Lab-made “mini-brains” are helping scientists makes a breakthrough involving a gene implicated in various neurodegenerative diseases linked to old age. These include frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), and Parkinson’s disease. Scientists in the United Kingdom say this work may pave the way for new detection methods and treatments to address these awful diseases before symptoms ever appear.
Scientists at the University of Bath explain that in its healthy state, the gene in question (called Angiogenin or ANG) actually plays a very important role in the speed at which undifferentiated stem cells develop into specialized nerve cells. The mutated version of the gene is where things go awry.
In its mutated form, ANG causes stem cells to persist in their original state far longer than they should. In lab experiments, this slowing down of the differentiation process resulted in striking neurodevelopmental defects across nerve cells upon reaching their adult form.
“This suggests nerve-cell degeneration may be primed by defects occurring during early development,” says Dr. Vasanta Subramanian, who led the research from the Department of Life Sciences, in a university release.
During an earlier study, the same Bath research group discovered that ANG, in its healthy form, works to protect nerve cells against damage, degeneration, and any impairment of function. Conversely, the mutated form of the gene makes nerve cells more susceptible to stress (a natural occurrence as cells age and experience wear and tear), eventually leading to premature cell death.
“This new discovery adds to our understanding of Angiogenin and its importance in protecting us from diseases associated with aging,” Dr. Subramanian adds.
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To conduct this latest study, the research team chose to focus on a family affected by both frontotemporal dementia and ALS. Genetic testing showed that certain family members had mutations in Angiogenin while others did not.
Scientists grew “mini-brains” in a lab for all the family members. A mini-brain is a tiny 3D structure grown using clusters of human stem cells. They serve as realistic models for scientists to study the step-by-step development of disease, and also serve as ideal structures to screen drugs. Study authors noted striking neurodevelopmental defects in the mini-brains of family members carrying the ANG mutation.
“This seems to indicate that subtle development defects play a role in disease susceptibility or onset,” Dr. Subramanian adds. “I envisage a time when we will be identifying people who are susceptible to these diseases, screening them for genetic mutations and offering early-intervention gene therapy to fix the defects.”
Section through a human brain organoid showing stem cells containing protective antibodies (stained green and red). The cells’ nuclei are stained blue. Credit: Ross Ferguson and Vasanta Subramanian
In conclusion, Dr. Subramanian stresses the need for more research in order to further clarify the mechanisms by which ANG protects cells and better understand its function in stem cells. This study received funding from the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), BRACE, and the Wellcome Trust VIP award.
“We applaud Dr Subramanian’s innovative research, which could make a big difference in tackling frontotemporal dementia. Better understanding of the Angiogenin gene and its link to FTD could support treatment to slow down or stop the disease in the future. This type of dementia tends to have an early onset between the ages of 45-65 years, and often has a devastating impact during middle age. We are hopeful that this BRACE funded research may play a key role in one day reducing the impact of the condition,” says BRACE CEO Chris Williams.
“Research into the brain and neurological disorders relies in large part on animal models and it is fantastic to see Vasanta’s mini-brain ‘organoids’ delivering new insights into neurodegenerative diseases. It is testament to the utility of these models that they are still being applied to new research questions, almost 15 years after we awarded Vasanta the initial funding to develop human cell-based alternatives to the use of animals in ALS (the most common form of motor neuron disease) research,” comments Dr. Jessica Eddy, NC3Rs Regional Program Manager.
Earth’s origins in our solar system may have just gotten even more mysterious. Researchers from the California Institute of Technology have revealed their new theory about two massive blobs within the planet’s surface. For decades, scientists have debated what these formations are. Now, the Caltech team has arrived at one conclusion — the remains of an ancient and forgotten planet are hiding at the center of our world.
In the 1980s, scientists were taken aback when they discovered these two massive blobs deep within the Earth, each larger than the size of the Moon. These blobs, one situated beneath the African continent and the other beneath the Pacific Ocean, showcased unusual characteristics when compared to their surroundings. Known as large low-velocity provinces (LLVPs), these structures puzzled researchers studying the Earth, its origins, and its inner workings.
The new study, published in the journal Nature, proposes a fascinating theory: these blobs are remnants of a planet that collided with Earth billions of years ago. This colossal impact is believed to be the same event that resulted in the creation of our Moon.
