prenatal en Intelligence, Cancer, and Eyjafjallajökull <span>Intelligence, Cancer, and Eyjafjallajökull</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p><span style="float: left; padding: 5px;"><a href=""><img alt="" src="" style="border:0;" /></a></span>This seems to have become unofficial volcano week, here at ScienceBlogs. If you haven't been following the coverage of the Eyjafjallajökull eruption at Erik Klemetti's <a href="">Eruptions</a> blog, you should consider doing so. Also, Dr. Isis has a <a href="">post</a> on how the eruption has fouled up all nuclear imaging plans at her place of research, and Ethan <a href="">explains</a> how volcanic lightening works.</p> <p>Our benevolent overlords have further <a href="">commented</a>: "Eyjafjallajökull's ill temper has been an unexpected object lesson in the complexity and interconnectedness of our environment, technology, and social networks." To that I say: yes! But what about cognition and intelligence?</p> <p>You say: what do cognition and intelligence have to do with the volcano? I say: everything. Kind of. Let's start at the beginning.</p> <!--more--><p>Put most simply, a <em><a href="">teratogen</a></em> is something in the environment that messes with a developing fetus. Specifically, teratogens are environmental agents that are relatively harmless to an adult, but that can result in birth defects and developmental disorders of varying severity in the child. It was once thought that, for mammals, the uterus completely protects the fetus from the external world. Then in the 1960s, it became painfully clear that this was not the case. Doctors had been prescribing <a href="">thalidomide</a> as a sedative drug since the 1950s, but more than 10,000 children in 46 countries were born with deformities as a result. Luckily, some clever physicians realized there was a link between these <a href="">birth defects</a> and maternal thalidomide use, and by 1961 it was no longer prescribed. Now, we know that <a href="">many</a> environmental agents have teratogenic effects.</p> <p>In the 18th century, higher rates of skin cancer were observed in roofers who were exposed to soot. In 1947, a relationship between coal tar and lung cancer was established. Soon after, it was discovered that it was <strong>polycyclic aromatic hydrocarbons (PAHs)</strong>, specifically, in coal and soot that was responsible for the cancer's development. By 1983, the <a href=";source=web&amp;ct=res&amp;cd=1&amp;ved=0CAcQFjAA&amp;;rct=j&amp;q=International+Agency+for+Research+on+Cancer&amp;ei=-oTOS_aTN4PkswPG2qyvDg&amp;usg=AFQjCNGpi03Bf5N1G2nrCmB-d-L3yM6lGw">International Agency for Research on Cancer</a> had identified thirty PAHs that were carcinogenic, and in 1997 the United States <a href=";source=web&amp;ct=res&amp;cd=1&amp;ved=0CA4QFjAA&amp;;rct=j&amp;q=Environmental+Protection+Agency&amp;ei=FYXOS5aVIo-KsgPL9civDg&amp;usg=AFQjCNGo7qU8DQ0jgrNXbDIXZMv6Xh2E_w">Environmental Protection Agency</a> identified sixteen PAHs as "highly toxic." There are over 200 unique PAHs present in cigarette smoke. </p> <p><img src="" alt="i-d08ee7dc74727cea50a27fd5ef2bbc08-PAH-thumb-400x300-47473.jpg" /><br /></p><div style="text-align: center;"><strong>Figure 1: A few typical PAH molecules. <a href="">Source</a>.</strong></div> <p>"Hydrocarbon" refers to the fact that these molecules are composed of carbon and hydrogen atoms. "Polycyclic" means that these molecules are collections of rings of carbon atoms, and "aromatic" refers to the kinds of chemical bonds that exist between the atoms.</p> <p>A study was just published online in the journal <a href="">Environmental Health Perspectives</a> concerning the relationship between these airborne carcinogens and intelligence, especially with respect to prenatal exposure. Are PAHs significantly teratogenic?</p> <p>So, a group of researchers wanted to investigate the relationship between prenatal PAH exposure and intelligence at age five. A cohort of 505 pregnant, healthy, non-smoking women were recruited in <a href=";um=1&amp;ie=UTF-8&amp;q=krakow,+poland&amp;fb=1&amp;gl=us&amp;ftid=0x471644c0354e18d1:0xb46bb6b576478abf&amp;ei=hnbOS6CnCZT2sgPK25ivDg&amp;sa=X&amp;oi=geocode_result&amp;ct=title&amp;resnum=1&amp;ved=0CA0Q8gEwAA">Krakow</a>, Poland between 2001 and 2006. They were all at least 18 years old when they entered the study, had no history of illicit drug use, no diabetes, no hypertension, and had lived in Krakow for at least one year prior to enrolling in the study.