Smoking cessation and weight gain

The Effects of Adipose-Derived Stem Cells in a Rat Model of Tobacco-Associated Erectile Dysfunction

Tobacco use is associated with erectile dysfunction (ED) via a number of mechanisms including vascular injury and oxidative stress in corporal tissue. Adipose derived stem cells (ADSC) have been shown to ameliorate vascular/corporal injury and oxidative stress by releasing cytokines, growth factors and antioxidants. We assessed the therapeutic effects of intracavernous injection of ADSC in a rat model of tobacco-associated ED. Thirty male rats were used in this study. Ten rats exposed to room air only served as negative controls. The remaining 20 rats were passively exposed to cigarette smoke (CS) for 12 weeks. At the 12-week time point, ADSC were isolated from paragonadal fat in all rats. Amongst the 20 CS exposed rats, 10 each were assigned to one of the two following conditions: (i) injection of phosphate buffered saline (PBS) into the corpora cavernosa (CS+PBS); or (ii) injection of autologous ADSC in PBS into the corpora cavernosa (CS+ADSC). Negative control animals received PBS injection into the corpora cavernosa (normal rats [NR] + PBS). After injections all rats were returned to their previous air versus CS exposure state. Twenty-eight days after injection, all rats were placed in a metabolic cage for 24-hour urine collection to be testing for markers of oxidative stress. After 24-hour urine collection all 30 rats also underwent erectile function testing via intracavernous pressure (ICP) testing and were then sacrificed. Corporal tissues were obtained for histological assessment and Western blotting. Mean body weight was significantly lower in CS-exposed rats than in control animals. Mean ICP, ICP /mean arterial pressure ratio, serum nitric oxide level were significantly lower in the CS+PBS group compared to the NR+PBS and CS+ADSC groups. Urine markers for oxidative stress were significantly higher in the CS+PBS group compared to the NR+PBS and CS+ADSC groups. Mean expression of corporal nNOS and histological markers for endothelial and smooth muscle cells was significantly lower, and tissue apoptotic index significantly higher, in the CS+PBS group compared to the NR+PBS and CS+ADSC groups. Our findings confirm that chronic tobacco exposure causes ultrastructural damage to the corporal tissue and increases systemic oxidative stress states. Treatment with ADSC ameliorates these adverse effects and holds promise as a potential therapy for tobacco-related ED.

Association between Smoking Status and Obesity in a Nationwide Survey of Japanese Adults

OBJECTIVE

A positive association between the number of cigarettes smoked per day and obesity has been reported, whereas how other smoking-related indices, such as pack-years and duration of smoking, are related with obesity has been less investigated. We analyzed the age-adjusted cross-sectional association between smoking and obesity in a general Japanese population.

METHODS

We used data from a nationwide epidemiological study of Japanese adults (N = 23,106). We compared the prevalence of obesity (defined as body mass index ≥ 25kg/m2) among groups classified by smoking behavior, pack-years, number of cigarettes per day, duration of smoking, and duration and time of smoking cessation.

RESULTS

In men, current smokers had a lower odds ratio (OR) for obesity of 0.80 (95% confidence interval (CI): 0.72-0.88) compared to non-smokers, whereas past smokers had a higher OR of 1.23 (95% CI: 1.09-1.37) compared to current smokers. In women, there were no differences in obesity between the three groups classified by smoking behavior. However, in both sexes, the prevalence of obesity tended to increase with pack-years and the number of cigarettes per day, but not with duration of smoking in current and past smokers. Further, in male smokers, the risks for obesity were markedly higher in short-term heavy smokers compared with long-term light smokers, even with the same number of pack-years. Regarding the impact of smoking cessation, female past smokers who quit smoking at an age > 55-years had an elevated OR of 1.60 (95% CI:1.05-2.38) for obesity.

CONCLUSIONS

In a general Japanese population, obesity is progressively associated with pack-years and number of cigarettes per day, but not with the duration of smoking. When investigating the association between obesity and cigarette smoking, the daily smoking burden and the duration of smoking require to be independently considered.

How can we Improve on Modeling Nicotine Addiction to Develop Better Smoking Cessation Treatments?

Clinically effective smoking cessation treatments are few in number, mainly varenicline, bupropion, and nicotine replacement therapy being prescribed by health organizations. Of the many compounds tested for smoking cessation, a good proportion fail in human trials despite positive findings in rodents. This chapter aims to cover the uses and some pit falls of current methodologies employed to discover clinical treatments in the laboratory. Complicating factors include the complex nature of genetics in tobacco smoking and the comorbidity associated with other psychiatric disorders, which has not been addressed fully in the rodent laboratory. This chapter reviews the evidence from intravenous nicotine self-administration studies and proposes modifications on how we can improve the validity of the animal models by incorporating clinically relevant factors considered to be critical in tobacco smoking. For example, choice procedures that incorporate alternative reinforcers, use of reinstatement models, and second-order schedules of reinforcement are proposed to have better scientific validity that may lead to better clinical outcomes. Furthermore, improved experimental methods will also improve our chances of discovering effective treatments that ultimately may mitigate the effects of tobacco smoking with regard to health worldwide.

The effects of nicotine self-administration and withdrawal on concurrently available chow and sucrose intake in adult male rats

Carbohydrate intake, preference, and taste thresholds may be altered in current and former cigarette smokers, which may mediate weight gain and risk for obesity in individuals who quit smoking. Attempts to model these effects in rodents have primarily used noncontingent nicotine administration. The purpose of this research was to characterize changes in chow and sucrose intake in rats during a 23-h access model of i.v. nicotine self-administration (NSA), in which rats lever-pressed for chow, sucrose, and nicotine under concurrent fixed-ratio (FR) 1 schedules. Male rats were assigned to one of three groups that differed in food and drug availability. The Nicotine C+S group had concurrent access to nicotine, chow, and sucrose. The Saline C+S group had access to saline, chow, and sucrose. The Nicotine C-Only group had access to nicotine and chow, but not sucrose. Changes in food intake and weight gain were assessed during baseline, NSA, and nicotine withdrawal (i.e., saline extinction). Weight gain was significantly slowed during NSA and increased during withdrawal, but did not differ between the nicotine groups. NSA produced a significant decrease in both chow and sucrose intake. Gradual tolerance to nicotine's effects on sucrose, but not chow intake, occurred. During withdrawal, chow and sucrose intake increased, with a larger percent increase in sucrose intake compared to chow. The proportion of total food intake from sucrose was greater at the end of withdrawal compared to baseline, indicating a history of nicotine intake changed dietary preference. Combined, these results indicate that sucrose intake is more resistant to nicotine's appetite suppressant effects and withdrawal from nicotine produces a greater increase in sweet food intake alongside general increases in chow intake. Changes in overall food intake in current and ex-smokers may lead to increased risk for obesity and other health problems, potentially limiting the benefit of quitting smoking.

Effect of cigarette smoking on insulin resistance risk

OBJECTIVES

Smoking is one of the main risk factors for cardiovascular disease (CVD). The mechanism(s) of the effects of smoking on CVD are not clearly understood; however, a number of atherogenic characteristics, such as insulin resistance have been reported. We aim to investigate the effects of cigarette smoking on insulin resistance and to determine the correlation between this parameter with smoking status characteristics.

STUDY DESIGN

This study was conducted on 138 non-smokers and 162 smokers aged respectively 35.6±16.0 and 38.5±21.9 years. All subjects are not diabetic.

METHODS

Fasting glucose was determined by enzymatic methods and insulin by chemiluminescence method. Insulin resistance (IR) was estimated using the Homeostasis Model of Assessment equation: HOMA-IR=[fasting insulin (mU/L)×fasting glucose (mmol/L)]/22.5. IR was defined as the upper quartile of HOMA-IR. Values above 2.5 were taken as abnormal and reflect insulin resistance.

RESULTS

Compared to non-smokers, smokers had significantly higher levels of fasting glucose, fasting insulin and HOMA-IR index. These associations remained significant after adjustment for confounding factors (age, gender, BMI and alcohol consumption). A statistically significant association was noted between the smoking status parameters, including both the number of cigarettes smoked/day and the duration of smoking, and fasting insulin levels as well for HOMA-IR index. Among smokers, we noted a positive correlation between HOMA-IR index and both plasma thiocyanates and urinary cotinine.

CONCLUSION

Our results show that smokers have a high risk to developing an insulin resistance and hyperinsulinemia, compared with a matched group of non-smokers, and may help to explain the high risk of cardiovascular diseases in smokers.

