Tag: smoking

Smoking Affects the Immune System Many Years after Quitting

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Researchers from Institut Pasteur have discovered that the immune impacts of smoking can last for many years, leaving smokers with effects on some of their bodies’ defence mechanisms acquired while smoking. These findings, which for the first time reveal a long-term memory of the effects of smoking on immunity, are published in the journal Nature.

Individuals’ immune systems vary significantly in terms of how effectively they respond to microbial attacks. But how can this variability be explained? What factors cause these differences? “To answer this key question, we set up the Milieu Intérieur cohort comprising 1000 healthy individuals aged 20 to 70 in 2011,” explains Darragh Duffy, Head of the Translational Immunology Unit at the Institut Pasteur and last author of the study. While certain factors such as age, sex and genetics are known to have a significant impact on the immune system, the aim of this new study was to identify which other factors had the most influence.”

The scientists exposed blood samples taken from individuals in the Milieu Intérieur cohort to a wide variety of microbes and observed their immune response by measuring levels of secreted cytokines(1). Using the large quantities of data gathered for individuals in the cohort, the team then determined which of the 136 investigated variables (body mass index, smoking, number of hours’ sleep, exercise, childhood illnesses, vaccinations, living environment, etc) had the most influence on the immune responses studied. Three variables stood out: smoking, latent cytomegalovirus infection(2) and body mass index. “The influence of these three factors on certain immune responses could be equal to that of age, sex or genetics,” points out Darragh Duffy.

As regards smoking, an analysis of the data showed that the inflammatory response, which is immediately triggered by infection with a pathogen, was heightened in smokers, and moreover, the activity of certain cells involved in immune memory was impaired. In other words, this study shows that smoking disrupts not only innate immune mechanisms, but also some adaptive immune mechanisms. “A comparison of immune responses in smokers and ex-smokers revealed that the inflammatory response returned to normal levels quickly after smoking cessation, while the impact on adaptive immunity persisted for 10 to 15 years,” observes Darragh Duffy. “This is the first time it has been possible to demonstrate the long-term influence of smoking on immune responses.”

Basically, the immune system appears to have something resembling a long-term memory of the effects of smoking. But how? “When we realised that the profiles of smokers and ex-smokers were similar, we immediately suspected that epigenetic processes were at play(3),” says Violaine Saint-André, a bioinformatician in the Institut Pasteur’s Translational Immunology Unit and first author of the study. “We demonstrated that the long-term effects of smoking on immune responses were linked to differences in DNA methylation(4) – with the potential to modify the expression of genes involved in immune cell metabolism – between smokers, ex-smokers and non-smokers.” It therefore appears that smoking can induce persistent changes to the immune system through epigenetic mechanisms.

“This is a major discovery elucidating the impact of smoking on healthy individuals’ immunity and also, by comparison, on the immunity of individuals suffering from various diseases,” concludes Violaine Saint-André.

Notes:

(1) proteins secreted by a large number of immune cells to communicate among themselves and participate in immune defense.

(2) a virus in the herpes family that is often asymptomatic though dangerous to foetuses.

(3) changes in DNA that affect how genes are expressed, i.e. how they are used by cells.

(4) methylation is a type of chemical modification. Methyl groups position themselves on DNA, changing the way in which the genome is read in the cell.

Source: Institut Pasteur

Memory Loss and Confusion More Common among Middle-aged Smokers

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Middle-aged smokers are much more likely to report having memory loss and confusion than nonsmokers, and the likelihood of cognitive decline is lower for those who have quit, even recently, according to a new study appearing in the Journal of Alzheimer’s Disease.

The study is the first to examine the relationship between smoking and cognitive decline using a one-question self-assessment asking people if they’ve experienced worsening or more frequent memory loss and/or confusion.

The findings build on previous research that established relationships between smoking and Alzheimer’s Disease and other forms of dementia, and could point to an opportunity to identify signs of trouble earlier in life, said Jenna Rajczyk, lead author of the study.

It’s also one more piece of evidence that quitting smoking is good not just for respiratory and cardiovascular reasons, but to preserve neurological health, said Rajczyk, a PhD student in Ohio State’s College of Public Health, and senior author Jeffrey Wing, assistant professor of epidemiology.

