Complex interactions may matter most for longevity

 

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David Rand, left, and Chen-Tseh Zhu managed 18 different lines of fruit flies, feeding groups from each line five different diets. They were able to examine the effects on longevity of three different elements: diet, mitochondrial DNA, and nuclear DNA.

If studying a single gene or a diet that might extend longevity is like searching for a fountain of youth, then a new study calls for looking at something more like the whole watershed. Brown University biologists who experimentally throttled three such factors in fruit flies found that lifespan depended more on interactions among the factors than on the factors themselves.

"I think the main lesson is that these interaction effects are as significant or important as the [single] effects, such as diet effects alone or genetic effect alone," said David Rand, professor of biology and senior author of the study published in the journal PLoS Genetics. "Traditionally that's what people have focused on: looking for a gene that extends longevity or a diet that extends longevity."

When researchers have looked at single or even pairs of factors in a wide variety of organisms, they've made many valuable findings about the biology of aging, Rand said. But sometimes scientists have been unable to replicate each other's findings in seemingly similar experiments. Often this is attributed to mysterious "background effects," presumably other genes that were not properly accounted for. The new study chose to put such background effects into the foreground to examine dietary effects on aging in several panels of different nuclear and mitochondrial genetic pairings.

The study's results suggest that many observed effects of calorie or diet restriction or different genes on lifespan may depend on a more intricate context than has been understood so far.

Rather than despairing that combinatorial interactions of diets, nuclear genes, and mitochondrial genes make the underlying biology of aging intractably complex, Rand and lead author Chen-Tseh Zhu said studies that explicitly embrace such multifactorial interactions can lead researchers to understand the inherent biological complexity of the aging process: Many genes, many cells, and many environments all contribute to the aging process. With such observations they could then trace which mitochondrial genes moderate which nuclear genes in response to a particular diet.

"Focused studies of single factors that prove unrepeatable in different backgrounds are not general results," Rand said. "But the interaction between these factors may get us closer to generalities."

Zhu makes an analogy to personalized medicine, in which doctors and scientists hope that by digging deeper into a person's genomic details, they'll be able to predict whether specific drugs can be targeted to individuals with particular combinations of genes, thus avoiding dangerous side effects or producing better treatment.

"Personalized genomic medicine is not to disprove what has been done in medicine so far, but to bring it to another level so that in the future when you are going to design the best medication for a given person you want to investigate their genes and their metabolism," said Zhu, a postdoctoral scholar. "A combination of factors brings you more information."

Complicated combinations

For the study Rand, Zhu and undergraduate co-author Paul Ingelmo generated 18 lines of flies by mixing and matching different mitochondrial and nuclear genomes in individuals from two different species. Then they fed members of each of those fly populations from a menu of five different diets. Some diets held calories constant but varied the balance between yeast (protein) and sugar (carbs), while some diets varied the total calories but kept the proportions of nutrients constant.

In several cases described in the paper, the team saw how interactions among the three factors they manipulated could produce results that would thoroughly frustrate people who were too focused on just one factor.

For example, in flies with the "w1118" nuclear genome and the "OreR" mitochondrial genome, lifespan was greatest with the high-sugar, low-yeast diet and significantly worse with the diet that balanced yeast and sugar evenly. But for flies with the same nuclear genome but the "Zim" mitochondrial genome, the balanced diet was just as good, if not slightly better than the high-sugar, low-yeast meals.

So is it time to recommend that w1118 flies buzz over to the candy store for diet five? That, it turns out, depends on their mitochondrial genome, according to the research.

Another illustrative finding was that the sirt1 nuclear gene, which is an important but controversial gene in aging research, Rand said, shows different effects on longevity given different mitochondrial genomes.

Future work can focus on tracing the physiological and biochemical pathways suggested by these multidimensional interactions, Rand said.

"What this does is identify genetic interactions that themselves are modified by diet," Rand said. "It just means we have to drill down on these things and understand how the various genes that affect aging interact with one another. If you get the right combination of genes, you might be able to map a two-gene response to different diets right down to individual molecules 'talking to each other' in different ways."

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Story Source:

The above story is based on materials provided by Brown University. Note: Materials may be edited for content and length.

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Journal Reference:

1. Chen-Tseh Zhu, Paul Ingelmo, David M. Rand. G×G×E for Lifespan in Drosophila: Mitochondrial, Nuclear, and Dietary Interactions that Modify Longevity. PLoS Genetics, 2014; 10 (5): e1004354 DOI: 10.1371/journal.pgen.1004354

Walking may have profound benefits for patients with kidney disease

 

May 15, 2014

American Society of Nephrology (ASN)

Among patients with chronic kidney disease who were followed for an average of 1.3 years, those who walked for exercise were 33% less likely to die and 21% less likely to need dialysis or a kidney transplant. Physical inactivity is common among patients with chronic kidney disease (CKD). The researchers found that the presence of other, or comorbid, conditions such as cardiovascular disease and diabetes was similar between walking and non-walking patients.

