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Chronic fatigue syndrome: going viral?
Editorial
Corbis
Chronic fatigue syndrome: going viral?
For more on the research linking viral infection with CFS see Arch Pediatr Adolesc Med 2010; 164: 817–23; Science 2009; 326: 585–89; and Proc Natl Acad Sci USA 2010; 107: 15874–79. For more on the studies that failed to replicate the finding in Science see BMJ 2010; 340: c1018; Retrovirology 2010; 7: 57; and PLoS ONE 5: e8519.
The controversy surrounding the possible causes of chronic fatigue syndrome (CFS) resurfaced this month, after results published in the Archives of Paediatrics and Adolescent Medicine showed that children with the disease had higher levels of oxidative stress and white blood cell apoptosis than controls—findings suggesting that the children with CFS are fighting a viral infection. The theory that CFS may be viral in origin first came to prominence in October, 2009, when a study in Science showed that 68 (67%) of 101 patients with CFS who were tested were infected with the murine leukaemia virus XMRV, compared with eight (3·7%) of 218 controls. A string of negative results followed, with several groups unable to detect any trace of XMRV in patients with CFS. But a study published recently in Proceedings of the National Academy of Sciences reported a strong association between CFS and a murine virus very similar to XMRV. However, it is impossible to say at this stage whether these murine leukaemia viruses cause CFS, or whether they are bystander infections.
It is already established that many cases of CFS are preceded by an acute viral infection. Studies in cohorts of patients with infectious mononucleosis caused by Epstein–Barr virus (EBV) show that a small proportion do not recover from post-infection fatigue, and subsequently go on to develop CFS. But it seems unlikely that CFS is a consequence of EBV, because most people make a full recovery. There is a general consensus that CFS is a heterogeneous family of disorders, and it seems most likely that these disorders arise from a constellation of pathophysiological causes. The results in the Archives of Paediatrics and Adolescent Medicine received great media attention. But they do not prove that CFS is a physical disease. CFS is still far from being a well-defined entity. When the totality of available evidence is considered, the uncertainty around our understanding of the physical–psychological interaction taking place in patients with CFS only strengthens the case for giving research into chronic fatigue the high priority it deserves. ■ The Lancet
Science Photo Library
Tobacco use in the USA
For more on smoking prevalence in the USA see http://www.cdc.gov/mmwr/ preview/mmwrhtml/ mm5935a3.htm?s_ cid=mm5935a3_w For more on second-hand smoke exposure prevalence in the USA see http://www.cdc. gov/mmwr/preview/ mmwrhtml/mm5935a4.htm?s_ cid=mm5935a4_w
930
Smoking is the number one cause of preventable morbidity and mortality in the USA. An estimated 446 000 Americans die each year from smokingrelated diseases, which cost the US health-care system US$193 billion. Last week, the Centers for Disease Control Morbidity and Mortality Weekly Report (MMWR) regrettably confirmed that smoking prevalence in the USA has stalled since 2005. 46 million Americans (one in five adults) use tobacco. Smokers are more likely to be male, poor, high school dropouts, and to live in the south and midwest. A related piece in MMWR reports that 40% of nonsmoking Americans (88 million people) are exposed to second-hand smoke, and that 98% of children aged between 3 and 11 years who live with a smoking parent have detectable tobacco toxins in their body. Second-hand smoke not only harms children’s health, but means those children are twice as likely to become smokers themselves. Who is to blame for this alarming lack of decline in tobacco use? The tobacco industry is known for its
continuous efforts to bypass strict tobacco advertisement regulations by creating new products that appeal specifically to young smokers. Local governments are also responsible for neglecting the tobacco problem. Currently, $25 billion from cigarette taxes is available to states, but only $700 million (3%) is being spent on smoking prevention and cessation programmes. California is one of the few exceptions—its aggressive statewide antismoking campaign reduced smoking prevalence by 40% between 1998 and 2006 (now at a national low of 13%), while the state’s lung cancer rate fell four times faster than the national average. The USA’s static smoking prevalence should be a wake-up call for federal, state, and local lawmakers to do more. Comprehensive state anti-smoking campaigns need to be enforced and nationwide smoke-free legislation (currently covering only 47% of Americans) must be implemented. Parents and patients must be re-educated on the dangers of tobacco use and exposure to second-hand smoke. Americans need a reminder that tobacco is harmful. ■ The Lancet www.thelancet.com Vol 376 September 18, 2010
Corbis
Chronic fatigue syndrome: going viral?
