Women who give birth after age 40 are nearly twice as likely to have a child with autism as those under 25, but it is unlikely that delayed parenthood plays a big role in the current autism epidemic, California researchers reported Monday.
The findings were expected to draw widespread attention because of the intense public interest in autism, but their true impact was expected to be simply in suggesting further avenues of research.
Surprisingly, the age of the father plays little role unless the mother is younger than 30 and the father is over 40, according to the analysis of all births in California in the 1990s.
The number of women over age 40 in California giving birth increased by 300% in the 1990s, while the diagnosis of autism increased by 600%. At first glance, it might seem that the rise in older pregnancies could be responsible for the rise in autism, which is now thought to affect as many as one child in every 100. But the authors, from UC Davis, calculate that older mothers account for less than 5% of the increase in autism diagnoses.
"There is a long history of blaming parents" for the development of autism, said senior author Dr. Irva Hertz-Picciotto, a professor of public health sciences and a researcher at the UC Davis MIND Institute who has been studying potential causes for the autism increase. "We're not saying this is the fault of mothers or fathers. We're just saying this is a correlation that will direct research in the future."
Researchers have long known that the age of the parents plays a role in a child's risk of developing autism, but how big a role and how that role varies with the sex of the parent has remained confusing, with contradictory results reported in different studies.
To investigate, Hertz-Picciotto, graduate student Janie E. Shelton and epidemiologist Daniel J. Tancredi of UC Davis analyzed all the singleton births in California during the 1990s for which information was available about the ages of both parents, a total of about 4.9 million births and 12,159 cases of autism.
Because of the large sample size, they were able to show how the risk was affected by each parent's age. They reported in the February issue of the journal Autism Research that women over 40 were 77% more likely to deliver an autistic child than those younger than 25 and 51% more likely than those age 25 to 29, independent of the age of the father.
For men over 40, there was a 59% increased risk of autism if the mother was younger than 30, but virtually no increased risk if the mother was over 30.
The researchers also calculated that the recent trend toward delayed childbearing contributed about a 4.6% increase in autism diagnoses over the decade.
"Five percent is probably indicating that there is something besides maternal age going on because we are seeing a rise in every age group of parents," Shelton said.
Also, noted Hertz-Picciotto, older women may be followed more closely during pregnancy, which would mean more ultrasounds -- which a few researchers have suggested might play a role in autism. Older women are more likely to suffer gestational diabetes and to develop autoimmune disorders, both of which have been linked to an increased risk of autism.
"We still have a real long way to go" in determining the causes of autism, she concluded
Sunday, February 14, 2010
FDA addresses radiation safety
The Food and Drug Administration has decided to impose new safety controls on medical imaging devices and encourage development of more precise dosing standards in a bid to reduce unnecessary exposure of patients to diagnostic radiation.
The agency also will promote a personal medical imaging history card that will enable patients to keep track of the number of images, and the amount of radiation, they receive over time, according to a medical imaging safety initiative unveiled Tuesday.
The safety push comes months after Cedars-Sinai Medical Center in Los Angeles discovered that it had accidentally exposed more than 260 patients to eight times the normal dose of radiation for CT brain scans over a period of 18 months.
Two other Los Angeles County healthcare facilities -- Providence St. Joseph Hospital in Burbank and Glendale Adventist Medical Center -- and one hospital in Huntsville, Ala., reported possible overdoses by imaging equipment to at least 104 people.
"We're aware that the exposure of the American public to [diagnostic] radiation was increasing fairly dramatically over the past 20 years," said Jeffrey Shuren, director of the FDA's Center for Devices and Radiological Health. "These tests can provide tremendous medical benefit. We're trying to optimize that benefit while lowering the risk."
The FDA will hold a public meeting March 30 and 31 to collect suggestions about new safety features and training that should be required for CT and fluoroscopic devices, Shuren said.
Equipment might be automatically calibrated to a recommended dose for a given procedure, so that any dosage increase would require an action by the operator. Equipment might also be designed to require identification of the operator as a way of tracking errors.
