Overweight, Obesity, and Mortality in a Large Prospective Cohort of Persons 50 to 71 Years Old
By Kenneth F. Adams et al.
Background: Obesity, defined by a body-mass index (BMI) (the weight in kilograms divided by the square of the height in meters) of 30.0 or more, is associated with an increased risk of death, but the relation between overweight (a BMI of 25.0 to 29.9) and the risk of death has been questioned.
Methods: We prospectively examined BMI in relation to the risk of death from any cause in 527,265 U.S. men and women in the National Institutes of Health-AARP cohort who were 50 to 71 years old at enrollment in 1995-1996. BMI was calculated from self-reported weight and height. Relative risks and 95 percent confidence intervals were adjusted for age, race or ethnic group, level of education, smoking status, physical activity, and alcohol intake. We also conducted alternative analyses to address potential biases related to preexisting chronic disease and smoking status.
Results: During a maximum follow-up of 10 years through 2005, 61,317 participants (42,173 men and 19,144 women) died. Initial analyses showed an increased risk of death for the highest and lowest categories of BMI among both men and women, in all racial or ethnic groups, and at all ages. When the analysis was restricted to healthy people who had never smoked, the risk of death was associated with both overweight and obesity among men and women. In analyses of BMI during midlife (age of 50 years) among those who had never smoked, the associations became stronger, with the risk of death increasing by 20 to 40 percent among overweight persons and by two to at least three times among obese persons; the risk of death among underweight persons was attenuated.
Conclusions: Excess body weight during midlife, including overweight, is associated with an increased risk of death.
1). What most glaringly identifies the sample concerned as not a random one is of course the percentage of women. A random sample would comprise about 50% women but there were actually twice as many men as women in this sample. So the population to which the findings may be generalized is essentially unknown, though a guess that it is a population who were worried about their health would probably not be too far astray.
2). The results were "adjusted" for physical inactivity. That is entirely inappropriate. Overweight people undoubtedly exercise less so the adjustment in effect creates an artificial population with no relevance to the real world. It is also possible that the adjustment for alcohol intake was inappropriate.
3). The overall results were, as usual, that people of middling weight lived longest. It was only in selected subsets of the sample that people of middling weight died somewhat younger. It is those subsets, however, that have attracted most media attention. If it were my practice in my own research to generalize from arbitrary subgroups of non-samples, I could prove anything too.
4). BMI is now in any case a rather contentious index of "obesity", for the amusing reason that in some populations it shows that overweight people live longer, as indeed it did in the present study.
5). The article looks at obesity at only one point in the lifespan. Weight tends to increase unevenly with age so that some people become overweight in later life who were not previously so. So what is true of those who are overweight in later life may not at all be true of (say) childhood obesity, and vice versa. This is a lacuna rather than a flaw in the study but it is yet another reason why the results of the study should not be generalized.
Since the conclusion given in the journal abstract is wildly inappropriate to the data, however, the media can hardly be blamed for their dramatizations, for once. It would seem that the prestigious academic journal -- NEJM -- in which the study appeared has gone the way of the BMJ in becoming a largely politically correct organ. 12:17 AM
U.K.: Organic milk controversy: "Organic milk is healthier than standard pasteurised milk, scientists have said in a call on the Government to revise official advice. A letter written by 14 scientists that was received today by the Food Standards Agency (FSA) claims that organic milk has higher levels of Omega 3 essential fatty acids, which are thought to boost health and provide protection from coronary heart disease. The authors of the letter want the FSA to change its stance on organic milk and “recognise that there are differences that exist between organic and nonorganic milk”. But the FSA said: “On the basis of current evidence, the agency’s assessment is that organic food is not significantly different in terms of food safety and nutrition from food produced conventionally.”