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Just over 21% of patients reported walking as their most common form of exercise. During follow-up, those who walked were 33% less likely to die and 21% less likely to need dialysis or a kidney transplant.

For individuals with kidney disease, walking may help prolong life and reduce the risk of needing dialysis or a kidney transplant. That's the conclusion of a study appearing in an upcoming issue of the Clinical Journal of the American Society of Nephrology (CJASN).

Physical inactivity is common among patients with chronic kidney disease (CKD). Che-Yi Chou MD, PhD, Chiz-Tzung Chang, PhD (China Medical University Hospital, in Taiwan) and their colleagues looked to see if an activity as simple as walking might provide benefits to patients. The researchers studied all 6,363 patients with CKD stages 3 to 5 in the CKD program of China Medical University Hospital from June 2003 to May 2013. Patients were an average of 70 years old, and they were followed for an average of 1.3 years.

Just over 21% of patients reported walking as their most common form of exercise. During follow-up, those who walked were 33% less likely to die and 21% less likely to need dialysis or a kidney transplant. The more patients walked, the more they benefited. Compared with those who did not walk, patients who walked 1-2, 3-4, 5-6, and ≥ 7 times per week were 17%, 28%, 58%, and 59% less likely to die during the study, respectively. They were also 19%, 27%, 43%, and 44% less likely to need dialysis or a transplant.

The researchers found that the presence of other, or comorbid, conditions such as cardiovascular disease and diabetes was similar between walking and non-walking patients.

"We have shown that CKD patients with comorbidities were able to walk if they wanted to, and that walking for exercise is associated with improved patient survival and a lower risk of dialysis," said Dr. Chou. "A minimal amount of walking -- just once a week for less than 30 minutes -- appears to be beneficial, but more frequent and longer walking may provide a more beneficial effect."

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Story Source:

The above story is based on materials provided by American Society of Nephrology (ASN). Note: Materials may be edited for content and length.

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Journal Reference:

1. I.-R. Chen, S.-M. Wang, C.-C. Liang, H.-L. Kuo, C.-T. Chang, J.-H. Liu, H.-H. Lin, I.-K. Wang, Y.-F. Yang, C.-Y. Chou, C.-C. Huang. Association of Walking with Survival and RRT Among Patients with CKD Stages 3-5. Clinical Journal of the American Society of Nephrology, 2014; DOI: 10.2215/CJN.09810913

Many smokers still surprised by facts about tobacco's dangers

 

May 15, 2014

Health Behavior News Service, part of the Center for Advancing Health

Between half and one-third of smokers presented with corrective statements about the dangers of smoking indicated that some of the information was new to them and motivated them to quit, finds a new study. "The tobacco industry systematically deceived the public for decades, denying that smoking was dangerous or addictive," explained one of the study's authors, adding that cigarette makers were actually designing their products to be more addictive to increase sales.

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A new study in the American Journal of Preventive Medicine finds that many smokers still find accurate and detailed facts about the dangers of tobacco both new and motivating in terms of their desire to quit. This finding proved to be especially marked among members of groups that are most likely to be smokers today.

"The tobacco industry systematically deceived the public for decades, denying that smoking was dangerous or addictive," explained one of the study's authors James Thrasher, associate professor at the University of South Carolina Arnold School of Public Health.

Meanwhile cigarette makers were actually designing their products to be more addictive to increase sales. Because of their deceitfulness, a landmark court ruling in 2006 stated that the industry had to provide "corrective statements" about their past deceptions on five topics: health effects of smoking for smokers; health effects of secondhand smoke for nonsmokers; cigarette and nicotine addictiveness; industry design of cigarettes to increase addiction; and the lack of relative safety of low-tar and light cigarettes.

For nearly a decade, though, implementation of this ruling has been delayed while the industry has fought back in the courts. During this delay, tobacco marketing continues to make tobacco use seem like a "normal, important part of everyday behavior," the authors wrote.

"Our study found that many smokers are still unaware of tobacco industry lies," said Thrasher. He added that smokers indicate that receiving factual, corrective information about the dangers of smoking motivates them to quit; also that members of groups that are highly targeted by the tobacco industry were especially responsive to the corrective statements. These groups include women, African Americans, Latinos and lower-income people. "This study suggests that the longer we wait to give smokers this information about the tobacco industry's lies, the more smokers will continue to consume tobacco" noted Thrasher.

1,404 smokers ranging in age from18 to 64 years old and of diverse ethnic, gender and income groups were presented with the corrective statements. Between one half and one third of the study participants stated that some information in the corrective statements was novel to them. Those who experienced novelty were likelier to express anger at the industry, to find the message(s) relevant and to feel motivated to quit by the message(s). Novelty ratings ran consistently higher among African Americans and Latinos than among non-Hispanic whites.

Should corrective statements one day be "widely disseminated and highly visible, they will serve a key public education function," says Andrea Villanti, Ph.D., MPH, associate director for regulatory science and policy at the American Legacy Foundation. By correcting previous lies, she says, they "may have a role in preventing youth from initiating smoking and increasing cessation among adults."

