The acute effects of smokeless tobacco on central aortic blood pressure and wave reflection characteristics

Central and Peripheral Hemodynamics in Young Adults Who Use Water Pipes and the Acute Effects of Water-Pipe Use

BACKGROUND

Tobacco use via water pipe (commonly referred to as water-pipe smoking [WPS]) is popular among young adults globally and exposes those who smoke to toxicants.

RESEARCH QUESTION

Is WPS associated with impaired measures of arterial function and does WPS acutely impair these measures in young adults?

STUDY DESIGN AND METHODS

We assessed heart rate (HR), brachial and aortic BP, HR-adjusted augmentation index (AI), and carotid-femoral pulse wave velocity (CFPWV) in 62 individuals who use water pipes and 34 individuals who have never used a water pipe recruited from the community (mean age, 22.5 ± 3.0 years; 48% female). Measurements were obtained before and after an outdoor session of WPS among participants who use water pipes and among the control group of participants who have never used a water pipe. Measurements were compared after vs before exposure and between those who use and those who do not use water pipes, adjusting for possible confounders using linear regression.

RESULTS

Participants who use water pipes and control participants had similar demographic characteristics. BP and HR increased acutely after WPS (brachial systolic BP by 4.13 mm Hg [95% CI, 1.91-6.36 mm Hg]; aortic systolic BP by 2.31 mm Hg [95% CI, 0.28-4.33 mm Hg]; brachial diastolic BP by 3.69 mm Hg [95% CI, 1.62-5.77 mm Hg]; aortic diastolic BP by 3.03 mm Hg [95% CI, 0.74-5.33 mm Hg]; and HR by 7.75 beats/min [95% CI, 5.46-10.04 beats/min]), but not in the control group. AI was significantly higher in participants who use water pipes compared with those who do not (9.02% vs 3.06%; P = .03), including after adjusting for BMI and family history of cardiovascular disease (β = 6.12; 95% CI, 0.55-11.69; P = .03) and when assessing habitual tobacco use via water-pipe extent (water pipes used/day × water-pipe use duration) in water-pipe-years (β = 2.51/water-pipe-year; 95% CI, 0.10-4.92/water-pipe-year; P = .04). However, CFPWV was similar in those who use water pipes and those who do not, and AI and CFPWV did not change acutely after WPS.

INTERPRETATION

In apparently healthy young individuals from the community, habitual WPS was associated with increased AI, a predictor of cardiovascular risk, and one WPS session acutely increased HR and brachial and aortic BP.

The association of waterpipe smoking with arterial stiffness and wave reflection in a community-based sample

PURPOSE

The evidence linking waterpipe smoking to cardiovascular disease is limited. We evaluated the association of waterpipe smoking (WPS) with arterial stiffness and wave reflection measured by augmentation pressure (AP), augmentation index (AIx), and carotid-femoral pulse wave velocity (CFPWV), which are validated predictors of cardiovascular disease.

MATERIALS AND METHODS

Community-based, cross-sectional study including 205 exclusive waterpipe smokers and 199 matched never-smokers aged 35 years or older (mean age 51.7 ± 8.9 years, 36% females). Smoking and its extent were assessed using a validated questionnaire and urine cotinine levels. CFPWV, AP, AIx (AP/aortic pulse pressure) and heart rate adjusted AIx (AIx@75) were determined using tonometry and compared between smokers and non-smokers, and the association of WPS with tonometry measures was assessed using linear regression adjusting for possible confounders.

RESULTS

Waterpipe smokers and non-smokers had similar mean age and sex distribution. Compared to non-smokers, waterpipe smokers had significantly higher adjusted AP (10.5 ± 3.9 vs. 9.4 ± 3.9 mmHg respectively; p = 0.01), AIx (28.1 ± 8.4 vs. 25.7 ± 8.5% respectively; p = 0.01) and AIx@75 (24.2 ± 8.7 vs. 21.8 ± 8.9% respectively; p = 0.01). AIx was significantly associated with WPS extent, measured by a number of waterpipe smoked/day (β = 1.04/waterpipe, 95%CI:[0.50-1.58]), duration of waterpipe smoking (β = 0.77/10-years, 95%CI:[0.16-1.38]), their products in waterpipe-years (β = 0.30/10-waterpipe-year, 95%CI:[0.12-0.47]) and plasma cotinine (β = 0.56/100 ng/ml, 95%CI:[0.14-0.98]), adjusting for possible confounders, and so were AP and AIx@75. CFPWV however, was not associated with waterpipe smoking.