To understand this better, it’s important to know that seismic waves, which are waves of energy that travel through the Earth, behave differently when they encounter different materials. In the 1980s, researchers observed that seismic waves were slowing down significantly when passing through certain areas deep within the Earth’s mantle, leading to the discovery of the LLVPs. These regions are thought to contain a higher proportion of iron, making them denser and causing the slowdown of seismic waves.
The blobs, seen from the (a) North and (b) South Poles. (Credit: Cottaar and Lekic, 2016.)
Dr. Qian Yuan, a geophysicist and the lead researcher of this study, recalls a moment of revelation during a seminar in 2019. The seminar, presented by Professor Mikhail Zolotov from Arizona State University, discussed the giant-impact hypothesis — a theory suggesting that the Moon was formed following a massive collision between Earth and a smaller planet named Theia. However, no trace of Theia had ever been found, until Yuan connected the dots.
“Right after Mikhail had said that no one knows where the impactor is now, I had a ‘eureka moment’ and realized that the iron-rich impactor could have transformed into mantle blobs,” says Yuan in a university release.
Through extensive modeling and simulations, the research team was able to confirm that the collision could have resulted in the creation of both the Moon and the LLVPs. Some of Theia’s mantle would have merged with Earth’s, eventually forming the two distinct blobs we observe today. The rest of the debris from the collision came together to form the Moon.
A question that naturally arises is: why did Theia’s material form into two distinct blobs instead of mixing uniformly with Earth’s mantle? The simulations conducted by the researchers revealed that a significant portion of the energy from the collision remained in the upper half of the mantle. This left the lower mantle relatively cooler, allowing the iron-rich material from Theia to stay largely intact and settle at the base of the mantle, much like the blobs in a lava lamp.
“A logical consequence of the idea that the LLVPs are remnants of Theia is that they are very ancient,” says Dr. Paul Asimow, one of the co-directors of the study. “It makes sense, therefore, to investigate next what consequences they had for Earth’s earliest evolution, such as the onset of subduction before conditions were suitable for modern-style plate tectonics, the formation of the first continents, and the origin of the very oldest surviving terrestrial minerals.”
BRISBANE, Australia — Climate change will soon have a dire impact on household dogs and cats, a recent study warns. Researchers in Australia explain that the warming of the planet presents risks to domesticated pets’ nutrition, behavior, environment, and overall physical and mental health.
Among the other animals flagged as vulnerable due to climate change are bats, zebrafish, stony creek frogs, koalas, African elephants, chickens, and dairy cows. The team from the University of Queensland underlines the importance of prioritizing certain areas to ensure the longevity and welfare of animals, be it in the food industry, as household pets, or those under conservation in natural habitats and zoos.
“While researchers have extensively examined the effects of climate change on animals, the direct correlation between climate change and animal welfare, particularly in the context of wild animals, remains relatively scarce in existing studies,” says Dr. Edward Narayan, the study’s lead author and senior lecturer of animal science in the School of Agriculture and Food Science at The University of Queensland, in a media release.
Chesapeake Bay Retriever playing ball in the water (Photo by Kerrie T on Shutterstock)
Dr. Narayan’s research group, The Stress Lab, has sought to fill this gap by examining a wide range of animals from various global locations, considering the impact of climate change on the five identified domains of animal welfare.
“We hope that future researchers will apply the animal welfare domains to evaluate how climate change impacts on animals, and further research will pave the way to the protection of animals from the catastrophic impacts of climate change,” notes Dr. Narayan.
Key findings from the study include:
Dairy cows under heat stress can see a 35-percent drop in milk production. However, mitigation strategies like sunshades and sprinklers can help alleviate the stress.
Broiler chickens exposed to high temperatures exhibit more cases of necrosis, affecting their quality of life and meat value. Birds, with their limited capacity to regulate heat due to the lack of sweat glands, might benefit from air-conditioned environments.
Droughts and decreasing resources directly correlate with increasing elephant mortalities. The African elephant’s significant daily needs are compromised as climate change results in the declining availability of water and vegetation.
Marsupials, including the koala, are facing population declines, driven majorly by climate change. Rising temperatures compel koalas to use more energy to regulate their body temperatures.
