Hi I've always admired Anne Streissguth's work and often use it to illustrate multiple regression as a way to strengthen (although not definitively demonstrate) causal inferences. Here's an excerpt from:
Streissguth et al (1989). IQ at Age 4 in Relation to Maternal Alcohol Use and Smoking During Pregnancy. Developmental Psychology, 25, 3-11. "This study indicates that prenatal alcohol exposure is significantly related to child IQ at 4 years of age, in a relatively healthy, generally middle-class sample. Self-reported consumption of over three drinks a day on the average was associated with an average IQ decrement of almost 5 IQ points, after adjustment for a wide variety of other factors that also predict child IQ. This decrement represents an estimated tripling of the risk of subnormal intelligence (i.e., IQ < 85) for a child of "average background" in our sample. ... 2. The statistical models referred to here as "threshold" models should not be regarded as "biological" thresholds, because other outcomes from this study have shown strong linear effects of prenatal alcohol exposure. ..." Among the many control variables were several that independently predicted child IQ at age 4, at least one of which I know of no warnings about, namely aspirin use (and its significant interaction with child's gender ... I could not discern from quick read direction of this interaction or of separate gender main effect ... the two coefficients suggest effect of aspirin for one gender and no effect perhaps for other?). Antibiotic use had a similar negative effect as aspirin and alcohol. Despite the numerous (statistically) controlled variables, Streissguth correctly cautions against causal inferences and argues for interpretation in conjunction with experimental animal studies. Very nice illustration of possible confounding factors in nonexperimental studies and ways to (partially) address them. Take care Jim James M. Clark Professor of Psychology 204-786-9757 204-774-4134 Fax [email protected] >>> Paul C Bernhardt <[email protected]> 07-Feb-09 8:57:33 AM >>> This is precisely the calculus my wife and I have employed over the past 7 months of her pregnancy (expecting in late March). That is, since the evidence is unclear on what is safe, but clearly none is safe, then none is the right answer. There were celebrations we attended in which we would have liked the answer to be Ε‘one glass a day is OK* but not having really good evidence to support that left us saying, *no, thank you* at parties, and using Fre alcohol free sparkling wine for New Years. -- Paul Bernhardt Frostburg State University Frostburg, MD, USA On 2/6/09 11:50 AM, "DeVolder Carol L" <[email protected]> wrote: > > > > > > > > > Dear Tipsters, > > I tried posting this on the other list (PSYTEACH) but it was rejected because > it serves no purpose to carry this any further since it has strayed from the > *teaching of psychology.* This list is easier, and if you*re not interested, > then just delete it. I think it relates to teaching psych because I want to > provide my students with what I consider valid information. So, I*m copying > what I sent to the other list for what it*s worth. The question on PSYTEACH to > which I am referring dealt with how much alcohol is safe during pregnancy, and > whether we are using scare tactics to unnecessarily frighten people. > > I've been waiting to write this message because I wanted to hear back from a > colleague, Dr. Jennifer Thomas, at San Diego State University. In my opinion, > Jennifer is a well-respected expert in this field and is past president of > the Alcohol Spectrum Disorders Study Group. I also went to grad school with > Jen and remember her work with rat pups and their exposure to alcohol (that's > my disclosure about potential bias, but really I'd still consider her an > expert). I asked her for her opinion on acceptable levels of alcohol ingestion > during pregnancy and the threshold for adverse fetal effects, and she > acknowledged that there is very active debate on the topic, with the consensus > in the US being somewhat different from the consensus in the UK. (The position > in the US is abstinence, in the UK the accepted level is a glass per day.) In > her words, "The problem really is that there is so much variability in > response to alcohol(genetics, nutrition, other exposures) that one cannot make > a prediction of the risk for an individual and so there is NO known safe level > of alcohol exposure during pregnancy. We certainly see changes with low > levels of exposure with the animal models. It is more difficult to study in > humans." Jennifer also pointed me to two sites, which I am including here: > http://www.rsoa.org/fas.html <http://www.rsoa.org/fas.html> and > http://www.rsoa.org/fas-Response.pdf <http://www.rsoa.org/fas-Response.pdf> . > The second link has a reference list. > > My opinion remains unchanged--I still believe in complete abstinence during > all phases of pregnancy. I realize there are anecdotes about people who drink > and their "baby came out just fine," but I'd rather be safe than sorry as much > as possible. > > Carol > > > > Carol DeVolder, Ph.D. > > Professor of Psychology > > Chair, Department of Psychology > > St. Ambrose University > > Davenport, Iowa 52803 > > phone: 563-333-6482 > > e-mail: [email protected] > > > > > --- > To make changes to your subscription contact: > > Bill Southerly ([email protected]) > --- To make changes to your subscription contact: Bill Southerly ([email protected]) --- To make changes to your subscription contact: Bill Southerly ([email protected])
