FAITH LAPIDUS: This is SCIENCE IN THE NEWS, in VOA Special English. I'm Faith Lapidus.
BOB DOUGHTY: And I'm Bob Doughty. This week, we talk about smoking – the leading cause of cancer worldwide.
FAITH LAPIDUS: Barack Obama completed his first routine physical examination as President of the United States last week. Doctors reported that Mister Obama is in excellent health. They say all evidence suggests that he will remain so during his presidency.
The doctors gave the president suggestions so that he can stay healthy. One is for him to continue with efforts to stop smoking. Mister Obama has spoken publicly about those efforts in the past. The new report shows his battle against smoking is continuing.
BOB DOUGHTY: President Obama is not alone. More than one billion people around the world are smokers. Health experts have been warning about links between smoking and disease for years.
Smoking kills an estimated five million people worldwide every year. Experts say smoking is the leading cause of preventable death. And, it is the second leading cause of death, after cancer.
Smoking is also the leading cause of cancer. Experts say forty percent of cancers could be prevented by avoiding health risks like smoking and tobacco use.
Smoking also causes forty-two percent of cases of chronic respiratory disease, including asthma, bronchitis and emphysema. And, it causes ten percent of cardiovascular diseases, like heart disease and stroke.
FAITH LAPIDUS: The medical research community is continually reporting reasons why smokers should stop. A recent study found that people who smoke are nearly two times as likely as non-smokers to develop Alzheimer's disease. Alzheimer's weakens or destroys memory and reasoning.
In the study, researchers examined forty-three published studies about the link between Alzheimer's disease and smoking. They found that smoking increased the risk of Alzheimer's developing by one and seven-tenths percent. The researchers work at the University of California in San Francisco. Their findings were published in the Journal of Alzheimer's Disease.
In an earlier study, seven thousand people were observed for an average of seven years. Each person was fifty-five years or older. Those who smoked were fifty percent more likely to develop memory loss than those who never smoked, or who had quit.
BOB DOUGHTY: Other research has linked smoking to Amyotrophic Lateral Sclerosis. ALS is a deadly disease affecting the motor nerves and the voluntary muscles. Last year, a study in the medical journal Neurology found smoking to be an established risk factor in developing the disease. Some of the evidence even suggested smoking may be directly responsible for ALS.
Smoking also increases the risk of developing age-related macular degeneration. AMD is the leading cause of blindness among adults fifty and older. Research has shown AMD is two to three times more common among smokers than other people.
FAITH LAPIDUS: A recent study examined how smoking affects a person's risk of AMD later in life. Researchers at the University of California in Los Angeles studied nearly two thousand women.
Four percent of the women were smokers. Each woman had pictures of her retinas taken at age seventy-eight. The researchers compared these retinal images with pictures taken five years later when the women were eighty-three. They studied the pictures for signs of AMD and to see whether smoking influenced the women's chances of developing the disease.
The women who smoked had an eleven percent higher rate of AMD than the other women. In women over eighty, those who smoked were five and a half times more likely to develop AMD than the women who did not smoke. A report on the study was published in the American Journal of Ophthalmology.
BOB DOUGHTY: People who smoke are not only hurting themselves. They also can harm non-smokers. The World Health Organization estimates that secondhand smoke kills six hundred thousand people each year.
The International Union Against Cancer says about seven hundred million children breathe smoke-filled air. Expectant mothers who smoke are more likely to have babies with health problems and low birth weight. Such babies may suffer health problems as they grow.
FAITH LAPIDUS: Even after all the warnings, the WHO says one billion three hundred million people still smoke. The number of smokers is expected to grow to one billion seven hundred million by twenty twenty-five. Smoking rates have decreased in the United States and Europe. But rates have risen in other areas.
WHO officials say eighty-four percent of all smokers live in developing countries. Nations in the Western Pacific Ocean have the highest smoking rates. One-third of all smokers live in East Asia and the Pacific. The area has the largest number of male smokers. It also has the fastest growing number of female and child smokers. Every day, diseases linked to tobacco use kill more than three thousand people in the area.