Domestic animals are not spared either. Certain dog breeds are prone to heat stroke, and a rise in temperature can reduce the time they spend outdoors. In the United Kingdom, the study revealed that about 87 percent of dog owners curtailed their pets’ outdoor activities during hotter weather.
“As climate change drives more wild populations to ecological limitations, there will be potential welfare consequences and considerations to explore; for example, when vulnerable species would need to be transferred to new environments (e.g., captive breeding), should food and habitat become limiting resources,” says Dr. Narayan. “Likewise, production animals and other domesticated species will be impacted by the extreme environmental changes with consequences on each of the dimensions within the five domains of animal welfare.”
The image shows in vivo super-resolution analysis taken with a Lattice-Structured Illumination Microscope
The quest to gain a greater and more in-depth understanding about how signals are transmitted between cells has taken a remarkable step forward.
New research, led by experts from the University of Exeter’s Living Systems Institute, has discovered a new synergy between transport and signalling within cells for the first time.
In all multicellular organisms, cells ‘communicate’ with each other in order to be able to grow and function properly.
In order to conduct this communication, cells express signal molecules and hand them over to the neighbouring cells which provide the exact docking molecules – similar to a key being placed into a lock – which in turn activates a cascade of responses in the cell.
One of the most essential messaging systems is the Wnt signalling network, which acts as the key to fit a lock called Ror2 to change the movement of these cells.
In the new research, scientists used special techniques to mark Wnt5b and Ror2 fluorescently in developing zebrafish embryos.
Then, using state-of-the-art high-resolution microscopy from the Bioimaging Centre, they were able see how these components move around in real time.
They found that the Wnt5b and Ror2 were made by the very same cells, and travel together from one cell to another using tiny cellular extensions called cytonemes. The research team discovered the ‘key and lock’ are connected throughout the journey to the new cell, rather than travel separately.
The research challenges conventional understandings of how cells respond to signals, and suggests that even cells without the right lock can react if they get a functional key-lock duo through these thin cytonemes.
The experts now want to explore how these tiny threads form, how the key-lock pairs are carried along these cell threads to the correct cells, and if this also happens in other critical signalling systems in the body.
The next phase of the research could help advance understanding of illnesses like cancer, where this signalling process goes wrong, and develop new strategies to combat these devastating disorders.
Professor Steffen Scholpp, lead author of the study and an expert in Cell and Developmental Biology at the LSI, said: “As cell signalling underpins multicellular life, our research findings will be transformative for the biosciences. Based on these results, we must redefine our strategies for controlling signalling. Cytonemes can now be targeted for designing new therapeutics for many diseases caused by defective cell communication.”
Even without advanced imaging, thrombectomy was beneficial for large-volume stroke.
Three recent trials showed varying degrees of benefit from endovascular thrombectomy (EVT) in ischemic stroke patients with a large volume (large core) of ischemic tissue at baseline. These studies relied on perfusion imaging to depict the core size, which involves contrast administration. Since perfusion imaging is not available at all centers, a simplified imaging protocol is of interest. These authors conducted a clinical trial at 41 centers in which patients with large-volume strokes, judged by ASPECTS (Alberta Stroke Program Early Computed Tomographic Score) on noncontrast computed tomography (CT) or diffusion-weighted imaging, were randomized to medical management (MM) alone or MM plus EVT. The primary endpoint was a shift on the modified Rankin Scale (mRS) at 90 days. Safety outcomes included mortality and symptomatic intracranial hemorrhage (sICH). Patients with an ASPECTS of 3 to 5 were eligible.
Over a 5-year period, 253 patients (median age, 74 years; 49% women) were enrolled. The median NIH stroke scale score was quite severe (19), and the median time from symptom onset to groin puncture was 4.2 hours. In 82% of enrolled patients, CT was the imaging method. At 90 days, there was a shift in the distribution of mRS scores favoring endovascular therapy (adjusted common odds ratio, 2.58). An outcome of mRS score of 0 to 3 was achieved in 31% of the EVT group versus 13% of the MM group. Mortality at 90 days was significantly lower in the EVT group (40% vs. 51%), and sICH occurred in 5% of both groups.