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Story Source:

The above story is based on materials provided by Health Behavior News Service, part of the Center for Advancing Health. The original article was written by Milly Dawson. Note: Materials may be edited for content and length.

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Journal Reference:

1. Christy L. Kollath-Cattano, Erika N. Abad-Vivero, James F. Thrasher, Maansi Bansal-Travers, Richard J. O’Connor, Dean M. Krugman, Carla J. Berg, James W. Hardin. Adult Smokers’ Responses to “Corrective Statements” Regarding Tobacco Industry Deception. American Journal of Preventive Medicine, 2014; DOI: 10.1016/j.amepre.2014.02.006

Why the West is anxious about China's economic slowdown

 

May 19, 2014

The recent World Bank report that "China will overtake the United States to become the largest economy" has triggered global concern. Some are taken aback by the fast-paced growth of the Chinese economy; others question the conclusion that China will become the largest economy.
In fact, in recent years there has been a constant chatter of voices talking down China's economy, especially during its economic slowdown this year.
"Before the first quarter of this year, when the National Bureau of Statistics (NBS) announced its economic growth data, Goldman Sachs had predicted China's economic growth rate would be only 6 percent for the first quarter." Economist Ma Guangyuan says that the figures released by the NBS represented a strong riposte to the international investment bank, but they did not put a stop to the questioning voices.
Asking China to engage in a blind acceleration is unreasonable
At an early stage of the G20 finance ministers and central bank governors meeting held in July last year, a number of European countries expressed the hope that China would take aggressive stimulus measures to improve its growth in order to promote the economic recovery of other countries. Today, there is still a popular sentiment in the West that China should bear the primary burden of supporting international economic growth, ignoring the fact that China's intensive economic development model has run its course.
The reality is that the West has become too dependent on China's rapid growth, and that this growth is not sustainable. Structural contradictions, resource constraints, and environmental pressures, stemming from long-term government investment, are becoming more and more serious. Internal and external demand has declined, and some developed countries are now adopting protectionist measures that have led to a new decline in Chinese exports. Competitive currency devaluation in some developed countries has caused hot money flows, the continued appreciation of the RMB, and imported inflation.
"The argument that China's economic slowdown is a drag on global growth is inconsistent with the facts”, says Xu Hongcai, director of the Information Department of the China Center for International Economic Exchanges.
China's contribution to the global economic recovery and sustainable development is remarkable. China has maintained growth at more than 7 percent, it provides more than 10 million jobs a year, and it is currently the world's biggest economy in terms of foreign trade, all of which contribute to global economic growth.
China to contribute more to the world
With the deepening of China's economic reform, Western countries should gradually adapt to the "new normal" of China's economy, under which: first, China's economy will slow down from rapid growth to moderate or high growth, second, there will be a shift in China's economic growth model from intensive growth to innovative and consumer-driven growth, and third, precautions against risk should play a more important role, according to Li Huiyong, an analyst at Shenyin Wanguo Securities.
Although in the transition process, China's economic growth will experience a slowdown, the quality and efficiency of the economy will be greatly improved, with a transition from the "world factory" to the "world market" - from "Made in China" to "Created in China". China's contribution to the world economy will continue to grow.
During the transition process the technology, capital, and experience of developed countries can be introduced to the Chinese market and they can play a positive role in China, says Xu Hongcai.
In the context of economic globalization, China has always advocated the liberalization of trade and the facilitation of investment, but it has also pursued an upgrade of the industrial structure, energy saving, and improvements to the energy structure, which have positive implications for the world economy and for ecological and environmental protection.

Why It's Hard to Stick With Rheumatoid Arthritis Treatment

 

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If dealing with rheumatoid arthritis is a full-time job, the treatment for RA is a task that requires painstaking attention to detail and a whole-hearted commitment to a long-term goal.
While the payoff can be huge—preventing or at least slowing down potentially disabling joint destruction—it's still hard for patients to stick with the treatment, whether it's pills, self-administered injections, or three-hour-long infusions given in a doctor's office.
Consider also that RA medications can be pricey and have side effects and that there's the psychological impact of having to undergo lifelong treatment, and you have a recipe for noncompliance—the medical term for people who don't take their medicine as directed.
"Compliance is a huge issue," confirms Christopher Ritchlin, MD, MPH, a rheumatologist and professor of medicine at the University of Rochester Medical Center in New York. According to a 2007 study, some people with RA missed their meds between 10% and 36% of the time, depending on the drug taken. Other studies have reported noncompliance rates as high as 70%.
"I can deal with bouts of pain, but the fact that it's chronic and never going away, that's the hardest thing to deal with," says Angela Lundberg, 32, who was diagnosed at 18.
It's especially tempting to skip medication when the beneficial effects aren't obvious unless you're looking at an X-ray showing the condition's progression (or even if they are obvious). Still, research suggests that without treatment joints will deteriorate more rapidly and the journey to disability will be quicker. Hence, it's important to find ways to stay motivated.

