cortical Thickness in Heavy Smokers.

Insula plays an essential role in maintaining the addiction to cigarette smoking and smoking-related alterations on the insular volume and density have been reported in smokers. However, less is known about the effects of chronic cigarette smoking on the insular cortical thickness. In this study, we explored the region-specific changes of insular cortical thickness in heavy smokers and their relations with smoking-related variables. 37 heavy smokers (29 males, mean age 47.19 ± 7.22 years) and 37 non-smoking healthy controls (29 males, mean age 46.95 ± 8.45 years) participated in the study. Subregional insular cortical thickness was evaluated and compared between the two groups. Correlation analysis was performed to investigate relationships between the insular cortical thickness and clinical characteristics in heavy smokers. There was no statistical difference on the cortical thickness in the left insula (p = 0.536) between the two groups while heavy smokers had a slightly thinner cortical thickness in the right insula (p = 0.048). In addition, heavy smokers showed a greater cortical thinning in the anterior (p = 0.0084) and superior (p = 0.0054) segment of the circular sulcus of the right insula as well as the inferior (p = 0.012) segment of the circular sulcus of the left insula. Moreover, the cortical thickness of the superior segment of the circular sulcus of the left insula was correlated negatively with nicotine severity (r = −0.423; p = 0.009) and the longer cigarette exposure was associated with the cortical thinning in the long insular gyrus and central sulcus of the right insula (r = −0.475; p = 0.003). Our findings indicate that chronic cigarette use is associated with region-specific insular thinning, which has the potential to improve our understanding of the specific roles of insular subregions in nicotine addiction.

Effect of Paired Associative Stimulation on Corticomotor Excitability in Chronic Smokers.

Chronic smoking has been shown to have deleterious effects on brain function and is an important risk factor for ischemic stroke. Reduced cortical excitability has been shown among chronic smokers compared with non-smokers to have a long-term effect and so far no study has assessed the effect of smoking on short-term motor learning. Paired associative stimulation (PAS) is a commonly used method for inducing changes in excitability of the motor cortex (M1) in a way that simulates short-term motor learning. This study employed PAS to investigate the effect of chronic cigarette smoking on plasticity of M1. Stimulator output required to elicit a motor-evoked potential (MEP) of approximately 1 mV was similar between the groups prior to PAS. MEP response to single pulse stimuli increased in the control group and remained above baseline level for at least 30 min after the intervention, but not in the smokers who showed no significant increase in MEP size. The silent period was similar between groups at all time points of the experiment. This study suggests that chronic smoking may have a negative effect on the response to PAS and infers that chronic smoking may have a deleterious effect on the adaptability of M1.

Effect of cigarette smoking on salivary electrolyte composition in a sub-urban Nigerian population

Background: Cigarette smoking is a factor that affects the health of humans. It has been shown to be an important risk factor for a variety of disorders such as disease of the lungs, brain damage and has also been linked to the development of periodontal disease. There are, however, few and conflicting studies on its effect on salivary electrolyte composition. Aim: The aim of this study is to evaluate the effect of chronic cigarette smoking on electrolyte concentration of saliva and to determine its effect on normal oral homeostasis. Methods: A total of 40 male subjects of between 25–40 years were divided into two groups, A and B. Group A comprised of 20 smokers and Group B, 20 non-smokers. Saliva from each subject was collected into a plain sample bottles and immediately analysed. Results: Results showed a significantly lower concentration of Na + and Cl − and a significantly higher HCO 3 − and K + in smokers than non-smokers. Conclusion: This shows that the concentration of electrolytes in the saliva may be affected by the chronic use of tobacco which could have adverse consequences on the normal homeostasis of the oral environment especially with regard to increased salivary alkalinity as a result of increased salivary bicarbonate.

The effects of chronic smoking on total cerebral blood volume measured by carotid and vertebral artery doppler ultrasonography.