Shuren said regulators also are looking at software upgrades and other fixes to existing equipment.
In addition, the FDA is encouraging the development of a voluntary national database to determine the optimal dosages for a given procedure, fine-tuned to variables such as age and body type. Such a database also would allow individual practitioners to measure their use of radiation against that of their peers, Shuren said.
The FDA effort will build on data gathering already underway by the American College of Radiology and the National Council for Radiation Protection.
Some medical radiation experts questioned whether the FDA went far enough.
Requiring scanner manufacturers to add safeguards to their machines would have prevented the CT overdoses at Cedars-Sinai Medical Center, said David Brenner, director of the Center for Radiological Research at Columbia University Medical Center. But "it doesn't address what I see as the central issue: too many CT scans being done without medical justification," he said.
The number of CT scans performed in the U.S. each year has climbed to more than 70 million, more than triple the number in 1995.
The trend is driven by a variety of factors, including economic incentives for doctors and hospitals to order tests, and doctors' fear of being sued if they miss a problem.
CT has become standard procedure in emergency rooms for diagnosing head injuries, kidney stones and appendicitis. Scans are often repeated as part of routine follow-up or if a patient is transferred.
Shuren said the FDA was not directly addressing the question of medical justification because "it's really outside FDA's scope." But Shuren pointed out that putting imaging history cards in the hands of patients will call attention to previous exposures to diagnostic radiation.
The agency also will promote a personal medical imaging history card that will enable patients to keep track of the number of images, and the amount of radiation, they receive over time, according to a medical imaging safety initiative unveiled Tuesday.
The safety push comes months after Cedars-Sinai Medical Center in Los Angeles discovered that it had accidentally exposed more than 260 patients to eight times the normal dose of radiation for CT brain scans over a period of 18 months.
Two other Los Angeles County healthcare facilities -- Providence St. Joseph Hospital in Burbank and Glendale Adventist Medical Center -- and one hospital in Huntsville, Ala., reported possible overdoses by imaging equipment to at least 104 people.
"We're aware that the exposure of the American public to [diagnostic] radiation was increasing fairly dramatically over the past 20 years," said Jeffrey Shuren, director of the FDA's Center for Devices and Radiological Health. "These tests can provide tremendous medical benefit. We're trying to optimize that benefit while lowering the risk."
The FDA will hold a public meeting March 30 and 31 to collect suggestions about new safety features and training that should be required for CT and fluoroscopic devices, Shuren said.
Equipment might be automatically calibrated to a recommended dose for a given procedure, so that any dosage increase would require an action by the operator. Equipment might also be designed to require identification of the operator as a way of tracking errors.
Shuren said regulators also are looking at software upgrades and other fixes to existing equipment.
In addition, the FDA is encouraging the development of a voluntary national database to determine the optimal dosages for a given procedure, fine-tuned to variables such as age and body type. Such a database also would allow individual practitioners to measure their use of radiation against that of their peers, Shuren said.
The FDA effort will build on data gathering already underway by the American College of Radiology and the National Council for Radiation Protection.
Some medical radiation experts questioned whether the FDA went far enough.
Requiring scanner manufacturers to add safeguards to their machines would have prevented the CT overdoses at Cedars-Sinai Medical Center, said David Brenner, director of the Center for Radiological Research at Columbia University Medical Center. But "it doesn't address what I see as the central issue: too many CT scans being done without medical justification," he said.
The number of CT scans performed in the U.S. each year has climbed to more than 70 million, more than triple the number in 1995.
The trend is driven by a variety of factors, including economic incentives for doctors and hospitals to order tests, and doctors' fear of being sued if they miss a problem.
CT has become standard procedure in emergency rooms for diagnosing head injuries, kidney stones and appendicitis. Scans are often repeated as part of routine follow-up or if a patient is transferred.
Shuren said the FDA was not directly addressing the question of medical justification because "it's really outside FDA's scope." But Shuren pointed out that putting imaging history cards in the hands of patients will call attention to previous exposures to diagnostic radiation.