For more on the research linking viral infection with CFS see Arch Pediatr Adolesc Med 2010; 164: 817–23; Science 2009; 326: 585–89; and Proc Natl Acad Sci USA 2010; 107: 15874–79. For more on the studies that failed to replicate the finding in Science see BMJ 2010; 340: c1018; Retrovirology 2010; 7: 57; and PLoS ONE 5: e8519.
The controversy surrounding the possible causes of chronic fatigue syndrome (CFS) resurfaced this month, after results published in the Archives of Paediatrics and Adolescent Medicine showed that children with the disease had higher levels of oxidative stress and white blood cell apoptosis than controls—findings suggesting that the children with CFS are fighting a viral infection. The theory that CFS may be viral in origin first came to prominence in October, 2009, when a study in Science showed that 68 (67%) of 101 patients with CFS who were tested were infected with the murine leukaemia virus XMRV, compared with eight (3·7%) of 218 controls. A string of negative results followed, with several groups unable to detect any trace of XMRV in patients with CFS. But a study published recently in Proceedings of the National Academy of Sciences reported a strong association between CFS and a murine virus very similar to XMRV. However, it is impossible to say at this stage whether these murine leukaemia viruses cause CFS, or whether they are bystander infections.
It is already established that many cases of CFS are preceded by an acute viral infection. Studies in cohorts of patients with infectious mononucleosis caused by Epstein–Barr virus (EBV) show that a small proportion do not recover from post-infection fatigue, and subsequently go on to develop CFS. But it seems unlikely that CFS is a consequence of EBV, because most people make a full recovery. There is a general consensus that CFS is a heterogeneous family of disorders, and it seems most likely that these disorders arise from a constellation of pathophysiological causes. The results in the Archives of Paediatrics and Adolescent Medicine received great media attention. But they do not prove that CFS is a physical disease. CFS is still far from being a well-defined entity. When the totality of available evidence is considered, the uncertainty around our understanding of the physical–psychological interaction taking place in patients with CFS only strengthens the case for giving research into chronic fatigue the high priority it deserves. ■ The Lancet
Science Photo Library
Tobacco use in the USA
For more on smoking prevalence in the USA see http://www.cdc.gov/mmwr/ preview/mmwrhtml/ mm5935a3.htm?s_ cid=mm5935a3_w For more on second-hand smoke exposure prevalence in the USA see http://www.cdc. gov/mmwr/preview/ mmwrhtml/mm5935a4.htm?s_ cid=mm5935a4_w
930
Smoking is the number one cause of preventable morbidity and mortality in the USA. An estimated 446 000 Americans die each year from smokingrelated diseases, which cost the US health-care system US$193 billion. Last week, the Centers for Disease Control Morbidity and Mortality Weekly Report (MMWR) regrettably confirmed that smoking prevalence in the USA has stalled since 2005. 46 million Americans (one in five adults) use tobacco. Smokers are more likely to be male, poor, high school dropouts, and to live in the south and midwest. A related piece in MMWR reports that 40% of nonsmoking Americans (88 million people) are exposed to second-hand smoke, and that 98% of children aged between 3 and 11 years who live with a smoking parent have detectable tobacco toxins in their body. Second-hand smoke not only harms children’s health, but means those children are twice as likely to become smokers themselves. Who is to blame for this alarming lack of decline in tobacco use? The tobacco industry is known for its
continuous efforts to bypass strict tobacco advertisement regulations by creating new products that appeal specifically to young smokers. Local governments are also responsible for neglecting the tobacco problem. Currently, $25 billion from cigarette taxes is available to states, but only $700 million (3%) is being spent on smoking prevention and cessation programmes. California is one of the few exceptions—its aggressive statewide antismoking campaign reduced smoking prevalence by 40% between 1998 and 2006 (now at a national low of 13%), while the state’s lung cancer rate fell four times faster than the national average. The USA’s static smoking prevalence should be a wake-up call for federal, state, and local lawmakers to do more. Comprehensive state anti-smoking campaigns need to be enforced and nationwide smoke-free legislation (currently covering only 47% of Americans) must be implemented. Parents and patients must be re-educated on the dangers of tobacco use and exposure to second-hand smoke. Americans need a reminder that tobacco is harmful. ■ The Lancet www.thelancet.com Vol 376 September 18, 2010