Friday, June 21, 2013
Risk of autism is up to 50% higher in children exposed to traffic fumes and air pollution
Here we go again: People living in unprestigious locations -- such as near traffic -- will be poorer and less healthy for that reason alone. And depending on who they marry and all sorts of other things, some nurses will be poorer than others
Researchers from the Harvard School of Public Health found the risk was doubled for women living in the most polluted locations.
'Our findings raise concerns since, depending on the pollutant, 20 per cent to 60 per cent of the women in our study lived in areas where risk of autism was elevated,' said lead scientist Dr Andrea Roberts.
Autism, a developmental disorder that interferes with social and communication skills, affects around 500,000 people in the UK.
It covers a 'spectrum' of conditions that may be mild or very severe, requiring round-the-clock care.
For the new study, researchers identified 325 women who had a child with autism and 22,000 who had children without the disorder.
Data collected by the U.S. Environmental Protection Agency and published in the journal Environmental Health Perspectives was used to assess pollution exposure in the areas where the women lived.
The scientists found a clear link between being pregnant somewhere with high levels of pollution and having an autistic child.
Diesel and mercury pollution showed the strongest link.
Women living in the top fifth of locations with the highest levels of these pollutants were twice as likely to give birth to a child with autism as those in areas with the lowest levels.
Other types of air pollution, including lead, manganese, methylene chloride and combined metals, had weaker associations with autism risk.
Women with the highest levels of exposure to these substances were about 50 per cent more likely to have a child who develops autism.
Most pollutants were more strongly associated with autism in boys than in girls.
Boys are in any case much more likely to have the disorder. The findings form part of the Nurse's Health Study II, a major U.S. investigation of environmental factors behind disease in a large group of more than 116,000 female nurses.
Women living in the top fifth of locations with the highest levels of pollutants were twice as likely to give birth to a child with autism as those in areas with the lowest levels
Senior author Dr Mark Weisskopf, also from Harvard, said: 'Our results suggest that new studies should begin the process of measuring metals and other pollutants in the blood of pregnant women or newborn children to provide stronger evidence that specific pollutants increase risk of autism.
'A better understanding of this can help to develop interventions to reduce pregnant women's exposure to these pollutants.'
Air pollutants contain many toxins that are known to affect neurological function and foetal development.
The researchers wrote: 'To our knowledge, our study is the first to examine the association between air pollution and ASD (autism spectrum disorder) across the United States..
'We observed significant positive linear trends between pollutant concentration and ASD, for diesel particulate matter, lead, manganese, methylene chloride, mercury and nickel.'
Beware the pretense of science
Donald J. Boudreaux comments on the FDA and other regulators from first principles
Judging from statements that regularly issue from politicians and the punditry — and from ivory-tower sages — you'd think that questions about what outcomes the economy “should” produce typically have answers that are objective, correct and specific. “Is this new drug safe?” “Is that amount of pollution too high?” “Are wages for those workers too low?” “What's the minimum number of days of paid vacation that workers should get annually?”
In response to such questions, the moralist within each of us demands specific answers: “Yes!” “No!” “Yes!” “Fourteen days!” It's satisfying to distinguish right from wrong, good from bad, saints from sinners, objectively correct answers from objectively incorrect ones.
But human nature makes the demand for such answers futile in many cases.
One reason is that each of us — as a worker, consumer, entrepreneur, investor, homeowner, voter, concerned citizen — is different from others of us. There is no objectively correct minimum number of days of paid vacation annually for workers as a group. Suppose I have a lower preference for leisure than you do. My preference cannot be projected onto you; it's just my preference. But because of my particular preference for little leisure, I'm more likely than are you to find and not to quit a job that offers fewer vacation days than your job offers.
Likewise, there's no objective yes-or-no answer to the question “Is this drug safe?” Your tolerance for risk might be higher than mine, and so you — unlike me — would prefer to take a certain drug rather than do without it. Your preference is neither right nor wrong; it's just your preference.
In both of the above examples — only two of countless ones — government-imposed standards cannot possibly be objectively correct. If government mandates that every worker get at least two weeks of paid vacation annually, the government will make those workers who prefer less leisure worse off. Forced to raise the amount of worker pay dispensed in the form of paid vacations, employers will lower the amount of worker pay dispensed in other forms such as cash or employer contributions to employee pensions. Such a regulation will make people who attach little value to leisure worse off.
The same holds true for drugs. Because no drug is completely risk-free, and because different people have different tolerances for risk, there's absolutely no scientifically objective way for the FDA to determine if a new drug is objectively too risky or not. That question is one of personal preferences and not one of science. And that question isn't miraculously transformed into a scientific question by government charging teams of scientists to assess whether this or that drug is “too risky.”
The pretense of science is not science. If government officials truly wish to be scientifically driven, they would allow each of us adults to choose which drugs we wish to take, regardless of the objective likelihood that someone will die or be seriously injured if he or she chooses to be treated with some drug.
Put differently, the scientifically correct level of riskiness of drugs for me is whatever level of riskiness I choose to tolerate. I — not some third party, not even one with an M.D. and who is appointed by government — am the only person on Earth capable of knowing the truth about what is, for me, the appropriate level of riskiness of drugs. Ditto for you.
Posted by jonjayray at 12:21 AM