CONCLUSION

In a community-based sample, exclusive WPS and its extent were associated with a dose-dependent increase in AIx and AP, accounting for other risk factors, suggesting that waterpipe smokers are at increased risk of cardiovascular disease.

Association between Cigarette Smoking and Physical Fitness Level of Korean Adults and the Elderly

Although previous studies have examined the relationship between smoking and physical fitness, they only considered current smoking status and the same fitness measurements regardless of age. This study investigated differences in physical fitness based on tobacco smoking habits. A total of 2830 non-elderly adults (NEA; 19–64 years) and 629 elderly (65–89 years) participated in the study, using data extracted from a Korean national database. One-way ANCOVA and ANOVA were conducted to analyze the results. The subjects were classified into three groups (smokers, those who had quit, and never-smokers). In NEA men, a significant difference was observed in 50-m dash (p = 0.003) and 20-m shuttle-run (p < 0.001), while in elderly men differences were only seen in sit-ups (p = 0.015). In the case of NEA and elderly women, no significant differences were observed in physical fitness levels (p > 0.05). The decreased fitness level due to smoking was more noticeable in men than in women, and in NEA more than in elderly persons. A non-smoking policy and customized training based on age or gender are necessary to increase fitness and improve health conditions.

The Effect of Dipping Tobacco on Pulse Wave Analysis among Adult Males

BACKGROUND

The current study investigated the effect of dipping tobacco (DT) use on arterial wall stiffness which is a known marker of increased risk of cardiovascular events.

METHODS

A case-control study which included 101 adult males was carried out in Al-Shaab Teaching Hospital. Blood pressure and pulse wave analysis parameters were recorded in 51 DT users (study group) before and after 30 minutes of placing tobacco and in 50 nontobacco users (control group). Anthropometric measurements were collected using data collection sheet. Data were entered into a computer and analyzed by using the software Statistical Package for the Social Sciences (SPSS) version 20 (SPSS Inc., Chicago, IL, USA).

RESULTS

At baseline measurements, heart rate (HR) was significantly lower in the study group compared to the control group (66.15 ± 9.21 vs. 72.87 ± 10.13 beats/min; P value ≤ 0.001). Subendocardial viability ratio (SEVR) was significantly higher in the study group compared to the control group (203.44 ± 30.34 vs. 179.11 ± 30.51%; P value ≤ 0.001). Acute effects of DT compared to pretobacco dipping showed significant increase in HR (72.50 ± 10.89 vs. 66.15 ± 9.21 beats/min; P value ≤ 0.001) and significant decrease in augmentation pressure (AP) (4.30 (2.30-8.00) vs. 3.30 (0.60-6.3) mmHg; P value ≤ 0.001), ejection duration (ED) (271.65 ± 19.42 vs. 279.53 ± 20.47 ms; P value ≤ 0.001), and SEVR (187.11 ± 29.81 vs. 203.44 ± 30.34; P value ≤ 0.001). Linear regression analysis for AP predictor showed that only HR and AIx@75 affect and predict the values of AP (Beta ± SE; -0.242 ± 0.019, P value ≤ 0.001; 0.685 ± 0.014, P value ≤ 0.001).

CONCLUSIONS

Long-term use of DT was not associated with permanent changes in heart rate and blood pressure. Acute tobacco dipping caused an acute increase in heart rate and oxygen demands of myocardium.

Smokeless tobacco: Risk factor for cardiovascular and breathing in young Indian adolescent

BACKGROUND

Teenagers are the foremost susceptible population to smokeless tobacco usage and limited studies have surveyed the influence of smokeless tobacco on cardiac and respiratory response.