Blood worth bottling: "Blood products taken from people who have recovered from bird flu could be useful for treating other patients in the event of a pandemic, research has suggested. An analysis of how such transfusions were used in hospitals during the Spanish flu pandemic of 1918 has indicated that they reduced the risk of death and eased symptoms, raising the prospect that a similar approach could be used against H5N1 influenza. Although vaccines and antiviral drugs such as Tamiflu are likely to be the front line of defence today, blood plasma transfusions could provide a valuable back-up. They could prove a particularly valuable weapon against the H5N1 virus in developing countries with poor access to vaccines and antivirals, scientists said yesterday." 12:12 AM
Wednesday, August 30, 2006
Morning sickness theory: "Morning sickness seems to come with the territory for some women in the first few months of pregnancy. And scientists now reckon they know the reason. It could all be down to the woman’s diet – it’s the body’s way of protecting the fetus from a ‘bad’ diet. A woman who eats healthily is more likely to sail through the first few months of pregnancy without any of the unpleasant symptoms of morning sickness, unlike the woman whose diet is predominantly made up of processed and fast foods. A research study has discovered that women are far more likely to suffer if they eat large quantities of sugars, sweeteners, and fried foods. Researchers analysed 56 studies on morning sickness, collated from 21 countries, and found a link with diets that were high in sugars, sweeteners and oil crops used in frying foods. Other suspect foods include large amounts of meat, and stimulants such as coffee and alcohol. Conversely, cereals and pulses reduced the risk of morning sickness."
"Drug naive"? "Perhaps it’s because we don’t get out much these days, but we’ve just stumbled on an expression we’ve never before encountered, and yet seems to be all the rage within the pharma culture in the States: it’s ‘drug-naive’. Although it’s a term that can’t be found in any medical dictionary, it’s already being extensively used in research, and a quick Google search reveals pages of its usage. While we couldn’t get an authoritative definition, we assume it refers to a patient who has never before taken a pharmaceutical drug. And, like so many expressions from the drug industry, it’s wonderful. It’s a great way of sign-posting your future audience, and so we assume patient files could be marked ‘drug-naïve’ under the category ‘Hot prospects’. We noticed it in an advertisement for Avandamet, a drug to help achieve glycemic control in patients with type 2 diabetes." 12:27 AM
Cancer vaccine now on sale: "The world's first vaccine to protect against cancer goes on sale in Australia from today as federal health experts continue to assess an application from its makers to include it in the free national immunisation program for all girls. The inventor of the cervical cancer vaccine, Australian of the Year Ian Frazer, was due to attend launches today in Sydney and later Brisbane. He is expected to be honoured by the Beattie Government before injecting some of the first patients with the vaccine, called Gardasil. A third launch will be held in Melbourne later today. The vaccine will be available from pharmacies with a doctor's prescription. Pending a decision on government subsidies, patients will have to pay the full cost -- which, depending on the size of wholesale and pharmacy mark-ups, is likely to be between $150 and $155 for each of the three doses required, or $460 for the three-dose course. If the Government's Pharmaceutical Benefits Advisory Committee approves an application by the vaccine's makers to provide Gardasil free to schoolgirls, a nationwide immunisation program could be launched in February 2008. Professor Frazer became a national celebrity last year after trials published in The Lancet Oncology showed Gardasil attained a 100 per cent success rate in protecting young women against lesions and cervical warts caused by four strains of the human papillomavirus, or HPV."
A local government jumps onto the obesity bandwagon: "Brisbane will bypass the State Government and seek federal funding to fight obesity. Lord Mayor Campbell Newman is spearheading a campaign by Australia's capital cities to combat the national epidemic. With 62 per cent of men and 45 per cent of women now overweight or obese, the capitals are seeking direct Commonwealth funding to run preventable community-based health programs, which would also target drug addiction, health research and childhood diseases. "I know the Federal Government is concerned about the costs of administering programs through the states," Cr Newman said. "A lot of money does go into administration, and we are offering the opportunity through these programs to very efficiently get money out there on the ground." In its submission to a federal health inquiry, the Council of Capital City Lord Mayors argues that capital cities are the Commonwealth's "logical partner" to provide preventative community health programs. "One of the focus areas is on addressing the main causes of preventable disease including poor nutrition and physical activity," it said".