“The association we saw was most significant in the 45–59 age group, suggesting that quitting at that stage of life may have a benefit for cognitive health,” Wing said. A similar difference wasn’t found in the oldest group in the study, which could mean that quitting earlier affords people greater benefits, he said.

Researchers used data from the 2019 Behavioral Risk Factor Surveillance System Survey to compare subjective cognitive decline (SCD) measures for current smokers, recent former smokers, and those who had quit years earlier. The analysis included 136 018 people 45 and older, and about 11% reported SCD.

The prevalence of SCD among smokers in the study was almost 1.9 times that of nonsmokers. The prevalence among those who had quit less than 10 years ago was 1.5 times that of nonsmokers. Those who quit more than a decade before the survey had an SCD prevalence just slightly above the nonsmoking group.

“These findings could imply that the time since smoking cessation does matter, and may be linked to cognitive outcomes,” Rajczyk said.

The simplicity of SCD, a relatively new measure, could lend itself to wider applications, she said.

“This is a simple assessment that could be easily done routinely, and at younger ages than we typically start to see cognitive declines that rise to the level of a diagnosis of Alzheimer’s Disease or dementia,” Rajczyk said. “It’s not an intensive battery of questions. It’s more a personal reflection of your cognitive status to determine if you’re feeling like you’re not as sharp as you once were.”

Many people don’t have access to more in-depth screenings, or to specialists, making the potential applications for measuring SCD even greater, she said.

Wing said it’s important to note that these self-reported experiences don’t amount to a diagnosis, nor do they confirm independently that a person is experiencing decline out of the normal ageing process. But, he said, they could be a low-cost, simple tool to consider employing more broadly.

Source: Ohio State University

Emphysema Found to be More Common in Marijuana Smokers

Anatomical model of lungs
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Airway inflammation and emphysema are more common in marijuana smokers than cigarette smokers, according to a study published in Radiology. Researchers said the difference may be due to the way that marijuana is smoked, which is usually inhaled more deeply and without a filter.

Marijuana is one of the most widely used psychoactive substances in the world and the most-commonly smoked substance after tobacco. Its use has increased in recent years amid legalisation of recreational marijuana in many countries. The growing use has created an urgent need for information on marijuana’s effects on the lungs, something that is currently lacking.

“We know what cigarettes do to the lungs,” said study author Giselle Revah, MD, a cardiothoracic radiologist and assistant professor at the University of Ottawa. “There are well researched and established findings of cigarette smoking on the lungs. Marijuana we know very little about.” 

To find out more, Dr Revah and colleagues compared chest CT results from 56 marijuana smokers with those of 57 non-smoking controls and 33 tobacco-only smokers.

Pulmonary emphysema in (A, B) marijuana and (C, D) tobacco smokers. (A) Axial and (B) coronal CT images in a 44-year-old male marijuana smoker show paraseptal emphysema (arrowheads) in bilateral upper lobes. (C) Axial and (D) coronal CT images in a 66-year-old female tobacco smoker with centrilobular emphysema represented by areas of centrilobular lucency (arrowheads). (Murtha, et al.)

Lack of filtering partly to blame

Three-quarters of the marijuana smokers had emphysema, a lung disease that causes difficulty with breathing, compared with 67% of the tobacco-only smokers. Only 5% of the non-smokers had emphysema. Paraseptal emphysema, which damages the tiny ducts that connect to the air sacs in the lungs, was the predominant emphysema subtype in marijuana smokers compared to the tobacco-only group.

Airway inflammation was also more common in marijuana smokers than non-smokers and tobacco-only smokers, as was gynecomastia, enlarged male breast tissue due to a hormone imbalance. Gynecomastia was found in 38% of the marijuana smokers, compared with 11% of the tobacco-only smokers and 16% of the controls. 

The researchers found similar results among age-matched subgroups, where the rates of emphysema and airway inflammation were again higher in the marijuana smokers than the tobacco-only smokers.

There was no difference in coronary artery calcification between age-matched marijuana and tobacco-only groups.

