Day: 09/22/2012

The TB/HIV Syndemic.

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Since Robert Koch’s 1882 discovery of Mycobacterium tuberculosis, substantial progress has been made in tuberculosis (TB) control. Nevertheless, in the latter part of the 20th century, a long period of neglect of both quality program implementation and research led to persistently high TB incidence rates and failure to develop new tools to adequately address the problem. Today, most of the world continues to rely on the same diagnostic test invented by Koch approximately125 years ago and on drugs developed 40 years ago. The world now faces a situation in which approximately 160 persons die of TB each hour (1.45 million died in 2009), in which a quarter of all deaths in persons with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) (PWHA) are caused by TB, and in which the evolution of the bacteria has outpaced the evolution of its treatment to such an extent that some forms of TB are now untreatable (1). More recently, renewed attention has been given to reducing the global burden of TB ,but much remains to be done.

Misconceptions Regarding TB

Misconceptions about TB infection and disease impede patient care, program implementation, and policy innovation. The first misconception is that TB infection and TB disease are the same. For TB disease prevention and control purposes, the global population can be divided into three discrete groups: those without TB infection, those with TB infection, and those whose TB infection has developed into TB disease. The lifetime risk that a person with TB infection will develop TB disease is 5%–10%; that risk is much higher among PWHA (3,4). A successful control strategy must, therefore, address each group.

A second misconception about TB is that it is no longer a major public health problem. In fact, of the 7 billion persons in the world, 2.3 billion are already infected with TB, and about 9 million develop TB disease each year. Furthermore, TB causes about 1.4–2 million deaths annually .

A third misconception is that TB can be diagnosed easily by a physician or laboratory. To diagnose TB infection, only two tests are validated currently: the tuberculin skin test (TST) and the interferon gamma blood test. Unfortunately, TST is neither sensitive nor specific for TB infection, and both tests can be difficult to implement in resource-limited settings. To diagnose TB disease, most laboratories examine sputum with a microscope to look for TB bacilli, the same approach that Koch invented. In PWHA, the sensitivity of microscopic examination is low, approximately 40% (5–7). Given the high risk for death in PWHA who have untreated TB, this low sensitivity is a critical challenge that must be addressed. Culture of sputum for M. tuberculosis is considered the gold standard test, but it is difficult to use and, in resource-limited settings, challenging to implement. Culturing M. tuberculosis, a slow-growing airborne pathogen, requires laboratories that employ high levels of biosafety and specialized technicians. In 2010, the Xpert MTB/Rif assay, a sensitive, easy-to-use, polymerase chain reaction (PCR)–based test was validated. With no need for sophisticated biosafety or specialized technicians and a turn-around time of 2 hours for both TB diagnosis and detection of drug resistance, this assay has the potential to improve TB control in the developing world (8). Limiting its current use is the relatively high cost of the necessary equipment and supplies, a lack of evidence that the assay’s use is feasible in routine practice, and the fact that it has not yet been demonstrated to improve patient outcomes in resource-limited settings.

TB/HIV Syndemic*

TB and HIV act synergistically within a population to cause excess morbidity and mortality. PWHA are more likely to develop TB disease because of their immunodeficiency; HIV infection is the most powerful risk factor for progressing from TB infection to disease (4). Diagnosing TB disease among PWHA is particularly challenging because PWHA who have pulmonary TB frequently have negative sputum smears and up to one third might have completely normal chest radiographs (5). Furthermore, TB in PWHA often occurs outside the lungs, evading traditional diagnostic tests. Because TB is both common and difficult to diagnose, many PWHA feel ill but are unaware that they have TB. A recent review found that when systematic efforts were undertaken to diagnose TB, approximately 8% of patients who went to HIV care and treatment facilities were found to have TB disease (9), although the exact proportion varies substantially depending on the epidemiology of TB in the area. Finally, TB is a frequent cause of death for PWHA, particularly if HIV disease is advanced and antiretroviral therapy (ART) has not yet been initiated. Persons with both diseases must adhere to complex drug regimens that might interact with each other and might have overlapping toxicities.

Combating the Dual Burden of Disease

TB disease and death can be prevented in PWHA by early TB diagnosis and effective treatment of both diseases. Early diagnosis and treatment ensure that TB treatment is provided before the illness reaches an advanced stage, thereby decreasing mortality, and ensures that the duration of infectiousness is limited, thereby reducing transmission of TB to others. TB disease also can be prevented by treating persons with TB infection. Treatment of TB infection requires reliably excluding the presence of TB disease to avoid the development of drug resistance; drug resistance could emerge if a patient receives a single drug to treat TB infection when the patient, in fact, requires a multidrug regimen to treat TB disease.