</p> <p>First, each woman participated in a 45 minute questionnaire. Then, each woman's air was continuously monitored for 48 hours at some point during the second or third trimester. They were given small backpacks to carry around with them that continuously monitored the air, and they were instructed to keep it next to their beds at night. After delivery, a sample of (umbilical) cord blood and of venous blood was taken from the mother, to measure the concentration of PAHs in the blood. Then, after the children reached five years of age, they were given a handful of standardized intelligence tests. 214 children were included in the study.</p> <p>What they found was that higher prenatal exposure to PAHs was associated with decreased scores on the standardized intelligence tests, after controlling for potentially confounding variables; the average decrease was 3.8 IQ points. The results suggest that prenatal airborne PAH exposure negatively affects childrens' intelligence by age 5, and has potential implications for future academic achievement.</p> <p>Polycyclic aromatic hydrocarbons (PAHs) are air pollutants that are produced by the incomplete combustion of organic materials. Most environmental PAHs are anthropogenic - that is, produced by humans - such as from coal burning power plants, diesel- and gas-powered vehicles, and home heating systems. PAHs are also present in tobacco smoke as well as in charred foods. </p> <p>But I was particularly interested to learn about the natural sources of PAHs, so I did some digging. Forest fires are an important source of PAHs, and <a href=";_udi=B6T54-4HDY8WG-1C&amp;_user=1181656&amp;_coverDate=12%2F31%2F1977&amp;_rdoc=1&amp;_fmt=high&amp;_orig=search&amp;_sort=d&amp;_docanchor=&amp;view=c&amp;_searchStrId=1303214464&amp;;_acct=C000051901&amp;_version=1&amp;_urlVersion=0&amp;_userid=1181656&amp;md5=ec4b0257fe220ad14c1bd563d6d82924">so</a> <a href="">are</a> <a href="">VOLCANIC</a> <a href="">ERUPTIONS</a>!! It may be that humans are a bigger source of PAHs than volcanoes. But lately, in case you hadn't noticed, there've been a lot of polycyclic aromatic hydrocarbons in the air around Iceland.</p> <p><img src="" alt="i-a8e3e1e42b75a727c2a239c448a0e777-iceland-cloud-8492108-thumb-500x281-47475.jpg" /><br /></p><div style="text-align: center;"><strong>Figure 2: The ash plume from the 2010 Eyjafjallajökull eruption. (From <a href="">this post</a> at the Eruptions blog).</strong></div> <p>The ash cloud was <a href="">expected</a> to have reached North America sometime this past Monday. It should be noted that some <a href=",0,5266020.story">reports</a> say that there isn't much to worry about with respect to this eruption, health-wise. Even still, the effects of this (and other) eruptions are sure to be widespread and we may indeed not realize or predict what the long-term effects may be. </p> <p>Who wants to start distributing air quality backpacks to pregnant women in Iceland? Nothing like a little opportunistic science!</p> <p><strong><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.jtitle=Environmental+Health+Perspectives&amp;rft_id=info%3A%2F10.1289%2Fehp.0901070&amp;;rft.atitle=Prenatal+Exposure+to+Airborne+Polycyclic+Aromatic++%0D%0AHydrocarbons+and+Children%E2%80%99s+Intelligence+at+Age+5+in+a+%0D%0AProspective+Cohort+Study+in+Poland&amp;rft.issn=&amp;;rft.volume=&amp;rft.issue=&amp;rft.spage=&amp;rft.epage=&amp;rft.artnum=&amp;;;;;;;;;;;;rfe_dat=bpr3.included=1;bpr3.tags=Biology%2CChemistry%2CGeosciences%2CPsychology%2CHealth%2CNeuroscience%2CDevelopmental+Psychology%2C+Public+Health%2C+Organic+Chemistry%2C+Cancer%2C+Developmental+Neuroscience%2C+Environmental+Health">Susan Claire Edwards,, Wieslaw Jedrychowski,, Maria Butscher,, David Camann,, Agnieszka Kieltyka,, Elzbieta Mroz,, Elzbieta Flak,, Zhigang Li,, Shuang Wang,, Virginia Rauh,, &amp; Frederica Perera (2010). Prenatal Exposure to Airborne Polycyclic Aromatic<br /> Hydrocarbons and Children's Intelligence at Age 5 in a<br /> Prospective Cohort Study in Poland <span style="font-style: italic;">Environmental Health Perspectives</span> : <a rev="review" href="10.1289/ehp.0901070">10.1289/ehp.0901070</a></span></strong></p> <p><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.jtitle=Acta+poloniae+pharmaceutica&amp;rft_id=info%3Apmid%2F15481250&amp;;rft.atitle=Polycyclic+aromatic+hydrocarbons%3A+physicochemical+properties%2C+environmental+appearance+and+impact+on+living+organisms.