OBJECTIVE

This study aims to measure consequence (cardiovascular and breathing) of smokeless tobacco usage (gutkha and chewing tobacco) among young Indian men.

METHOD

On random basis, the applicants were divided into Group I (n=50) - healthy control group, Group II (n=50) - smokeless tobacco users. Anthropometric measurements and recording of blood pressure (BP), pulse wave analysis (PWV), heart rate variability (HRV) and pulmonary function test (PFT) was performed.

RESULT

We observed that altogether anthropometric variables were comparable among all individuals. In blood pressure variable, except DBP, other variables for example SBP, PP and MAP were significantly increased in Group II individuals, once compare to Group I. Pulse wave analysis, (such as, AP, AIx, and SEVR), was comparable in individuals of both groups. As compare to Group I, HR was significantly increased in Group II. In HRV investigation, NN, VLF, LF, LF(nu), LF/HF were increased significantly and TSP, HF, HF(nu) were decreased significantly in Group II with compare to Group I. In PFT analysis, FVC was comparable among individuals of both the group and conversely, significant decrease in FEV₁, FEV₁/FVC, FEF_25-75 and PEFR in Group II when compare with Group I.

CONCLUSION

This study illustrate that smokeless tobacco practice has increasing adverse effects on cardiovascular as well as breathing system and become an important public health problem.

Exercise performance increase in smokeless tobacco-user athletes after overnight nicotine abstinence

The use of nicotine administered through smokeless tobacco (snus) has increased among athletes. The purpose of this study was to investigate the ergogenic effects of snus on aerobic performance during exercise until exhaustion in athletes after abstinence or satiety nicotine conditions. The study utilized a randomized, controlled, within-subject design experiment. Sixteen male snus-user athletes completed an exercise until exhaustion at a constant load of their 80% of V ˙ O 2 max (calculated by a maximal incremental test) in two separate sessions, corresponding to nicotine conditions: 12-hour overnight abstinence and satiety. A portion of 1 g of snus (~8 mg/g of nicotine) was administered 25 minutes before each experimental test. In each session, time to exhaustion (TTE), global rating of perceived exertion, cardiovascular and metabolic responses, and muscle and cerebral oxygenation were measured. Nicotine and cotinine analysis confirmed session conditions (abstinence or satiety). Snus induced a significant increase (+13.1%) of TTE following abstinence (24.1 ± 10.7 minutes) compared to satiety condition (20.9 ± 8.0 minutes; P = 0.0131). The baseline values revealed that abstinence of snus induced significant increase in the oxygenation of the muscular tissues (+4%), in metabolic values and in cardiovascular parameters, when compared to satiety condition. Our results indicate an increase of exercise performance (+13.1% TTE) due to snus administration in an abstinence condition. Considering that twelve hours of abstinence from snus-contained nicotine affected metabolic, cardiovascular and muscular tissue oxygenation, we suggest that snus administration at test time might relieve these withdrawal changes and yield an increase in time to exhaustion.

Acute Effect of Hookah Smoking on Arterial Stiffness and Wave Reflections in Adults Aged 18 to 34 Years of Age

Hookah (waterpipe) smoking is rapidly increasing in popularity worldwide. Despite being heavily advertised in the media as a healthier alternative to cigarettes, the toxicology of hookah smoke suggest otherwise. Cigarette smoking unequivocally causes an acute increase in arterial stiffness, but whether hookah does the same is unknown. In 48 young healthy habitual hookah but not cigarette smokers, we measured heart rate, peripheral and central blood pressure, carotid-femoral pulse wave velocity (measure of arterial stiffness), aortic augmentation index (measure of wave reflection), plasma nicotine, and exhaled carbon monoxide before and after ad lib hookah smoking. Hookah smoking increased heart rate by +16 ± 1 beats/min and mean brachial arterial pressure by +6 ± 1 mm Hg (both p <0.05, mean ± SE). Most importantly, it increased carotid-femoral pulse wave velocity and aortic augmentation index by +0.66 ± 0.09 m/s^-1 and +8.76 ± 3.99%, respectively (p <0.05, mean ± SE), denoting increased acute arterial stiffness. These vascular effects were accompanied by increases in plasma nicotine concentration (+5.8 ± 1.2 ng/ml, p <0.05) and expired carbon monoxide (+25.44 ± 1.68 ppm, p <0.05). All these parameters were unchanged during time-control studies (n = 14). Thus, in contrast to effective media marketing of hookah as a safer alternative to cigarettes, the present study shows for the first time that in young adult hookah smokers, a single hookah smoking session causes an acute increase in arterial stiffness of comparable magnitude to what has been previously reported for cigarettes. Further research is warranted to determine whether habitual hookah smoking accelerates the age-dependent development of hypertension and its cardiovascular complications.