Until recently, no internationally accepted, evidence-based, sensitive approach existed to screen PWHA for TB disease, although some preliminary data had begun to suggest that commonly used approaches were inadequate. CDC investigators partnered with the U.S. Agency for International Development (USAID), ministries of health, and nongovernmental organizations in three Southeast Asian countries to derive a TB screening algorithm that would solve this problem. This study concluded that asking patients about three symptoms (i.e., cough, fever of any duration, or night sweats lasting longer than 3 weeks) accurately categorized PWHA for targeted interventions. Patients with none of these three symptoms can be considered free of TB disease and offered treatment to prevent TB disease, if indicated; patients with at least one of these symptoms should have further diagnostic tests performed for TB disease (5,6) These criteria mark a significant improvement over the 2007 World Health Organization (WHO) guidelines in which screening was based primarily on the presence of chronic cough (10). Screening for cough lasting more than 2 weeks was only 33% sensitive for TB disease in this study; screening for the combination of symptoms increased sensitivity to 93% .The increased sensitivity under the new criteria will lead to fewer missed diagnoses of TB disease, at the cost of requiring TB diagnostic evaluation for more people.

Although this approach simplifies TB screening, a comparable approach for simplifying diagnosis of TB disease remains elusive. In the same study, investigators learned that adding liquid culture of two sputum specimens more than doubled the yield of TB case detection among PWHA, compared with microscopic examination alone of the same two sputum specimens, as recommended by WHO at the time (76% versus 31% sensitivity) (6). Unfortunately, liquid culture is not widely available in resource-poor settings and requires high levels of training, biosafety, and supervision. It is hoped that introduction of the Xpert MTB/Rif assay, which is more sensitive than smear but less sensitive than liquid culture, along with other emerging diagnostic techniques, will improve diagnostic accuracy in PWHA who have symptoms of TB (8).

In persons who screen negative for TB disease, treatment of TB infection should be considered. The tuberculin skin test (TST) identifies persons with TB infection who can benefit from isoniazid preventive therapy (IPT), a regimen that involves ingesting isoniazid daily for at least 6 months. In the pre-ART era, clinical trials confirmed that IPT was effective in reducing the development of TB disease in TST-positive PWHA by 64% (11). Subsequently, in 1998, WHO recommended that all PWHA living in TB-endemic countries receive 6 months of IPT, and that TST screening generally was not needed in countries with a high burden of TB. Follow-up studies found that the benefit of IPT waned as early as 6 months after completion of IPT. In 2009, only 0.3% of PWHA globally received IPT (1). ART also can reduce the risk for TB disease in PWHA by 54%–92% and might have a synergistic effect when used with IPT (12). In collaboration with the Botswana Ministry of Health, and with funding from CDC and USAID, CDC conducted a clinical trial in Botswana to evaluate how much better TB could be prevented with a 36-month regimen of IPT in PWHA who had access to government-provided ART. This study found that among those with positive TSTs, 36 months of IPT reduced TB incidence by 74%, compared with persons receiving only 6 months IPT. When the analysis was limited to TST-positive trial participants randomized to the 36-month IPT arm who successfully completed the initial 6 months of IPT, the reduction in TB was 92%. As with previous studies, no significant benefit from IPT was observed for TST-negative participants. ART provided an added benefit to IPT’s protective effect, reducing TB risk a further 50% in all groups (13).

These findings have enormous implications for controlling the TB epidemic in countries with a high burden of HIV. If 36 months of IPT were provided to all TST-positive PWHA in Botswana, countrywide TB incidence would decline 45%†. A cost-effectiveness model of 10,000 PWHA in Botswana demonstrated that providing 36 months of IPT for PWHA with a positive TST result, in addition to ART for those with CD4 <250 cells/µL, could avert more incident TB cases with fewer resources than increasing the threshold for ART initiation alone (CD4 <350 or 500), suggesting any cost-effective TB prevention strategy should include the provision of IPT for TST-positive PWHA.