To evaluate the effects of chronic cigarette smoking on total cerebral blood flow in healthy adults by Doppler ultrasonography (US). We evaluated 50 smoker (median age 29) and 50 nonsmoker (median age 28) healthy, 20- to 40-year-old subjects without any cardiovascular and cerebrovascular disease. Peak systolic maximal blood flow velocity (PSV), end-diastolic maximal blood flow velocity (EDV), time-averaged mean blood flow velocity (TAMV), resistance index (RI), and pulsatility index (PI) were measured in the left and right carotid and vertebral arteries, and total cerebral blood flow volume was calculated. There was no significant difference of smoking rate between genders. Blood pressure and PSV values were similar in both groups. EDV values of internal carotid artery (ICA) and vertebral artery (VA) were lower and RI and PI values were higher in smokers. TAMV, total ICA (-10.8%) and VA (-6%) flow volume, and tCBF (-9.2%) were lower in smokers. Doppler US is an effective tool to detect tCBF volume decrease in chronic cigarette smokers. Although minimal, this decrease, as demonstrated here in asymptomatic, healthy people, might be critical in patients with subclinical cerebral arterial insufficiency. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:561-565, 2017.

Acute and Chronic Effect of Cigarette Smoking on Pupil Size, Accommodation and Tear film

Purpose: To evaluate the acute and chronic effects of cigarette smoking on pupil size, accommodation and tear film. Methods: Thirty non-smokers and twenty-five cigarette smokers were recruited. For acute effect of smoking all smoking subjects were asked to smoke an identical single cigarette containing 0.5 mg nicotine. Photopic and mesopic pupil sizes, contrast visual acuities, contrast sensitivities, higher-order aberrations (HOAs), accommodations and tear-film stability were measured before smoking and immediately after smoking. The pupil sizes and HOA were measured with Pupilometer (VIP, NeurOptics) and Wavefront Analyzer (KR-1W) as 4 mm area of pupil size respectively. 100% and 10% contrast visual acuity, and contrast sensitivities were measured and amplitude of accommodations were assessed by push-up method and the tear film stability was assessed by TBUT (tear break-up time). For the chronic effect of smoking, all measurements of the cigarette smokers without smoking were compared with those of non-smokers. Results: For acute effect of smoking, pupil size decreased significantly after smoking regardless of illuminance and luminance level (p 0.05), the amplitudes of accommodation and tear film stability were decreased significantly after smoking (p<0.05). Conclusions: Acute effect of smoking resulted in decreased pupil size, accommodation, and tear film stability, and improved in low contrast visual acuity. However, chronic effect of smoking has no influence on pupil size, visual acuity, accommodation, tear film stability that it is thought that smoking has temporary effect on visual function.

The Effect of Chronic Cigarette Use on Cognitive Function

In this study, we aimed to investigate the effect of chronic cigarette smoking on the cognitive function in people who have no other mental or physical illness other than tobacco use disorder. The study was carried out on three groups: smokers (n = 71), former smokers (n = 39), and non-smokers (n = 49). The Wisconsin Card Sorting Test (WCST), Stroop Color and Word Test (ST), Trail Making Test (TMT), Auditory Verbal Learning Test (AVLT), and Serial Digit Learning Test (SDLT) were applied to the 3 groups participating in the study. Groups were compared with the Three-Factor Covariance Analysis. Stroop test 4th card time score which determined the basic level of color discourse in the smoker group was significantly higher than the non-smoker group. The Trail Making Test-B time scores were significantly higher in the smoker group than the non-smoker group. And Trail Making Test-B time points were significantly higher in the former smoker group than nonsmoker group. Auditory Verbal Learning Test - verbal learning scores were lower in the smoker group than the non-smoker and former smoker group. There was no significant difference in verbal learning scores between the non-smoking and former smoker groups. The neurocognitive deficits in smokers appear to be related to dose and duration. This study suggests that auditory verbal memory, visualspatial processing, and attention areas may be a selective area of disability in smokers. A major limitation is the fact that general cognitive performance levels of participants was not assessed by a general criteria such as Wechsler Adult Intelligence Scale (WAIS).