Comment
This is a valuable study since it shows that, even without perfusion imaging, patients with large-volume strokes can be identified and can have improved neurologic outcome with timely EVT. The overall mortality rates are sobering but are lower in the EVT group. Since two out of three patients undergoing EVT can still die or become dependent within 90 days, shared decision making with patients’ families is critical.
In a multinational open-label trial, an all-oral 9-month bedaquiline-containing regimen and a 6-month bedaquiline regimen with injectable kanamycin were superior to a 9-month control injectable regimen.
The incidence of resistant tuberculosis (TB) continues to rise worldwide, in part because treatment protocols are prolonged, complex, and painful, all potentially leading to medication failures. Several small single-nation studies have found that bedaquiline-based regimens appear effective for these infections (NEJM JW Infect Dis Mar 2020 and N Engl J Med 2020 382:893; NEJM JW Infect Dis Mar 2022 and Am J Respir Crit Care Med 2022; 205:1214; NEJM JW Infect Dis Sep 2022 and N Engl J Med 2022; 387:810). Now, investigators sponsored by USAID and the manufacturer of bedaquiline have performed a randomized, phase 3, noninferiority, unmasked study — STREAM stage 2 — on the treatment of multidrug-resistant TB in seven countries between March 2016 and January 2020.
In all, 517 patients with confirmed pulmonary TB with rifampicin resistance but without resistance to fluoroquinolones or aminoglycosides were eligible for the modified intention-to-treat analysis. A 9-month oral regimen using bedaquiline instead of injectable kanamycin had an 83% favorable outcome rate at 76 weeks, compared with 71% for the 9-month injectable control regimen (P<0.0001). A 6-month regimen using bedaquiline plus 8 weeks of injectable kanamycin had a 91% favorable outcome rate, compared with 69% in the control arm (P<0.0001). In both the 9-month and 6-month studies, treatment changes and extensions were more common in the control group, and failure or recurrence of infection was significantly less common in the two bedaquiline arms (P<0.016 and P<0.0001, respectively).
Comment
Regimens using bedaquiline, either as an all-oral treatment or combined with 2 months of kanamycin, were superior to the currently recommended 9-month regimen. As editorialists note, the WHO announced in May 2022 that it will recommend an all-oral 6-month regimen of bedaquiline, pretomanid, linezolid, and moxifloxacin (BPaLM) for resistant TB. The STREAM stage 2 regimens could serve as alternatives, particularly in the presence of linezolid resistance or toxicity.
In an open-label randomized trial, postexposure doxycycline significantly reduced bacterial STI incidence in at-risk MSM and transgender women who were on PrEP or were living with HIV.
With the rising incidence of bacterial sexually transmitted infections (STIs) in many countries, particularly among men who have sex with men (MSM) and transgender women, better interventions are needed. Postexposure prophylaxis (PEP) with doxycycline (DOXY) after condomless sex was shown to be beneficial against syphilis and chlamydia but not gonorrhea in a study conducted in France (NEJM JW Infect Dis Jan 2 2018 and Lancet Inf Dis 2017 Dec 8; [e-pub]). Now, researchers have evaluated the same strategy in MSM or transgender women who were on preexposure prophylaxis (PrEP) or were living with HIV (PLWH) in the U.S. In all, 501 participants (327 [PrEP group] and 174 [PLWH group]) were randomized to a single 200-mg dose of DOXY PEP or standard of care (SOC) without DOXY. The primary endpoint was diagnosis of a new bacterial STI per follow-up quarter.
Within the PrEP group, an STI was diagnosed in 61 of 570 quarterly visits (11%) for those receiving DOXY versus 82 of 257 visits (32%) for SOC. A significant 66% reduction was seen for the three STIs, including a 55% reduction in gonorrhea incidence. For the PLWH group, a new STI was diagnosed in 36 of 305 quarterly visits (12%) in the DOXY arm compared with 39 of 128 visits (30%) in the SOC arm. The reduction in new STI diagnoses for the PLWH group was 62% (also significant) for those receiving DOXY, including a 57% reduction in new gonorrhea diagnoses. DOXY resistance was seen in 4 of 15 gonorrhea cases (27%) at baseline and 5 of 14 cases (38%) in the DOXY group versus 2 of 16 (12%) in the SOC group. The investigators concluded that DOXY PEP represents an effective strategy for reducing bacterial STIs in this high-risk population.