From Evidence to Guidance to Global TB Control

The strong evidence provided by the studies described above has been combined with results from other studies to update the global guidelines for TB screening and prevention (14). A recent WHO publication outlines four updated recommendations for resource-constrained settings: 1) PWHA should be screened with the new symptom-based algorithm, and those who do not report current cough, fever, weight loss, or night sweats are unlikely to have active TB and should be offered IPT (a minor modification to the algorithm developed in the CDC Southeast Asia study); 2) PWHA who report any of the aforementioned symptoms are considered suspects for TB disease and should be evaluated further for TB and other diseases as clinically indicated; 3) PWHA who are TST positive or have unknown TST status and are unlikely to have TB disease based on symptom screening should receive IPT for at least 6 months; and 4) in settings where feasible, PWHA should receive IPT for at least 36 months, or even lifelong. Where feasible, TST should be used to help identify those who would benefit most from IPT (15).

TB control relies on an international strategy known as “DOTS” (directly observed treatment, short course) that includes finding as many highly infectious patients with TB as possible, initiating effective treatment, directly observing drug ingestion to ensure adherence, and standardized monitoring, evaluation, and reporting. DOTS has saved approximately 7 million lives globally since 1990 (1). In the United States, the experience in New York City provides an example of the progress that can be made through full implementation of the DOTS strategy (16). However, although TB prevalence and deaths around the world did fall in the period after widespread global DOTS implementation, treatment programs generally have not resulted in a rapid reduction in global TB incidence (17). Multiple factors explain this phenomenon: insufficient resources and commitment to implement DOTS, in part because TB occurs predominantly in the poorest populations; a focus entirely on treatment of TB disease but not TB infection; the HIV epidemic; the emergence of multidrug resistant TB strains; and limited attention to the social determinants of sustained TB transmission and reactivation. Modeling studies suggest that detecting more infectious TB cases and successfully treating them will, on its own, be insufficient to drive down TB incidence and prevalence quickly and that the global TB strategy must address the large burden of latent TB infection that exists globally (18). The simplified symptom-based screening approach derived in the Southeast Asian study and the effective approach to chemoprophylaxis documented in the Botswana clinical trial help address this need.

The Way Forward

In a 2010 “call to action,” global leaders in TB control outlined crucial areas that must be addressed to accelerate the decline in global TB incidence to more than 1% per year and to meet the target for the 2015 Millennium Development Goal. Achieving this will require fully implementing the DOTS strategy globally, and it will also require going far beyond that to address the limited impact that would be expected with DOTS alone, as outlined in WHO’s latest STOP TB strategy (20). WHO calls for improvements in TB screening and diagnosis, including the use of newer TB diagnostic assays. In addition to these steps, treatment of latent TB infection also is needed (18). In settings with a high prevalence of HIV infection, implementing IPT can reduce TB incidence greatly. Finally, scientific advances are needed in three key areas to develop 1) an effective TB vaccine; 2) a shorter, simpler anti-TB drug regimen with efficacy against both drug-susceptible and drug-resistant TB; and 3) new diagnostic tests that can simply and accurately diagnose both TB infection and disease (21).

The fundamentals of TB control are early and accurate TB diagnosis, effective treatment, and prevention. The gap between what we know and what we need to know is large, but the gap between what we know and what we are implementing in practice is both larger and more harmful. By closing both our knowledge gap and our implementation gap, we can eliminate this deadly syndemic.

Source: CDC

Cervical Cancer Screening.

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Cervical cancer is the easiest female cancer to prevent, with regular screening tests and follow-up. Two screening tests can help prevent cervical cancer or find it early—

  • The Pap test (or Pap smear) looks for precancers, cell changes on the cervix that might become cervical cancer if they are not treated appropriately.
  • The HPV test looks for the virus (human papillomavirus) that can cause these cell changes.

The Pap test is recommended for all women, and can be done in a doctor’s office or clinic. During the Pap test, the doctor will use a plastic or metal instrument, called a speculum, to widen your vagina. This helps the doctor examine the vagina and the cervix, and collect a few cells and mucus from the cervix and the area around it. The cells are then placed on a slide or in a bottle of liquid and sent to a laboratory. The laboratory will check to be sure that the cells are normal.

If you are getting the HPV test in addition to the Pap test, the cells collected during the Pap test will be tested for HPV at the laboratory. Talk with your doctor, nurse, or other health care professional about whether the HPV test is right for you.

When you have a Pap test, the doctor may also perform a pelvic exam, checking your uterus, ovaries, and other organs to make sure there are no problems. There are times when your doctor may perform a pelvic exam without giving you a Pap test. Ask your doctor which tests you are having, if you are unsure.

If you have a low income or do not have health insurance, you may be able to get a free or low-cost Pap test through the National Breast and Cervical Cancer Early Detection Program. Find out if you qualify.