Nicotinic acetylcholine receptor availability in cigarette smokers: effect of heavy caffeine or marijuana use.

Upregulation of α4β2* nicotinic acetylcholine receptors (nAChRs) is one of the most well-established effects of chronic cigarette smoking on the brain. Prior research by our group gave a preliminary indication that cigarette smokers with concomitant use of caffeine or marijuana have altered nAChR availability. We sought to determine if smokers with heavy caffeine or marijuana use have different levels of α4β2* nAChRs than smokers without these drug usages. One hundred and one positron emission tomography (PET) scans, using the radiotracer 2-FA (a ligand for β2*-containing nAChRs), were obtained from four groups of males: non-smokers without heavy caffeine or marijuana use, smokers without heavy caffeine or marijuana use, smokers with heavy caffeine use (mean four coffee cups per day), and smokers with heavy marijuana use (mean 22days of use per month). Total distribution volume (Vt/fp) was determined for the brainstem, prefrontal cortex, and thalamus, as a measure of nAChR availability. A significant between-group effect was found, resulting from the heavy caffeine and marijuana groups having the highest Vt/fp values (especially for the brainstem and prefrontal cortex), followed by smokers without such use, followed by non-smokers. Direct between-group comparisons revealed significant differences for Vt/fp values between the smoker groups with and without heavy caffeine or marijuana use. Smokers with heavy caffeine or marijuana use have higher α4β2* nAChR availability than smokers without these drug usages. These findings are likely due to increased nicotine exposure but could also be due to an interaction on a cellular/molecular level.

The Effect of Smoking on Corneal Endothelial Cells

ABSTRACTPurpose: To investigate the effect of chronic cigarette smoking on the endothelial cells of the cornea via non-contact specular microscopy. Method: In this prospective, cross-sectional study, 25 eyes of 25 chronic smokers and 21 eyes of 21 age-matched, healthy non-smokers were enrolled. The Fagerström Test for Nicotine Dependence on Cigarettes was used to determine the nicotine dependency level. The level of cotinine, a major metabolite of nicotine, was measured in urine samples from the control group to detect whether they were passively affected by cigarette smoke. All participants underwent measurement of tear break-up time (TBUT), central corneal thickness (CCT), and axial length. Endothelial cell density and endothelial cell morphology were evaluated by non-contact specular microscopy. Results: On average, the cigarette smokers consumed 19.2 ± 8.3 cigarettes per day and had been smoking for 14.5 ± 6.8 years. The mean TBUT value was significantly lower in the smoker group compared to the non-smoker group (p < 0.05). No statistically significant difference was found in the mean CCT, mean endothelial cell density, or parameters of endothelial cell morphology between smokers and non-smokers. Conclusion: This study showed that cigarette smoking seems to affect the TBUT value but no effects were found on the parameters of corneal endothelial cells.

Altered spontaneous brain activity in heavy smokers revealed by regional homogeneity.

Task-state and resting-state functional magnetic resonance imaging (fMRI) studies have revealed different brain responses in chronic cigarette smokers compared with healthy controls. However, little is known about the differences between chronic cigarette smokers and healthy subjects regarding the local synchronization of spontaneous brain activity in the resting state. In this study, we used regional homogeneity (ReHo) analysis based on resting-state fMRI to investigate intrinsic brain activity in heavy smokers. Thirty-one heavy smokers and 33 healthy non-smokers were included in this study. ReHo was used to measure spontaneous brain activity, and whole-brain voxel-wise comparisons of ReHo were performed to detect brain regions with altered spontaneous brain activity between groups. Compared with non-smokers, heavy smokers showed decreased ReHo primarily in brain regions associated with the default-mode, frontoparietal attention, and inhibitory control networks; heavy smokers showed increased ReHo predominately in regions related to motor planning. Our results suggest that heavy smokers may have altered spontaneous brain activity in some brain regions that are associated with higher cognitive networks. Moreover, our study improves the understanding of the effects of chronic cigarette smoking on spontaneous brain activity and the pathophysiological mechanisms of nicotine dependence.