Next >: How treatment helps

Your Half-Marathon Training Guide

 

Ready to try a half-marathon? Try this 12-week plan for experienced runners who want to build up to running 13 miles.

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Running just might be the most convenient workout going. You don't need to be a skilled athlete, and there's no fancy equipment involved; just lace up your sneaks and go. It's also one of the most efficient ways to blast fat and burn calories—about 600 an hour.

Sure, walking has its benefits, but research shows that running kicks its butt when it comes to shedding pounds. One recent study of 47,000 runners and walkers, from the Lawrence Berkeley National Laboratory in Berkeley, Calif., found that the runners burned more calories and had a far greater decrease in BMI over a six-year period. The joggers who started out heaviest (those with a BMI over 28) lost up to 90 percent more weight than the walkers did.
Dropping pounds and toning up are hardly the only benefits of this killer cardio workout: You'll also reduce your risk of heart disease and diabetes, boost your mood, temper stress and build muscle, especially in the lower body and core. You don't even need to dedicate a lot of time to reap these rewards; do 20 to 30 minutes, three to four days a week, and you'll see significant improvement.
Ready to hit the road? Here's a plan for experienced runners. And it's smart to add in one day of cross-training (think cycling or swimming) to rev up calorie burn and help prevent injury. Soon enough, you'll feel as if you were born to run.
Your stats: You run three to four times a week for at least five miles nonstop.
The goal: Boost your overall performance—speed, endurance and distance—over the course of 12 weeks, then challenge yourself with a half-marathon.
Your coach: Andrew Kastor is coaching director at Asics L.A. Marathon and head coach at Mammoth Track Club in Mammoth, California.
The plan: In Week 1, run three to four miles at an easy pace (think 5 on a scale of 1 to 10) on your first day; four to five miles on Days 2 and 3; and five to six on Day 4. In subsequent weeks, keep doing one easy-pace day, and vary half-mile-long to mile-long speed intervals. The detailed schedule also tells you how to add in race-pace workouts, so you can hold your speed for longer distances.
HERE'S YOUR GUIDE: Expert Half-Marathon Training Plan
Train smarter!
1. Buddy up
Face it, sometimes you just don't feel like going for a run, especially when you've been seriously challenging yourself. Having someone by your side is a great way to make the miles more tolerable and maintain your performance. "When you train with a group or pack, you almost always run a little harder or faster," says Kastor. Grab a friend or find a new jogging pal at buddyup.com or the Road Runners Club of America (rrca.org). Choose partners who are a bit better than you; you want a challenge but don't want to get burned out or injured.
2. Take the plunge
Kastor, who works with many elite runners (including Olympian Deena Kastor, his wife), recommends a cold bath right after a hard workout. "It helps reduce inflammation by constricting the blood vessels, so there's less blood pooling through the muscle tissue, and you're not as sore the next day," he explains. Massage can speed recovery, too: Give yourself a five-minute rubdown using a foam roller; roll slowly up and down your legs, butt, shoulders and back. You can also alleviate soreness by gently pressing into the area with your fingers.
3. Write down your goal
You're amping up your workouts—pump up your motivation, too! Jot your goal time for the half-marathon or just 13.1 on a sticky note, and post it onto your mirror. As Kastor puts it: "Seeing that number will remind you to make the best choices for your body."
MORE: 7 Tips for Running Your First Race

Lower Cholesterol May Lessen Risk of Some Cancers

 

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THURSDAY, Nov. 5 (Health.com) — Most people know that healthy cholesterol levels can help protect your heart. But new research suggests another potential benefit: a lower risk of developing some types of cancer.
In fact, low total cholesterol is associated with about 60% less risk of the most aggressive form of prostate cancer, and higher levels of good cholesterol (HDL) may protect against lung, liver, and other cancers, according to two studies published this week in the journal Cancer Epidemiology, Biomarkers & Prevention.

Thats quite a reversal of fortune for low cholesterol, which has, in the past, been associated with a higher cancer risk. The new studies suggest that low cholesterol may not deserve its bad reputation, earned from a series of studies in the 1980s that said people with low cholesterol might be at risk of cancer.
In fact, cholesterol may drop in people with undiagnosed cancer, meaning that low cholesterol may be a result—not a cause—of cancer.
In the first study, men with HDL cholesterol above roughly 55 mg/dL had an 11% decrease in overall cancer risk, including lung and liver cancer. (HDL levels between 40 and 50 are average for men.) The study, conducted by National Cancer Institute (NCI) researchers who looked at about 29,000 male smokers in Finland over an 18-year period, is the largest to show a relationship between HDL and cancer.
"Very few studies measured [HDL], and any relationship between HDL and overall cancer risk had therefore not been adequately evaluated," the NCI's Demetrius Albanes, MD, the lead author of the study, said at a press briefing.
While the findings are new and intriguing, more research needs to be conducted to confirm a link between HDL and cancer risk reduction.
“[Its] a very new, exciting question, but we need to do a great deal more research before we have any clear answers," says Eric Jacobs, PhD, an epidemiologist with the American Cancer Society, who co-wrote an editorial accompanying the studies. For his part, Dr. Albanes stressed that the results need to be confirmed, especially in women and nonsmokers.