Brief exposure to Swedish snus causes divergent vascular responses in healthy male and female volunteers

Introduction

The use of Swedish oral moist snuff, known as snus, has for a long time been limited to the Scandinavian countries. With declining cigarette sales in the western world, tobacco companies have looked to the development of alternative tobacco products. In 2006 snus products were launched in the US. Even though several studies have demonstrated negative health effects, snus is often depicted as harmless.

The aim of the present study was to investigate acute vascular effects of snus as measured by arterial stiffness as well as blood pressure and heart rate.

Methods

Two separate randomized double-blind crossover studies with the same study design were pooled for analysis. Twenty-nine healthy snus-users (17 females, 12 males) were included. Snus (Göteborgs Rapé) and tobacco free snus (Onico) were administered in a randomized order at two separate visits. Arterial stiffness, blood pressure and heart rate were measured at baseline as well as every five minutes for 40 minutes during exposure. Following snus removal, measurements continued for 30 minutes post exposure. Arterial stiffness was measured using pulse wave velocity (Vicorder) and pulse wave analysis (Sphygmocor).

Results

Compared to placebo, snus significantly increased systolic and diastolic blood pressure as well as heart rate, however, only in females (p = 0.004, p = 0.006 and p<0.001 respectively). No changes were seen in arterial stiffness measurements in either gender.

Conclusion

We observed an increase in blood pressure and heart rate only in females, but not in males due to snus usage as compared to placebo. This novel finding was surprising and needs to be further investigated considering most of the earlier studies have mainly focused on male snus users and the increasing usage of snus among females.

Acute effects of snus in never-tobacco users: a pilot study

BACKGROUND

Snus tobacco characteristics may attract non-tobacco users, including relatively low, but pharmacologically active, doses of nicotine. Lower nicotine doses may limit adverse drug effects while also producing a physiologically active response.

OBJECTIVES

This pilot study is the first to profile the acute effects of snus on physiological and subjective assessments in a sample of never-tobacco users.

METHODS

Eleven never-tobacco users (five women; <100 uses/lifetime) were recruited from the community via university-approved advertisements. Using a within-subject design, participants consumed six pouches in ascending dose order (0, 1.6, 3.2, 4.8, 6.4, and 8.0 mg nicotine) within one session. The start of each snus bout was separated by 45 minutes, and pre- and post-pouch assessments included ratings of drug effects and physiological response.

RESULTS

The average heart rate and systolic blood pressure increased significantly from pre- to post-pouch use as a function of dose, though these increases were reliable for 8.0 mg nicotine only (p < .05). Collapsed across time, diastolic blood pressure was significantly higher for 8.0 mg nicotine than for all other doses (p < .05). Subjective ratings for "excessive salivation" and "satisfying" increased significantly from pre- to post-pouch use (p < .05), independent of dose.

CONCLUSION

Significant increases in physiological response at some doses suggest that users were exposed to pharmacologically active doses of nicotine. The lack of reliable subjective effects may be the product of the dosing regimen or the relatively small sample size. Findings highlight the need for identification of doses of snus that may promote abuse among naïve users.