When to Get Screened

You should start getting regular Pap tests at age 21. The Pap test, which screens for cervical cancer, is one of the most reliable and effective cancer screening tests available.

The only cancer for which the Pap test screens is cervical cancer. It does not screen for ovarian, uterine, vaginal, or vulvar cancers. So even if you have a Pap test regularly, if you notice any signs or symptoms that are unusual for you, see a doctor to find out why you’re having them. If your Pap test results are normal, your doctor may tell you that you can wait three years until your next Pap test.

If you are aged 30 years or older, you may choose to have an HPV test along with the Pap test. Both tests can be performed by your doctor at the same time. When both tests are performed together, it is called co-testing. If your test results are normal, your chance of getting cervical cancer in the next few years is very low. Your doctor may then tell you that you can wait as long as five years for your next screening. But you should still go to the doctor regularly for a checkup.

If you are 21–65 years old, it is important for you to continue getting a Pap test as directed by your doctor—even if you think you are too old to have a child or are not having sex anymore. However, if you are older than 65 and have had normal Pap test results for several years, or if you have had your cervix removed as part of a total hysterectomy for non-cancerous conditions, like fibroids, your doctor may tell you that you do not need to have a Pap test anymore.

For more information, please read the U.S. Preventive Services Task Force overview of cervical cancer screening recommendations.

How to Prepare for Your Pap Test

You should not schedule your Pap test for a time when you are having your period. If you are going to have a Pap test in the next two days—

  • You should not douche (rinse the vagina with water or another fluid).
  • You should not use a tampon.
  • You should not have sex.
  • You should not use a birth control foam, cream, or jelly.
  • You should not use a medicine or cream in your vagina.

Pap Test Results

It can take up to three weeks to receive your Pap test results. If your test shows that something might not be normal, your doctor will contact you and figure out how best to follow up. There are many reasons why Pap test results might not be normal. It usually does not mean you have cancer.

If your Pap test results show cells that are not normal and may become cancer, your doctor will let you know if you need to be treated. In most cases, treatment prevents cervical cancer from developing. It is important to follow up with your doctor right away to learn more about your test results and receive any treatment that may be needed.

Source: CDC.

 

 

Can it! Soda studies cite stronger link to obesity.

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As Americans debate what is most to blame for the nation’s obesity epidemic, researchers say they have the strongest evidence yet that sugary drinks play a leading role and that eliminating them would, more than any other single step, make a huge difference.

Three studies published Friday in the New England Journal of Medicine represent the most rigorous effort yet to see if there is a link between sugar-sweetened beverages and expanding U.S. waistlines.

“I know of no other category of food whose elimination can produce weight loss in such a short period of time,” said Dr. David Ludwig, director of the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital, who led one of the studies. “The most effective single target for an intervention aimed at reducing obesity is sugary beverages.”

Previous research on the subject has been mixed, and beverage makers fiercely contest the idea that a single source of daily calories can bear so much responsibility.

“We know, and science supports, that obesity is not uniquely caused by any single food or beverage,” said the American Beverage Association (ABA) in a statement. “Studies and opinion pieces that focus solely on sugar-sweetened beverages, or any other single source of calories, do nothing meaningful to help address this serious issue.”

The NEJM studies, as well as an editorial and opinion pieces on the topic of sugary drinks and obesity, land as concern about obesity and its impact on public health is rising.

A report released this week projected that at least 44 percent of U.S. adults could be obese by 2030, compared to 35.7 percent today, bringing an extra $66 billion a year in obesity-related medical costs.

Last week, New York City adopted a regulation banning the sale of sugary drinks in containers larger than 16 ounces at restaurants and other outlets regulated by the city health department.

Sugary drinks are in the crosshairs because from 1977 to 2002 the number of calories Americans consumed from them doubled, government data show, making them the largest single source of calories in the diet. Adult obesity rates, 15 percent in the late 1970s, more than doubled in that period. The ABA points out, however, that consumption has since fallen, yet obesity rates keep rising.

Although most observational studies find that people who drink sugary beverages are more likely to be obese than people who do not, no cause-and-effect has been proved. People who drink sugary beverages, especially children, also watch more TV and eat more calorie-dense fast food, raising the possibility that liquid sugar is not the main culprit.

A 2008 analysis of 12 studies, led by a scientist who went on to work for the ABA, concluded that the association between sugary drinks and body-mass index (BMI) “was near zero.”