&amp;rft.issn=0001-6837&amp;;rft.volume=61&amp;rft.issue=3&amp;rft.spage=233&amp;rft.epage=40&amp;rft.artnum=&amp;;;;rfe_dat=bpr3.included=1;bpr3.tags=Biology%2CChemistry%2CGeosciences%2COrganic+Chemistry%2C+Cancer%2C+Environmental+Health">SkupiÅska K, Misiewicz I, &amp; Kasprzycka-Guttman T (2004). Polycyclic aromatic hydrocarbons: physicochemical properties, environmental appearance and impact on living organisms. <span style="font-style: italic;">Acta poloniae pharmaceutica, 61</span> (3), 233-40 PMID: <a rev="review" href="">15481250</a></span></p> </div> <span><a title="View user profile." href="/author/jgoldman" lang="" about="/author/jgoldman" typeof="schema:Person" property="schema:name" datatype="">jgoldman</a></span> <span>Wed, 04/21/2010 - 00:30</span> <div class="field field--name-field-blog-tags field--type-entity-reference field--label-inline"> <div class="field--label">Tags</div> <div class="field--items"> <div class="field--item"><a href="/tag/developmental-psychology" hreflang="en">Developmental Psychology</a></div> <div class="field--item"><a href="/tag/psychological-science" hreflang="en">Psychological Science</a></div> <div class="field--item"><a href="/tag/ash" hreflang="en">ash</a></div> <div class="field--item"><a href="/tag/birth-defects" hreflang="en">birth defects</a></div> <div class="field--item"><a href="/tag/cancer" hreflang="en">cancer</a></div> <div class="field--item"><a href="/tag/carcinogen" hreflang="en">carcinogen</a></div> <div class="field--item"><a href="/tag/child" hreflang="en">child</a></div> <div class="field--item"><a href="/tag/child-development" hreflang="en">child development</a></div> <div class="field--item"><a href="/tag/children" hreflang="en">children</a></div> <div class="field--item"><a href="/tag/coal" hreflang="en">coal</a></div> <div class="field--item"><a href="/tag/cognition" hreflang="en">cognition</a></div> <div class="field--item"><a href="/tag/intelligence" hreflang="en">intelligence</a></div> <div class="field--item"><a href="/tag/iq" hreflang="en">iq</a></div> <div class="field--item"><a href="/tag/pollution" hreflang="en">pollution</a></div> <div class="field--item"><a href="/tag/pregnancy" hreflang="en">pregnancy</a></div> <div class="field--item"><a href="/tag/prenatal" hreflang="en">prenatal</a></div> <div class="field--item"><a href="/tag/soot" hreflang="en">soot</a></div> <div class="field--item"><a href="/tag/teratogen" hreflang="en">teratogen</a></div> <div class="field--item"><a href="/tag/volcano" hreflang="en">volcano</a></div> </div> </div> <section> <article data-comment-user-id="0" id="comment-2452800" class="js-comment comment-wrapper clearfix"> <mark class="hidden" data-comment-timestamp="1271833484"></mark> <div class="well"> <strong></strong> <div class="field field--name-comment-body field--type-text-long field--label-hidden field--item"><p>Nice post! </p> <p>Another take on this topic is that the volcano's uncertain resembles the situation for a patient with an unpredictable illness, when the doctors render differing opinions and the prognosis is uncertain - <a href=""></a></p> </div> <drupal-render-placeholder callback="comment.lazy_builders:renderLinks" arguments="0=2452800&amp;1=default&amp;2=en&amp;3=" token="laXgdRCl5njkZu3vx5kblY5_CjcbJKQDXHVzMGMlNQw"></drupal-render-placeholder> </div> <footer> <em>By <a rel="nofollow" href="" lang="" typeof="schema:Person" property="schema:name" datatype="">Elaine Schattner (not verified)</a> on 21 Apr 2010 <a href="">#permalink</a></em> <article typeof="schema:Person" about="/user/0"> <div class="field field--name-user-picture field--type-image field--label-hidden field--item"> <a href="/user/0" hreflang="und"><img src="/files/styles/thumbnail/public/default_images/icon-user.png?itok=yQw_eG_q" width="100" height="100" alt="User Image" typeof="foaf:Image" class="img-responsive" /> </a> </div> </article> </footer> </article> <article data-comment-user-id="0" id="comment-2452801" class="js-comment comment-wrapper clearfix"> <mark class="hidden" data-comment-timestamp="1271925805"></mark> <div class="well"> <strong></strong> <div class="field field--name-comment-body field--type-text-long field--label-hidden field--item"><p>Interesting entry. It's good to read about some Polish researches on foreign blogs.