The effects of chronic cigarette smoking on gray matter volume: influence of sex.

Cigarette smoke contains nicotine and toxic chemicals and may cause significant neurochemical and anatomical brain changes. Voxel-based morphometry studies have examined the effects of smoking on the brain by comparing gray matter volume (GMV) in nicotine dependent individuals (NDs) to nonsmoking individuals with inconsistent results. Although sex differences in neural and behavioral features of nicotine dependence are reported, sex differences in regional GMV remain unknown. The current study examined sex differences in GMV in a large sample of 80 NDs (41 males) and 80 healthy controls (41 males) using voxel-based morphometry. Within NDs, we explored whether GMV was correlated with measures of cigarette use and nicotine dependence. High-resolution T1 structural scans were obtained from all participants. Segmentation and registration were performed in SPM8 using the optimized DARTEL approach. Covariates included age and an estimate of total global GMV. Differences were considered significant at p≤0.001, with a whole brain FWE-corrected cluster probability of p<0.025. Among NDs compared to Controls less GMV was observed in the thalamus and bilateral cerebellum and greater GMV was observed in the bilateral putamen and right parahippocampus. Lower thalamic GMV was observed in both female and male NDs compared to Controls. Female NDs also had lower GMV in the left cerebellum and in the ventral medial and orbitofrontal cortices with no areas of greater GMV. Male NDs had lower GMV in bilateral cerebellum and greater GMV in bilateral parahippocampus and left putamen. Within male NDs, GMV in the left putamen was correlated with number of pack years. This study, conducted in a large cohort, contributes to our knowledge of brain morphology in nicotine addiction and provides additional evidence of sex-specific effects on GMV in NDs. Identifying brain vulnerabilities with respect to sex provides a methodological framework for personalized therapies to improve relapse rates for both sexes.

Altered brain functional networks in heavy smokers.

Recent neuroimaging studies have demonstrated that cigarette smoking is associated with changed brain structure and function. However, little is known about alterations of the topological organization of brain functional networks in heavy smokers. Thirty-one heavy smokers and 33 non-smokers underwent a resting-state functional magnetic resonance imaging scan. The whole-brain functional networks were constructed by thresholding the correlation matrices of 90 brain regions and their topological properties were analyzed using graph network analysis. Non-parametric permutation tests were performed to investigate group differences in network topological measures and multiple regression analysis was conducted to determine the relationships between the network metrics and smoking-related variables. Both heavy smokers and non-smokers exhibited small-world architecture in their brain functional networks. Compared with non-smokers, however, heavy smokers showed altered topological measurements characterized by lower global efficiency, higher local efficiency and clustering coefficients and greater path length. Furthermore, heavy smokers demonstrated decreased nodal global efficiency mainly in brain regions within the default mode network, whereas increased nodal local efficiency predominated in the visual-related regions. In addition, heavy smokers exhibited an association between the altered network metrics and the duration of cigarette use or the severity of nicotine dependence. Our results suggest that heavy smokers may have less efficient network architecture in the brain, and chronic cigarette smoking is associated with disruptions in the topological organization of brain networks. Our findings may further the understanding of the effects of chronic cigarette smoking on the brain and the pathophysiological mechanisms underlying nicotine dependence.

