Posts tagged tobacco smoking
Articles and news from the latest research reports.
World Alzheimer Report 2014: Evidence for dementia risk reduction
The World Alzheimer Report 2014 ‘Dementia and Risk Reduction: An analysis of protective and modifiable factors’, released today, calls for dementia to be integrated into both global and national public health programmes alongside other major non communicable diseases (NCDs).
Alzheimer’s Disease International (ADI) commissioned a team of researchers, led by Professor Martin Prince from King’s College London, to produce the report. ADI is publishing this report, in conjunction with World Alzheimer’s Day (21 September) and as a part of World Alzheimer’s Month, an international campaign to raise awareness and challenge stigma.
The report reveals that control of diabetes and high blood pressure as well as measures to encourage smoking cessation and to reduce cardiovascular risk, have the potential to reduce the risk of dementia even in late-life. The report found that diabetes can increase the risk of dementia by 50%. Obesity and lack of physical activity are important risk factors for diabetes and hypertension, and should, therefore, also be targeted.
While cardiovascular health is improving in many high income countries, many low and middle income countries show a recent pattern of increasing exposure to cardiovascular risk factors, with rising rates of diabetes, heart disease and stroke.
Smoking cessation is strongly linked in the report with a reduction in dementia risk. For example, studies of dementia incidence among people aged 65 years and over show that ex-smokers have a similar risk to those who have never smoked, while those who continue to smoke are at much higher risk.
Furthermore, the study revealed that those who have had better educational opportunities have a lower risk of dementia in late-life. Evidence suggests that education has no impact on the brain changes that lead to dementia, but reduces their impact on intellectual functioning.
The evidence in the report suggest that if we enter old age with better developed, healthier brains we are likely to live longer, happier and more independent lives, with a much reduced chance of developing dementia. Brain health promotion is important across the life span, but particularly in mid-life, as changes in the brain can begin decades before symptoms appear.
The report also urges NCD programs to be more inclusive of older people, with the message that it’s never too late to make a change, as the future course of the global dementia epidemic is likely to depend crucially upon the success or failure of efforts to improve global public health, across the population. Combining efforts to tackle the increasing global burden of NCDs will be strategically important, efficient and cost effective. Leading a healthier lifestyle is a positive step towards preventing a range of long-term diseases, including cancer, heart disease, stroke and diabetes.
However, survey data released by Bupa* has shown that many people are unclear about the causes and actions they can take to potentially reduce their risk of dementia. Just over a sixth (17%) of people realised that social interaction with friends and family could impact on the risk. Only a quarter (25%) identified being overweight as a possible factor, and only one in five (23%) said physical activity could affect the risk of developing dementia and losing their memories. The survey also revealed that over two thirds (68%) of people surveyed around the world are concerned about getting dementia in later life.
Professor Martin Prince, from King’s College London’s Institute of Psychiatry, Psychology & Neuroscience (IoPPN) and author of the report, commented: “There is already evidence from several studies that the incidence of dementia may be falling in high income countries, linked to improvements in education and cardiovascular health. We need to do all we can to accentuate these trends. With a global cost of over US$ 600 billion, the stakes could hardly be higher.”
Marc Wortmann, Executive Director, Alzheimer’s Disease International said: “From a public health perspective, it is important to note that most of the risk factors for dementia overlap with those for the other major non communicable diseases (NCDs). In high income countries, there is an increased focus on healthier lifestyles, but this is not always the case with lower and middle income countries. By 2050, we estimate that 71% of people living with dementia will live in these regions, so implementing effective public health campaigns may help to reduce the global risk.”
Professor Graham Stokes, Global Director of Dementia Care, Bupa, said: “While age and genetics are part of the disease’s risk factors, not smoking, eating more healthily, getting some exercise, and having a good education, coupled with challenging your brain to ensure it is kept active, can all play a part in minimising your chances of developing dementia. People who already have dementia, or signs of it, can also do these things, which may help to slow the progression of the disease.”
* These figures, unless otherwise stated, are from YouGov Plc. Total sample size was 8,513, from the UK (2,401), Australia (1,000), Chile (1,000), China (1,031), Poland (1,002), and Spain (1,077). Fieldwork was undertaken online, between 17–25 July 2014. The figures have been weighted and are representative of all adults (aged 18+) in each country. An even weighting was applied to each country to find a ‘Global Average’.
Nicotine withdrawal reduces response to rewards across species
Cigarette smoking is a leading cause of preventable death worldwide and is associated with approximately 440,000 deaths in the United States each year, according to the U.S. Centers for Disease Control and Prevention, but nearly 20 percent of the U.S. population continues to smoke cigarettes. While more than half of U.S. smokers try to quit every year, less than 10 percent are able to remain smoke-free, and relapse commonly occurs within 48 hours of smoking cessation. Learning about withdrawal and difficulty of quitting can lead to more effective treatments to help smokers quit.
In a first of its kind study on nicotine addiction, scientists measured a behavior that can be similarly quantified across species like humans and rats, the responses to rewards during nicotine withdrawal. Findings from this study were published online on Sept. 10, 2014 in JAMA Psychiatry.
Response to reward is the brain’s ability to derive and recognize pleasure from natural things such as food, money and sex. The reduced ability to respond to rewards is a behavioral process associated with depression in humans. In prior studies of nicotine withdrawal, investigators used very different behavioral measurements across humans and rats, limiting our understanding of this important brain reward system.