</p> </div> <drupal-render-placeholder callback="comment.lazy_builders:renderLinks" arguments="0=2452801&amp;1=default&amp;2=en&amp;3=" token="V-STOUbRlSHV2o-kVJyBBIGRX-hSoHTJqFm7xIVINMU"></drupal-render-placeholder> </div> <footer> <em>By <span lang="" typeof="schema:Person" property="schema:name" datatype="">True_Q (not verified)</span> on 22 Apr 2010 <a href="">#permalink</a></em> <article typeof="schema:Person" about="/user/0"> <div class="field field--name-user-picture field--type-image field--label-hidden field--item"> <a href="/user/0" hreflang="und"><img src="/files/styles/thumbnail/public/default_images/icon-user.png?itok=yQw_eG_q" width="100" height="100" alt="User Image" typeof="foaf:Image" class="img-responsive" /> </a> </div> </article> </footer> </article> </section> <ul class="links inline list-inline"><li class="comment-forbidden"><a href="/user/login?destination=/thoughtfulanimal/2010/04/21/intelligence-cancer-and-eyjafj%23comment-form">Log in</a> to post comments</li></ul> Wed, 21 Apr 2010 04:30:00 +0000 jgoldman 138418 at Ask an IVF baby: does smoking while pregnant lead to antisocial behaviour? <span>Ask an IVF baby: does smoking while pregnant lead to antisocial behaviour?</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field--item"><p><a href=""><img class="inset" src="" alt="Blogging on Peer-Reviewed Research" width="70" height="85" /></a>Our health isn't just affected by the things we do after we're born - the conditions we face inside our mother's womb can have a lasting impact on our wellbeing, much later in life. This message comes from a growing number of studies that compare a mother's behaviour during pregnancy to the subsequent health of her child. </p> <p><img src="" alt="i-e80f11433b70778c06d08316c2f0b73b-Smokingwoman.jpg" />But all of these studies have a problem. Mothers also pass on half of their genes to their children, and it's very difficult to say which aspects of the child's health are affected by conditions in the womb, and which are influenced by mum's genetic legacy. </p> <p>Take the case of smoking. Doing it <a href="">while pregnant</a> is bad news for the foetus, and studies have suggested that children whose mothers smoke during pregnancy are more likely to be born prematurely, be born lighter, have poorer lung function, and be more likely to <a href="">die suddenly</a> before their first birthday. More controversially, they may even show higher levels of behavioural problems including <a href=";itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum">autistic disorders</a> and antisocial tendencies. </p> <p>Biologically, these results make sense, but many of these risks can be inherited too. For example, genetic factors can strongly influence both a person's <a href=";aid=232267">susceptibility to nicotine addiction</a> and their propensity for violent behaviour. A mother's genes could also affect the birth weight of her child. </p> <p>To untangle these influences, the ideal experiment would involve randomly implanting foetuses either in the wombs of their own mothers, or those of unrelated women.<span>  </span>That's possible in animals but deliberately doing so in humans would be both unethical and impractical. Nonetheless, <a href="">Frances Rice</a> from Cardiff University realised that this experiment was actually well underway. </p> <p>Since the advent of <a href="">in vitro fertilisation</a> (IVF) technology in the late 1970s, many mothers have nourished babies in their womb, who weren't genetically related to them. Here was an ideal chance to study the effects of conditions in the womb, without any confusion caused by shared genes. </p> <!