Postural Stability in Cigarette Smokers and During Abstinence from Alcohol

Static postural instability is common in alcohol-dependent individuals (ALC). Chronic alcohol consumption has deleterious effects on the neural and perceptual systems subserving postural stability. However, little is known about the effects of chronic cigarette smoking on postural stability and its changes during abstinence from alcohol. A modified Fregly ataxia battery was administered to a total of 115 smoking (sALC) and nonsmoking ALC (nsALC) and to 71 smoking (sCON) and nonsmoking light/nondrinking controls (nsCON). Subgroups of abstinent ALC were assessed at 3 time points (TPs; approximately 1, 5, 34 weeks of abstinence from alcohol); a subset of nsCON was retested at 40 weeks. We tested whether cigarette smoking affects postural stability in CON and in ALC during extended abstinence from alcohol, and we used linear mixed effects modeling to measure change across TPs within ALC. Chronic smoking was associated with reduced performance on the Sharpened Romberg eyes-closed task in abstinent ALC at all 3 TPs and in CON. The test performance of nsALC increased significantly between 1 and 32 weeks of abstinence, whereas the corresponding increases for sALC between 1 and 35 weeks were nonsignificant. With long-term abstinence from alcohol, nsALC recovered into the range of nsCON and sALC recovered into the range of sCON. Static postural stability decreased with age and correlated with smoking variables but not with drinking measures. Chronic smoking was associated with reduced static postural stability with eyes closed and with lower increases of postural stability during abstinence from alcohol. Smoking cessation in alcohol dependence treatment may facilitate recovery from static postural instability during abstinence.

The Effect of Chronic Smoking on Lens Density in Young Adults

To investigate the effect of chronic cigarette smoking on lens density by Pentacam HR lens densitometry in young adults. Sixty chronic smokers who smoked at least 10 cigarettes per day for at least 2 years and 60 age- and sex-matched healthy control subjects were included in this prospective cross-sectional, comparative study. Presence of an ocular or systemic disease that might affect lens were determined as exclusion criteria. All individuals underwent complete ocular examination. Lens densitometry (LD) measurements were performed with Pentacam HR (Oculus, Wetzlar, Germany), dividing the lens into 3 areas: anterior area (anterior subcapsular and anterior cortical), nuclear area, and posterior area (posterior subcapsular and posterior cortical). Three-dimensional scan modes were used for measurements. The mean ages of group 1 and 2 were 25.85 ± 4.32 and 25.60 ± 5.14 years, respectively. The mean LD values in the 3 areas were higher in group 1 than group 2. However, only the mean LD value at the anterior area of group 1 was found to be statistically significantly higher (p = 0.047). There was no statistically significant difference in the mean LD measurements at the nuclear and posterior areas between the groups. Our study demonstrated that the mean LD value of the anterior area was significantly higher in group 1, suggesting that chronic smoking may contribute to anterior cortical and subcapsular cataract development in young adults.

Effect of smoking on selected blood parameters

Background: Smoking is not only a physical recidivism, but also a psychological inveteracy. Chronic effects of cigarette smoking on haematological parameters, with a good control side by side, were studied by very few. Evectics (including deaddiction) should be based on harm profile. Aims & Objectives: To find out age-wise Hb, BP, leucocyte (total/ differential) count, monocyte count, and eosinophil count in smokers. Materials and Methods: Study was carried out on a group of 108 otherwise healthy subjects from medical college campus –including 36 each in non-smoker, light-smoker and heavy smoker group – further subdivided into 9 each in 4 age ranges of 21-30years, 31-40 years, 41-50 years and 51-60 years. Data regarding age, sex, height, weight and various blood parameters were noted as per standard methods. Results: Chronic effects of smoking on cardiovascular system were found. SBP of both light and heavy smokers were significantly less than control group. DBP of light smokers and non-smokers did not differed very much. TLC and eosinophil count was higher while monocyte count was lower in smokers (insignificantly low in light smokers). Conclusion: The TLC and eosinophil count rise, while BP and monocyte counts fall in smokers. Smoking may lead to isolated systolic hypertension. In Evectics, the improvement/ outcome can be measured by assessing the rate/ extent of normalization of these parameters.