See Me Smoke-Free: Protocol for a Research Study to Develop and Test the Feasibility of an mHealth App for Women to Address Smoking, Diet, and Physical Activity

BACKGROUND

This paper presents the protocol for an ongoing research study to develop and test the feasibility of a multi-behavioral mHealth app. Approximately 27 million women smoke in the US, and more than 180,000 women die of illnesses linked to smoking annually. Women report greater difficulties quitting smoking. Concerns about weight gain, negative body image, and low self-efficacy may be key factors affecting smoking cessation among women. Recent studies suggest that a multi-behavioral approach, including diet and physical activity, may be more effective at helping women quit. Guided imagery has been successfully used to address body image concerns and self-efficacy in our 3 target behaviors-exercise, diet and smoking cessation. However, it has not been used simultaneously for smoking, diet, and exercise behavior in a single intervention. While imagery is an effective therapeutic tool for behavior change, the mode of delivery has generally been in person, which limits reach. mHealth apps delivered via smart phones offer a unique channel through which to distribute imagery-based interventions.

OBJECTIVE

The objective of our study is to evaluate the feasibility of an mHealth app for women designed to simultaneously address smoking, diet, and physical activity behaviors. The objectives are supported by three specific aims: (1) develop guided imagery content, user interface, and resources to reduce weight concern, and increase body image and self-efficacy for behavior change among women smokers, (2) program a prototype of the app that contains all the necessary elements of text, graphics, multimedia and interactive features, and (3) evaluate the feasibility, acceptability, and preliminary efficacy of the app with women smokers.

METHODS

We created the program content and designed the prototype application for use on the Android platform in collaboration with 9 participants in multiple focus groups and in-depth interviews. We programmed and tested the application's usability with 6 participants in preparation for an open, pre- and posttest trial. Currently, we are testing the feasibility and acceptability of the application, evaluating the relationship of program use to tobacco cessation, dietary behaviors, and physical activity, and assessing consumer satisfaction with approximately 70 women smokers with Android-based smart phones.

RESULTS

The study was started January 1, 2014. The app was launched and feasibility testing began in April 1, 2015. Participants were enrolled from April 1-June 30, 2015. During that time, the app was downloaded over 350 times using no paid advertising. Participants were required to use the app "most days" for 30 days or they would be dropped from the study. We enrolled 151 participants. Of those, 78 were dropped or withdrew from the study, leaving 73 participants. We have completed the 30-day assessment, with a 92% response rate. The 90-day assessment is ongoing. During the final phase of the study, we will be conducting data analyses and disseminating study findings via presentations and publications. Feasibility will be demonstrated by successful participant retention and a high level of app use. We will examine individual metrics (eg, duration of use, number of screens viewed, change in usage patterns over time) and engagement with interactive activities (eg, activity tracking).

CONCLUSIONS

We will aggregate these data into composite exposure scores that combine number of visits and overall duration to calculate correlations between outcome and measures of program exposure and engagement. Finally, we will compare app use between participants and non-participants using Google Analytics.

Possible role of afferent autonomic signals in abdominal organs in anorexic and cardiovascular responses to nicotine injection in rats

Smoking generally causes an increase in nicotine levels in the blood, affecting the brain components, such as the hypothalamus (feeding-related area) or the brain stem (cardiovascular control area). In terms of nicotine transmission to the brain, a new insight that the afferent vagal nerve in the liver is important for sensing increased nicotine levels in the blood and informing the brain was reported in an experiment with rats. However, it has not been clarified whether the afferent autonomic nerve system is implicated in feeding and cardiovascular responses to nicotine. Here, we examined the possible role of afferent autonomic nerve transmission in rats in regulating feeding behavior and cardiovascular functions by nicotine. An intravenous injection of nicotine dose dependently increased the blood pressure (BP) in urethane-anesthetized rats; high nicotine doses also led to an increase in BP in conscious rats. Further, an intravenous injection of nicotine for 3 days reduced food intake and body weight gain in rats. The weight-reducing action of intravenous nicotine was abolished by blocking the afferent sympathetic signals in the abdominal organs, but not the vagal nerve signals. Moreover, the hypertensive action of nicotine was not abolished either by afferent sympathectomy or by vagotomy. Thus, these data suggest that nicotine injected into the vein acts on the afferent sympathetic nerve in the abdominal organs and transmits signals to the brain for reducing body weight, but not for suppressing appetite or increasing BP.

Evaluation of Post Cessation Weight Gain in a 1-Year Randomized Smoking Cessation Trial of Electronic Cigarettes

Stop smoking it is often associated to weight gain that is one of the most important causes for relapse. This is the first study to describe long-term changes in body weight in smokers invited to quit or reduce smoking by switching to ECs. Conventional cigarettes consumption and body weight were measured prospectively in a randomized controlled trial of smokers invited to switch to ECs. Post cessation weight changes from baseline at week-12, -24 and -52 were compared among 1) high, medium and zero nicotine strength products and 2) pooled continuous smoking failure, smoking reduction and abstinence phenotypes. Saliva cotinine levels and appetite levels were also measured. No significant changes in body weight were observed among high, medium and zero nicotine strength products. Differences among continuous smoking phenotypes were significant only at week-12 (p = 0.010) and week-24 (p = 0.012) with quitters gaining 2.4{plus minus}4.3 Kg and 2.9{plus minus}4.4 Kg respectively. However, weight gain at week-52 (1.5{plus minus}5.0 Kg) was no longer significant compared to Failures and Reducers. No confounding factors could explain the significant changes in body weight. Smokers who quit smoking by switching to ECs may limit their post-cessation weight gain, with substantial reversal in weight gain being manifest at late time points.

Interventions to Address Medical Conditions and Health-Risk Behaviors Among Persons With Serious Mental Illness: A Comprehensive Review

People with serious mental illness (SMI) have mortality rates 2 to 3 times higher than the overall US population, largely due to cardiovascular disease. The prevalence of cardiovascular risk factors such as obesity and diabetes mellitus and other conditions, such as HIV/AIDS, is heightened in this group. Based on the recommendations of a National Institute of Mental Health stakeholder meeting, we conducted a comprehensive review examining the strength of the evidence surrounding interventions to address major medical conditions and health-risk behaviors among persons with SMI. Peer-reviewed studies were identified using 4 major research databases. Randomized controlled trials and observational studies testing interventions to address medical conditions and risk behaviors among persons with schizophrenia and bipolar disorder between January 2000 and June 2014 were included. Information was abstracted from each study by 2 trained reviewers, who also rated study quality using a standard tool. Following individual study review, the quality of the evidence (high, medium, low) and the effectiveness of various interventions were synthesized. 108 studies were included. The majority of studies examined interventions to address overweight/obesity (n = 80). The strength of the evidence was high for 4 interventions: metformin and behavioral interventions had beneficial effects on weight loss; and bupropion and varenicline reduced tobacco smoking. The strength of the evidence was low for most other interventions reviewed. Future studies should test long-term interventions to cardiovascular risk factors and health-risk behaviors. In addition, future research should study implementation strategies to effectively translate efficacious interventions into real-world settings.

Smoking Cessation Carries a Short-Term Rising Risk for Newly Diagnosed Diabetes Mellitus Independently of Weight Gain: A 6-Year Retrospective Cohort Study

Background. The effects of smoking on human metabolism are complex. Although smoking increases risk for diabetes mellitus, smoking cessation was also reported to be associated with weight gain and incident diabetes mellitus. We therefore conducted this study to clarify the association between smoking status and newly diagnosed diabetes mellitus. Methods. An analysis was done using the data of a mass health examination performed annually in an industrial park from 2007 to 2013. The association between smoking status and newly diagnosed diabetes mellitus was analyzed with adjustment for weight gain and other potential confounders. Results. Compared with never-smokers, not only current smokers but also ex-smokers in their first two years of abstinence had higher odds ratios (ORs) for newly diagnosed diabetes mellitus (never-smokers 3.6%, OR as 1; current smokers 5.5%, OR = 1.499, 95% CI = 1.147-1.960, and p = 0.003; ex-smokers in their first year of abstinence 7.5%, OR = 1.829, 95% CI = 0.906-3.694, and p = 0.092; and ex-smokers in their second year of abstinence 9.0%, OR = 2.020, 95% CI = 1.031-3.955, and p = 0.040). Conclusion. Smoking cessation generally decreased risk for newly diagnosed diabetes mellitus. However, increased odds were seen within the first 2 years of abstinence independently of weight gain.

Back on track-Smoking cessation and weight changes over 9 years in a community-based cohort study

OBJECTIVE

To examine the impact of smoking cessation on body weight compared with normal long-term weight development.

METHODS

Of 1970 adults (20-69 years) in a rural town in Denmark invited to take part in the study in 1998-2000, 1374 (70%) participated. After 9 years, 1121 participated in the follow-up study. Weight changes were compared using multivariable regression models.