--more--><p>Among the many possible detriments of smoking during pregnancy, Rice focused her attention on two - birth weight and antisocial behaviour. Antisocial behaviour has obvious consequences for the child's later life and infants who are very light at the point of birth have <a href="">higher risks of poor health</a> and chronic conditions as adults. </p> <p>Rice examined the fates of 774 "test-tube babies", 204 of whom were born to mothers who were genetically unrelated to them. The children are currently between 5-8 years old. Their medical records revealed how heavy they were at birth, and Rice gave their mothers a series of questionnaires to work out if they smoked while pregnant. </p> <p>She found that babies born to smokers weighed about a pound less than those born to non-smokers. The difference was statistically significant, and it held no matter whether their mothers were genetically related to them or not. Any one of the numerous poisons in tobacco smoke could be responsible for this effect; previous studies have pointed the finger at carbon monoxide, a major part of tobacco smoke, and nicotine, which constricts blood vessels and is a neurotoxin in its own right. Either way, this result provides very strong evidence that smoking directly affects the weight of an infant by changing conditions in the womb. </p> <p>Rice found a different pattern when she considered antisocial behaviour. Using another questionnaire given<span>  </span>to both parents, she catalogued each child's portfolio of disruptive behaviour, from tantrums to stealing to bullying. Overall, the children were more likely to behave antisocially if their mothers smoked than if they didn't, as many other studies have found. But this only held true for related pregnancies - among mums who were unrelated to their children, smoking had no impact on their inclination for troublemaking. </p> <p class="center"><img src="" alt="i-f17c2ef1649191ea5e21c2547b2c3b92-Smokingpregnancy.jpg" /></p> <p>Rice was also careful to adjust her results for many other factors that could have biased them. She took the child's gender and number of siblings into account, as well as the mother's educational level, age, degree of stress in the third trimester, and her own level of antisocial behaviour. Having accounted for this wide assortment of biases, Rice believes that the link between smoking during pregnancy and antisocial behaviour has little to do with conditions in the womb, and is probably due to other factors inherited from biological parent to child. </p> <p>There is a big problem with this data, which weakens its conclusions. The number of mothers who were genetically unrelated to their babies <em>and </em>smoked during pregnancy was very low - just nine women out of a total of 204. That's a pretty small sample to base rigorous conclusions on but admittedly, it does help matters that studies looking at naturally conceived children found similar links between smoking and birth weight. </p> <p>Other studies disagree on the subject of prenatal smoking and disruptive behaviour. Some reviews have concluded that the existing evidence <a href="">supports</a> a true link. Others have agreed with Rice's study, and <a href="">found</a> that the effect is almost entirely due to a combination of inherited genes and inherited environments. Take away the influence of genetics, the child's social background, their parents' antisocial behaviour, and the connection either disappears or is severely reduced. </p> <p>Rice's results certainly support this second conclusion, but they aren't strong enough to seal the debate. Future studies would benefit from larger samples, but the method is very interesting and potentially useful. It could be used to answer wider questions about how much of a child's life is influenced by its time in the womb. </p> <p>Some scientists have tried to separate the effects of nature and nurture by looking at the bodies and behaviours of adopted children, who are genetically unrelated to their parents and even come from different races or nationalities. Rice's method is very similar; the main difference is that the child is "adopted" into a womb while it's still an embryo, rather than into a home while it's a toddler. </p> <p><strong>Reference:</strong><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.jtitle=Proceedings+of+the+National+Academy+of+Sciences&amp;rft_id=info%3Adoi%2F10.1073%2Fpnas.0808798106&amp;;rft.atitle=Disentangling+prenatal+and+inherited+influences+in+humans+with+an+experimental+design&amp;rft.issn=0027-8424&amp;;rft.volume=&amp;rft.issue=&amp;rft.spage=0&amp;rft.epage=0&amp;;;;;;;;rfe_dat=bpr3.included=1;bpr3.tags=">F. Rice, G. T. Harold, J. Boivin, D. F. Hay, M. van den Bree, A. Thapar (2009). Disentangling prenatal and inherited influences in humans with an experimental design <span style="font-style: italic;">Proceedings of the National Academy of Sciences</span> DOI: <a rev="review" href="">10.1073/pnas.0808798106</a></span> </p> <p><strong>More on reproduction: </strong> </p> <p><a href="">Maternal hormone shuts down baby's brain cells during birth</a> </p> <p><a href="">Did conflict between old and young women drive origin of menopause?