Next : Can cholesterol-lowering drugs help?

What Your Heart Needs Now

 

 

Things to do in your 30s, 40s, and beyond

(ISTOCKPHOTO)

The statistics are sobering: Heart disease is the number-one killer of women in the United States. And an estimated eight million women have it. Whats more, a new study shows that in recent years, the overall heart disease risk for Americans—especially women—hasnt continued the healthy downward trend it showed in previous decades. Ready for some good news? You can do more to prevent heart disease than almost any other serious condition. Start with these age-specific steps.

(ISTOCKPHOTO)

Declare a trans fat–free zone
Commonly used to extend the shelf life of packaged foods like cookies and crackers, and also found in margarine, trans fats pack a double whammy: They raise bad cholesterol (LDL), while lowering good, protective HDL (your LDL should be below 100; your HDL, above 60). In a Harvard University study, women with the highest level of trans fats in their blood had triple the risk of heart disease. Take a cue from major U.S. cities like New York and Philadelphia (which have banned trans fats from restaurants), and pitch them out of your pantry.
On ingredient lists, they show up as “hydrogenated” and “partially hydrogenated” oils. But scrutinize any product touted as “trans fat–free” at the supermarket too: Some manufacturers have replaced hydrogenated oils with tropical oils that are high in saturated fat, which also raises LDL cholesterol. Eating out in a city where trans fats arent banned? Skip the fried stuff; many restaurants still use the oils for frying.

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Use your ob-gyn as a partner
During your prime reproductive years, you may visit your ob-gyn more than you go to your regular doctor. Make sure you talk to her about your heart as well as gynecological health, particularly because blood pressure (BP) can rise if youre taking birth control pills or when youre pregnant.
Women who develop preeclampsia (pregnancy-related hypertension) are prone to heart disease later in life. And, in general, “how your heart handles pregnancy offers a snapshot of how it will look in middle age,” says Sharonne Hayes, MD, director of the Womens Heart Clinic at the Mayo Clinic, in Rochester, Minn. To keep BP from creeping up (the safe zone is lower than 120 over 80), substitute herbs and spices for salt; try cumin for a healthy twist on popcorn, for instance. Too much salt causes blood vessels to retain water, which can lead to high BP.

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Simmer down
If you boil over when the shopper in front of you has 16 grocery items in the 15-or-fewer lane, beware: Losing your temper can damage your arteries, according to research by C. Noel Bairey Merz, MD, director of the Womens Heart Center and endowed chair in Womens Health at the Cedars-Sinai Heart Institute in Los Angeles. “Raging causes your blood pressure to surge and stay up there,” Dr. Merz says. Thats why its crucial to get a grip on anger at an early age, before it takes a toll. Instead of venting when a situation makes you furious, take a few deep breaths and describe to yourself whats making you angry. That should help you calm down.

Did you know?

 

Famous people and their drug use

Tabagismo e Alcoolismo: Tratamento

 

 

Há 1,1 bilhão de fumantes no mundo, segundo a OMS, matando mais que o álcool e drogas ilegais.
O fumo é o maior responsável pelas faringites, bronquites, falta de apetite, tremores, perturbações da visão, diversos tipos de câncer, sobretudo do pulmão e doenças cardiovasculares como a angina do peito e o enfarte do miocárdio.
Além do câncer do pulmão, de que o fumo é maior causador, produz bronquite crônica, enfisema pulmonar, coronariopatias, úlceras do estômago e do duodeno, câncer da língua, da faringe, do esôfago e da bexiga.
A ação da nicotina é exercida pelo sistema sobre o sistema parassimpático e simpático e pela liberação de adrenalina e influi na diminuição do consumo do oxigênio e, além de prejudicar o organismo em geral, vai diretamente ao cérebro, coração e circulação.

Apenas um cigarro é suficiente para contrair todos os vasos sanguíneos do corpo. E a fumaça de um cigarro, é o bastante para contrair os vasos capilares das pernas e dos pés.

O fumante sofre, em cada trago, endurecimento das artérias, fazendo o coração trabalhar mais depressa, enquanto os pulmões absorvem monóxido de carbono, amônio, ácido carbônico, piridina e substâncias alcatroadas que passam a circulação do sangue. O monóxido de carbono também origina dores de cabeça; o amônio irrita as narinas e a garganta, a piridina irrita os brônquios e as substâncias alcatroadas engrossam a língua, sujam os dentes e determinam câncer na boca e na língua.A nicotina, em si, diminui a vitalidade do fumante e de seus filhos.
A fumaça do cigarro provoca uma reação violenta nos centros nervosos, produzindo a degeneração das células do cérebro.
Uma vez que o hábito de fumar conduz o viciado a um estado de intoxicação crônica e o leva a uma dependência física e psíquica, sente o fumante dificuldade em abandoná-lo.