Studies in which children cut their intake of sugary drinks found modest benefits, but “they were considered unconvincing,” said Martijn Katan of VU University in Amsterdam: “Most had a small number of subjects and followed them for only a short time.” He and his colleagues aimed to do better.

BUILDING A BETTER STUDY

For DRINK (Double-Blind Randomized Intervention in Kids), they gave 641 children aged about 5 to 12 and with a healthy BMI of just under 17 one 8-ounce (250 milliliter) noncarbonated drink per day, sweetened artificially or with sugar. The sugar-free drinks were specially formulated to look and taste like sugary ones so the kids would not know which they had.

About a quarter of the kids stopped drinking the beverages. Among those who stuck it out for 18 months, the sugar-free kids gained less body fat, 2.2 pounds (1 kilogram) less weight, and 0.36 units less BMI than the sugary-drink kids, the researchers report in the NEJM.

Why? There is good evidence that liquid sugar does not produce a feeling of fullness that other calories do. “When children substituted a sugar-free drink, their bodies did not sense the absence of calories, and they did not replace them with other food or drinks,” said Katan.

DRINK doesn’t answer whether switching to zero-calorie drinks would help obese kids. But another study in the same issue of NEJM suggests it might.

Researchers at Boston Children’s had zero-calorie drinks delivered to 110 obese 15-year-olds who had BMIs of about 30 (where obesity starts), counseled them not to drink sugary beverages and offered other support.

After a year the teens had cut their intake of sugary drinks from almost two a day to zero and their daily calorie intake by 454. They had gained an average of 3.5 pounds (1.6 kilograms). By comparison, 114 teens who continued to consume sugar-sweetened beverages gained 7.7 pounds (3.5 kg) on average and ten times the BMI units: 0.63 compared to 0.06.

Once the deliveries stopped the two groups diverged less. After two years, teens who had received the no-cal drink deliveries had gained 9.5 pounds (4.3 kg) and 0.71 unit of BMI, compared to the control group’s 11.2 pounds (5.5 kg) and 1.0 unit of BMI.

“It isn’t surprising that after the intervention stopped, old behaviors crept back,” said Ludwig of the New Balance Center. An “obesogenic” environment that promotes calorie-laden foods “overwhelms individuals’ ability to maintain behavioral change” such as avoiding sugary drinks.

Hispanic teens benefited the most: Those receiving no-cal deliveries gained 14 fewer pounds after one year and almost 20 fewer pounds after two. That raised the possibility that genetic factors influence the effect of sugary drinks.

To investigate gene-environment-obesity links, scientists at Harvard School of Public Health looked at 33,097 people from long-term ongoing health studies, such as the Nurses’ Health Study, identifying how many sugary drinks they consume and whether they have any of 32 genes linked to obesity.

The effect of genes on the likelihood of becoming obese was twice as large among people who drank one or more sugary drinks per day as among those who had less than one a month, the scientists report in the NEJM. In other words, belting back soda and sugary tea may turbocharge the genetic risk of obesity.

Conversely, eating a healthy diet devoid of sugary drinks keeps fat genes inactive. People with “fat genes” can be thinner if they avoid sugary drinks and other high-calorie foods.

Source: yahoo news.

 

Studies more firmly tie sugary drinks to obesity.

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New research powerfully strengthens the case against soda and other sugary drinks as culprits in the obesity epidemic.

A huge, decades-long study involving more than 33,000 Americans has yielded the first clear proof that drinking sugary beverages interacts with genes that affect weight, amplifying a person’s risk of obesity beyond what it would be from heredity alone.

This means that such drinks are especially harmful to people with genes that predispose them to weight gain. And most of us have at least some of these genes.

In addition, two other major experiments have found that giving children and teens calorie-free alternatives to the sugary drinks they usually consume leads to less weight gain.

Collectively, the results strongly suggest that sugary drinks cause people to pack on the pounds, independent of other unhealthy behavior such as overeating and getting too little exercise, scientists say.

That adds weight to the push for taxes, portion limits like the one just adopted in New York City, and other policies to curb consumption of soda, juice drinks and sports beverages sweetened with sugar.

Soda lovers do get some good news: Sugar-free drinks did not raise the risk of obesity in these studies.

“You may be able to fool the taste” and satisfy a sweet tooth without paying a price in weight, said an obesity researcher with no role in the studies, Rudy Leibel of Columbia University.

The studies were being presented Friday at an obesity conference in San Antonio and were published online by the New England Journal of Medicine.

The gene research in particular fills a major gap in what we know about obesity. It was a huge undertaking, involving three long-running studies that separately and collectively reached the same conclusions. It shows how behavior combines with heredity to affect how fat we become.