Non-Smoking Tobacco Affects Endothelial Function in Healthy Men in One of the Largest Health Studies Ever Performed; The Nord-Trøndelag Health Study in Norway; HUNT3

BACKGROUND

Oral tobacco (snuff) is taking a large market share in Scandinavia, especially with young users. However, long-term health effects are unknown. Small studies show association between snuff and reduced endothelial function, representing an early stage of vascular injury that often precedes manifest cardiovascular disease by several years. We therefore determined the associations between snuff and endothelial function in a large sample of healthy Norwegian men.

METHODS AND DESIGN

In the Fitness substudy of the Nord-Trøndelag Health Study (HUNT3), endothelial function was measured by flow-mediated dilation (FMD). Aerobic fitness was measured by peak oxygen uptake (VO2peak). A cross-sectional design including 1 592 self-reported healthy men compared these observations with records of present tobacco use, standard cardiovascular risk factors, and socioeconomic status, using general linear models.

RESULTS

FMD was lower in snuff users (FMD: 4.12%, 3.63, 4.61) compared to non-users (FMD: 4.52%, 4.27, 4.78) after adjustment for age (difference: -0.57%, -1.12, -0.01). After further adjustment for potential confounders, FMD still tended to be lower in snuff users than in non-users (difference: -0.53%, -1.09, 0.02). This difference was even more pronounced in the inactive snuff users (-0.83%, -1.59, -0.06) and in the low fit snuff users (-0.74%, CI -0.55, 0.079).

CONCLUSIONS

Oral tobacco is associated with a tendency towards reduced endothelial function, indicating vascular changes that precede cardiovascular disease. The strongest associations were found in men with low physical activity or reduced aerobic fitness.

Enhanced external counterpulsation reduces indices of central blood pressure and myocardial oxygen demand in patients with left ventricular dysfunction

Enhanced external counterpulsation (EECP) therapy decreases angina episodes and improves quality of life in patients with left ventricular (LV) dysfunction. However, the underlying mechanisms relative to the benefits of EECP therapy in patients with LV dysfunction have not been fully elucidated. The purpose of this study was to investigate the effects of EECP on indices of central haemodynamics, aortic pressure wave reflection characteristics, and estimates of LV load and myocardial oxygen demand in patients with LV dysfunction. Patients with chronic stable angina and LV ejection fraction < 40% but > 30%, were randomized to either an EECP group (LV ejection fraction = 35.1 ± 4.6%; n = 10) or sham-EECP group (LV ejection fraction = 34.3 ± 4.2%; n = 7). Pulse wave analysis of the central aortic pressure waveform and LV function were evaluated by applanation tonometry before and after 35 1-h sessions of EECP or sham-EECP. Enhanced external counterpulsation therapy was effective in reducing indices of LV wasted energy and myocardial oxygen demand by 25% and 19%, respectively. In addition, indices of coronary perfusion pressure and subendocardial perfusion were increased by 9% and 30%, respectively, after EECP. Our data indicate that EECP may be useful as adjuvant therapy for improving functional classification in heart failure patients through reductions in central blood pressure, aortic pulse pressure, wasted LV energy, and myocardial oxygen demand, which also suggests improvements in ventricular-vascular interactions.

Effects of diaphragm respiration exercise on pulmonary function of male smokers in their twenties

[Purpose] We investigated how diaphragm respiration exercises can affect pulmonary function in long-term male smokers in their twenties. [Subjects and Methods] Twenty-eight healthy males between 20 and 29 years of age were randomly divided into an experimental and a control group (14 members each). The experiment was conducted during 30 min sessions, 3 times a week for 4 weeks. The experimental group performed diaphragm respiration exercises and the control group performed exercises using MOTOmed. Pulmonary function (tidal volume, breathing capacity, inspiratory reserve volume, inspiratory capacity, and expiratory reserve volume) was evaluated and analyzed before and after the experiment. [Results] Our results revealed significant increases in tidal volume, inspiratory reserve volume, inspiratory capacity, and breathing capacity in the experimental group. These increases were greater in the experimental group than in the control group. [Conclusion] In our study, the experimental group which performed diaphragm respiration exercises showed a greater improvement in pulmonary function compared with the control group. It is hypothesized that greater improvement in pulmonary function is expected if diaphragm respiration exercises are implemented taking into account the age of the smokers.