</a> </p> <p><a href=";h1=;t1=" title="Subscribe using any feed reader!"><strong>Subscribe to the feed</strong></a> </p> <p class="center"><a href=""><img src="" alt="i-5b4148252bd99d05e9ffe49a70c5ebe3-Bookbanner4.jpg" /></a> </p> </div> <span><a title="View user profile." href="/notrocketscience" lang="" about="/notrocketscience" typeof="schema:Person" property="schema:name" datatype="">edyong</a></span> <span>Tue, 02/03/2009 - 02:30</span> <div class="field field--name-field-blog-tags field--type-entity-reference field--label-inline"> <div class="field--label">Tags</div> <div class="field--items"> <div class="field--item"><a href="/tag/child-development" hreflang="en">child development</a></div> <div class="field--item"><a href="/tag/epigenetics" hreflang="en">epigenetics</a></div> <div class="field--item"><a href="/tag/genes-and-behaviour" hreflang="en">Genes and behaviour</a></div> <div class="field--item"><a href="/tag/genetics" hreflang="en">genetics</a></div> <div class="field--item"><a href="/tag/medicine-health" hreflang="en">Medicine &amp; Health</a></div> <div class="field--item"><a href="/tag/mental-health" hreflang="en">mental health</a></div> <div class="field--item"><a href="/tag/sex-and-reproduction" hreflang="en">Sex and reproduction</a></div> <div class="field--item"><a href="/tag/antisocial" hreflang="en">antisocial</a></div> <div class="field--item"><a href="/tag/baby-0" hreflang="en">baby</a></div> <div class="field--item"><a href="/tag/birth-weight" hreflang="en">birth weight</a></div> <div class="field--item"><a href="/tag/disruptive" hreflang="en">disruptive</a></div> <div class="field--item"><a href="/tag/utero" hreflang="en">in utero</a></div> <div class="field--item"><a href="/tag/ivf" hreflang="en">IVF</a></div> <div class="field--item"><a href="/tag/pregnancy" hreflang="en">pregnancy</a></div> <div class="field--item"><a href="/tag/pregnant" hreflang="en">pregnant</a></div> <div class="field--item"><a href="/tag/prenatal" hreflang="en">prenatal</a></div> <div class="field--item"><a href="/tag/smoking" hreflang="en">smoking</a></div> <div class="field--item"><a href="/tag/womb" hreflang="en">womb</a></div> <div class="field--item"><a href="/tag/epigenetics" hreflang="en">epigenetics</a></div> <div class="field--item"><a href="/tag/genetics" hreflang="en">genetics</a></div> <div class="field--item"><a href="/tag/mental-health" hreflang="en">mental health</a></div> </div> </div> <section> <article data-comment-user-id="0" id="comment-2341287" class="js-comment comment-wrapper clearfix"> <mark class="hidden" data-comment-timestamp="1233675993"></mark> <div class="well"> <strong></strong> <div class="field field--name-comment-body field--type-text-long field--label-hidden field--item"><p>This is really interesting. I wonder if this adds to the argument that epigenetics play a part in autism? Smoking can alter your epigenetic code, and there's evidence that epigenetic mutations contribute to the development of autism.</p> </div> <drupal-render-placeholder callback="comment.lazy_builders:renderLinks" arguments="0=2341287&amp;1=default&amp;2=en&amp;3=" token="vbXfJxFiROzKpdz1duLNQrwU1_pN67YsM7MSUsuLSzg"></drupal-render-placeholder> </div> <footer> <em>By <span lang="" typeof="schema:Person" property="schema:name" datatype="">Emily (not verified)</span> on 03 Feb 2009 <a href="">#permalink</a></em> <article typeof="schema:Person" about="/user/0"> <div class="field field--name-user-picture field--type-image field--label-hidden field--item"> <a href="/user/0" hreflang="und"><img src="/files/styles/thumbnail/public/default_images/icon-user.png?itok=yQw_eG_q" width="100" height="100" alt="User Image" typeof="foaf:Image" class="img-responsive" /> </a> </div> </article> </footer> </article> <article data-comment-user-id="0" id="comment-2341288" class="js-comment comment-wrapper clearfix"> <mark