BOB DOUGHTY: Scientists have found more than four thousand chemicals in cigarette smoke. At least two hundred fifty of them are known to be harmful. And, fifty have been found to cause cancer. They include arsenic, which can be used to kill plants and small animals. Cigarette smoke also contains formaldehyde – a liquid used to protect the look of dead bodies.
As bad as those chemicals are, nicotine may be the most threatening of them all. Nicotine is a poison found in tobacco. It gives smokers pleasure and keeps them coming back for more.
The body grows to depend on nicotine. Studies have found that nicotine can be as difficult to resist as alcohol or the drug cocaine. Experts say nicotine can kill a person when taken in large amounts. It does this by stopping the muscles used for breathing.
FAITH LAPIDUS: Menthol cigarettes are said to be no safer than other tobacco products. Menthol cigarettes produce a cool feeling in the smoker's throat. This may cause people to hold the smoke in their lungs longer than smokers of other products. As a result, scientists suspect that menthol cigarettes may be even more dangerous than other cigarettes.
Some smokers believe that cigarettes with low tar levels are safer. Tar is a substance produced when tobacco leaves are burned. It is known to cause cancer. America's National Cancer Institute has said that people who smoke low-tar cigarettes do not reduce their risk of getting diseases linked to smoking.
BOB DOUGHTY: So is there any way to smoke without harming your health? The majority of available research suggests not. Smoking even a few cigarettes can be dangerous. But, many of the harmful effects of smoking ARE reversible. They can be undone. That is why most medical experts advise people to stop smoking forever.
The American Cancer Society says blood pressure returns to normal twenty minutes after the last cigarette. Carbon monoxide levels in the blood return to normal after eight hours. The chance of heart attack decreases after one day. After one year, the risk of heart disease for a non-smoker is half that of a smoker.
FAITH LAPIDUS: There are many products available to help people reduce their dependence on cigarettes. Nicotine replacement products provide the body with small amounts of the chemical through forms other than cigarettes. The amounts of nicotine are slowly reduced over time.
Chantix and Zyban are two prescription medicines that have also been shown to help smokers quit. They do not contain nicotine. Chantix works on nicotine receptors in the brain to reduce the urge to smoke. Zyban works by increasing levels of dopamine in the brain. Dopamine is a chemical that produces pleasure.
BOB DOUGHTY: People who have quit smoking offer this helpful advice to those who want to stop. Stay away from alcohol. Take a walk instead of smoking. And, avoid people who are smoking. If possible, stay away from situations that trouble you. It is not easy to quit smoking. And, people never can completely control their own health. But as one doctor advises her patients, becoming a non-smoker is one way to gain control of your life.
This SCIENCE IN THE NEWS was written by June Simms. Brianna Blake was our producer. I'm Faith Lapidus.
And I'm Bob Doughty. Join us again next week for more news about Science in Special English on the Voice of America.