Having many of these genes does not guarantee people will become obese, but if they drink a lot of sugary beverages, “they fulfill that fate,” said an expert with no role in the research, Jules Hirsch of Rockefeller University in New York. “The sweet drinking and the fatness are going together, and it’s more evident in the genetic predisposition people.”

Sugary drinks are the single biggest source of calories in the American diet, and they are increasingly blamed for the fact that a third of U.S. children and teens and more than two-thirds of adults are obese or overweight.

Consumption of sugary drinks and obesity rates have risen in tandem — both have more than doubled since the 1970s in the U.S.

But that doesn’t prove that these drinks cause obesity. Genes, inactivity and eating fatty foods or just too much food also play a role. Also, diet research on children is especially tough because kids are growing and naturally gaining weight.

Until now, high-quality experiments have not conclusively shown that reducing sugary beverages would lower weight or body fat, said David Allison, a biostatistician who has done beverage research at the University of Alabama at Birmingham, some of it with industry support.

He said the new studies on children changed his mind and convinced him that limiting sweet drinks can make a difference.

In one study, researchers randomly assigned 224 overweight or obese high schoolers in the Boston area to receive shipments every two weeks of either the sugary drinks they usually consumed or sugar-free alternatives, including bottled water. No efforts were made to change the youngsters’ exercise habits or give nutrition advice, and the kids knew what type of beverages they were getting.

After one year, the sugar-free group weighed more than 4 pounds less on average than those who kept drinking sugary beverages.

“I know of no other single food product whose elimination can produce this degree of weight change,” said the study’s leader, Dr. David Ludwig of Boston Children’s Hospital and the Harvard School of Public Health.

The weight difference between the two groups narrowed to 2 pounds in the second year of the study, when drinks were no longer being provided. That showed at least some lasting beneficial effect on kids’ habits. The study was funded mostly by government grants.

A second study involved 641 normal-weight children ages 4 to 12 in the Netherlands who regularly drank sugar-sweetened beverages. They were randomly assigned to get either a sugary drink or a sugar-free one during morning break at their schools, and were not told what kind they were given.

After 18 months, the sugary-drink group weighed 2 pounds more on average than the other group.

The studies “provide strong impetus” for policies urged by the Institute of Medicine, the American Heart Association and others to limit sugary drink consumption, Dr. Sonia Caprino of the Yale School of Medicine wrote in an editorial in the journal.

The American Beverage Association disagreed.

“Obesity is not uniquely caused by any single food or beverage,” it said in a statement. “Studies and opinion pieces that focus solely on sugar-sweetened beverages, or any other single source of calories, do nothing meaningful to help address this serious issue.”

The genetic research was part of a much larger set of health studies that have gone on for decades across the U.S., led by the Harvard School of Public Health.

Researchers checked for 32 gene variants that have previously been tied to weight. Because we inherit two copies of each gene, everyone has 64 opportunities for these risk genes. The study participants had 29 on average.

Every four years, these people answered detailed surveys about their eating and drinking habits as well as things like smoking and exercise. Researchers analyzed these over several decades.

A clear pattern emerged: The more sugary drinks someone consumed, the greater the impact of the genes on the person’s weight and risk of becoming obese.

For every 10 risk genes someone had, the risk of obesity rose in proportion to how many sweet drinks the person regularly consumed. Overall calorie intake and lifestyle factors such as exercise did not account for the differences researchers saw.

This means that people with genes that predispose them to be obese are more susceptible to the harmful effects of sugary drinks on their weight, said one of the study leaders, Harvard’s Dr. Frank Hu. The opposite also was true — avoiding these drinks can minimize the effect of obesity genes.

“Two bad things can act together and their combined effects are even greater than either effect alone,” Hu said. “The flip side of this is everyone has some genetic risk of obesity, but the genetic effects can be offset by healthier beverage choices. It’s certainly not our destiny” to be fat, even if we carry genes that raise this risk.

The study was funded mostly by federal grants, with support from two drug companies for the genetic analysis.

Source: Yahoo news.

The World Biggest Air Plane.

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The biggest Air Plane in the world is “Antonov An-225 Mriya”. This biggest operating aircraft is belongs to Ukraine and designed to airlift the Energia rocket’s boosters and the Buran space shuttle for the Soviet space program. This Plane can carry 250 tons of cargo in one way trip. The Maximum speed of this Aircraft is 850 km/h.

Source: http://www.mostbeautifulpages.com