Validity of a novel wristband tonometer for measuring central hemodynamics and augmentation index

BACKGROUND

Central hemodynamic and augmentation indices are independent predictors of cardiovascular events and all-cause mortality that can be estimated noninvasively by pulse wave analysis. The purpose of this study was to assess the reliability and validity of a newly engineered wristband tonometer for acquiring radial artery pressure waveforms.

METHODS

Radial artery pulse pressure waveforms were evaluated with an established pencil-type and a novel wristband tonometer in 31 participants (aged 30.2±9.5 years) resting in a supine position. Pulse wave analysis was executed using the same validated generalized transfer function (SphygmoCor) for both tonometers.

RESULTS

A significant difference in time to data acquisition between tonometers was observed (-70.2±147.7 s; P < 0.05; wristband faster). The wristband tonometer had significantly lower within-subject coefficients of variation (CV) compared with the pencil-type tonometer in aortic pulse wave height (-2.67% ± 5.51%; P < 0.05) and time to reflection (-2.26% ± 6.16%; P < 0.01). No other differences in CV were observed. Slight but statistically significant mean differences between tonometers were observed in aortic systolic blood pressure (ASBP; 0.43±1.08 mm Hg; P < 0.05; wristband lower), aortic pulse pressure (APP; 0.43±0.96 mm Hg; P < 0.05; wristband lower), and round-trip travel time of the reflected pressure wave (Δtp; 3.58±12.86 ms; P < 0.05; wristband higher). However, ASBP, APP, and Δtp measurements were highly correlated (r = 0.9970, r = 0.9953, and r = 0.8838, respectively, P <0.0001) between tonometers; within-subject and between tonometer significant mean differences were within clinical ranges.

CONCLUSIONS

This novel, hands-free platform may be interchangeable with the commonly used pencil-type tonometer, heralding new directions in noninvasive in vivo vascular research and clinical application.

Should the augmentation index be normalized to heart rate?

Pulse wave analysis(PWA) is widely used to investigate systemic arterial stiffness. The augmentation index(AIx), the primary outcome derived from PWA, is influenced by the mean arterial pressure(MAP), age, gender and heart rate(HR). Gender- and age-specific reference values have been devised, and it is recommended that the MAP be used as a statistical covariate. The AIx is also commonly statistically adjusted to a HR of 75 b·min(-1); however, this approach may be physiologically and statistically inappropriate. First, there appears to be an important physiological chronic interaction between HR and arterial stiffness. Second, the method used to correct to HR assumes that the relationship with AIx is uniform across populations. A more appropriate practice may be to include HR as an independent predictor or covariate; this approach is particularly recommended for longitudinal studies, in which changes in HR may help to explain changes in arterial stiffness.

Exercise training reduces peripheral arterial stiffness and myocardial oxygen demand in young prehypertensive subjects

BACKGROUND

Large artery stiffness is a major risk factor for the development of hypertension and cardiovascular disease. Persistent prehypertension accelerates the progression of arterial stiffness.

METHODS

Forty-three unmedicated prehypertensive (systolic blood pressure (SBP) = 120-139 mm Hg or diastolic blood pressure (DBP) = 80-89 mm Hg) men and women and 15 normotensive time-matched control subjects (NMTCs; n = 15) aged 18-35 years of age met screening requirements and participated in the study. Prehypertensive subjects were randomly assigned to a resistance exercise training (PHRT; n = 15), endurance exercise training (PHET; n = 13) or time-control group (PHTC; n = 15). Treatment groups performed exercise training 3 days per week for 8 weeks. Pulse wave analysis, pulse wave velocity (PWV), and central and peripheral blood pressures were evaluated before and after exercise intervention or time-matched control.