RESULTS

The mean baseline weight of never-smokers was 76.4 kg (SD 16.0). The adjusted weight of smokers and ex-smokers differed by -4.2 kg (95% CI: -5.9, -2.6), and -0.7 kg (95% CI: -2.5, 1.1), respectively. The adjusted weight gain rate (kg/year) of never-smokers, smokers, and ex-smokers was 0.213, 0.127, and 0.105, respectively. The absolute post cessation weight gain (PCWG) was 5.0 kg (SD 7.0), and the adjusted PCWG was 2.8 kg (95% CI: 1.7, 3.9) compared with never-smokers, and 3.5 kg (95% CI: 2.3, 4.8) compared with smokers. The follow-up weight did not differ between quitters and never-smokers (0.1 kg; 95% CI: -2.4, 2.6).

CONCLUSION

Smokers weigh less than never-smokers. By quitting, they gain weight and end up weighing the same as comparable never-smokers. Weight gain rates differ by smoking status. Consequently, PCWG depends on the length of follow-up. Our graphical model indicates that smoking cessation results in a return to normal weight development.

The Association of Religious Affiliation and Body Mass Index (BMI): An Analysis from the Health Survey for England

Obesity and obesity-related morbidity and mortality are an ongoing concern in developed countries. Religion is associated with reduced premature mortality and morbidity. However, the association between religion and obesity is unclear and unexplored in the general English population. This cross-sectional study uses Health Survey for England 2012 data to investigate the association of religious affiliation and BMI. A representative sample of 7,414 adults (16 years or older) was included. Waist-to-hip ratio was measured in a smaller sample and was explored as a secondary outcome. Interviews were administered, questionnaires self-completed, and height and weight measured. Sequential linear regression models were used to adjust for health behaviours. Religious affiliation was associated with a 0.91 kg/m(2) higher BMI. Some of this was explained demographically, but it was not accounted for by smoking status, alcohol consumption or physical activity level. Evidence of this association was strongest among those affiliated to a Christian religion. A significantly higher WHR was also seen in Christian and Sikh men. English prospective studies measuring intrinsic religiosity and dietary energy are needed. Religious communities may need greater healthy weight promotion or benefit from tailored interventions built on their beliefs.

Smoking is associated with increased resting energy expenditure in the general population: The NEO study

OBJECTIVE

Animal studies and human studies in small selected populations have shown a positive association between nicotine smoking and resting energy expenditure (REE), but data in large cohorts are lacking. We aimed to investigate the association between smoking behavior and REE in a large, population-based study.

DESIGN

Population-based cross-sectional study.

METHODS

In this cross-sectional analysis of baseline measurements from the Netherlands Epidemiology of Obesity (NEO) study (n=6673), we included participants with REE measurement by indirect calorimetry who were not using lipid or glucose lowering drugs (n=1189). We used linear regression analysis to examine the association of smoking status (never, former, occasional, current smoker) and smoking quantity (pack years) with REE per kilogram (kg) fat free mass (FFM) and with REE adjusted for FFM. Models were adjusted for age, sex, ethnicity, educational level, physical activity, energy intake and body mass index (BMI).

RESULTS

Mean (standard deviation, SD) age was 55.2 (5.9) years and BMI was 26.3 (4.4) kg/m(2). 60% of the participants were women. Mean (SD) REE/FFM (kcal/day/kg FFM) was for male never smokers 25.1 (2.0), male current smokers 26.4 (2.8), female never smokers 28.9 (2.5) and female current smokers 30.1 (3.7). After adjustment, only current smokers had a higher REE/FFM (mean difference 1.28, 95% CI 0.64, 1.92), and a higher REE adjusted for FFM (mean difference 60.3 kcal/day, 95% CI 29.1, 91.5), compared with never smokers. There was no association between pack years and REE/FFM (mean difference -0.01, 95% CI -0.06, 0.04) or REE adjusted for FFM (mean difference 0.2, 95% CI -2.4, 2.8) in current smokers.

CONCLUSION

Current smoking is associated with a higher resting energy expenditure compared with never smoking in a large population-based cohort.

Prevalence, associated factors and heritabilities of metabolic syndrome and its individual components in African Americans: the Jackson Heart Study

OBJECTIVE

Both environmental and genetic factors play important roles in the development of metabolic syndrome (MetS). Studies about its associated factors and genetic contribution in African Americans (AA) are sparse. Our aim was to report the prevalence, associated factors and heritability estimates of MetS and its components in AA men and women.

PARTICIPANTS AND SETTING

Data of this cross-sectional study come from a large community-based Jackson Heart Study (JHS). We analysed a total of 5227 participants, of whom 1636 from 281 families were part of a family study subset of JHS.

METHODS

Participants were classified as having MetS according to the Adult Treatment Panel III criteria. Multiple logistic regression analysis was performed to isolate independently associated factors of MetS (n=5227). Heritability was estimated from the family study subset using variance component methods (n=1636).

RESULTS

About 27% of men and 40% of women had MetS. For men, associated factors with having MetS were older age, lower physical activity, higher body mass index, and higher homocysteine and adiponectin levels (p<0.05 for all). For women, in addition to all these, lower education, current smoking and higher stress were also significant (p<0.05 for all). After adjusting for covariates, the heritability of MetS was 32% (p<0.001). Heritability ranged from 14 to 45% among its individual components. Relatively higher heritability was estimated for waist circumference (45%), high density lipoprotein-cholesterol (43%) and triglycerides (42%). Heritability of systolic blood pressure (BP), diastolic BP and fasting blood glucose was 16%, 15% and 14%, respectively.

CONCLUSIONS

Stress and low education were associated with having MetS in AA women, but not in men. Higher heritability estimates for lipids and waist circumference support the hypothesis of lipid metabolism playing a central role in the development of MetS and encourage additional efforts to identify the underlying susceptibility genes for this syndrome in AA.

Obesity trends and risk factors in the South African adult population

BACKGROUND

Obesity prevalence is increasing globally and contributes substantially to the burgeoning burden of non-communicable diseases. South Africa is particularly affected by this increasing trend and cross-sectional evidence suggests socioeconomic and behavioural variables as possible drivers. However, no large scale longitudinal study has attempted the direct identification of risk factors for progression towards obesity.

METHODS

This study analysed data on 10,100 South African adults (18 years and over) randomly selected in 2008 and successfully recontacted in 2010 and 2012. Latent Growth Modelling was used to estimate the average rate of change in body mass index (BMI) during the study period, and to identify baseline characteristics associated with different trajectories.

RESULTS

The overall rate of change in BMI during the study period was +1.57 kg/m(2) per decade (95 % CI: 0.93 -2.22), and it was higher among women (+ 1.82 kg/m(2) per decade, 95 % CI: 1.06 -2.58) than among men (+ 1.03 kg/m(2) per decade; 95 % CI: 0.14 -1.93). Female gender, younger age, larger waist circumference, white population group and higher household income per capita were baseline characteristics associated with higher rates of change. The association between tobacco use and obesity was complex. Smoking was associated with greater waist circumference at baseline but lower rates of increase in BMI during the study period. Quitting smoking was an independent predictor of BMI increase among subjects with normal weight at baseline. Among subjects with baseline BMI lower than 25 kg/m(2), rates of changes were higher in rural than urban areas, and inversely related to the frequency of physical exercise.

CONCLUSIONS

A strong positive trend in BMI remains in South Africa and obesity prevalence is likely to increase. Trends are not homogeneous, and high risk groups (subjects with high socioeconomic status, rural dwellers, young women) and modifiable risk factors (physical inactivity) can be targeted. Subjects quitting smoking should receive additional weight-loss support in order that the numerous health benefits of cessation are not reduced by increasing BMI. Centrally obese subjects should be targeted in campaigns.

Is There an Association between Sleeping Patterns and Other Environmental Factors with Obesity and Blood Pressure in an Urban African Population?

Beyond changing dietary patterns, there is a paucity of data to fully explain the high prevalence of obesity and hypertension in urban African populations. The aim of this study was to determine whether other environmental factors (including sleep duration, smoking and physical activity) are related to body anthropometry and blood pressure (BP). Data were collected on 1311 subjects, attending two primary health care clinics in Soweto, South Africa. Questionnaires were used to obtain data on education, employment, exercise, smoking and sleep duration. Anthropometric and BP measurements were taken. Subjects comprised 862 women (mean age 41 ± 16 years and mean BMI 29.9 ± 9.2 kg/m²) and 449 men (38 ± 14 years and 24.8 ± 8.3 kg/m²). In females, ANOVA showed that former smokers had a higher BMI (p<0.001) than current smokers, while exposure to second hand smoking was associated with a lower BMI (p<0.001) in both genders. Regression analyses demonstrated that longer sleep duration was associated with a lower BMI (p<0.05) in older females only, and not in males, whilst in males napping during the day for > 30 minutes was related to a lower BMI (β = -0.04, p<0.01) and waist circumference (β = -0.03, p<0.001). Within males, napping for >30 minutes/day was related to lower systolic (β = -0.02, p<0.05) and lower diastolic BP (β = -0.02, p = 0.05). Longer night time sleep duration was associated with higher diastolic (β = 0.005, p<0.01) and systolic BP (β = 0.003, p<0.05) in females. No health benefits were noted for physical activity. These data suggest that environmental factors rarely collected in African populations are related, in gender-specific ways, to body anthropometry and blood pressure. Further research is required to fully elucidate these associations and how they might be translated into public health programs to combat high levels of obesity and hypertension.