SNOWSTORM AND CLIMATIC CHANGE
As record snowfall buried the nation's capital this week, the quickest joke around town was, "So much for global warming."
The quip was timely, given the recent controversies over Climategate -- the release of e-mails allegedly showing some leading climate scientists trying to suppress criticism -- and new questions about the integrity of the United Nations' Intergovernmental Panel on Climate Change.
After 55-plus inches of snow fell in the Washington area, critics are delighting in the irony, and those who warn of climate change are taking pains to say the snow fits the pattern of a warming world.
So who's right? If the earth is warming, why all the snow?
Snow and global warming aren't mutually exclusive, climate scientists say. For starters, the amount of recorded warming over the last century, about 1 degree Fahrenheit above preindustrial levels, is nowhere near enough to eradicate winter in the mid-Atlantic.
Also, weather is variable: The planet would have extreme highs and lows with or without an overall warming trend.
And for all the recent snow in Washington, it hasn't been that cold -- mostly in the 20s or low 30s. The average temperature in Washington in January, according to the National Climatic Data Center, was about a degree warmer than the average for the last 40 years.
But the reverse is also true: The fact that Vancouver, Canada, is experiencing record-high temperatures and importing snow for the Winter Olympics doesn't prove a warming trend.
Are the snowstorm and climate science completely unrelated, then?
Not necessarily. Increased snowfall fits a pattern suggested by many climate models, in which rising temperatures warm the world's bodies of water, leading to more evaporation.
Climate scientists say the amount of atmospheric moisture has increased, which they predict will bring more rain in warmer conditions and more snow in freezing temperatures.
"All you need is cold air and moisture to meet each other" to make snow, said Jay Gulledge, senior scientist for the Pew Center on Global Climate Change. "And with global warming, the opportunities to do that should be more frequent."
How will the snow affect the politics of the climate bill?
Probably not much, because proponents are pitching the bill as a boost to national security and a creator of clean-energy jobs, as opposed to a curb on global warming. The swing voters who will dictate the bill's fate are senators who more or less say they accept the science behind climate change.
On the other hand, the snow has given some novel arguments to opponents of the "cap and trade" system of limiting emissions, which is the heart of most climate proposals. Critics warn that such a system, in which emitters must obtain permits to cover the carbon dioxide and other greenhouse gases they release, would send electricity prices soaring -- particularly during extreme weather events.
William O'Keefe, a cap-and-trade critic and chief executive of the nonprofit George C. Marshall Institute, observed: "As Washington works to clear its streets from this week's 'snowpocalypse,' policymakers should work to clear a new path on climate policy."
The quip was timely, given the recent controversies over Climategate -- the release of e-mails allegedly showing some leading climate scientists trying to suppress criticism -- and new questions about the integrity of the United Nations' Intergovernmental Panel on Climate Change.
After 55-plus inches of snow fell in the Washington area, critics are delighting in the irony, and those who warn of climate change are taking pains to say the snow fits the pattern of a warming world.
So who's right? If the earth is warming, why all the snow?
Snow and global warming aren't mutually exclusive, climate scientists say. For starters, the amount of recorded warming over the last century, about 1 degree Fahrenheit above preindustrial levels, is nowhere near enough to eradicate winter in the mid-Atlantic.
Also, weather is variable: The planet would have extreme highs and lows with or without an overall warming trend.
And for all the recent snow in Washington, it hasn't been that cold -- mostly in the 20s or low 30s. The average temperature in Washington in January, according to the National Climatic Data Center, was about a degree warmer than the average for the last 40 years.
But the reverse is also true: The fact that Vancouver, Canada, is experiencing record-high temperatures and importing snow for the Winter Olympics doesn't prove a warming trend.
Are the snowstorm and climate science completely unrelated, then?
Not necessarily. Increased snowfall fits a pattern suggested by many climate models, in which rising temperatures warm the world's bodies of water, leading to more evaporation.
Climate scientists say the amount of atmospheric moisture has increased, which they predict will bring more rain in warmer conditions and more snow in freezing temperatures.