Dr. Revah said the results were surprising, especially considering that the patients in the tobacco-only group had an extensive smoking history.

“The fact that our marijuana smokers – some of whom also smoked tobacco – had additional findings of airway inflammation/chronic bronchitis suggests that marijuana has additional synergistic effects on the lungs above tobacco,” she said. “In addition, our results were still significant when we compared the non-age-matched groups, including younger patients who smoked marijuana and who presumably had less lifetime exposure to cigarette smoke.” 

The reasons for the differences between the two groups is likely due to several factors. Marijuana is smoked unfiltered, Dr Revah noted, while tobacco cigarettes are usually filtered. This results in more particulates reaching the airways from smoking marijuana.

In addition, marijuana is inhaled with a longer breath hold and puff volume than tobacco smoke.

“It has been suggested that smoking a marijuana joint deposits four times more particulates in the lung than an average tobacco cigarette,” Dr Revah said. “These particulates are likely airway irritants.”

The higher incidence of emphysema may also be due to the way that marijuana is smoked. Full inhalation with a sustained Valsalva manoeuvre, an attempt at exhalation against a closed airway, may lead to trauma and peripheral airspace changes. 

More research is needed, Dr Revah said, with larger groups of people and more data on how much and how often people are smoking. Future research could also look at the impact of different inhalation techniques, such as through a bong, a joint or a pipe.

“It would be interesting to see if the inhalation method makes a difference,” Dr Revah said.

For More Information

Read the Radiology study, “Chest CT Findings in Marijuana Smokers,” and the related editorial.

Source: Radiological Society of North America

New Laws Set to Turn the Screws on Smoking in South Africa

Cigarette butts
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New legislation will soon place further curbs on tobacco smoking in South Africa – and these laws will also now extend to e-cigarettes. In South Africa, lung cancer is the third most common cancer among men and seventh for women. More than two-thirds of lung cancer patients are diagnosed at an advanced stage, resulting in poorer outcomes for treatment.

The proposed laws impose harsher penalties against smoking in smoke-free zones, being punishable with a fine or up to three months imprisonment. More areas would be designated smoke-free zones, essentially ending the smoking sections currently set aside for restaurants and bars. This would also extend to the homes of people who employ domestic workers – the employers would not be able to smoke while those workers are present.

Smoking would also be banned in homes used for teaching, tutoring and commercial childcare. Shared residences would also have smoking banned in common areas, as would smoking in vehicles with occupants under the age of 18.

Cigarette packaging will also be targeted, with a move to plain packaging with graphic health warnings. It will no longer be legal to sell cigarettes through vending machines, nor display cigarettes at the point of sale. Sweets and toys resembling cigarettes would also be banned – however, the sugar ‘cigarettes’ that many may remember from their youth are already banned.

Vaping and e-cigarette products will also be liable to the same legislation, and are also soon to have an excise tax levied upon them.

Varenicline Effective in Helping Smokers with Diabetes to Quit

Cigarette butts
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A new study published in JAMA Network has found that varenicline helps patients with type 2 diabetes to quit smoking.

Not only is cigarette smoking a major risk factor for cardiovascular disease, it is highly prevalent among patients with type 2 diabetes. Smoking worsens the effects of hyperglycaemia and other risk factors, accelerating vascular damage in patients with diabetes.

Compared with nonsmokers with diabetes, smokers have greater risks of mortality, coronary heart disease, stroke, and peripheral arterial disease. Quitting smoking has been associated with reduced mortality risk in patients with type 2 diabetes, as welling achieving better glycaemic control and lower cardiometabolic risk factors.

Smokers with type 2 diabetes are more reluctant quit than smokers without diabetes in part due to fear of weight gain. Weight gain needs to be controlled as part of any cessation intervention. The smoking cessation drug varenicline has been shown to help people without diabetes to quit, but considering the special behavioural and metabolic conditions of smokers with type 2 diabetes, its use and efficacy warranted investigation,

To this end, Cristina Russo, MD, and colleagues conducted a multicentre, double-blind, placebo-controlled randomised clinical trial with 300 participants. Patients with type 2 diabetes, average age 57.4 years who were smoking at least 10 cigarettes a day, and who intended to quit were randomised to either twice-daily varenicline 1mg or placebo treatment. Both groups received smoking cessation counselling. The trial consisted of a 12-week treatment phase followed by a 40-week follow-up, nontreatment phase. Intention-to-treat data analysis was performed from December 2020 to April 2021.