The meningococcal peril: "Parents and health care workers must learn to quickly recognise the symptoms of meningococcal disease if more deaths are to be prevented, doctors warn. The plea comes after Sydney schoolgirl Brittany Pine almost died last month after her GP thought she had measles. In Brittany's case, her doctor advised the girl's mother Kristy to visit the Children's Hospital at Westmead, where emergency staff diagnosed rapidly advancing meningococcal septicemia. They treated the seven-year-old with intravenous antibiotics. Blacktown GP Michael Fasher said British data shows 50 per cent of children with meningococcal are misdiagnosed the first time they make contact with the health system. Dr Fasher said young doctors could confuse the initial rash for measles because the eradication of measles had been so successful, and many had never seen a case of measles. Parents also needed to know what symptoms to look out for as meningococcal disease could masquerade as influenza or gastro-like illness, he said. "The number one thing to look for is the progressive decrease in levels of consciousness." Brittany, from Maryong in Sydney, had missed a meningococcal C vaccination, provided free to children aged 1-19 until June next year." 12:20 AM
Tea healthier than a glass of water: "The belief that drinking tea leads to loss of fluids and possibly dehydration has been quashed by scientists. They say drinking four cups a day can be beneficial - and better than plain water. Tea not only rehydrates but also protects against heart disease and cancer - as well as cutting tooth decay and possibly improving bone strength. The key component is a group of antioxidants called flavonoids which help prevent cell damage. Like fruit and vegetables, tea is a good source of flavonoids - three cups contain eight times the capacity of an apple. "You don't find these antioxidants in pure water," chief scientist Carrie Ruxton said. The British research was published in the European Journal of Clinical Nutrition."
Pet therapy: "He might not look the hero type but pet dog Ralph has already saved one life and now spends his days helping others. Nellie Worringham, an 18-year-old Brisbane student, saved the lovable "bitzer" from an RSPCA shelter last year. Ralph went on to return the favour. Nellie had been batting depression and an eating disorder and had tried to take her own life. But now the mutt has given her reason to live. "Ralph changed everything for me. He is always there and whatever is happening with me he is always his happy self," she said. "He was someone that I had to look after, so I had to look after myself as well." Inspired by him, Nellie is back on her feet and studying at Yeronga TAFE to be a counsellor [The blind leading the blind?]. "Ralph comes too. We've both been studying the mental health course for the past six months and now I am on placement at a community mental health centre," she said. "Ralph is just a fantastic icebreaker with people. Patients can pet him and talk to him and we just take it from there. "Ralph has given me a reason to live. He has touched my heart in a way I never believed possible." [My most-quoted academic paper concerned attitude to pets]
U.K.: "Organic" is "in": "As celebrity crazes go, this latest one is reasonably harmless: not hard-core drinking, drug-taking or even excessive slimming. No, the current fad for celebs who make a living out of appearing on the covers of Heat magazine is nothing other than knobbly vegetables. And free-range pigs. Fried up, that is, with some organic onion rings. "Green" food, grown without pesticides or hormones, is so hot at the moment that no right-minded member of Soho House would dare to throw a dinner party without a slab of organic fare on the menu... Being green is now accepted as being rather chic; a straightforwardly good idea worth signing up to, rather than something outwardly virtuous which requires a keen commitment to body hair and a vegan diet... Yet probably the single most crucial factor in helping to encourage this cultural sea-change is the celebrity take-up of green zeal. Liz Hurley, whose adoration of an organically reared (and very hairy) Gloucester Old Spot ended up in most of the papers last week, is said to be converting her 400-acre Cotswolds farm to organic production and launching a brand of organic baby foods (whether the labels will be designed by Donatella Versace is, as yet, unknown)". 8:23 AM
Allergy mystery: "The number of children with allergies rose worldwide in the 1990s, but scientists have little idea why. A study involving 56 countries, including Australia, shows rates of asthma, eczema and hay fever increased between 1991 and 2003. The findings were published in the latest issue of British-based medical journal The Lancet. Australian allergies expert Guy Marks, from Sydney's Woolcock Institute of Medical Research, said there was a profound increase in the prevalence of asthma among Australian children during the 1980s and the mid-1990s. But the increase stopped in the late 1990s and may now even be decreasing. "It's a fascinating observation, but it's frustrating (because) we really can't say why," Dr Marks said.