Comment
Two studies presented at the 2023 Conference on Retroviruses and Opportunistic Infections also examined DOXY PEP. The ANRS DOXYVAC Study was stopped early after a 65% reduction in bacterial STIs was noted in the DOXY group and a benefit of the 4CMenB vaccine (50% reduction in new gonorrhea infection) was seen. In another study involving women on PrEP in Kenya, DOXY PEP was not effective for unclear reasons. Taken together, these studies support the use of DOXY PEP for at-risk MSM and transgender women but not at this time for cisgender women. Ongoing monitoring for trends in gonorrhea resistance as well as further confirmation of the 4CMenB vaccine’s benefits are warranted.
Deep-sea species are likely to be affected by seabed mining.
The controversial practice of mining the seabed for valuable minerals has taken a step forward after Norway became the first country to allow such exploration — disappointing scientists and environmental organizations who say that the method will irreversibly damage biodiversity and ecosystems.Seabed mining is coming — bringing mineral riches and fears of epic extinctions
“This is about greed not need and will come at a significant cost to our environment for present and future generations,” says Matthew Gianni, co-founder of the Deep Sea Conservation Coalition, an advocacy group in Amsterdam.
On 9 January, Norway’s parliament voted 80–20 in favour of allowing mining on its continental shelf in the Norwegian sea to map and investigate whether sulfides and manganese crusts on the seabed in its national jurisdiction could be extracted profitably. These metals are currently mined on land.
The Norwegian government, which has been pursuing its mining plan since 2020, says that seabed extraction is necessary to ensure sufficient supplies of metals such as manganese and cobalt used in the manufacturing of electric-vehicle batteries and other electronics to help the transition to a low-carbon economy. But many scientists including the European Academies Science Advisory Council — a group of national science academies — say that this claim is misleading, and argue that terrestrial metal resources are sufficient.
Although research on the ecological impacts of deep-sea mining is limited, studies are beginning to show that it could harm species on the seabed by crushing them with machinery or smothering them with plumes of sediment that are kicked up by mining activities1. Scientists discovered that species in the water column such as jellyfish are also at risk. Many researchers and governments are calling for a moratorium until more is known about the deep-sea ecosystem.
Advice ignored
The Norway vote means the government can issue permits to companies and other entities to explore a reported 281,000 square kilometers of the seabed. Permission to extract minerals for commercial activities will require a further parliamentary vote, but many scientists and environmental organizations see the vote as a gateway towards that goal.
Norwegian scientists say they are disappointed but not surprised by the move. They say that the government ignored their scientific advice and that of the nation’s environment agency in Trondheim. In response to a public consultation on the government’s mining plans, scientists said that too little is known about the biodiversity and ecosystem functions in the proposed sites to enable mining to go ahead safely.
“How can we make meaningful judgements of acceptable harm or risk when we know absolutely nothing about it?” says Peter Haugan, director of policy at the Institute of Marine Research in Bergen.
Helena Hauss, a marine ecologist at NORCE, an independent research institute with headquarters in Bergen, says that the proposed mining sites, which are like islands — inhabited by communities not found elsewhere — will be irreversibly destroyed. “This is difficult to align with the claim of the Norwegian government that this will be done in a sustainable and responsible way,” she says.
Environmental lawsuits
Haugan says that Norway’s decision could be illegal because the government lacked sufficient scientific evidence to assess the impacts of future mining activities, which is required under national law. He anticipates that environmental groups will launch lawsuits against the government on these grounds to try to stop mining from going ahead.
He is also concerned that the government will ignore science advice when requests for commercial exploitation are considered. The government suggests exploitation is around 20 years away, but environmental organizations say it could happen sooner.
Gianni says that companies who finance exploration of the seabed are likely to want commercial licences in return for their investments.
Norway’s push to open up its seabed for mining comes as international negotiations continue on whether to permit commercial harvesting of the sea floor in mineral rich areas outside of countries’ national jurisdiction, including the Clarion Clarion–Clipperton Zone (CCZ), a 4.5-million-square-kilometre area in the eastern Pacific Ocean between Hawaii and Mexico. Norway is one of the strongest proponents of deep-sea mining in the international discussions, says Gianni.