"Sayansi katika Habari, katika VOA Special English.""" Mimi ni Faith Lapidus. Bob Doughty: Na mimi ni Bob Doughty. Wiki hii, tunazungumza juu ya kuvuta sigara - kisababishi kikuu cha kansa ulimwenguni. Rais Barack Obama amemaliza uchunguzi wake wa kwanza wa kawaida wa kimwili kama Rais wa Marekani wiki iliyopita. Madaktari wameripoti kwamba Bw Obama ana afya nzuri sana. Wanasema ushahidi wote unaonyesha kwamba ataendelea kuwa hivyo wakati wa urais wake. Madaktari walimpa rais mapendekezo ili aweze kubaki na afya. Jambo la kwanza ni kwamba aendelee kujitahidi kuacha kuvuta sigareti. Rais Obama amezungumza hadharani kuhusu juhudi hizo katika siku za nyuma. Ripoti hiyo mpya inaonyesha kwamba mapambano yake dhidi ya kuvuta sigareti yanaendelea. "Bobi Wine: ""Obama si mtu wa pekee" Zaidi ya watu bilioni moja ulimwenguni pote ni wavutaji sigareti. Wataalamu wa afya wamekuwa wakionya kuhusu uhusiano kati ya kuvuta sigara na magonjwa kwa miaka mingi. Inakadiriwa kwamba uvutaji sigareti huua watu milioni tano ulimwenguni pote kila mwaka. Wataalamu wanasema uvutaji sigareti ndio kisababishi kikuu cha vifo vinavyoweza kuepukwa. Ni sababu ya pili ya vifo baada ya kansa. Uvutaji sigareti pia ndio kisababishi kikuu cha kansa. Wataalamu wanasema asilimia 40 ya saratani zinaweza kuzuiwa kwa kuepuka hatari za kiafya kama vile kuvuta sigara na matumizi ya tumbaku. Uvutaji sigara pia husababisha asilimia 42 ya visa vya magonjwa ya mfumo wa kupumua, kutia ndani pumu, bronchitis na emphysema. Pia, husababisha asilimia kumi ya magonjwa ya moyo, kama vile magonjwa ya moyo na kiharusi. FAITH LAPIDUS: Jumuiya ya utafiti wa kitiba inaripoti daima sababu kwa nini wavutaji sigareti wapaswa kuacha. Utafiti wa hivi karibuni unaonyesha kuwa watu wanaovuta sigara wana uwezekano mkubwa mara mbili kuliko watu wasiovuta sigara wa kupatwa na ugonjwa wa Alzheimer. Alzheimer's huathiri uwezo wa kukumbuka na kufikiri. Katika utafiti huo, watafiti walichunguza masomo 43 yaliyochapishwa kuhusu uhusiano kati ya ugonjwa wa Alzheimer na uvutaji sigara. Utafiti huo ulionyesha kuwa kuvuta sigara kunaongeza hatari ya kuugua ugonjwa wa Alzheimer kwa asilimia 1.7. Watafiti hao wanafanya kazi katika Chuo Kikuu cha California huko San Francisco. Matokeo ya utafiti huo yamechapishwa katika jarida la Journal of Alzheimer's Disease. Katika utafiti wa awali, watu elfu saba walionwa kwa wastani wa miaka saba. Kila mtu alikuwa na umri wa miaka hamsini na mitano au zaidi. Kwa wale waliovuta sigara, uwezekano wa kupoteza kumbukumbu ulikuwa mkubwa kuliko wale ambao hawakuvuta sigara au walioacha. Utafiti mwingine umeunganisha uvutaji sigara na ugonjwa wa Amyotrophic Lateral Sclerosis. ALS ni ugonjwa wa kusababisha kifo unaoathiri misuli ya mwili na misuli ya mwili. Utafiti uliochapishwa mwaka jana katika jarida la Neurology uligundua kuwa uvutaji sigara ni moja ya sababu za kuambukizwa ugonjwa huo. Hata hivyo, kuna ushahidi unaoonyesha kwamba kuvuta sigara kunaweza kusababisha ugonjwa huo. Kuvuta sigareti pia huongeza hatari ya kupatwa na ugonjwa wa kuharibika kwa rangi ya macho unaosababishwa na uzee. AMD ni sababu kuu ya upofu kwa watu wazima wenye