Avian flu vaccine? "An Australian company has successfully completed laboratory development of two avian influenza (H5N1 strain) vaccines for chickens, and is about to run trials on live chickens to see whether it protects them from avian influenza. Imugene managing director Dr Warwick Lamb said the development of an effective vaccine could be used to protect the world's poultry industry from further avian influenza outbreaks and halt the spread towards Australia. Dr Lamb said to control outbreaks, a viable vaccine must be safe, effective and able to be quickly and easily administered on a large scale. He said the vaccines used technology that allowed authorities to differentiate between infected and vaccinated birds. It delivers only a portion of the flu genetic material. "The vaccine candidates are specific to the H5N1 strain of avian influenza, but can be easily and quickly adapted to protect against other strains," Dr Lamb said."
Another stupid straight-line projection: "More than 12m adults and one million children will be obese by 2010 if no action is taken, a report by the Department of Health is predicting. The Health Survey for England also warns 19% of boys and 22% of girls aged two to 15 will be obese. The figures would mean the government would fail to meet its target to halt the rise in childhood obesity... The report warns that, based on current trends, 33% of men and 28% of women will be obese by 2010. The government says it is the "most accurate estimate so far" of future obesity rates. The data is published just days after a "minister for fitness" was appointed." 12:13 AM
Saturday, August 26, 2006
Politicized science produces bad public policy: "A new study about post-traumatic stress disorder (PTSD) among Vietnam veterans once again spotlights the need to separate the process of establishing veterans' benefits from scientific research. Researchers reported in Science (Aug. 18) that among 260 Vietnam vets studied, 18.7 percent had developed war-related PTSD during their lifetimes and 9.1 percent were currently suffering from PTSD."
Arthritis breakthrough? "Some relief may be in sight for arthritis sufferers thanks to a small Brisbane private biopharmaceutical development company, C-Bio Ltd. The group is behind what researchers yesterday hailed as a medical breakthrough, discovering a new anti-inflammatory compound which could provide new hope for arthritis sufferers. An exploratory study published in the international medical journal, The Lancet, shows that the compound, known as chaperonin 10, proved in a double blind trial that it was safe and effective in the treatment of rheumatoid arthritis. The study findings show that clinical improvement was obtained in all patients who completed the trial. A small group of patients in the trial at the highest dose level experienced up to a 70 per cent improvement in symptoms and clinical remission was achieved in 13 per cent of patients. The researchers, from a multicentre study group including the University of Queensland, Monash University in Melbourne and Royal Perth Hospital used a compound developed by the Brisbane-based C-Bio Ltd, funded in part by the Federal government".
Chicago chefs file suit over foie gras ban: "Saying the City Council stuck its beak where it didn't belong, a restaurant association sued the city Tuesday in hope of making foie gras legal again. Meanwhile, a handful of chefs said they will continue to serve the duck and goose liver delicacy -- it just won't appear on the bill. 'The law says we can't charge for it. It doesn't say we can't give it away,' said Michael Tsonton, chef and partner at Copperblue. The ban was approved by the City Council in April and implemented Tuesday. Animal rights activists contend that the production of foie gras, which involves force-feeding ducks and geese to enlarge their livers, is inhumane. The lawsuit showed that chefs aren't content muttering in their kitchens about the ban." 12:19 AM
Widely used drugs now dangerous: ""Several drugs to treat attention deficit hyperactivity disorder must include new warning information about the risk of heart problems and psychotic behavior, U.S. health officials said on Monday. The drugs, which include GlaxoSmithKline Plc's Dexedrine and Novartis AG's Ritalin, must include a warning about the possible risk of sudden death and serious heart problems, Food and Drug Administration spokeswoman Susan Bro told Reuters."