Subclinical atrial fibrillation is short-lasting and asymptomatic and can usually be detected only by long-term continuous monitoring with pacemakers or defibrillators. Subclinical atrial fibrillation is associated with an increased risk of stroke by a factor of 2.5; however, treatment with oral anticoagulation is of uncertain benefit.
Methods
We conducted a trial involving patients with subclinical atrial fibrillation lasting 6 minutes to 24 hours. Patients were randomly assigned in a double-blind, double-dummy design to receive apixaban at a dose of 5 mg twice daily (2.5 mg twice daily when indicated) or aspirin at a dose of 81 mg daily. The trial medication was discontinued and anticoagulation started if subclinical atrial fibrillation lasting more than 24 hours or clinical atrial fibrillation developed. The primary efficacy outcome, stroke or systemic embolism, was assessed in the intention-to-treat population (all the patients who had undergone randomization); the primary safety outcome, major bleeding, was assessed in the on-treatment population (all the patients who had undergone randomization and received at least one dose of the assigned trial drug, with follow-up censored 5 days after permanent discontinuation of trial medication for any reason).
Results
We included 4012 patients with a mean (±SD) age of 76.8±7.6 years and a mean CHA2DS2-VASc score of 3.9±1.1 (scores range from 0 to 9, with higher scores indicating a higher risk of stroke); 36.1% of the patients were women. After a mean follow-up of 3.5±1.8 years, stroke or systemic embolism occurred in 55 patients in the apixaban group (0.78% per patient-year) and in 86 patients in the aspirin group (1.24% per patient-year) (hazard ratio, 0.63; 95% confidence interval [CI], 0.45 to 0.88; P=0.007). In the on-treatment population, the rate of major bleeding was 1.71% per patient-year in the apixaban group and 0.94% per patient-year in the aspirin group (hazard ratio, 1.80; 95% CI, 1.26 to 2.57; P=0.001). Fatal bleeding occurred in 5 patients in the apixaban group and 8 patients in the aspirin group.
Conclusions
Among patients with subclinical atrial fibrillation, apixaban resulted in a lower risk of stroke or systemic embolism than aspirin but a higher risk of major bleeding.
There is no safe form of tobacco. Staying tobacco free is the best way to protect your health.
Tobacco hurts and kills people. In fact, smoking causes about 1 out of every 5 deaths in the United States.
There are many forms of tobacco on the market, and people often think some forms are safe and don’t cause health problems. This isn’t true.
Other tobacco products, like e-cigarettes, hookahs, edibles, heat-not-burn cigarettes, and smokeless tobacco, contain some of the same chemicals as regular combustible cigarettes. It’s important to know that even though e-cigarettes do not contain tobacco, the Food and Drug Administration (FDA) classifies them as “tobacco products.”
Regular (combustible) cigarettes
Regular cigarettes, called combustible cigarettes, contain tobacco, added chemicals, a filter, and a paper covering. People who smoke them expose themselves to over 7,000 chemicals when they inhale the smoke from their cigarettes. People around them are also exposed to the same chemicals through secondhand smoke.
Cigarette smoking accounts for almost all tobacco-related illnesses and deaths in the United States.
Light, hand-rolled, natural, or herbal cigarettes
Some people believe that “light” and “low-tar” cigarettes have lower health risks. But studies have shown that the risk of serious health effects is not lower in light or low-tar cigarettes. Because of this, the FDA has banned use of the terms “light,” “mild,” and “low” in any cigarette sales unless the FDA specifically allows it − and so far, it hasn’t.
Hand-rolled cigarettes are no safer than commercial brands. In fact, people who have always smoked hand-rolled cigarettes have a higher risk of cancers of the larynx (voice box), esophagus (swallowing tube), mouth, and pharynx (throat) when compared with people who smoke machine-made cigarettes.
Some cigarettes are now being sold as “all natural.” They’re marketed as having no chemicals or additives and rolled with 100% cotton filters. There’s no proof they are healthier or safer than other cigarettes, nor is there good reason to think they would be. Smoke from all cigarettes, natural or otherwise, has many chemicals that can cause cancer (carcinogens) and toxins that come from burning the tobacco itself, including tar and carbon monoxide.