umri wa miaka 50 na zaidi. Utafiti unaonyesha kwamba ugonjwa wa AMD ni mara mbili au tatu ya kawaida zaidi kati ya wavutaji sigareti kuliko watu wengine. Utafiti wa hivi karibuni unachunguza jinsi kuvuta sigara inavyoathiri hatari ya mtu ya kupata ugonjwa wa AMD baadaye maishani. Watafiti wa Chuo Kikuu cha California huko Los Angeles walifanya utafiti juu ya wanawake 2,000 waliozaliwa na wanawake. Asilimia nne ya wanawake walikuwa wavutaji sigareti. Kila mwanamke alikuwa na picha za retina zake zilizochukuliwa akiwa na umri wa miaka sabini na minane. Watafiti walichunguza picha hizo na picha zilizochukuliwa miaka mitano baadaye, wakati wanawake hao walipokuwa na umri wa miaka 83. Watafiti hao walichunguza picha hizo ili kujua ikiwa kuna dalili za ugonjwa huo na kama kuvuta sigara kunaweza kuathiri uwezekano wa mwanamke huyo kuugua ugonjwa huo. Wanawake waliosema sigara walikuwa na kiwango cha juu cha 11 ya AMD kuliko wanawake wengine. Katika wanawake wenye umri wa miaka 80 na zaidi, wale waliovuta sigara walikuwa na uwezekano wa mara tano na nusu zaidi ya kuambukizwa ugonjwa wa AMD kuliko wanawake ambao hawakuvuta sigara. Ripoti kuhusu utafiti huo ilichapishwa katika American Journal of Ophthalmology. """Watu wanaovuta sigara hawajidhuru wenyewe tu." Pia zinaweza kuwaumiza watu wasio wavutaji sigareti. Shirika la Afya Ulimwenguni linakadiria kwamba moshi wa sigara unawaua watu elfu mia sita kila mwaka. Shirika la Kimataifa la Kupinga Saratani linasema kwamba watoto milioni 700 hivi hupumua hewa yenye moshi. Kwa mfano, wanawake wanaovuta sigara wana uwezekano mkubwa zaidi wa kuzaa watoto wenye matatizo ya afya na wenye uzito mdogo. Watoto hao wanaweza kupatwa na matatizo ya afya wanapoendelea kukua. "Wakati huo huo, ""Hata baada ya maonyo yote, WHO inasema watu bilioni moja na mia tatu bado wanavuta sigara.""" Idadi ya wavutaji sigara inatarajiwa kuongezeka hadi bilioni moja mia saba milioni kufikia mwaka wa ishirini na tano. Kiwango cha uvutaji sigareti kimepungua nchini Marekani na Ulaya. Lakini viwango vimeongezeka katika maeneo mengine. Kulingana na WHO, asilimia 84 ya wavutaji sigara wanaishi katika nchi zinazoendelea. Nchi za Magharibi mwa Bahari ya Pasifiki zina viwango vya juu zaidi vya uvutaji sigareti. Thuluthi moja ya wavutaji sigareti wote wanaishi Mashariki mwa Asia na Pasifiki. Eneo hilo lina idadi kubwa zaidi ya wanaume wanaovuta sigareti. Pia, ni nchi yenye idadi kubwa zaidi ya wanawake na watoto wanaovuta sigareti. Kila siku, magonjwa yanayohusiana na matumizi ya tumbaku huua watu zaidi ya elfu tatu katika eneo hilo. Wanasayansi wamegundua kemikali zaidi ya elfu nne katika moshi wa sigareti. Angalau mia mbili na hamsini kati ya hizo zinajulikana kuwa zenye kudhuru. Na, hamsini zimegunduliwa kusababisha kansa. Hizi zinatia ndani arseniki, ambayo yaweza kutumiwa kuua mimea na wanyama wadogo. Moshi wa sigareti pia una formaldehyde - umajimaji unaotumiwa kulinda sura ya maiti. Kwa kuwa ni kemikali mbaya sana, nikotini ndiyo hatari zaidi. Nikotini ni sumu inayopatikana katika tumbaku. Inawapa wavutaji sigareti furaha na kuwafanya warudi kwa ajili ya zaidi. Mwili huanza kutegemea