Diferenças entre sexos nos determinantes da obesidade abdominal em adultos de 40 anos ou mais: estudo de base populacional

Objetivo:Verificar diferenças entre sexos na prevalência de excesso de peso abdominal e seus determinantes em adultos a partir de 40 anos de idade.Métodos:Estudo transversal de base populacional realizado no município de Cambé, Paraná, com 1.161 indivíduos de 40 anos de idade ou mais, residentes em todos os setores censitários urbanos. A obesidade abdominal foi definida como circunferência da cintura ≥88 cm para mulheres e ≥102 cm para homens. A análise de fatores associados foi realizada para cada sexo por meio da regressão de Poisson hierarquizada baseada em modelo teórico conceitual, com seleção de variáveis distais, intermediárias e proximais.Resultados:A prevalência de obesidade abdominal foi de 49,7% e aumentou com a idade para ambos os sexos. A prevalência em mulheres foi mais que o dobro da verificada em homens (RP=2,29; IC95%=1,98-2,65). Após ajuste, as variáveis que permaneceram associadas à obesidade abdominal em ambos os sexos foram: inatividade física no lazer, idade e hipertensão arterial. Classe econômica, tabagismo e diabetes associaram-se com a obesidade abdominal apenas entre as mulheres.Conclusão:As altas prevalências de obesidade abdominal, especialmente no sexo feminino, e a presença de alguns fatores associados distintamente em cada sexo evidenciam a necessidade de ações diferenciadas de enfrentamento.

The association between quitting smoking and weight gain: a systematic review and meta-analysis of prospective cohort studies

This systematic review and meta-analysis aimed to quantify weight gain after smoking cessation and the difference in weight gain between quitters and continuing smokers. Five electronic databases were searched before January 2015. Population-based prospective cohort studies were included if they recorded the weight change of adult smokers from baseline (before smoking cessation) to follow-up (at least 3 months after cessation). Thirty-five cohort studies were identified, including 63,403 quitters and 388,432 continuing smokers. The mean weight gain was 4.10 kg (95% confidence interval [CI]: 2.69, 5.51) and body mass index (BMI) gain was 1.14 kg m(-2) (95% CI: 0.50, 1.79) among quitters. Compared with continuing smoking, quitting smoking was significantly associated with absolute weight (adjusted mean difference [MD]: 2.61 kg; 95% CI: 1.61, 3.60) and BMI gain (adjusted MD: 0.63 kg m(-2) ; 95% CI: 0.46, 0.80). Subgroup analyses using geographic region found that the difference in weight gain was considerably greater in studies from North America than from Asia. Follow-up length was identified as a source of heterogeneity, such that studies with longer follow-up showed greater difference in weight gain. Effective strategies are needed to encourage smokers to quit irrespective of potential weight gain and to help quitters avoid excess weight gain.

Job-loss and weight gain in British adults: Evidence from two longitudinal studies

Overweight and obesity have been associated with unemployment but less is known about changes in weight associated with changes in employment. We examined weight changes associated with job-loss, retirement and maintaining employment in two samples of working adults in the United Kingdom. This was a prospective study of 7201 adults in the European Prospective Investigation of Cancer (EPIC)-Norfolk study (aged 39–76 years) and 4539 adults in the British Household Panel Survey (BHPS) who were followed up over 43 months and 26 months, respectively. In both samples, changes in measured (EPIC) and self-reported (BHPS) weight were computed for each participant and assessed in relation to three employment transitions: maintaining paid employment, retirement and job-loss. Regression models adjusted for potential confounders. Further analyses evaluated the contribution of diet, physical activity and smoking to weight gain. In EPIC-Norfolk, weight change differed across the three employment transitions for women but not men. The mean (95% CI) annualised change in weight for women who became unemployed over the follow-up period was 0.70 (0.55, 0.85) kg/y while those who maintained employment gained 0.49 (0.43, 0.55) kg/y (P = 0.007). Accounting for changes in smoking, diet and physical activity did not substantially alter the difference in weight gain among groups. In BHPS, job-loss was associated with weight gain of 1.56 (0.89, 2.23) kg/y, while those who maintained employment 0.60 (0.53, 0.68) kg/y (P < 0.001). In both samples, weight changes associated with retirement were similar to those staying in work. In BHPS, job-loss was also associated with significant declines in self-reported well-being and increases in sleep-loss.

Two UK-based samples of working adults reveal strong associations between job-loss and excess weight gain. The mediating behaviours are so far unclear but psychosocial mechanisms and sleep-loss may contribute to the excess weight gain among individuals who become unemployed.

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Job-loss is associated with a more weight gain in working UK adults.

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The association between job-loss and weight may be stronger for women.

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Changes in smoking, diet and physical activity did not explain weight gain.

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Job-loss is associated with loss of sleep due to worry.

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Behavioural and psychosocial impacts of job-loss need further elucidation.

Regulation of brown fat by AMP-activated protein kinase

Novel strategies are needed to reduce the obesity epidemic. One promising strategy is activation of brown adipose tissue (BAT), either via the brain or directly, which increases energy expenditure by combustion of fatty acids (FAs) into heat. The enzyme complex AMP-activated protein kinase (AMPK) is crucially involved in energy metabolism and is highly expressed in both brain and BAT, regulating thermogenesis. As a general rule, BAT activity and energy expenditure are increased either by suppression of AMPK activity in the brain, resulting in enhanced sympathetic outflow towards BAT, or by activation of AMPK in BAT. Targeting AMPK may thus hold therapeutic potential for the treatment of obesity and related disorders.

The Sequencing of a College Degree during the Transition to Adulthood: Implications for Obesity

In this study we consider the health implications of the sequencing of a college degree vis-à-vis familial roles during the transition to adulthood. We hypothesize that people who earned a college degree before assuming familial roles will have better health than people who earned a college degree afterwards. To test this hypothesis, we focus on obesity and use data from the National Longitudinal Study of Adolescent Health. Results show that marriage before completion of college was associated with a 50% higher probability of becoming obese when compared with marriage after completion of college. Parenthood before college completion was associated with a greater than twofold increase in the probability of becoming obese when compared to parenthood afterwards for black men. These findings suggest that the well-established association of education with health depends on its place in a sequence of roles.

Predictors of marked weight gain in a population of health care and industrial workers following smoking cessation

Background

Concerns about postcessational weight gain might hamper rather than encourage smokers to quit smoking.

Methods

We conducted a comprehensive multi-institutional smoking cessation program for health care and industrial workers (n = 654) employed at University Hospital Basel (Switzerland) and two local health industry companies (Novartis International AG, F. Hoffmann-La Roche AG). The program contained counselling with an option of pharmacological support. Changes in body weight were observed during 24 months of follow-up. Factors associated with longitudinal weight gain (>5 % of baseline weight) were identified by cox-regression analysis.

Results

In 51 % of permanent quitters no significant changes of mean body weight were observed after 12 (0.52 kg, SD ±2.87 kg) and 24 months (0.40 kg, SD ± 2.99 kg). Marked weight gain following smoking cessation was characterized by a wide margin of changes. In more than a half of former smokers (58 %) weight increases were moderate (<5 kg), whereas excessive increases (>10 kg) were seen in only 10 % of quitters. Lower baseline BMI (HR 0.60, 95 % CI 0.40- 0.80, p = 0.03), daily consumption of less than ten cigarettes (HR 0.53, 95 % CI 0.27- 0.63, p = 0.04) and ischemic cardiopathy (HR 0.21, 95 % CI 0.07-0.62; p < 0.01) were associated with a lower risk for weight gain. Employees with lower educational levels (HR 2.60, 95 % CI 1.60-5.50, p < 0.01), diabetes mellitus (HR 3.05, 95 % CI 2.20-8.06, p = 0.02) and those smoking to reduce boredom in life (HR 1.68, 95 % CI 1.21-2.33, p < 0.01) were at highest risk.

Conclusion

Marked postcessational weight gain occurs less often than expected, but remains difficult to be predicted. Our findings might be helpful to alleviate weight concerns in the average smoker willing to quit.

Misconceptions about smoking in patients with type 2 diabetes mellitus: a qualitative analysis

AIMS AND OBJECTIVES

To investigate the smoking behaviours, perceptions about quitting smoking and factors associated with intention to quit in patients with type 2 diabetes mellitus.