A nicotina é um dos venenos mais ativos. A nicotina e o alcatrão deve-se a maior soma de males acarretada aos fumantes. O fumante médio absorve nos pulmões mais de um litro de alcatrão por ano.
Os venenos do fumo agem no organismo pelas vias respiratórias e pelas vias digestivas. Pelas vias respiratórias, através da traquéia e brônquios, por onde chegam aos pulmões, onde são absorvidos e conduzidos ao sangue e, por este, a todos os demais órgãos. A nicotina, por intermédio da circulação, excita as glândulas supra-renais que segregam mais adrenalina. Conduzida ao sangue, provoca contração das paredes arteriais, ocasionando espamos das artérias. É assim que o fumo aumenta a pressão arterial, favorece problemas coronários e cardiovasculares.
Pelas vias digestivas, boca, estômago e intestinos, pois que, parte do venenos do fumo dissolve-se na saliva e é conduzida ao estômago, ocasionando a diminuição da secreção gástrica, dificultando a digestão, diminuindo o apetite e predispondo o fumante à úlcera gastroduodenal. Do aparelho digestivo os venenos do fumo são conduzidos ao sangue e aos diversos tecidos do corpo.
No fígado, grande parte da nicotina é transformada em ácido úrico, com o que ocasiona o surgimento do reumatismo e da gota.

O que está comprovado sobre a fumaça ambiental do tabaco:
- é inalada, absorvida e processada por não-fumantes
- é quimicamente similar a fumaça inalada pelo fumante, e esta é carcinogênica
- contém substâncias que causam câncer
- pode causar câncer e lesões genéticas (que originam câncer) em animais de laboratório
- está associada a problemas cardíacos
- causa problemas respiratórios em crianças de até 18 meses
- retarda o desenvolvimento fetal