nikotini. Uchunguzi umeonyesha kwamba ni vigumu kukabiliana na nikotini kama vile ni vigumu kukabiliana na kileo au dawa ya kulevya. Wataalamu wanasema nikotini yaweza kumuua mtu inapotumiwa kwa kiasi kikubwa. Inafanya hivyo kwa kuzuia misuli inayotumiwa kupumua. "Mfano: ""Minthol"" ni sigara ya kawaida, ambayo ni salama zaidi kuliko bidhaa nyingine za tumbaku." Sigareti zenye menthol hutokeza hisia ya baridi katika koo la mvutaji. Hii inaweza kusababisha watu kushikilia moshi katika mapafu yao kwa muda mrefu kuliko wavutaji wa bidhaa nyingine. Kwa sababu hiyo, wanasayansi wanashuku kwamba sigareti zenye menthol huenda zikawa hatari hata zaidi kuliko sigareti nyinginezo. Wavuvi fulani huamini kwamba sigareti zenye kiwango cha chini cha lami ni salama zaidi. Tar ni dutu inayotokezwa wakati majani ya tumbaku yanapochomwa. Inajulikana kusababisha kansa. Taasisi ya Kitaifa ya Saratani ya Marekani imesema kwamba watu wanaovuta sigareti zenye kiwango cha chini cha lami hawapungufu hatari yao ya kupatwa na magonjwa yanayohusiana na uvutaji sigareti. Je, kuna njia yoyote ya kuvuta sigareti bila kuharibu afya yako? Utafiti mwingi unaopatikana unaonyesha kwamba sivyo. Kuvuta sigareti chache tu kunaweza kuwa hatari. Lakini, madhara mengi ya kuvuta sigareti yanaweza kubadilishwa. Zinaweza kufutwa. Hiyo ndiyo sababu wataalamu wengi wa kitiba wanashauri watu waache kuvuta sigareti milele. Kulingana na Shirika la Kansa la Marekani, shinikizo la damu laweza kurudi kwa kawaida dakika 20 baada ya mtu kuvuta sigareti ya mwisho. Kiwango cha kaboni monoksidi katika damu hurudi kwa kawaida baada ya saa nane. Uwezekano wa kupatwa na mshtuko wa moyo hupungua baada ya siku moja. Baada ya mwaka mmoja, hatari ya kuugua ugonjwa wa moyo kwa mtu asiyevuta sigareti ni nusu ya ile ya mtu anayevuta sigareti. FAITH LAPIDUS: Kuna bidhaa nyingi zinazopatikana ili kuwasaidia watu kupunguza utegemezi wao kwa sigareti. Bidhaa za kuchukua nafasi ya nikotini hutoa kiasi kidogo cha kemikali hiyo kwa njia nyingine mbali na sigareti. Kiasi cha nikotini hupungua polepole kadiri wakati unavyopita. Chantix na Zyban ni dawa mbili za dawa ambazo pia zimeonyeshwa kusaidia wavutaji sigareti kuacha kuvuta sigareti. Hazina nikotini. Chantix hufanya kazi kwenye vipokezi vya nikotini katika ubongo ili kupunguza hamu ya kuvuta sigareti. Zyban hufanya kazi kwa kuongeza viwango vya dopamine katika ubongo. Dopamine ni kemikali inayotokeza furaha. "Bonnie: ""Watu ambao wameacha kuvuta sigara wanatoa ushauri huu wenye manufaa kwa wale wanaotaka kuacha." Epuka kunywa kileo. Nenda kutembea badala ya kuvuta sigareti. Na, waepuke watu wanaovuta sigareti. Ikiwa inawezekana, epuka hali zinazokusumbua. Si rahisi kuacha kuvuta sigareti. Na, watu hawawezi kamwe kudhibiti kabisa afya yao wenyewe. Lakini kama daktari mmoja anavyoshauri wagonjwa wake, kuwa mtu asiyevuta sigareti ni njia moja ya kudhibiti maisha yako. SCIENCE IN THE NEWS hii iliandikwa na June Simms. Brianna Blake alikuwa mtayarishaji wetu. Mimi ni Faith Lapidus. Na mimi ni Bob Doughty. Kujiunga na sisi tena wiki ijayo kwa habari zaidi kuhusu Sayansi katika Kiingereza maalum juu ya Sauti ya Amerika.