Driving under the influence of food to be banned? "Drivers who eat and drink at the wheel are on course for a crash diet. Tests have revealed that drivers are almost twice as likely to crash when eating or drinking, even if they compensate by driving more slowly and more carefully. And the RACQ believes it is so dangerous it could call for a ban. A new overseas study has found that eating and drinking while driving left drivers with a significantly higher "mental workload" which left them unable to brake in time to avoid a crash. The tests found that eating and drinking while driving was as dangerous and distracting as using a hand-held mobile phone, which is now banned and carries a penalty of $225 and three demerit points." [Tofu eating will probably remain OK, though]
Beware of raw Amazonian snails: "More than 70 people in Beijing have fallen ill with meningitis after they ate undercooked or raw snails at a restaurant in the city. City health officials issued an urgent notice to ban the sale of raw or half-cooked snails at restaurants. The Shuguo Yanyi Restaurant - where those who developed the illness had dined - would be punished, officials said. Doctors said that although some of the people affected were in a serious condition, no fatalities had been reported and three people had already left hospital. The snails in question, from the Amazon, were first introduced to China in the 1980s". 12:15 AM
Curry good for headaches: "Eating curry may be a better cure for headaches than aspirin, according to research. A study funded by the Scottish Executive has found that salicylic acid, the active ingredient in aspirin, occurs naturally in Indian food and that curry could help to treat migraines and prevent colon cancers. Spices such as cumin, turmeric and paprika, all of which are used in curries, are particularly rich sources of salicylic acid, the study said. Neither does Indian food cause some side-effects sometimes associated with long-term aspirin use, such as internal bleeding and ulcers, the study, conducted by the Rowett Research Institute, found. “One portion of vindaloo we examined contained 95mg of salicylic acid, more than the amount in an aspirin tablet. A low-dose aspirin tablet contains about 65mg of the acid.” Professor Garry Duthie, one of the study’s co-authors, said: “The dietary level of salicylic acid in curry is exceptionally high. I wouldn’t recommend a curry a day for headaches, but it is possible that someone with a headache who is a very good absorber of salicylic acid might find it went away if they had a vindaloo. “The hotter the curry is, the greater the possible benefits. A korma, with relatively low levels of spices, would be less effective than a vindaloo or a phal, the hottest curry widely available in Britain.” It is thought that curcumin, the component of turmeric that gives curry its distinctive yellow colour, is primarily responsible for its healthy effect."
Mouldy coffee is good coffee? "Don't turn your nose up to mouldy coffee - it tastes better, according to fungus experts. New Brazilian research has found that fungus in coffee crops makes for a flavoursome brew. More than 800 fungus experts from around the world will examine the recent findings and others at a week-long fungus conference this week in the far north Queensland city of Cairns. "The coffee research is exciting as it's likely to have implications on how coffee is grown and consumed in the future," says Professor Paul Gadek, a plant science researcher from James Cook University in Cairns. "Fungus naturally occurs on raw coffee beans and the Brazilian researchers found that the sweeter the species, the better the coffee tasted and smelt." Other topics to be discussed at the conference include fungi's ability to survive in space and its potential to destroy forests throughout the world."