Substâncias da Fumaça do Cigarro
Quando cigarros industrializados ou de fumo-de-rolo, cachimbos e charutos são acesos, algumas substâncias são inaladas pelo fumante e outras se difundem pelo ambiente. Essas substâncias são nocivas à saúde.
Todas as formas de uso do tabaco, inclusive os cigarros com mentol, filtros especiais, com baixos teores (light, exta-light) etc. tem uma composição semelhante, não havendo, portanto cigarros "saudáveis" ou cachimbos e charutos que façam menos mal. Isso ocorre porque, mesmo escolhendo produtos com menores teores de alcatrão e nicotina, os fumantes acabam compensando essa redução, fumando mais cigarros por dia e tragando mais freqüente ou profundamente, ou seja, fazendo outras modificações compensatórias em conseqüência da dependência à nicotina.
A fumaça do cigarro é uma mistura de cerca de 5 mil elementos diferentes. Ela é formada pelos seguintes componentes:
Nicotina - considerada droga pela OMS. Sua atuação no sistema nervoso central é como a da cocaína, com uma diferença: chega entre 2 e 4 segundos mais rápido ao cérebro que a própria cocaína. É uma droga psicoativa, responsável pela dependência do fumante. É por isso que o tabagismo é classificado no Código Internacional de Doenças (CID - 10) como grupo dos transtornos mentais e de comportamento decorrente do uso de substâncias psicoativas. A nicotina aumenta a liberação de catecolaminas, acelerando a freqüência cardíaca, com conseqüente vasoconstricção e hipertensão arterial. Provoca uma maior adesividade plaquetária, e juntamente com o monóxido de carbono leva à arterosclerose. Contribui assim para o surgimento de doenças cardiovasculares. No aparelho gastrointestinal, a nicotina estimula a produção de ácido clorídrico, podendo levar ao aparecimento de úlcera gástrica. Também estimula o sistema parassimpático, o que pode causar diarréia. A nicotina libera substâncias quimiotáxicas, que vão atrair para o pulmão os leucócitos neutrófilos polimorfonucleares, a maior fonte de elastase, que destrói a elastina e provoca o enfisema pulmonar (Orleans e Slade, 1993; Rosemberg, 1996).
Monóxido de Carbono (CO) - tem afinidade com a hemoglobina (HB) contida nos glóbulos vermelhos do sangue, que transportam oxigênio para os tecidos de todos os órgãos do corpo. A ligação do monóxido de carbono com a hemoglobina forma o composto chamado carboxihemoglobina, que dificulta a oxigenação do sangue, privando alguns órgãos do oxigênio e causando doenças como a arterosclerose.
Alcatrão - composto de mais de 40 substâncias comprovadamente carcinogênicas que incluem o arsênico, níquel, benzopireno e cádmio. Carcinogênicas são substâncias que provocam câncer como resíduos de agrotóxicos nos produtos agrícolas, como o DDT, e até substâncias radioativas, como é o caso do polônio 210.
Vale ressaltar que as substâncias da fumaça do cigarro tem efeitos sobre a saúde do fumante, mas também sobre a saúde do não-fumante, exposto à poluição do ambiente causada pelo cigarro.
Cigarros de Baixos Teores
O modo de fumar é determinado pela necessidade do fumante em consumir nicotina (que lhe traz a sensação de satisfação). Os fumantes utilizam artifícios para alcançar tal sensação ao fumarem cigarros com teores baixos, dando tragadas mais profundas. Assim, aumentam o número de tragadas por cigarros, aumentam o número de cigarros fumados e bloqueiam os orifícios de ventilação dos filtros para aumentar a concentração de fumaça inalada durante a tragada.
Esses artifícios são conhecidos como compensação e tem sido, extensivamente, documentados na literatura científica, sendo bem conhecidos da indústria do tabaco há mais de 20 anos. Testes demonstram que, em "condições de fumo realísticas", existe uma diferença muito pequena entre os cigarros denominados "light" e os comuns. Na verdade, eles podem até produzir quantidades maiores de alcatrão, nicotina e monóxido que os cigarros tradicionais testados.
Um estudo realizado na Inglaterra por Kozlwski et al. (1999) demonstrou que 58% dos filtros de cigarros examinados apresentavam sinais de bloqueio significativo e 19% sinais de bloqueio total. A partir dos resultados de uma pesquisa realizada em 1998, a ASH e The Observer mostraram que os cigarros com baixos teores podem propiciar os mesmos mecanismos compensatórios antes citados.
Por mais que a indústria do fumo afirme que realiza pesquisas visando ao desenvolvimento de produtos alternativos, na verdade, ela estuda produtos e formas de distribuir a nicotina em dispositivos que contenham menos teor de determinadas substâncias, como o alcatrão, por exemplo, e mantendo a nicotina, que causa a dependência.
Lutando contra o cigarro
Muitos tabagistas tentam parar de fumar sozinhos. A seguir algumas dicas possíveis de ser aplicada por qualquer pessoa para que seja obtido um melhor resultado. São para dificultar o gesto automático de fumar, tornando-o consciente:
1. Ter certeza de que quer fumar e não simplesmente acender um cigarro automaticamente, ou seja, pensar muito bem se de fato precisa fumar ou se pode deixar para mais tarde.
2. Parar de comprar cigarros.
3. Não comprar um maço de modo algum enquanto não acabar o último cigarro, mesmo que seja na boca da noite ou na véspera de uma viagem.
4. Quando não tiver cigarro, ter o brio de não ficar catando bitucas.
5. Não ter fósforo, isqueiro, fogo por perto.
6. Desfazer-se do isqueiro. O "som"(ruído) característico obtido ao se abrir um determinado isqueiro também pode ser prazeroso.
7. Jogar cinzeiro fora para dificultar o trabalho na hora de bater as cinzas em lugar adequado.
8. Colocar o maço de cigarros num lugar que lhe dê trabalho quando for pegá-lo; não andar com o maço no bolso nem deixá-lo na cabeceira, na escrivaninha, etc.
9. Se possível, colocar o maço em outro ambiente.
10. Não acender o cigarro somente porque você ficou com vontade ao ver alguém acendendo ou fumando um.
11. Demorar o máximo possível com o cigarro na mão antes de acendê-lo.
12. Dar no máximo três tragadas de cada cigarro, mesmo que o jogue fora quase inteiro (nicotina a menos).
13. Envergonhar-se de fumar.