At weeks 9 to 24, continuous smoking abstinence was significantly higher for the varenicline than placebo group (24.0% vs 6.0%). At weeks 9 to 12 (31.3% vs 7.3%) and weeks 9 to 52 (18.7% vs 5.3%) were significantly higher for the varenicline vs placebo group. Adverse events in the varenicline group compared with the placebo group were nausea, insomnia, abnormal dreams, anxiety, and irritability. Serious adverse events were infrequent in both groups and not treatment-related.

The researchers concluded that using varenicline in a smoking cessation programme for people with type 2 diabetes is effective in achieving long-term abstinence without serious adverse events.

How Lung Cells Stave off Lung Cancer in Smokers

Cigarette smoking
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Even though cigarette smoking is by far the main cause of lung cancer, only a minority of smokers develop the disease. A study reported in Nature Genetics suggests that some smokers may have robust mechanisms that protect them from lung cancer by keeping mutations in check. The findings could help identify those smokers who face an increased risk for the disease and therefore warrant especially close monitoring.

“This may prove to be an important step toward the prevention and early detection of lung cancer risk and away from the current herculean efforts needed to battle late-stage disease, where the majority of health expenditures and misery occur,” said Simon Spivack, MD, MPH, a co-senior author of the study.

For a long time, it has been assumed that smoking leads to lung cancer by triggering DNA mutations in normal lung cells. “But that could never be proven until our study, since there was no way to accurately quantify mutations in normal cells,” said Dr Jan Vijg, a study co-senior author. Dr Vijg overcame that obstacle a few years ago by developing an improved method for sequencing the entire genomes of individual cells.

Single-cell whole-genome sequencing methods can inadvertently introduce sequencing errors difficult to distinguish from true mutations – a major flaw when looking for rare and random mutations. To get around this, Dr Vijg developed a sequencing technique called single-cell multiple displacement amplification (SCMDA). 

The researchers used SCMDA to compare the mutational landscape of normal lung epithelial cells from two types of people: 14 never-smokers, ages 11 to 86; and 19 smokers, ages 44 to 81, who had smoked a maximum of 116 pack-years. (One pack-year of smoking equals 1 pack of cigarettes smoked per day for one year.) The cells were collected from patients who were undergoing bronchoscopy for diagnostic tests unrelated to cancer. “These lung cells survive for years, even decades, and thus can accumulate mutations with both age and smoking,” said Dr Spivack. “Of all the lung’s cell types, these are among the most likely to become cancerous.”

The researchers found that mutations accumulated in the lung cells of non-smokers as they age, and significantly more mutations were found in the lung cells of the smokers. “This experimentally confirms that smoking increases lung cancer risk by increasing the frequency of mutations, as previously hypothesised,” said Dr Spivack. “This is likely one reason why so few non-smokers get lung cancer, while 10% to 20% of lifelong smokers do.”
The study also revealed that the number of cell mutations detected in lung cells increased in a straight line with the number of pack years of smoking and, presumably, so did the lung cancer risk. However, the cell mutations stopped rising after 23 pack-years of exposure.

“The heaviest smokers did not have the highest mutation burden,” said Dr Spivack. “Our data suggest that these individuals may have survived for so long in spite of their heavy smoking because they managed to suppress further mutation accumulation. This leveling off of mutations could stem from these people having very proficient systems for repairing DNA damage or detoxifying cigarette smoke.”

The finding has led to a new research direction. “We now wish to develop new assays that can measure someone’s capacity for DNA repair or detoxification, which could offer a new way to assess one’s risk for lung cancer,” said Dr Vijg.

Source: Albert Einstein College of Medicine

Coffee Consumption Lowers Endometrial Cancer Risk

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Higher coffee consumption is linked with a lower risk of endometrial cancer, according to a new analysis which appears in the Journal of Obstetrics and Gynaecology Research. In addition, there was evidence that caffeinated coffee may provide better protection than decaffeinated coffee.