"All you need is cold air and moisture to meet each other" to make snow, said Jay Gulledge, senior scientist for the Pew Center on Global Climate Change. "And with global warming, the opportunities to do that should be more frequent."
How will the snow affect the politics of the climate bill?
Probably not much, because proponents are pitching the bill as a boost to national security and a creator of clean-energy jobs, as opposed to a curb on global warming. The swing voters who will dictate the bill's fate are senators who more or less say they accept the science behind climate change.
On the other hand, the snow has given some novel arguments to opponents of the "cap and trade" system of limiting emissions, which is the heart of most climate proposals. Critics warn that such a system, in which emitters must obtain permits to cover the carbon dioxide and other greenhouse gases they release, would send electricity prices soaring -- particularly during extreme weather events.
William O'Keefe, a cap-and-trade critic and chief executive of the nonprofit George C. Marshall Institute, observed: "As Washington works to clear its streets from this week's 'snowpocalypse,' policymakers should work to clear a new path on climate policy."
Obama nuke plant loan reflects new energy strategy
The Obama administration's planned loan guarantee to build the first nuclear power plant in the U.S in almost three decades is part of a broad shift in energy strategy to lessen dependence on foreign oil and reduce the use of other fossil fuels blamed for global warming.
President Barack Obama called for "a new generation of safe, clean nuclear power plants" in his Jan. 27 State of the Union speech and followed that by proposing to triple loan guarantees for new nuclear plants. He wants to use nuclear power and other alternative sources of energy in his effort to shift energy policy.
Obama in the coming week will announce the loan guarantee to build the nuclear power plant, an administration official said Friday. The two new Southern Co. reactors to be built in Burke, Ga., are part of a White House energy plan that administration officials hope will draw Republican support.
Loan guarantees for other sites are expected to be announced in the coming months, the official said, who would speak only on condition of anonymity ahead of Obama's announcement. The federal guarantees are seen as essential for construction of any new reactor because of the expense involved. Critics call the guarantees a form of subsidy and say taxpayers will assume a huge risk, given the industry's record of cost overruns and loan defaults.
"The last thing Americans want is another government bailout for a failing industry, but that's exactly what they're getting from the Obama administration," said Ben Schreiber, an analyst for the environmental group Friends of the Earth. "This is great news for Wall Street but a bad deal for Main Street."
Even with next week's announcement, construction of the first reactor is still years away. The Southern Co. has applied to the Nuclear Regulatory Commission for a construction and operating license for the plant, one of 13 such applications the agency is considering. NRC spokesman Eliot Brenner said the earliest any of those could be approved would be late 2011 or early 2012.
The Southern Co. has begun site preparation in Burke but cannot begin construction without NRC approval.
Obama's budget for the coming year would add $36 billion in new federal loan guarantees on top of $18.5 billion already budgeted — but not spent — for a total of $54.5 billion. That's enough to help build six or seven new nuclear plants, which can cost $8 billion to $10 billion each.
The proposed new reactors would generate power for some 1.4 million people and employ about 850 people, the administration official said, adding that the Georgia project would create about 3,000 construction jobs.
Spiraling costs, safety concerns and opposition from environmentalists have kept utilities from building any new nuclear power plants in the U.S. since the early 1980s. The 104 nuclear reactors now in operation in 31 states provide about 20 percent of the nation's electricity. But they are responsible for 70 percent of the power from pollution-free sources, including wind, solar and hydroelectric dams that Obama has championed as a way to save the environment and economy at the same time.
Environmentalists and fiscal hawks oppose new nuclear plants and note that they come at the same time Obama has proposed eliminating a long-planned nuclear waste dump at Yucca Mountain in Nevada. Obama has appointed a commission to find a safe solution for dealing with nuclear waste, but in the meantime the government has no long-term plan to store commercial radioactive waste.
Republicans like South Carolina Sen. Lindsey Graham welcome the shift, but some pro-nuclear Republicans remain nervous about the heart of the Obama-backed climate bill — a plan to limit heat-trapping pollution, which would raise energy costs.