Even herbal cigarettes with no tobacco give off tar, particulates, and carbon monoxide and are dangerous to your health.
Menthol cigarettes
Menthol cigarettes are not safer than unflavored cigarettes. In fact, they could be even more dangerous.
Menthol cigarettes tend to be “easier” to smoke – the added menthol produces a cooling sensation in the throat when the smoke is inhaled. It lessens the cough reflex and covers the dry feeling in the throat that people who smoke often have. People who smoke menthol cigarettes can inhale deeper and hold the smoke in longer. This helps to explain why people who smoke menthol cigarettes and get lung cancer often have their cancers located in certain parts of the lung. It also might be a reason why it is harder for people who smoke menthol cigarettes to quit.
The specific dangers of menthol cigarettes are an active area of research, but they are at least as dangerous as unflavored cigarettes. It’s important to note the tobacco industry often targets African Americans for the sale of menthol cigarettes.
Cigars and little cigars
Many people view cigar smoking as more sophisticated and less dangerous than cigarette smoking. Yet one large cigar can contain as much tobacco as an entire pack of cigarettes.
Most cigars are made of a single type of aged, air-cured or dried tobacco that’s fermented in a multi-step process. The fermentation causes chemical and bacterial reactions that change the tobacco. This is what gives cigars a different taste and smell from cigarettes. Cigars come in many sizes:
The smallest, known as little cigars or small cigars, are about the size of cigarettes. Other than the fact that they are brown and maybe a little longer, they look like cigarettes. They come in flavors like mint, chocolate, or fruit, and many have filters. They’re often sold in packs of 20. Most people smoke these small cigars exactly the same way as cigarettes.
Slightly larger cigars are called cigarillos, blunts, or cheroots. They contain more tobacco than little cigars, and are also often flavored. Studies suggest that some people smoke them more like cigarettes than cigars, inhaling and smoking every day. They look like small versions of traditional cigars, but they can be bought in small packs.
True large cigars may contain more than half an ounce of tobacco – as much as a whole pack of cigarettes. It can take from 1 to 2 hours to smoke a traditional large cigar.
Almost all people who smoke cigarettes inhale, but most people who smoke larger cigars don’t. This could be because cigar smoke tends to irritate the nose, throat, and breathing passages. A new trend among cigar companies is to change the fermenting process to make cigar smoke easier to inhale. The filters on the smaller cigars also help people inhale.
There’s a lot of nicotine in cigars Full size cigars can have as much nicotine as an entire pack of cigarettes. Cigarettes have an average of about 8 milligrams (mg) of nicotine, but only deliver about 1 to 2 mg of nicotine. Many popular brands of larger cigars have between 100 and 200 mg, or even as many as 444 mg of nicotine.
No matter the size, cigars are tobacco, and the smoke from them contains the same cancer-causing substances found in cigarette smoke. All cigars are dangerous to your health.
People who smoke regular cigars are 4 to 10 times more likely to die from cancers of the mouth, throat, larynx, and esophagus than people who don’t smoke cigars. For those who inhale, cigar smoking appears to be linked to death from cancer of the pancreas and bladder, too.
Smoking more cigars each day or inhaling cigar smoke leads to more exposure and higher health risks. The health risks linked to occasional cigar smoking (less than daily) are less clear. Like cigarettes, cigars give off secondhand smoke, which is also dangerous.
Electronic or e-cigarettes (vaping devices)
Using electronic or e-cigarettes is often called vaping or JUULing. JUUL is a certain very popular brand of e-cigarette. The liquid in these devices is heated and creates an aerosol of tiny particles (sometimes called a “vapor”) that is inhaled by users. Although the term “vapor” may make it sound harmless, it is not water vapor. Instead, it’s an aerosol that consists of propylene glycol plus flavor ingredients, and it can be harmful. E-cigarette aerosol can also contain nicotine and other substances that are addictive and can cause lung disease, heart disease, and cancer.
It’s especially important to know that all JUULs and most other e-cigarettes contains nicotine, the same addictive drug that is in regular cigarettes, cigars, hookah, and other tobacco products.