Risk factors for endometrial cancer include long-term exposure to excess oestrogen, obesity, nulliparity, diabetes mellitus, and hypertension, whereas protective factors include physical activity, aspirin intake, and certain dietary habits.

The analysis, which included 24 studies on coffee intake (12 case–control and 12 cohort studies), had 9833 new cases of endometrial cancer occurring in 699 234 individuals.

People in the highest category of coffee intake had a 29% lower relative risk of developing endometrial cancer than those in the lowest category. Additionally, women with a higher BMI or who smoked saw a greater benefit in risk reduction, though they still had a higher risk overall.

The authors of the analysis highlight several mechanisms that have been associated with the potential anti-cancer effects of coffee:

“Coffee contains many bioactive components, such as phenolic compounds. These polyphenols can increase the homocysteine concentrations in the plasma and inhibit DNA methylation in a dose-dependent manner, which prevents the downregulation of tumour suppressor proteins and DNA repair enzymes involved in carcinogenesis.”

They conclude that more studies with larger sample sizes are needed to better understand the effects of subgroups such as smoking status, as well as the benefits of coffee consumption in relation to endometrial cancer.

Source: Wiley

Smoking During Pregnancy Can Impact a Subsequent Pregnancy

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University of Southampton researchers have found that the link between smoking at the start of pregnancy and having a smaller baby may extend to future pregnancies.

The research team studied data between 2003 and 2018 for nearly 17 000 mothers who received antenatal care for their first two pregnancies. 

The findings, published in PLOS One, showed that, compared to non-smokers, women who smoked at the start of their first pregnancy were more likely to have a baby born smaller than expected in their second pregnancy. This held true even where they quit by the start of their second pregnancy.

The link between smoking during a pregnancy and that baby’s birth weight is well established. However, until now there has been limited evidence on the impact of maternal smoking on following pregnancies.

This study found that for women who smoked but did not smoke at the start of either pregnancy, there was no extra risk of a small for gestational age (SGA) baby in the second pregnancy compared to non-smokers. A mother who smoked ten or more cigarettes a day at the start of both of her first two pregnancies had the highest odds of SGA birth.

Study leader Dr Nisreen Alwan, Associate Professor at the University of Southampton, said: “It is important to encourage women to quit smoking before pregnancy and to not resume smoking after the baby is born. Resources that support mothers to quit and maintain smoking cessation are needed.”

First author Elizabeth Taylor said: “Women who smoke between pregnancies can reduce the risk of having a SGA baby by stopping smoking before the start of their next pregnancy. The period between pregnancies is when most mothers have close contact with health and care professionals and may require support to stop smoking.”

It is hoped that these findings and future research will encourage healthcare professionals and commissioners to provide better support to women before and between pregnancies, helping them to quit smoking, leading to better health for both mothers and children.

Source: University of Southampton

Despite Smoking Less, Women Find it Harder to Quit

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A large study has found that women smoke fewer cigarettes than men but are less likely to quit.

Study author Ms Ingrid Allagbe, PhD student at the University of Burgundy, said: “In our study, women who used smoking cessation services had higher rates of overweight or obesity, depression, and anxiety compared to men and kicked the habit less often. Our findings highlight the need to provide smoking cessation interventions tailored to the needs of women.”

This study, presented at ESC Congress 2021, compared characteristics and abstinence rates of men and women visiting smoking cessation services between 2001 and 2018 in France, obtained from a nationwide database. The participants were smokers with at least one additional risk factor for cardiovascular disease: overweight/obese (body mass index [BMI] 25 kg/m² or above); high cholesterol; diabetes; high blood pressure; history of stroke, heart attack or angina.

Participants were classified as having mild, moderate, or severe nicotine dependence. Smoking abstinence (at least 28 consecutive days) was self-reported and confirmed by measurement of exhaled carbon monoxide less than 10 parts per million (ppm).

Participant height, weight, age, education level, chronic conditions, and number of cigarettes smoked each day were recorded. Participants were classified as having anxiety and depression symptoms or not according to their medical history, use of anti-anxiety medication or antidepressants, and the Hospital Anxiety and Depression Scale (HADS).