President Barack Obama called for "a new generation of safe, clean nuclear power plants" in his Jan. 27 State of the Union speech and followed that by proposing to triple loan guarantees for new nuclear plants. He wants to use nuclear power and other alternative sources of energy in his effort to shift energy policy.
Obama in the coming week will announce the loan guarantee to build the nuclear power plant, an administration official said Friday. The two new Southern Co. reactors to be built in Burke, Ga., are part of a White House energy plan that administration officials hope will draw Republican support.
Loan guarantees for other sites are expected to be announced in the coming months, the official said, who would speak only on condition of anonymity ahead of Obama's announcement. The federal guarantees are seen as essential for construction of any new reactor because of the expense involved. Critics call the guarantees a form of subsidy and say taxpayers will assume a huge risk, given the industry's record of cost overruns and loan defaults.
"The last thing Americans want is another government bailout for a failing industry, but that's exactly what they're getting from the Obama administration," said Ben Schreiber, an analyst for the environmental group Friends of the Earth. "This is great news for Wall Street but a bad deal for Main Street."
Even with next week's announcement, construction of the first reactor is still years away. The Southern Co. has applied to the Nuclear Regulatory Commission for a construction and operating license for the plant, one of 13 such applications the agency is considering. NRC spokesman Eliot Brenner said the earliest any of those could be approved would be late 2011 or early 2012.
The Southern Co. has begun site preparation in Burke but cannot begin construction without NRC approval.
Obama's budget for the coming year would add $36 billion in new federal loan guarantees on top of $18.5 billion already budgeted — but not spent — for a total of $54.5 billion. That's enough to help build six or seven new nuclear plants, which can cost $8 billion to $10 billion each.
The proposed new reactors would generate power for some 1.4 million people and employ about 850 people, the administration official said, adding that the Georgia project would create about 3,000 construction jobs.
Spiraling costs, safety concerns and opposition from environmentalists have kept utilities from building any new nuclear power plants in the U.S. since the early 1980s. The 104 nuclear reactors now in operation in 31 states provide about 20 percent of the nation's electricity. But they are responsible for 70 percent of the power from pollution-free sources, including wind, solar and hydroelectric dams that Obama has championed as a way to save the environment and economy at the same time.
Environmentalists and fiscal hawks oppose new nuclear plants and note that they come at the same time Obama has proposed eliminating a long-planned nuclear waste dump at Yucca Mountain in Nevada. Obama has appointed a commission to find a safe solution for dealing with nuclear waste, but in the meantime the government has no long-term plan to store commercial radioactive waste.
Republicans like South Carolina Sen. Lindsey Graham welcome the shift, but some pro-nuclear Republicans remain nervous about the heart of the Obama-backed climate bill — a plan to limit heat-trapping pollution, which would raise energy costs.
Thursday, February 11, 2010
Somali pirates hold science to ransom
SOMALI pirates terrorising the Indian Ocean are a hazard to more than shipping and tourists. They are also killing important scientific research and may be indirectly damaging the ocean's ecosystem.
Fishing boats in the Indian Ocean routinely carry scientists who gather data about fish stocks and threatened species while ensuring that boats comply with fishing rules. The piracy threat has put a stop to that. "We can't monitor and we can't do experiments because of the pirates," says Laurent Dagorn of France's Research Institute for Development (IRD).
Boats now carry guards and no longer have room for scientists, who have had to confine their own research vessels to port. IRD has cancelled all of its cruises in the last nine months.
By eliminating scientific observers, piracy may be indirectly increasing by-catch. It could also be encouraging the use of damaging fishing methods like "fish-attracting devices" - bamboo rafts held together with netting that are left at sea for days or weeks. Fish such as tuna congregate under FADs, making them easier to catch, but FADs also snag and kill turtles and sharks. Michel Goujon, director of the French tuna-boat owners' association, Orthongel, has evidence that their use is on the rise.
Regional governments accept the need to resume research. But, "I don't see any sign that piracy is going to decrease", says Goujon. "In fact, every time a ransom is paid it's an incentive for new attacks."
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