BACKGROUND

Smoking causes type 2 diabetes mellitus. There has been limited research on the needs and concerns of smokers with type 2 diabetes mellitus about quitting smoking.

DESIGN

The study used a qualitative design.

METHODS

Patients diagnosed with type 2 diabetes mellitus who had a history of smoking were recruited at the outpatient diabetic clinics of two major local hospitals in Hong Kong for a semi-structured interview (n = 42), guided by the theory of planned behaviour.

RESULTS

At data saturation, 22 current smokers and 20 ex-smokers with type 2 diabetes mellitus were recruited. The current smokers reported they had not quit smoking because of satisfaction with present health status, and misconceptions about the association between diabetes and smoking, and the perceived hazards of quitting. In contrast, ex-smokers had a positive opinion about quitting smoking, accepted advice about quitting from health professionals and received more family support than current smokers. Psychological addiction and weight gain after cessation made quitting challenging.

CONCLUSIONS

Satisfaction with health status, inadequate knowledge about the relationship between type 2 diabetes mellitus and smoking, and misconceptions about quitting smoking resulted in negative attitudes toward quitting by type 2 diabetes mellitus smokers. Smoking peers, psychological addiction and post-cessation weight gain hindered the quitting process.

RELEVANCE TO CLINICAL PRACTICE

Education on the causal link between smoking, type 2 diabetes mellitus and its complications is important to raise health awareness and counter misconceptions about quitting smoking. Behavioural counselling with weight control strategies should be part of a comprehensive smoking cessation intervention for type 2 diabetes mellitus smokers.

Come to Where Insulin Resistance Is, Come to AMPK Country

The link between smoking and insulin resistance, despite weight loss, is well established; however, the underlying mechanisms remain elusive. A recent article published in Nature Medicine by Wu et al. (2015) reports that nicotine, the main bioactive component of tobacco smoke, activates AMPKα2 in adipocytes, leading to impaired insulin sensitivity.

Body Mass Index: Obesity, BMI, and Health: A Critical Review

The body mass index (BMI) is the metric currently in use for defining anthropometric height/weight characteristics in adults and for classifying (categorizing) them into groups. The common interpretation is that it represents an index of an individual's fatness. It also is widely used as a risk factor for the development of or the prevalence of several health issues. In addition, it is widely used in determining public health policies.The BMI has been useful in population-based studies by virtue of its wide acceptance in defining specific categories of body mass as a health issue. However, it is increasingly clear that BMI is a rather poor indicator of percent of body fat. Importantly, the BMI also does not capture information on the mass of fat in different body sites. The latter is related not only to untoward health issues but to social issues as well. Lastly, current evidence indicates there is a wide range of BMIs over which mortality risk is modest, and this is age related. All of these issues are discussed in this brief review.

Plasma zinc α2-glycoprotein levels are elevated in smokers and correlated with metabolic syndrome

BACKGROUND

Smoking is a strong risk factor of metabolic syndrome. Zinc α2-glycoprotein (ZAG) is a protein involved in metabolic syndrome. This study aims to investigate the effect of smoking on plasma ZAG levels and its relations to metabolic syndrome.

MATERIALS AND METHODS

A group of 41 cigarette smokers and 47 non-smokers were enrolled. ZAG levels were measured to correlate to participants' demographic and metabolic parameters.

RESULTS

Plasma ZAG levels of smokers were higher than those of controls (P < 0.0001). Plasma ZAG levels were positively correlated with male gender (P = 0.0002), number of cigarettes smoked per day (P < 0.0001), smoking duration in years (P < 0.0001), smoking index (P < 0.0001) and nicotine dependence score (P < 0.0001). In the multiple regression analysis, smoking was a strong independent factor affecting plasma ZAG levels (P = 0.0034). Plasma ZAG levels elevated progressively with the number of metabolic syndrome components (P = 0.0143). In the multiple regression analysis, plasma ZAG was an independent factor for metabolic syndrome.

CONCLUSIONS

Plasma ZAG levels are high in smokers and correlate with metabolic syndrome. Our results indicate ZAG is an independent risk factor, but also interacted with smoking, for the metabolic syndrome.

A short-term smoking cessation may increase the risk of developing metabolic syndrome

Smoking cessation is beneficial for health. However, its potential harmful impact on metabolic syndrome has yet to be clarified. Six smokers who attended the smoking cessation clinic were recruited and given the nicotine replacement therapy for 3 months. The values of body weight, BMI, systolic blood pressure, and fasting glycemia were significantly elevated after smoking cessation. We recommend that clinicians should monitor these cardiovascular risk factors in subjects attempting smoking cessation.

Association of a lifestyle index with MRI-determined liver fat content in a general population study

BACKGROUND

In prior studies, lifestyle indices were associated with numerous disease end points, but the association with fatty liver disease (FLD), a key correlate of cardiometabolic risk, is unknown. The aim was to investigate associations between a lifestyle index with liver fat content.

METHODS

Liver fat was quantified by MRI as liver signal intensity (LSI) in 354 individuals selected from a population-based cohort from Germany. Exposure to favourable lifestyle factors was quantified using an additive score with each factor modelled as a dichotomous trait. Favourable lifestyle factors were defined as waist circumference below 102 (men) or 88 cm (women), physical activity ≥3.5 h/week, never-smoking and a favourable dietary pattern, which was derived to explain liver fat variation. In a cross-sectional study, multivariable adjusted linear and logistic regression was applied to investigate the association between the lifestyle index (range 0-4, exposure) and LSI (modelled as a continuous trait or dichotomised as a FLD indicator variable, respectively).

RESULTS

Individuals with four favourable lifestyle factors (n=9%) had lower LSI values (ß -0.40; 95% CI -0.61 to -0.19) and a lower OR (0.09; 95% CI 0.03 to 0.30) for FLD compared with individuals with zero favourable lifestyle factors (n=10%).

CONCLUSIONS

A healthy lifestyle pattern was associated with less liver fat. Prospective studies are warranted.

Smoking cessation-related weight gain--beneficial effects on muscle mass, strength and bone health

AIMS

To examine the effects of smoking cessation on body composition and muscle strength in comparison with continued smoking.

DESIGN AND SETTING

Twelve-month longitudinal study of adult smokers conducted in Haifa, Israel.

PARTICIPANTS

Eighty-one smokers recruited from a smoking cessation programme combining group counselling and varenicline treatment.

MEASUREMENTS

Measurements were taken at the beginning of the programme and after 12 months. Body composition was assessed by dual-energy X-ray absorptiometry. Muscle strength was measured by handgrip dynamometry and predicted one-repetition maximum tests. Dietary intake and physical activity levels were estimated using questionnaires. Smoking status was determined by urine cotinine. The effect of smoking cessation was assessed using univariate and multivariable linear regression analyses.

FINDINGS

Forty-one participants (age 44 ± 12 years) completed all baseline and follow-up measurements (76% continued smokers; 24% quitters). All measures of body composition and muscle strength were increased among quitters when compared with continued smokers. Adjusted differences [95% confidence interval (CI)] between quitters and smokers were: body weight 4.43 kg (1.56-7.31 kg); lean mass 1.26 kg (0.24-2.28 kg); fat mass 3.15 kg (0.91-5.39 kg); bone mineral content 48.76 g (12.06-85.54 g); bone mineral density 0.024 g/cm(2) (0.004-0.043 g/cm(2) ); handgrip strength 3.6 kg (1.12-6.08 kg); predicted one-repetition maximum of chest press 7.85 kg (1.93-13.76 kg); and predicted one-repetition maximum of leg press 17.02 kg (7.29-26.75 kg).

CONCLUSIONS

Smoking cessation is associated with weight gain mainly through accumulating extra fat, but is also associated with increased muscle mass, muscle strength and bone density.

Socio-demographic and behavioural determinants of weight gain in the Swiss population

Background

In Switzerland, socio-demographic and behavioural factors are associated with obesity, but no study ever assessed their impact on weight gain using prospective data.

Methods

Data from 4,469 participants (53.0% women), aged 35 to 75 years at baseline and followed for 5.5 years. Weight gain was considered as a rate (kg/year) or as gaining ≥5 kg during the study period.