Effect of Smoking on Choroidal Thickness in Healthy Smokers

Purpose: To evaluate the acute and chronic effects of cigarette smoking on the choroidal thickness of young male smokers with smoking histories exceeding 10 years using spectral domain optical coherence tomography (SD OCT).Materials and methods: The right eyes of 40 never-smoking and 30 smoking healthy subjects were included in this study. We measured the choroidal thicknesses of the never-smoking subjects as a control group. The choroidal thicknesses of the smoking subjects were measured before, 5, 30 and 60 min after smoking. Choroidal thickness measurements were taken at the fovea and at two points that were 1500 µm nasal and temporal to the fovea.Results: No significant difference was found for the retinal thickness, choroidal thicknesses, spherical equivalent, intraocular pressure and central corneal thickness of the smokers and non-smokers (p > 0.05 for all). In the measurements that were taken after smoking, a statistically significant increase was found in choroidal thickness that was observed between 0 and 5 min for the central, nasal and temporal segments (p < 0.001 for all).Conclusions: Smoking caused acute, significant increase in choroidal thickness that returned to baseline levels after 1 h. The choroidal and retinal thicknesses did not differ significantly between the healthy young smokers and non-smokers.

Effects of chronic smoking on central corneal thickness, endothelial cell, and dry eye parameters

Objective: To evaluate the effect of chronic cigarette smoking on dry eye parameters, endothelial cells, and corneal thickness.Design: Prospective cross-sectional case series.Methods: In this cross-sectional study, 49 eyes of 49 chronic smokers (smoker group) and 53 eyes of 53 age-matched, healthy non-smokers (non-smoker group) were enrolled. All participants underwent measurements of tear breakup time (TBUT), central corneal thickness (CCT) measurements with contact pachymeter and the Schirmer test with anesthesia. Corneal endothelial cells were evaluated by non-contact specular microscopy and photographed for analysis of cell density and hexagonality and the coefficient of variation in cell size.Results: The mean Schirmer score and TBUT value were significantly lower in the smoker group compared to the non-smoker group (p = 0.015) and p < 0.001, respectively). No statistically significant difference was found in the mean CCT, mean endothelial cell density, endothelial cell size, SD of size, and CV of size between smokers and non-smokers (p > 0.05). However, a lower percentage of endothelial hexagonal cells were observed in smokers than non-smokers (p < 0.001).Discussion and conclusion: Our results suggest that cigarette smoking seems to affect the Schirmer score, TBUT value, and hexagonal cells of the corneal endothelium.

Interactive effects of chronic cigarette smoking and age on hippocampal volumes

BackgroundPrevious cross-sectional MRI studies with healthy, young-to-middle-aged adults reported no significant differences between smokers and non-smokers on total hippocampal volume. However, these studies did not specifically test for greater age-related volume loss in the total hippocampus or hippocampal subregions in smokers, and did they did not examine relationships between hippocampal and subfield volumes and episodic learning and memory performance. MethodsHealthy, young-to-middle-aged (45±12 years of age) smokers (n=39) and non-smokers (n=43) were compared on total hippocampal and subfield volumes derived from high-resolution 4Tesla MRI, emphasizing testing for greater age-related volume losses in smokers. Associations between hippocampal volumes and measures of episodic learning and memory were examined. ResultsSmokers showed significantly smaller volumes, as well as greater volume loss with increasing age than non-smokers in the bilateral total hippocampus and multiple subfields. In smokers, greater pack-years were associated with smaller volumes of the total hippocampus, presubiculum, and subiculum. In the entire cohort, performance on measures of learning and memory was related to larger total hippocampal and several subfield volumes, predominately in the left hemisphere. ConclusionsChronic cigarette smoking in this young-to-middle aged cohort was associated with smaller total hippocampal and subfield volumes, which were exacerbated by advancing age. Findings also indicated an adverse smoking dose/duration response (i.e., pack-years) with total hippocampal and select subfield volumes. These hippocampal volume abnormalities in smokers may be related to the deficiencies in episodic learning and memory in young-to-middle-aged smokers reported in previous studies.