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Op dinsdag 6 april 2010 10:24 schreef McKillem het volgende:Heel sappig nieuwsbericht maar zonder waarden en grafieken volstrekt waardeloos.
Cognitive test scores in male adolescent cigarette smokers compared to non-smokers: a population-based study.Weiser M, Zarka S, Werbeloff N, Kravitz E, Lubin G.
Department of Psychiatry, Sheba Medical Center, Tel Hashomer, 52621 Israel. mweiser@netvision.net.il
BACKGROUND: Although previous studies indicate that people with lower intelligence quotient (IQ) scores are more likely to become cigarette smokers, IQ scores of siblings discordant for smoking and of adolescents who began smoking between ages 18-21 years have not been studied systematically. METHODS: Each year a random sample of Israeli military recruits complete a smoking questionnaire. Cognitive functioning is assessed by the military using standardized tests equivalent to IQ. RESULTS: Of 20 221 18-year-old males, 28.5% reported smoking at least one cigarette a day (smokers). An unadjusted comparison found that smokers scored 0.41 effect sizes (ES, P < 0.001) lower than non-smokers; adjusted analyses remained significant (adjusted ES = 0.27, P < 0.001). Adolescents smoking one to five, six to 10, 11-20 and 21+ cigarettes/day had cognitive test scores 0.14, 0.22, 0.33 and 0.5 adjusted ES poorer than those of non-smokers (P < 0.001). Adolescents who did not smoke by age 18, and then began to smoke between ages 18-21 had lower cognitive test scores compared to never-smokers (adjusted ES = 0.14, P < 0.001). An analysis of brothers discordant for smoking found that smoking brothers had lower cognitive scores than non-smoking brothers (adjusted ES = 0.27; P = 0.014).
CONCLUSION: Controlled analyses from this large population-based cohort of male adolescents indicate that IQ scores are lower in male adolescents who smoke compared to non-smokers and in brothers who smoke compared to their non-smoking brothers. The IQs of adolescents who began smoking between ages 18-21 are lower than those of non-smokers. Adolescents with poorer IQ scores might be targeted for programmes designed to prevent smoking.Uitgebreide discussie (van bovenstaande studie)As a group, male adolescent smokers have lower cognitive test scores compared to non-smokers. Male adolescents who smoke more than a pack of cigarettes a day scored 0.5 ES (equivalent to 7.5 IQ points) below nonsmokers after adjustments for SES.
These findings are present in smokers from both high as well as low SES levels. These findings are not due to nicotine withdrawal, as male adolescents who did not smoke during the draft board assessment, but did start smoking during their military service also had cognitive test scores significantly poorer than non-smoking adolescents.
Even analyses within families of sib-pairs discordant for smoking showed that the smoking brothers had significantly lower cognitive test scores compared to their non-smoking brothers. The cognitive test scores of former smokers were intermediate; better than that of current smokers,
but poorer than the cognitive test scores of non-smokers. These data, based on a large population-based
cohort, expand upon and strengthen the results of previously published longitudinal studies which reported
that childhood IQ is associated with increased risk of later smoking [1–4,7]. A similar finding was reported in relation to adolescent IQ, which has been shown to be strongly associated with educational level, socioeconomic position and income later in life [23]. These longitudinal data support the possible causal effect of low IQ and the onset of cigarette smoking, and mitigate against claims that cigarette smoking damages cognitive abilities [21].
Of particular interest is the analysis showing that the 1863 adolescents who did not smoke during the draft
board cognitive assessment but did begin to smoke between ages 18 and 21 had lower cognitive test scores
compared to never-smokers. These data are in contrast with a very small (n = 18) group taken from a similar
study using IQ data from the Swedish army [2], which found that individuals who reported being non-smokers
at age 18 but who did smoke at follow-up (mean age = 36) had, on average, higher IQ scores. The source of
the apparent discrepancy between their findings and ours might be that their data were based on a very small
number of adolescents. Given that variables such as truancy and school disengagement are generally associated with lower IQ [24], it has been hypothesized that the association between lower IQ and smoking is mediated by smokers socializing with other disaffected young people, who encourage each other to smoke. The current study does not support this hypothesis as the Israeli military has mandatory induction, including people with higher as well as lower levels of functioning.
This the first study to systematically assess differences in IQ among siblings discordant for smoking, finding that the smoking siblings had lower IQ scores than their nonsmoking siblings. This is in line with a previous study of 52 same-sex sibling pairs discordant for smoking [25], reporting that the smoking siblings had significantly fewer years of education and significantly higher scores on measures of depression, childhood attention deficit hyperactive disorder (ADHD) and alcohol dependence than their non-smoking siblings. This might be interpreted as strengthening the association between smoking and IQ, beyond the genetic and environmental factors shared by siblings. The results of the current study are not affected by the higher prevalence of mental illness among smokers [12], who also have lower scores on cognitive tests [13,14], as
they were excluded form the analysis. It is therefore most reasonable to conclude that less intelligent adolescents are more prone to smoke cigarettes. This is compatible with other research indicating that low IQ increases risk for other behaviours related to poor health outcomes,including heavy alcohol abuse, obesity and hypertension
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[ Bericht 22% gewijzigd door dramatiek op 06-04-2010 11:03:37 ]