A total of 37 949 smokers were included in the study, of whom 43.5% were women. The average age of women in the study was 48 years, while the average age of men was 51 years. More women (55%) reported a bachelor’s degree level of education or higher compared to men (45%).

Both men and women had a high burden of cardiovascular risk factors. High cholesterol was more common in men (33%) than women (30%), as was high blood pressure (26% vs 23%, respectively) and diabetes (13% vs 10%, respectively).

Women were more likely (27%) to be overweight or obese compared to men (20%), and more likely (37.5%) to have symptoms of anxiety or depression than men (26.5%). Chronic obstructive pulmonary disease was more common in women (24%) compared to men (21%) as was asthma (16% vs 9%, respectively).

However, women smoked fewer cigarettes per day (23) than men (27). Severe nicotine dependence was less common, 56% of women compared to 60% of men, and abstinence was less common in women (52%) than men (55%).

Ms Allagbe said: “The findings suggest that despite smoking fewer cigarettes and being less nicotine dependent than men, women find it more difficult to quit. Possible contributors could be the higher prevalence of anxiety, depression and overweight or obesity among women. It has previously been reported that women may face different barriers to smoking cessation related to fear of weight gain, sex hormones, and mood.”

She concluded: “The results indicate that comprehensive smoking cessation programmes are needed for women that offer a multidisciplinary approach involving a psychologist, dietitian, and physical activity specialist.”

Source: European Society of Cardiology

Parental History Not The Only Premature Heart Attack Risk

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A new study has shown that, while parental history is a contributing factor, young heart attack victims are more likely to be smokers, obese, and have high blood pressure or diabetes compared to their peers.

“The findings underline the importance of preventing smoking and overweight in children and adolescents in order to reduce the likelihood of heart disease later in life,” said study author Professor Harm Wienbergen of the Bremen Institute for Heart and Circulation Research.

“Understanding the reasons for heart attacks in young adults is important from a societal perspective due to their employment and family responsibilities,” he continued. “However, there are limited data on the predictors of heart events in this group.”

The researchers compared the clinical characteristics of consecutive patients admitted to hospital with acute myocardial infarction at 45 years of age or younger against randomly selected individuals from the German population. Cases and controls were matched according to age and gender. The case-control study enrolled a total of 522 patients with 1191 matched controls from a national database.

The researchers found that the proportion of active smokers was more than three-fold higher in the young heart attack group compared to the general population (82.4% vs 24.1%). Patients were more likely to have high blood pressure (25.1% vs 0.5%), diabetes (11.7% vs 1.7%) and a parental history of premature heart attack (27.6% vs 8.1%) compared to their peers. Patients were more often obese, with a median body mass index (BMI) of 28.4 kg/m2 compared to 25.5 kg/m2 for controls. In contrast, the proportion consuming alcohol at least four times a week was higher in the general population (11.2%) compared to heart patients (7.1%).

The researchers analysed the independent risk factors for the occurrence of acute myocardial infarction at 45 years of age or younger. The analysis was adjusted for age, sex, high blood pressure, diabetes, active smoking, body mass index, alcohol consumption, years of school education, and birth in Germany.

Hypertension was associated with an 85-fold odds of a heart attack aged 45 or under. The corresponding odds of a premature heart attack associated with active smoking, diabetes mellitus, parental history and obesity (BMI 30 kg/m2 or above) were 12, 5, 3 and 2. Alcohol consumption was associated with a lower odds of heart attack at a young age with an odds ratio of 0.3.

Prof Wienbergen said: “Our study shows that smoking and metabolic factors, such as hypertension, diabetes and obesity, are strongly associated with an increased likelihood of premature acute myocardial infarction. A protective effect of moderate alcohol consumption has been described by other studies and is confirmed in the present analysis of young patients.”

He concluded: “Our study suggests that family history is not the only predisposing factor for early heart attacks. The findings add impetus to the argument that young people should be educated about why it is important to avoid smoking and have a healthy body weight.”

Source: European Society of Cardiology