Results

Rate of weight gain was lower among participants who were older (mean ± standard deviation: 0.46 ± 0.92, 0.33 ± 0.88, 0.21 ± 0.86 and 0.06 ± 0.74 kg/year in participants aged [35-45], [45-55], [55–65] and [65+] years, respectively, P<0.001); physically active (0.27 ± 0.82 vs. 0.35 ± 0.95 kg/year for sedentary, P < 0.005) or living in couple (0.29 ± 0.84 vs. 0.35 ± 0.96 kg/year for living single, P < 0.05), and higher among current smokers (0.41 ± 0.97, 0.26 ± 0.84 and 0.29±0.85 kg/year for current, former and never smokers, respectively, p<0.001). These findings were further confirmed by multivariable analysis. Multivariable logistic regression showed that receiving social help, being a current smoker or obese increased the likelihood of gaining ≥5 Kg: Odds ratio (OR) and 95% confidence interval (CI) 1.43 (1.16-1.77); 1.63 (1.35-1.95) and 1.95 (1.57-2.43), respectively, while living in couple or being physically active decreased the risk: 0.73 (0.62-0.86) and 0.72 (0.62-0.83), respectively. No association was found between weight gain and gender, being born in Switzerland or education.

Conclusions

In Switzerland, financial difficulties (indicated by receiving social help) and current smoking were associated with increases in body weight over a 5 years follow-up. Living in couple, being older or physically active were protective against weight gain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1451-9) contains supplementary material, which is available to authorized users.

Provider Advice on Exercise and Diet Among Adults With Comorbid Serious Psychological Distress and Diabetes or Diabetes Risk Factors

Purpose

To examine the lifetime prevalence and correlates of provider advice to increase exercise and reduce dietary fat intake among adults with comorbid serious psychological distress (SPD) and diabetes or diabetes risk factors.

Methods

Study sample (n = 5942) was selected from the Medical Expenditure Panel Survey Household Component (MEPS-HC) series of 2007-2011. SPD was defined as a score of ≥13 on the Kessler Psychological Distress Scale (K6). Multivariate logistic regression was used to examine correlates of lifetime provider advice.

Results

Less than half of adults with SPD had been advised to increase exercise (49.4%) or reduce dietary fat intake (45.6%). The prevalence of receiving provider advice increased in a linear fashion as the number of diabetes risk factors increased and was the highest among those with diabetes. Provision of provider advice was strongly associated with clinical factors rather than individuals’ sociodemographic characteristics and current health behaviors.

Conclusions

Health care providers are missing opportunities to provide exercise and low-fat dietary advice to patients with SPD before they manifest clinical risk factors associated with diabetes. It is important that providers counsel them as early as possible about exercise and nutritional changes that reduce the risks associated with diabetes.

Blunted striatal responses to favorite-food cues in smokers

BACKGROUND

Although tobacco-smoking is associated with relatively leaner body mass and smoking cessation with weight gain, the brain mechanisms underlying these relationships are not well understood. Smokers compared to non-smokers have shown diminished neural responses to non-tobacco rewarding stimuli (e.g., monetary rewards), but brain responses to favorite-food cues have not been investigated relative to smoking status. We hypothesized that smokers would exhibit diminished neural responses compared to non-smokers in response to favorite-food cues in motivation-reward and emotion-regulating regions of the brain.

METHODS

Twenty-three smokers and 23 non-smokers matched based on body mass index (BMI), age, and gender listened to personalized favorite-food cue, stress, and neutral-relaxing audiotapes during fMRI.

RESULTS

During favorite-food cue exposure, smokers versus non-smokers exhibited diminished activations in the caudate, putamen, insula, and thalamus. Neural responses during stress and neutral-relaxing conditions were similar across groups. Subjective food-craving ratings were similar across groups.

CONCLUSIONS

The relatively diminished neural responses to favorite-food cues in smokers may contribute to lower BMI.

Socioeconomic Status, Smoking, Alcohol use, Physical Activity, and Dietary Behavior as Determinants of Obesity and Body Mass Index in the United States: Findings from the National Health Interview Survey

OBJECTIVES

The aim of this research was to study the socio-demographic and behavioral determinants of obesity and Body Mass Index (BMI) in the United States, using a nationally representative sample.

METHODS

We used data from the 2010 US National Health Interview Survey. Analyses were limited to adults 18 years and older (N=23,434). Multivariate regression analyses were conducted to estimate the associations between covariates and obesity and BMI.

RESULTS

Overall, 28.1% in the sample were obese and the mean BMI was 27.6 kg/m(2). In adjusted models, we found that older age, non-Hispanic Black race, lower education and income levels, Midwestern and Southern region of residence, former smoking, infrequent alcohol use, physical inactivity, consumption of less fruits, vegetables, brown rice and more cheese, fried potato and meat, were associated with obesity. These factors were also associated with higher BMI, along with male gender and higher consumption of meat, fried potatoes and cheese.

CONCLUSIONS AND GLOBAL HEALTH IMPLICATIONS

The association of many of the socio-demographic and behavioral factors with obesity and higher BMI found in our study was consistent with previous findings. Persistence of such associations suggest a need for better understanding of the underlying mechanism as well as for evaluation of the current programs and policies targeted at reducing the obesity burden in the United States. In view of the rising global obesity epidemic, especially in the low- and middle-income countries, our findings could help guide development of effective health and social policies and programs aimed at reducing the obesity burden in other parts of the world.

Weight gain and smoking: perceptions and experiences of obese quitline participants

Background

Weight gain that commonly accompanies smoking cessation can undermine a person’s attempt to quit and increase the risk for metabolic disorders. Research indicates that obese smokers have more weight concerns and gain more weight after quitting than non-obese smokers, yet little is known about possible reasons for these outcomes. We sought to gain an understanding of obese smokers’ experiences of quitting and their attitudes and beliefs about the association between smoking and weight gain.

Methods

In-depth semi-structured interviews were conducted with obese smokers who called a state tobacco quitline. Interviewers elicited discussion of obese smokers’ thoughts about smoking, the effects of quitting on change in weight, challenges they faced with quitting, and how quitlines might better serve their needs.

Results

Participants (n = 29) discussed their fear of gaining weight after quitting, their beliefs about smoking and their weight and significant experiences related to quitting. Participants’ awareness of weight gain associated with quitting was based on prior experience or observation of others who quit. Most viewed cessation as their primary goal and discussed other challenges as being more important than their weight, such as managing stress or coping with a chronic health condition. Although weight gain was viewed as less important than quitting, many talked about changes they had made to mitigate the anticipated weight gain.

Conclusions

Weight gain is a concern for obese smokers interested in quitting. Understanding the relative importance of body weight and other challenges related to smoking cessation can help tailor interventions for the specific group of smokers who are obese and interested in smoking cessation.

Association between smoking and total energy expenditure in a multi-country study

BACKGROUND

The association between smoking and total energy expenditure (TEE) is still controversial. We examined this association in a multi-country study where TEE was measured in a subset of participants by the doubly labeled water (DLW) method, the gold standard for this measurement.

METHODS

This study includes 236 participants from five different African origin populations who underwent DLW measurements and had complete data on the main covariates of interest. Self-reported smoking status was categorized as either light (<7 cig/day) or high (≥7 cig/day). Lean body mass was assessed by deuterium dilution and physical activity (PA) by accelerometry.

RESULTS

The prevalence of smoking was 55% in men and 16% in women with a median of 6.5 cigarettes/day. There was a trend toward lower BMI in smokers than non-smokers (not statistically significant). TEE was strongly correlated with fat-free mass (men: 0.70; women: 0.79) and with body weight (0.59 in both sexes). Using linear regression and adjusting for body weight, study site, age, PA, alcohol intake and occupation, TEE was larger in high smokers than in never smokers among men (difference of 298 kcal/day, p = 0.045) but not among women (162 kcal/day, p = 0.170). The association became slightly weaker in men (254 kcal/day, p = 0.058) and disappeared in women (-76 kcal/day, p = 0.380) when adjusting for fat-free mass instead of body weight.

CONCLUSION

There was an association between smoking and TEE among men. However, the lack of an association among women, which may be partly related to the small number of smoking women, also suggests a role of unaccounted confounding factors.

Daily physical activity and alcohol use across the adult lifespan

OBJECTIVE

In contrast to proposals that physical activity (PA) can be a substitute for alcohol use, people who engage in greater overall PA generally consume more alcohol on average than less-active peers. Acknowledging that both PA and alcohol use vary considerably from day-to-day, this study evaluated whether established associations reflect daily behavioral coupling within-person, are an artifact of procedures that aggregate behavior over time, or both.

METHODS

A life span sample of 150 adults (aged 19-89 years) completed three 21-day measurement bursts of a daily diary study. At the end of each day, they reported on their PA and alcohol consumption. Data were analyzed in a negative binomial multilevel regression.

RESULTS

As expected, both behaviors exhibited limited between-person variation. After controlling for age, gender, and seasonal and social calendar influences, daily deviations in PA were significantly associated with daily total alcohol use. Once the within-person process linking PA and alcohol use was controlled, usual PA and total alcohol use were not associated.

CONCLUSIONS

The established between-person association linking PA and alcohol use reflects the aggregation of a daily process that unfolds within-people over time. Further work is needed to identify mediators of this daily association and to evaluate causality, as well as to investigate these relations in high-risk samples.