Testosterone is good for you: "Low testosterone may boost the risk of death in men over 40, a new study has found. A U.S. team found that older men with relatively low testosterone had an 88% increased risk of death compared with men with normal testosterone levels. But they don't yet know why. The report was published in the Aug. 14/28 issue of the Archives of Internal Medicine. As men age, their testosterone levels gradually decline. After age 30, levels decrease by about 1.5% per year. Low testosterone levels can result in decreased muscle mass and bone density, insulin resistance and low sex drive, as well as less energy, more irritability and feelings of depression, the researchers noted. In the study, Shores and her colleagues studied 858 men over 40 to see whether low testosterone levels were associated with an increased risk of death. Among these men, 19% had low testosterone levels, 28% had an equivocal testosterone level (meaning that their tests revealed an equal number of low and normal levels) and 53% had normal levels. "Low testosterone in older men was associated with an increased risk for mortality," Shores concluded. During 4.3 years of follow-up, 20.1% of men with normal testosterone levels died, compared with 24.6% of men with equivocal levels and 34.9% of men with low testosterone levels, Shores' team found." 1:03 AM
Gold and silver are good medicine: "Scientists have developed a new 'golden bullet' to help in the fight against deadly cancers. Adding tiny particles of gold to an existing cancer drug boosts its power by 50 per cent, they have found. This then helps the medicine kill off more malignant cells while leaving healthy tissue unharmed... The new study by a team at the University of East Anglia is based on a system which uses a light sensitive drug to target cancer cells. The drug homes in on the the tumour and when exposed to light, it starts to produce an active form of oxygen. This oxygen is toxic to the cancer cells so makes them die off. Dr David Russell and his team wanted to see if there was any way of boosting the effectiveness of the system, officially called photo-dynamic therapy. They attached gold nanoparticles to the drug and used it on cervical cancer cells in the laboratory. It emerged that the gold led to 50 per cent more of the active oxygen, known as 'singlet oxygen', being produced. As expected this then led to more cells taking up the drug and dying off... Professor David Philips, an expert in photo-dynamic therapy from Imperial College London said results so far bode well for the future studies. It is also not the first time that scientists have turned to precious metals to help fight disease. Experts have long known silver can tackle the superbug and can be highly toxic to other bacteria. Silver's antibacterial properties were used by sailors in the past, who put silver coins in barrels of water to purify it. The metal is still used today in water purification and is also used in some plasters and hospital dressings to try to prevent infections with MRSA."
Prosperity is making the Chinese fat too: "People in China are becoming overweight at an alarming rate, a Chinese medical professor has said. Professor Wu Yangfeng said that in the 15 years between 1985 and 2000, the number of overweight and obese children increased 28-fold. He made his comments in a special China edition of the British Medical Journal.... China used to be seen as a country with a lean population, but not any more. Today a fifth of the world's overweight and obese people live in China - and the numbers are rising dramatically. Professor Wu Yangfeng said this posed a considerable health problem, calling on the Chinese authorities to act now to prevent further increase. There seems to be a range of underlying causes - from changes in diet to reduced levels of exercise and a rapid increase in the use of cars." 12:11 AM
Saturday, August 19, 2006
We wuz wrong! -- again: "Doctors have cast doubt on the standard way of measuring whether people are obese or overweight. New research suggests shortcomings in the system of Body Mass Index (BMI) in identifying whether someone is at risk of dying prematurely. Studies show that heart patients identified as 'overweight' by BMI actually survived longer than those judged to have a 'normal' weight. This is because the system fails to identify if a person's excess weight is muscle rather than fat. If someone is heavy because of muscle, they are less likely to die younger - and should not be classed as overweight - compared to someone whose excess weight is mostly fat. According to the BMI, which has formed the basis of defining healthy and abnormal weight for more than 100 years, more than half the UK population is overweight and a further 20 per cent obese".
Now it's pomegranates that are good for you: "Prostate cancer will claim the lives of an estimated 30,000 men in the United States this year. The second leading cause of cancer death in men, its incidence climbs with age. In Western countries, the disease is reaching nearly epidemic proportions among the elderly. However, the cancer can grow so slowly that many men with prostate cancer will die of something else first. A mystery has always been what factors might improve a man's