Because their use is so recent, little is known about the possible harms of long-term e-cigarette use. Studies in lab animals have documented lung damage and some chromosomal abnormalities that may signal a risk for cancer. Because this is such a rapidly evolving field, there is no consensus yet about the harms of vaping. More research is needed over a longer period of time to know what the long-term health effects may be.
There have been reports of severe lung illnesses in some people who vape. Most (but not all) of these cases have been linked to the vaping of off-market cannabis products that contain vitamin E acetate oil. The American Cancer Society is closely watching for new research about the effects of using e-cigarettes and other new tobacco products. Read more in What Do We Know About E-cigarettes?
Clove cigarettes (kreteks)
Clove cigarettes, also called kreteks (KREE-teks), are a tobacco product with the same health risks as cigarettes. Kreteks are imported from Indonesia. They contain tobacco, ground cloves, clove oil, and other additives.
Like other flavored cigarettes, kreteks are used mostly by younger people. They are nearly ideal in design as a “trainer cigarette” – giving kids another way to try tobacco and get addicted to nicotine. The false image of these products as clean, natural, and safer than regular cigarettes seems to attract some young people who might otherwise not start smoking. But they are not safer than cigarettes, and researchers are looking into whether the cloves might even cause additional problems.
Kreteks have been linked to lung problems, such as lower oxygen levels, fluid in the lungs, and inflammation. People who smoke regular kreteks have up to 20 times the risk for abnormal lung function (blocked airways or poor oxygen uptake) compared with people who don’t smoke.
Bidis (flavored cigarettes)
Bidis or “beedies” are thin, flavored cigarettes that originated in India and other Southeast Asian countries. They are hand-rolled in an unprocessed tobacco, tendu, or temburi leaf (plants native to Asia) and may be tied with colorful strings on the ends. They tend to cost less than regular cigarettes and they give the person using them a quick buzz from the high levels of nicotine.
Even though bidis have less tobacco than regular cigarettes, they deliver 3 to 5 times more nicotine than regular cigarettes, as well as other harmful substances, such as tar and carbon monoxide. They are unfiltered. And because they are thinner than regular cigarettes, they require about 3 times as many puffs per cigarette.
Some people think they are safer and more natural than regular cigarettes. But bidis appear to have all of the same health risks of regular cigarettes, including many types of cancer. People who smoke bidis have much higher risks of heart attacks, emphysema, chronic bronchitis, and cancer than those who don’t smoke bidis.
Hookahs (water pipes)
Hookah is also called narghile (NAR-guh-lee) smoking. It started in Asia and the Middle East. A water pipe is used to burn tobacco that has been mixed with flavors such as honey, mint, licorice, molasses, or fruit, and the flavored smoke is inhaled through a long hose. Usually, the tobacco mixture, which is called shisha (SHE-shuh), is heated using charcoal. (The charcoal itself produces carbon monoxide and other toxins.)
Hookah smoking has become popular among younger people in the US as a social event which lets them spend time together and talk as they pass the mouthpiece around.
Newer forms of hookah smoking include steam stones that have been soaked in fluid and are used instead of tobacco and battery powered hookah pens. Both of these create a vapor that’s inhaled. Hookah pens work the same way as electronic or e-cigarettes [see Electronic or e-cigarettes (vaping devices)]. Some sellers advertise that these are purer and healthier alternatives to regular hookahs, but this has not been proven.
Hookahs are marketed as a safe alternative to cigarettes. This claim is false. The water does not filter out the toxins. In fact, hookah smoke has been shown to contain toxins like carbon monoxide, nicotine, tar, and heavy metals, in concentrations that are as high, or even higher, than those in cigarette smoke – it carries many of the same health risks. But because the use of hookahs is generally less frequent than the use of cigarettes, it is likely that a person’s overall exposure to the toxic ingredients is less.
Several types of cancer, including lung cancer, have been linked to hookah smoking. It affects the heart, too, causing coronary artery disease, an increased heart rate, and high blood pressure. Lung damage, carbon monoxide intoxication, chronic bronchitis, emphysema, dental problems, and osteoporosis have also been linked to hookah use. There’s also a risk of passing infections while sharing a hookah.
Hookahs also put out secondhand smoke from both the tobacco and the burning charcoal used as a heat source.
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