Leptin and smoking cessation: secondary analyses of a randomized controlled trial assessing physical activity as an aid for smoking cessation

Background

Smokers have a lower body weight compared to non-smokers. Smoking cessation is associated with weight gain in most cases. A hormonal mechanism of action might be implicated in weight variations related to smoking, and leptin might be implicated. We made secondary analyses of an RCT, with a hypothesis-free exploratory approach to study the dynamic of leptin following smoking cessation.

Methods

We measured serum leptin levels among 271 sedentary smokers willing to quit who participated in a randomized controlled trial assessing a 9-week moderate-intensity physical activity intervention as an aid for smoking cessation. We adjusted leptin for body fat levels. We performed linear regressions to test for an association between leptin levels and the study group over time.

Results

One year after smoking cessation, the mean serum leptin change was +3.23 mg/l (SD 4.89) in the control group and +1.25 mg/l (SD 4.86) in the intervention group (p of the difference < 0.05). When adjusted for body fat levels, leptin was higher in the control group than in the intervention group (p of the difference < 0.01). The mean weight gain was +2.91 (SD 6.66) Kg in the intervention and +3.33 (SD 4.47) Kg in the control groups, respectively (p not significant).

Conclusions

Serum leptin levels significantly increased after smoking cessation, in spite of substantial weight gain. The leptin dynamic might be different in chronic tobacco users who quit smoking, and physical activity might impact the dynamic of leptin in such a situation.

Clinical trial registration number

NCT00521391

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2458-14-911) contains supplementary material, which is available to authorized users.

Weight gain prior to entry into a weight-loss intervention study among overweight and obese breast cancer survivors

PURPOSE

Changes in cancer therapy, in addition to changes in obesity prevalence, suggest the need for a current assessment of weight gain patterns following breast cancer diagnosis. The aim of this study was to evaluate factors associated with weight gain among breast cancer survivors prior to enrolling into a behavioral weight loss intervention.

METHODS

Anthropometric measures and data on weight-related factors were collected at baseline on 665 breast cancer survivors. Postdiagnosis weight gain was determined between entry into the trial and previous diagnosis up to 5 years. Multivariate logistic regression analyses were used to evaluate the association between weight gain and influencing factors.

RESULTS

The mean weight gain was 4.5 % body weight (standard deviation = 10.6); 44 % of women experienced ≥5 % body weight gain. The risk of weight gain was inversely associated with age (adjusted odds ratio (ORadj) = 0.97, 95 % confidence interval (95 % CI) 0.95-0.99), Hispanic ethnicity (ORadj = 0.30, 95 % CI 0.13-0.68), and overweight (ORadj = 0.11, 95 % CI 0.05-0.23) or obese (ORadj = 0.03, 95 % CI 0.02-0.07) status at diagnosis and positively associated with time elapsed since diagnosis (ORadj = 1.19/year, 95 % CI 1.04-1.36). Women prescribed aromatase inhibitors were 46 % less likely to gain weight compared to women prescribed selective estrogen-receptor modulators (ORadj = 0.54, 95 % CI 0.31-0.93). The risk of weight gain was positively associated with smoking at diagnosis (ORadj = 2.69, 95 % CI 1.12-6.49) although this was attributable to women who subsequently quit smoking.

CONCLUSIONS

Postdiagnosis weight gain is common and complex and influenced by age, ethnicity, weight, smoking status, time elapsed since diagnosis, and endocrine-modulating therapy.

IMPLICATIONS FOR CANCER SURVIVORS

Weight gain continues to be a concern following a diagnosis of breast cancer. Factors influencing this weight gain include age, ethnicity, weight, smoking status, time elapsed since diagnosis, and endocrine-modulating therapy. Effective weight management strategies are needed for this population of women.

The joint influence of gender and amount of smoking on weight gain one year after smoking cessation

Weight gain is often associated with smoking cessation and may discourage smokers from quitting. This study estimated the weight gained one year after smoking cessation and examined the risk factors associated with weight gain in order to identify socio-demographic groups at higher risk of increased weight after quitting. We analyzed data from 750 adults in two randomized controlled studies that included smokers motivated to quit and found a gradient in weight gain according to the actual duration of abstinence during follow-up. Subjects who were abstinent for at least 40 weeks gained 4.6 kg (SD = 3.8) on average, compared to 1.2 kg (SD = 2.6) for those who were abstinent less than 20 weeks during the 1-year follow-up. Considering the duration of abstinence as an exposure variable, we found an age effect and a significant interaction between sex and the amount of smoking before quitting: younger subjects gained more weight than older subjects; among light smokers, men gained more weight on average than women one year after quitting, while the opposite was observed among heavy smokers. Young women smoking heavily at baseline had the highest risk of weight gain after quitting.

The aetiology of obesity beyond eating more and exercising less

Although recent increases in availability of energy dense, processed foods and reductions in institutionally driven physical activity have created an environment that is permissible for obesity to occur, several other factors may contribute to the development of obesity in this context. We review evidence for eleven such factors: endocrine disruptors, intrauterine effects, epigenetics, maternal age, differential fecundity and assortative mating by body mass index, microorganisms, reduction in variability of ambient temperatures, smoking cessation, sleep debt, and pharmaceutical iatrogenesis. Evidence for the role of endocrine disruptors, microorganisms, ambient temperatures, sleep and reproductive factors is accumulating, but additional research is needed to confirm the causative role of these factors in human obesity. However, the role of certain pharmaceuticals and smoking cessation in development of human obesity is clear. Practice points for consideration and future research needed are highlighted for each factor.

Cross-sectional association between cigarette smoking and abdominal obesity among Austrian bank employees

OBJECTIVES

There is increasing evidence that smoking is associated with abdominal obesity and other risk factors for the metabolic syndrome. The aim of this study is to investigate these associations in a sample of healthy Austrian adults.

SETTING AND PARTICIPANTS

Data of 986 employees of an Austrian company (405 men and 581 women; participation rate approximately 80%) obtained during their annual medical check-up at the workplace were analysed.

PRIMARY AND SECONDARY OUTCOME MEASURES

Information on smoking status, education level, physical activity, diet, body weight, height, body mass index (BMI), waist circumference and biochemical parameters was obtained. The influence of smoking on health and anthropometric measures was investigated.

RESULTS

No differences in total body fat and/or body fat distribution were found between non-smokers, smokers and former smokers; however, among daily smokers, the number of cigarettes smoked per day was significantly associated with higher body weight (p=0.001) and BMI (p=0.009). Male and female smokers had significantly higher white cell count than non-smokers and former smokers. Heavy smokers also had an unhealthier lipid profile (lower high-density lipoprotein cholesterol) and higher fasting glucose levels even after controlling for physical activity and calorie intake.

CONCLUSIONS

Contrary to the beliefs of many smokers, heavy smoking is associated with higher body weight and unfavourable metabolic changes.

Weight change in patients attempting to quit smoking post-myocardial infarction

BACKGROUND

Current guidelines recommend smoking cessation and weight management for secondary prevention in patients post-myocardial infarction. However, little is known about the effects of smoking cessation on weight change post-myocardial infarction.

METHODS

We examined patterns of weight change and its effects on blood pressure and glycemic control using data from a randomized trial investigating the effect of bupropion on smoking cessation in patients post-myocardial infarction. Weight change was compared among 3 groups of patients: those who were completely abstinent (n = 92), those who smoked intermittently (n = 49), and those who smoked persistently (n = 38) during the 12-month follow-up. Analyses were restricted to patients who attended all follow-up visits.

RESULTS

The median weight at baseline was 77.1 kg (interquartile range [IQR], 66.0, 87.5), and 64.3% of patients were overweight/obese (body mass index ≥25.0 kg/m(2)). The median weight gain at 12 months was 4.0 kg (IQR, 0-7.0), with more than one third gaining >5 kg. The proportion of patients who were overweight/obese increased by approximately 10%, and 23.2% of patients moved up a body mass index category. Abstainers gained a median of 4.8 kg (IQR, 1.0, 8.6), intermittent smokers gained a median of 2.0 kg (IQR, -2.0, 5.0), and persistent smokers gained a median of 3.0 kg (IQR, -0.8, 6.0). Weight gain was associated with an increase in blood pressure and requirements for hypoglycemic medications at 12 months.

CONCLUSIONS

The majority of patients attempting to quit smoking gain weight 12 months post-myocardial infarction, with abstainers gaining more weight than those who return to smoking. Weight gain was associated with an increased prevalence of hypertension and diabetes.