14. Questionar se vale a pena fumar, mesmo que corra o risco de morrer como aquele parente que teve dores, permaneceu acamado, emagreceu, fez radioterapia, ficou feio, fez a família sofrer, gastou o que tinham e... acabou falecendo.
15. Lembrar que nas escolas o cigarro é proibido pela Lei 9760/97.
Se essa luta íntima contra o cigarro não der certo, ainda há muitas esperanças de cura para esse vício. Psicoterapias, grupos de auto-ajuda e recursos médicos, como nicotina em adesivos e antidepressivos, são os meios mais eficazes.
(Fonte: Anjos Caídos, Içami Tiba. Editora Gente, 6ª edição)
Dez razões para parar de fumar
1 - Após 6 horas sem fumar, a pressão e o coração se normalizam. Após 30 dias, estão completamente normais
2 - Após 1 dia sem cigarro, o pulmão funciona melhor
3 - Após 2 dias sem fumar, o olfato e o paladar sofrem uma significativa melhora
4 - Após 3 semanas, os exercícios físicos ficam mais fáceis de serem executados
5 - A circulação sanguínea melhora após 2 meses sem cigarro
6 - Após 3 meses, o número de espermatozóides normaliza e há um significativo aumento em sua qualidade
7 - Após 1 ano o risco de problemas cardíacos está reduzido
8 - Após 5 anos sem fumar, o risco de problemas no coração são iguais aos de uma pessoa que nunca tenha fumado
9 - Dentes, mãos e pele clareiam após o término do vício
10 - Aumento da qualidade de vida, disposição e humor
(Revista Cyber Mondo Ciência e Tecnologia - Ano1 nº2)
Fumo e doenças cardiovasculares
- Fumar aumenta o risco de doenças coronárias como angina no peito e infarto do miocárdio
- Triplica o risco de morte por infarto em homens com menos de 55 anos
- Aumenta em 10 vezes o risco de tromboembolia venosa e infarto em mulheres que tomam anticoncepcionais orais
- Aumenta o risco de insuficiência vascular periférica, causando má circulação nas pernas e impotência sexual
Fumo e doenças neurovasculares
- Fumar triplica o risco de derrame cerebral  (acidente vascular cerebral - AVC)
Fumo e câncer
O cigarro contém mais de 40 substâncias cancerígenas que aumentam o risco de câncer na:
- boca, faringe, laringe e traquéia
- pulmões - risco 12 a 20 vezes maior
- esôfago, estômago
- rins, bexiga, colo do útero, etc
Fumo e doenças respiratórias
Fumar aumenta a queda da capacidade respiratória com a idade e aumenta o risco de problemas respiratórios como:
- tosse, chiado e falta de ar
- bronquite crônica e enfisema
- causa 90% da doença pulmonar obstrutiva crônica (DPOC) e aumenta seu risco em 10 vezes
- laringite (rouquidão)
- infecções das vias respiratórias
- crise de asma
Fumo e pele
Fumar eleva o risco de rugas prematuras e de celulite e interfere na cicatrização de feridas cirúrgicas
Fumo e gravidez
Fumar aumenta o risco de infertilidade e de complicações da gravidez.
A gestante fumante tem maior chance de abortar, de ter filho prematuro, de baixo peso e de morte do filho no período perinatal.
Fumar reduz a expectativa de vida
A chance de viver até os 73 anos é de 42% em fumantes e 78% em não-fumantes
Fumar prejudica o tratamento de doenças
Como gastrite, úlcera péptica, esofagite de refluxo, angina, insuficiência cardíaca, bronquite, enfisema e asma
Fumar aumenta as complicações pós-operatórias
Especialmente em idosos, obesos e pacientes em tratamento de doenças cardíacas ou respiratórias
Fumo Passivo
As pessoas que estão próximas dos fumantes, especialmente em ambientes fechados, inalam mais de 400 substâncias que podem prejudicar a saúde.
O fumante passivo tem maior risco de câncer de pulmão e infarto do miocárdio.
As crianças que convivem com pais fumantes têm maior risco de infecções respiratórias, bronquiolites, asma, otites e infecções de garganta (amigdalites).
Cigarro e Gravidez: Parceria Perigosa
As mulheres têm um motivo a mais para deixar de fumar: durante a gravidez, esse hábito pode fazer imenso mal ao feto. Quando a mãe fuma durante a gestação, o bebê recebe as substâncias tóxicas do cigarro por meio da placenta. A nicotina provoca o aumento do batimento cardíaco do feto, e a criança pode nascer com peso reduzido, menor estatura e alterações neurológicas importantes. Isso sem falar que a gestante tem um risco aumentado de sofrer um aborto espontâneo, entre outras implicações ao longo dos nove meses. Para piorar o quadro, durante a amamentação, as substâncias tóxicas continuam sendo transmitidas ao bebê via leite materno.
Portanto, mulheres, procurem abandonar o cigarro logo agora, porque depois de já estarem grávidas a luta contra o tabaco fica ainda mais difícil. Porém é fundamental.
Fonte: Revista Documento Verdade, Ano1, Nº03, Pg.32. Editora Escala.
Correlatos Psicossociais do Tabagismo
Correlatos Sociais
No mundo desenvolvido, particularmente nos países onde há campanhas/políticas antifumo bem organizadas, o tabagismo é estreitamente relacionado com a situação socioeconômica, sendo mais prevalente entre pobres, trabalhadores braçais semiqualificados, desempregados, indivíduos com baixos níveis culturais e mães solteiras. Além disso, essa demarcação entre os grupos sociais está se acentuando: nas últimas 3 décadas a prevalência do tabagismo caiu mais de 50% nas classes mais elevadas da sociedade britânica, mas permaneceu imutável nos grupos mais desvalidos. De modo semelhante, os índices de cessação do tabagismo no Reino Unido mostram grande relação inversa com a privação social.
Correlatos Psiquiátricos
A depressão é um fator importante de risco de dependência de nicotina. Nos fumantes é maior a prevalência de história de depressão significativa e, nesses casos, a probabilidade de cessação do tabagismo é menor do que nos indivíduos sem história de depressão. Sugeriu-se que a associação entre depressão e tabagismo pode ser devida a uma predisposição genética comum às duas doenças. Outros fatores de risco da dependência de nicotina incluem esquizofrenia (70 a 90% dos esquizofrênicos são fumantes) e abuso de múltiplas drogas, particularmente álcool, cocaína e heroína.
Assim, é provável que a maioria que continua fumando é composta por aqueles com problemas psiquiátricos ou sociais. Além disso, é provável que esses fumantes sejam mais dependentes do tabaco e menos interessados em abandoná-lo.