Sunday, October 07, 2007


That's not the least bit surprising -- as smokers tend to be lower class anyhow and class is a strong predictor of school success. The interesting thing is that there is an effect that goes beyond class. What might it be? IQ, I suspect. Smokers are less likely to be bright and IQ is highly hereditary. This study is therefore NO evidence that secondhand smoke is harmful (though it may be). It probably shows simply that dumber parents have dumber kids. Popular summary below followed by journal abstract

Smoking parents may not only affect their children's health with secondhand smoke, they may also damage their academic performance

Surprising findings in the Journal of Adolescent Health this week show that exposure to secondhand smoke at home decreases the chances of passing school exams by 30 per cent. The study was based on information from 6380 pregnant women and their children. Academic performance was measured on the British Ordinary Level (O-Level) and Advanced Level (A-Level) exams, usually taken at age 16 and 18, respectively. Information was gathered on children's exposure to smoking prior to birth and as teenagers, as well as their gender and socio-economic status. Even after accounting for these other factors, passive smoking at home still increased the chances of failing exams. The findings should further encourage parents to stop smoking around their children, or quit altogether, say the authors.


Adolescent Environmental Tobacco Smoke Exposure Predicts Academic Achievement Test Failure

By Bradley N. Collins et al.

Purpose: Research has linked prenatal tobacco exposure to neurocognitive and behavioral problems that can disrupt learning and school performance in childhood. Less is known about its effects on academic achievement in adolescence when controlling for known confounding factors (e.g., environmental tobacco smoke [ETS]). We hypothesized that prenatal tobacco exposure would decrease the likelihood of passing academic achievement tests taken at 16 and 18 years of age.

Methods: This study was a longitudinal analysis of birth cohort data including 6,380 pregnant women and offspring from the 1958 National Child Development Study (NCDS). Academic pass/fail performance was measured on British standardized achievement tests ("Ordinary Level" [O-Level] and Advanced Level: [A-Level]). Prenatal tobacco exposure plus controlling variables (ETS, teen offspring smoking and gender, maternal age at pregnancy, maternal smoking before pregnancy, and socioeconomic status) were included in regression models predicting O- and A-Level test failure.

Results: Significant predictors of test failure in the O-Level model included exposure to maternal (OR = 0.71, p < .0001) and paternal (OR = 0.70, p < .0001) ETS, as well as teen smoking, female gender, and lower SES. Prenatal tobacco exposure did not influence failure. Similar factors emerged in the A-Level model except that male gender contributed to likelihood of failure. Prenatal exposure remained nonsignificant.

Conclusions: Our model suggests that adolescent exposure to ETS, not prenatal tobacco exposure, predicted failure on both O- and A-Level achievement tests when controlling for other factors known to influence achievement. Although this study has limitations, results bolster growing evidence of academic-related ETS consequences in adolescence.

J Adolesc Health 2007;41:363-370


Very small numbers here so the cerebral palsy finding may not mean anything but it obviously deserves further investigation. Overall, the results are in fact reassuring. Popular summary below followed by abstract:

Pregnant women at risk of premature labour are usually given a single injection of corticosteroids to help the baby's lungs to mature. Some women are given multiple injections, but a new study in the New England Journal of Medicine has found that giving multiple doses of corticosteroids increases the risk of cerebral palsy in babies. Women given an initial dose of corticosteroids between 23 and 31 weeks of pregnancy were randomly assigned to receive either weekly injections of the corticosteroid betamethasone or placebo injections. In total, 556 children born to these women were given physical and brain function tests at two to three years of age. Six children whose mothers received multiple corticosteroid injections had cerebral palsy, compared to only one child in the placebo group. While the number of affected children was small, the authors conclude that the increased risk is concerning and warrants further study.


Long-Term Outcomes after Repeat Doses of Antenatal Corticosteroids

By Ronald J. Wapner et al.

Background: Previous trials have shown that repeat courses of antenatal corticosteroids improve some neonatal outcomes in preterm infants but reduce birth weight and increase the risk of intrauterine growth restriction. We report long-term follow-up results of children enrolled in a randomized trial comparing single and repeat courses of antenatal corticosteroids.

Methods: Women at 23 through 31 weeks of gestation who remained pregnant 7 days after an initial course of corticosteroids were randomly assigned to weekly courses of betamethasone, consisting of 12 mg given intramuscularly and repeated once at 24 hours, or an identical-appearing placebo. We studied the children who were born after these treatments when they were between 2 and 3 years of corrected age. Prespecified outcomes included scores on the Bayley Scales of Infant Development, anthropometric measurements, and the presence of cerebral palsy.

Results: A total of 556 infants were available for follow-up; 486 children (87.4%) underwent physical examination and 465 (83.6%) underwent Bayley testing at a mean (~SD) corrected age of 29.3~4.6 months. There were no significant differences in Bayley results or anthropometric measurements. Six children (2.9% of pregnancies) in the repeat-corticosteroid group had cerebral palsy as compared with one child (0.5% of pregnancies) in the placebo group (relative risk, 5.7; 95% confidence interval, 0.7 to 46.7; P=0.12).

Conclusions: Children who had been exposed to repeat as compared with single courses of antenatal corticosteroids did not differ significantly in physical or neurocognitive measures. Although the difference was not statistically significant, the higher rate of cerebral palsy among children who had been exposed to repeat doses of corticosteroids is of concern and warrants further study.

N Engl J Med 2007;357:1190-1198


Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.


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