The role of alpha-7 nicotinic receptors in food intake behaviors

Nicotine alters appetite and energy expenditure, leading to changes in body weight. While the exact mechanisms underlying these effects are not fully established, both central and peripheral involvement of the alpha-7 nicotinic acetylcholine receptor (α7nAChR) has been suggested. Centrally, the α7nAChR modulates activity of hypothalamic neurons involved in food intake regulation, including proopiomelanocortin and neuropeptide Y. α7nAChRs also modulate glutamatergic and dopaminergic systems controlling reward processes that affect food intake. Additionally, α7nAChRs are important peripheral mediators of chronic inflammation, a key contributor to health problems in obesity. This review focuses on nicotinic cholinergic effects on eating behaviors, specifically those involving the α7nAChR, with the hypothesis that α7nAChR agonism leads to appetite suppression. Recent studies are highlighted that identify links between α7nAChR expression and obesity, insulin resistance, and diabetes and describe early findings showing an α7nAChR agonist to be associated with reduced weight gain in a mouse model of diabetes. Given these effects, the α7nAChR may be a useful therapeutic target for strategies to treat and manage obesity.

Association of cigarette smoking and metabolic syndrome in a Puerto Rican adult population

Metabolic syndrome (MetSyn) is related to an increased risk for type 2 diabetes and cardiovascular disease. Smokers are at greater risk than nonsmokers of becoming insulin resistant and to develop cardiovascular disease. This study aimed to explore the association between cigarette smoking, MetSyn and its components among Puerto Rican adults. A representative sample of 856 persons aged 21-79 years from the San Juan Metropolitan area participated in this study. Demographic and lifestyle characteristics, including smoking habits, were gathered from a self-reported questionnaire. MetSyn was defined according to the revised NCEP-ATP III criteria and measured using biochemical measurements and anthropometric indices. Logistic regression models were used to estimate prevalence odds ratios (POR) and its 95 % confidence intervals (CI). MetSyn was significantly (P < 0.001) more prevalent in former smokers (48.4 %) as compared to current (42.7 %) and never smokers (40.0 %). However, after adjusting for possible confounders, current smokers who used more than 20 cigarettes per day were 2.24 (95 % CI = 1.00-4.99) times more likely to have MetSyn as compared to never smokers. Heavy smokers were also more likely to have high triglyceride levels (POR = 2.22, 95 % CI = 1.12-4.38) and low HDL-cholesterol levels (POR = 2.49, 95 % CI = 1.28-4.86) as compared to never smokers. This study supports previous reports of an increased risk of MetSyn among current smokers, particularly those with a heavier consumption. Tobacco control strategies, such as preventing smoking initiation and disseminating evidence-based cessation programs, are necessary to reduce the burden of MetSyn in Puerto Rico.

Early changes in the components of the metabolic syndrome in a group of smokers after tobacco cessation

AIM

We aimed to examine the prevalence of early changes in some components of metabolic syndrome after smoking cessation.

METHODS

Forty-eight heavy smokers from the Tobacco Cessation Clinic (24 women/24 men), average age of 49.4 years, were included in this study. They smoked a mean of 19.92 cigarettes per day and had smoked 33.23 packages per year during 33.4 years. Participants were included in a treatment group based on cognitive behavior therapy (CBT); 16 participants received varenicline and the other 16 nicotine replacement therapy (NRT). The target quit day was scheduled for week 3 through abrupt cessation. Abstinence was confirmed with exhaled carbon monoxide (CO) levels. Blood pressure, body mass index (BMI), and waist circumference (WC) were evaluated weekly. Glucose, triglycerides, high density lipoproteins (HDL-C), and insulin to determine the homeostasis model assessment (HOMA) index were determined in blood samples at weeks 1, 4, and 10. As a control group 96 healthy nonsmokers were matched by age and sex.

RESULTS

The mean BMI in smokers was 26.94 kg/m(2) and in nonsmokers 26.23 kg/m(2). Smokers showed hypertension, hypertriglyceridemia, and lower levels of HDL-C than nonsmokers. Percentages of cessation in week 3 were 81% for NRT and 93% for CBT and varenicline. The mean weight increase at the end of the treatment was 1.09 kg in the CBT group, 1.06 kg in the NRT group, and 1.17 kg in the varenicline group. The prevalence of metabolic syndrome was 31.25% in week 1 and 29.16% at the end. There were reductions in the number of subjects with hypertension, glucose alterations, hypertriglyceridemia, and low HDL levels.

CONCLUSIONS

Benefits of quitting smoking exceeded by far the risks associated with the amount of weight gained.

Nicotine improves obesity and hepatic steatosis and ER stress in diet-induced obese male rats

Nicotine, the main addictive component of tobacco, promotes body weight reduction in humans and rodents. Recent evidence has suggested that nicotine acts in the central nervous system to modulate energy balance. Specifically, nicotine modulates hypothalamic AMP-activated protein kinase to decrease feeding and to increase brown adipose tissue thermogenesis through the sympathetic nervous system, leading to weight loss. Of note, most of this evidence has been obtained in animal models fed with normal diet or low-fat diet (LFD). However, its effectiveness in obese models remains elusive. Because obesity causes resistance towards many factors involved in energy homeostasis, the aim of this study has been to compare the effect of nicotine in a diet-induced obese (DIO) model, namely rats fed a high-fat diet, with rats fed a LFD. Our data show that chronic peripheral nicotine treatment reduced body weight by decreasing food intake and increasing brown adipose tissue thermogenesis in both LFD and DIO rats. This overall negative energy balance was associated to decreased activation of hypothalamic AMP-activated protein kinase in both models. Furthermore, nicotine improved serum lipid profile, decreased insulin serum levels, as well as reduced steatosis, inflammation, and endoplasmic reticulum stress in the liver of DIO rats but not in LFD rats. Overall, this evidence suggests that nicotine diminishes body weight and improves metabolic disorders linked to DIO and might offer a clear-cut strategy to develop new therapeutic approaches against obesity and its metabolic complications.

Impact of baseline weight on smoking cessation and weight gain in quitlines

BACKGROUND

The use and effectiveness of tobacco quitlines by weight is still unknown.

PURPOSE

This study aims to determine if baseline weight is associated with treatment engagement, cessation, or weight gain following quitline treatment.

METHODS

Quitline participants (n = 595) were surveyed at baseline, 3 and 6 months.

RESULTS

Baseline weight was not associated with treatment engagement. In unadjusted analyses, overweight smokers reported higher quit rates and were more likely to gain weight after quitting than obese or normal weight smokers. At 3 months, 40 % of overweight vs. 25 % of normal weight or obese smokers quit smoking (p = 0.01); 42 % of overweight, 32 % of normal weight, and 33 % of obese quitters gained weight (p = 0.05). After adjusting for covariates, weight was not significantly related to cessation (approaching significance at 6 months, p = 0.06) or weight gain.

CONCLUSIONS

In the first quitline study of this kind, we found no consistent patterns of association between baseline weight and treatment engagement, cessation, or weight gain.

Changes of plasma adiponectin levels after smoking cessation

OBJECTIVE

Cigarette smoking is associated with a variety of health problems including cardiovascular, pulmonary, neoplasms, endocrinopathies including diabetes, the metabolic syndrome, and chronic inflammation. Adiponectin is an adipocyte-derived plasma protein that is closely associated with insulin sensitivity and the metabolic syndrome. The aim of this study was to evaluate the changes of plasma adiponectin levels after smoking cessation.

METHODS

Thirty seven smokers that wanted to stop smoking without any nicotine replacement therapy or medication were recruited for this study. Fifteen smokers succeeded in stopping smoking (validated by urine cotinine levels ≤50 ng/mL) and 22 smokers failed. Therefore, only the 15 that succeeded were included in the analysis. The plasma adiponectin levels were determined using a commercially available enzyme-linked immunosorbent assay.

RESULTS

The mean age of the successful 15 was 35±9.3 years old. They were all males. The daily smoking habit was a mean of 13.5±5.4 cigarettes per day. The mean Nicotine Dependence Syndrome Scale (NDSS) and Fagerstrom Test for Nicotine Dependence (FTND) scores were 55.6±9.6 and 2.9±1.9. During the study period of three months, the mean body mass index (BMI), body fat mass (BFM), waist-hip ratio (WHR) and body weight increased by 1.1 kg/m(2), 3.0%, 0.02%, and 2.9 kg, respectively. The baseline mean adiponectin level in the subjects was 11.9±5.2 mg/L. The mean adiponectin levels measured at one and three months were 16.0±5.1 mg/L and 14.7±4.5 mg/L respectively. The mean plasma adiponectin levels of the successful group was significantly increased after four weeks when compared to the baseline (z=-2.401, p=0.016). However, the decrease in plasma adiponectin levels at one and three months was not statistically significant.

CONCLUSION

Even though the decrease over the next two months was not significant, these findings, the increase of plasma level of adiponectin after smoking cessation, provide preliminary data for future research on the possible mechanisms associated with smoking cessation and changes in body metabolism.