class="hidden" data-comment-timestamp="1233727184"></mark> <div class="well"> <strong></strong> <div class="field field--name-comment-body field--type-text-long field--label-hidden field--item"><p>In trying to separate out the environmental effects of smoking during pregnancy from genetic influences, has it ever occurred to anyone to compare differences between the children of smoking and non-smoking fathers with those between the children of smoking and non-smoking mothers? </p> <p>If a father smoking has no effect on his offspring but a mother smoking does, then it is clearly directly environmental, whereas equal effects from both parents would show it to be genetic.</p> <p>Wouldn't this be a far simpler way to clarify the issue than trying to extrapolate from a tiny sample of people whose fertility problems mark them out as so different from the wider population that we cannot be sure the results can be generalised.</p> </div> <drupal-render-placeholder callback="comment.lazy_builders:renderLinks" arguments="0=2341288&amp;1=default&amp;2=en&amp;3=" token="5hB-RacNrRihS4wJ2_goVebzk2lgshYXj6IqCPHqq6w"></drupal-render-placeholder> </div> <footer> <em>By <span lang="" typeof="schema:Person" property="schema:name" datatype="">Ruth (not verified)</span> on 04 Feb 2009 <a href="">#permalink</a></em> <article typeof="schema:Person" about="/user/0"> <div class="field field--name-user-picture field--type-image field--label-hidden field--item"> <a href="/user/0" hreflang="und"><img src="/files/styles/thumbnail/public/default_images/icon-user.png?itok=yQw_eG_q" width="100" height="100" alt="User Image" typeof="foaf:Image" class="img-responsive" /> </a> </div> </article> </footer> </article> <article data-comment-user-id="0" id="comment-2341289" class="js-comment comment-wrapper clearfix"> <mark class="hidden" data-comment-timestamp="1233973945"></mark> <div class="well"> <strong></strong> <div class="field field--name-comment-body field--type-text-long field--label-hidden field--item"><p>The problem with studying smoking, marijuana, suspected environmental toxins, and other harmful and/or addictive substances appears to be the ethical issues in actually giving these substances to study participants. This seems to have precluded RCTs and limited researchers to observational studies. </p> <p>One strategy for getting around this could be to start with a population of heavy substance users, randomly assign them into treatment and control groups and make substance use <i>cessation</i> the treatment. The study could probably be designed to account for spontaneous dosage changes by subjects in the control arm, but at least for addictive substances, they are unlikely to quit of their own accord. The treatment group could be encouraged, perhaps by the promise of monetary reward, or a reduced sentence to keep to the cessation program, possibly under heavy supervision and frequent blood tests. </p> <p>This could help clarify things like - whether heavy smoking leads to Parkinson's disease/Schizophrenia, merely alleviates their symptoms or neither. Similarly for the link between marijuana and Schizophrenia. It could also help to distinguish between the genetic and environmental effects in children exposed to tobacco smoke by their parents.</p> </div> <drupal-render-placeholder callback="comment.lazy_builders:renderLinks" arguments="0=2341289&amp;1=default&amp;2=en&amp;3=" token="Ui-P7Ssg7DhhwU89HaUcUIJMGWj9IhdFr36Bc_J_XIY"></drupal-render-placeholder> </div> <footer> <em>By <span lang="" typeof="schema:Person" property="schema:name" datatype="">Stagyar zil Doggo (not verified)</span> on 06 Feb 2009 <a href="">#permalink</a></em> <article typeof="schema:Person" about="/user/0"> <div class="field field--name-user-picture field--type-image field--label-hidden field--item"> <a href="/user/0" hreflang="und"><img src="/files/styles/thumbnail/public/default_images/icon-user.png?itok=yQw_eG_q" width="100" height="100" alt="User Image" typeof="foaf:Image" class="img-responsive" /> </a> </div> </article> </footer> </article> </section> <ul class="links inline list-inline"><li class="comment-forbidden"><a href="/user/login?destination=/notrocketscience/2009/02/03/ask-an-ivf-baby-does-smoking-while-pregnant-lead-to-antisoci%23comment-form">Log in</a> to post comments</li></ul> Tue, 03 Feb 2009 07:30:25 +0000 edyong 120035 at