Using a translational behavioral approach, Michele Pergadia, Ph.D., associate professor of clinical biomedical science in the Charles E. Schmidt College of Medicine at Florida Atlantic University, who completed the human study while at Washington University School of Medicine, Andre Der-Avakian, Ph.D., who completed the rat study at the University of California San Diego (UCSD), and colleagues, including senior collaborators Athina Markou, Ph.D. at UCSD and Diego Pizzagalli, Ph.D. at Harvard Medical School, found that nicotine withdrawal similarly reduced reward responsiveness in human smokers - particularly those with a history of depression - as well as in nicotine-treated rats.
Pergadia, one of the lead authors, notes that replication of experimental results across species is a major step forward, because it allows for greater generalizability and a more reliable means for identifying behavioral and neurobiological mechanisms that explain the complicated behavior of nicotine withdrawal in humans addicted to tobacco.
"The fact that the effect was similar across species using this translational task not only provides us with a ready framework to proceed with additional research to better understand the mechanisms underlying withdrawal of nicotine, and potentially new treatment development, but it also makes us feel more confident that we are actually studying the same behavior in humans and rats as the studies move forward," said Pergadia.
Pergadia and colleagues plan to pursue future studies that will include a systematic study of depression vulnerability as it relates to reward sensitivity, the course of withdrawal-related reward deficits, including effects on relapse to smoking, and identification of processes in the brain that lead to these behaviors.
Pergadia emphasizes that the ultimate goal of this line of research is to improve treatments that manage nicotine withdrawal-related symptoms and thereby increase success during efforts to quit.
"Many smokers are struggling to quit, and there is a real need to develop new strategies to aid them in this process. Therapies targeting this reward dysfunction during withdrawal may prove to be useful," said Pergadia.
Stimulating the Brain Blunts Cigarette Craving
Cigarette smoking is the leading cause of preventable deaths globally. Unfortunately smoking cessation is difficult, with more than 90% of attempts to quit resulting in relapse.
(Image: Jupiterimages)
There are a growing number of available methods that can be tried in the effort to reduce smoking, including medications, behavioral therapies, hypnosis, and even acupuncture. All attempt to alter brain function or behavior in some way.
A new study published in Biological Psychiatry now reports that a single 15-minute session of high frequency transcranial magnetic stimulation (TMS) over the prefrontal cortex temporarily reduced cue-induced smoking craving in nicotine-dependent individuals.
Nicotine activates the dopamine system and reward-related regions in the brain. Nicotine withdrawal naturally results in decreased activity of these regions, which has been closely associated with craving, relapse, and continued nicotine consumption.
One of the critical reward-related regions is the dorsolateral prefrontal cortex, which can be targeted using a brain stimulation technology called transcranial magnetic stimulation. Transcranial magnetic stimulation is a non-invasive procedure that uses magnetic fields to stimulate nerve cells. It does not require sedation or anesthesia and so patients remain awake, reclined in a chair, while treatment is administered through coils placed near the forehead.
Dr. Xingbao Li and colleagues at Medical University of South Carolina examined cravings triggered by smoking cues in 16 nicotine-dependent volunteers who received one session each of high frequency or sham repetitive transcranial magnetic stimulation applied over the dorsolateral prefrontal cortex. This design allowed the researchers to ferret out the effects of the real versus the sham stimulation, similar to how placebo pills are used in evaluating the effectiveness and safety of new medications.
They found that craving induced by smoking cues was reduced after participants received real stimulation. They also report that the reduction in cue-induced craving was positively correlated with level of nicotine dependence; in other words, the TMS-induced craving reductions were greater in those with higher levels of nicotine use.
Dr. John Krystal, Editor of Biological Psychiatry, commented, “One of the elegant aspects of this study is that it suggests that specific manipulations of particular brain circuits may help to protect smokers and possibly people with other addictions from relapsing.”
"While this was only a temporary effect, it raises the possibility that repeated TMS sessions might ultimately be used to help smokers quit smoking. TMS as used in this study is safe and is already FDA approved for treating depression. This finding opens the way for further exploration of the use of brain stimulation techniques in smoking cessation treatment," said Li.
(Source: alphagalileo.org)
Cigarette smoking increases the risk of subarachnoid hemorrhage (SAH) in a dose-responsive manner, and cessation correlates with a reduction in SAH risk, according to a study published online Aug. 30 in the Journal of Neurology, Neurosurgery & Psychiatry.
To examine the risk of SAH in relation to smoking cessation, Chi Kyung Kim, M.D., from Seoul National University Hospital in Korea, and colleagues performed a nationwide multicenter case control study involving 426 SAH patients and 426 matched controls. Structured questionnaires were used to assess lifestyle, medical history, and smoking habits.
The researchers found that 37.4 percent of SAH patients and 24.2 percent of controls were current smokers (adjusted odds ratio, 2.84), after adjusting for potential confounders. The risk of SAH was found to increase in a dose-responsive fashion with cumulative dose of smoking (pack years). There was a significant reduction in SAH to 59 percent with smoking cessation (at least five years). A history of heavy smoking (at least 20 cigarettes per day) correlated with a 2.3-fold increased risk of SAH, compared with participants who had never smoked (P < 0.05).
"We have demonstrated that cigarette smoking increases the risk of SAH, but smoking cessation decreases the risk in a time-dependent manner, although this beneficial effect may be diminished in previous heavy smokers," the authors write. "To forestall tragic SAH events, our results call for more global and vigorous efforts for people to stop smoking."