RESULTS

PHRT and PHET reduced resting SBP by 9.6±3.6mm Hg and 11.9±3.4mm Hg, respectively, and DBP by 8.0±5.1mm Hg and 7.2±3.4mm Hg, respectively (P < 0.05). PHRT and PHET decreased augmentation index (AIx) by 7.5% ± 2.8% and 8.1% ± 3.2% (P < 0.05), AIx@75 by 8.0% ± 3.2% and 9.2% ± 3.8% (P < 0.05), and left ventricular wasted pressure energy, an index of extra left ventricular myocardial oxygen requirement due to early systolic wave reflection, by 573±161 dynes s/cm(2) and 612±167 dynes s/cm(2) (P < 0.05), respectively. PHRT and PHET reduced carotid-radial PWV by 1.02±0.32 m/sec and 0.92±0.36 m/sec (P < 0.05) and femoral-distal PWV by 1.04±0.31 m/sec and 1.34±0.33 m/sec (P < 0.05), respectively. No significant changes were observed in the time-control groups.

CONCLUSIONS

This study suggests that both resistance and endurance exercise alone effectively reduce peripheral arterial stiffness, central blood pressures, augmentation index, and myocardial oxygen demand in young prehypertensive subjects.

Use of snus and acute myocardial infarction: pooled analysis of eight prospective observational studies

The use of snus (also referred to as Scandinavian or Swedish moist smokeless tobacco), which is common in Sweden and increasing elsewhere, is receiving increasing attention since considered a tobacco smoke "potential reduction exposure product". Snus delivers a high dose of nicotine with possible hemodynamic effects, but its impact on cardiovascular morbidity and mortality is uncertain. The aim of this study was to investigate whether snus use is associated with risk of and survival after acute myocardial infarction (AMI). Data from eight prospective cohort studies set in Sweden was pooled and reanalysed. The relative risk of first time AMI and 28-day case-fatality was calculated for 130,361 men who never smoked. During 2,262,333 person-years of follow-up, 3,390 incident events of AMI were identified. Current snus use was not associated with risk of AMI (pooled multivariable hazard ratio 1.04, 95 % confidence interval 0.93 to 1.17). The short-term case fatality rate appeared increased in snus users (odds ratio 1.28, 95 % confidence interval 0.99 to 1.68). This study does not support any association between use of snus and development of AMI. Hence, toxic components other than nicotine appear implicated in the pathophysiology of smoking related ischemic heart disease. Case fatality after AMI is seemingly increased among snus users, but this relationship may be due to confounding by socioeconomic or life style factors.

Association of age with timing and amplitude of reflected pressure waves during exercise in men

BACKGROUND

Increased elastic conduit artery stiffness with aging is associated with early wave reflection and increased wasted left ventricular pressure energy (LVE(W)). The effects of aging on central hemodynamics during exercise have not been well characterized. This study sought to investigate changes in central hemodynamics during cycle exercise in young, middle-aged, and older men.

METHODS

Central blood pressure and wave reflection characteristics were measured noninvasively using radial artery applanation tonometry at rest and during cycling exercise (45, 55, and 65% of predicted maximum heart rate (HR(max))) in 14 young (24 ± 1 years), 16 middle-aged (49 ± 2 years) and 13 older (73 ± 2 years) men.

RESULTS

Repeated measures analysis of variance revealed significant group-by-time interactions for heart rate, central diastolic blood pressure (DBP), central pulse pressure (PP), PP amplification (PPA), central aortic pressure augmentation (AP), aortic augmentation index (AI(X)), and LVE(W). Magnitude of change from baseline was significantly different in the older group compared to young and middle-aged groups in response to exercise at 65% of predicted HR(max) for AP (+3 ± 1 mm Hg vs. -7 ± 1, P < 0.001 and -3 ± 1 mm Hg, P < 0.001) and LVE(W) (+724 ± 215 dynes s/cm(2)·min vs. -494 ± 199, P < 0.001 and -315 ± 192, P < 0.001).

CONCLUSIONS

This study suggests that changes in the timing and amplitude of reflected pressure waves during exercise alter the hemodynamic response to exercise with aging. In response to exercise, AP and LVE(W) increased in older subjects while young and middle-aged subjects exhibited a decline in AP and no change in LVE(W).