Sex and gender differences in tobacco smoking among adolescents in French secondary schools

Aim. We investigated the relationship between sex (genetic/biological) and gender (environmental/ cultural) factors in relation to adolescent tobacco smoking. Methods. A representative sample of 11,582 students from French secondary public schools participated in the study by completing a self-administered, standardised questionnaire. Results. Using the WHO classification for smoking in the youth, 15.6% of the adolescents were regular smokers, 7.7% occasional smokers, 17.9% experimental smokers and 4.8% ex-smokers, with no statistically significant gender difference. Taking non-smoking as a reference, puberty had a much greater effect on the likelihood of being a regular smoker [OR=18.0 (95% Confidence Interval: 9.6- 32)] than of being an experimental/occasional smoker [OR=3.7 (2.9-4.6)] among girls. For boys, the effect of puberty was not as great [OR=4.7 (3.5-6.5)] for regular vs. [OR=2.1 (1.8-2.5)] for experimental/occasional smokers). Similarly, illicit drug use had a larger effect on the likelihood of being regular smoker vs. non-smoker [OR=15.0 (12.0-20.0) in boys and 12 (8.8-16.0) in girls] than of being experimental/occasional smoker vs. a non-smoker [OR=4.8 (3.7-6.1) and 2.9 (2.1-3.9) respectively]. Other factors related to regular smoking were exposure to passive smoking and regular alcohol consumption. Living with both parents was a protective factor for life and regular smoking in both genders. Conclusions. Our results show that influential factors of sex-related (puberty), gender-specific (environmental tobacco smoking, alcohol consumption, drug abuse) or sex/gender (regular sexual intercourse) are related to the smoking behaviour in French adolescents

Origin and evolution of the light nuclides

After a short historical (and highly subjective) introduction to the field, I discuss our current understanding of the origin and evolution of the light nuclides D, He-3, He-4, Li-6, Li-7, Be-9, B-10 and B-11. Despite considerable observational and theoretical progress, important uncertainties still persist for each and every one of those nuclides. The present-day abundance of D in the local interstellar medium is currently uncertain, making it difficult to infer the recent chemical evolution of the solar neighborhood. To account for the observed quasi-constancy of He-3 abundance from the Big Bang to our days, the stellar production of that nuclide must be negligible; however, the scarce observations of its abundance in planetary nebulae seem to contradict this idea. The observed Be and B evolution as primaries suggests that the source composition of cosmic rays has remained quasi-constant since the early days of the Galaxy, a suggestion with far reaching implications for the origin of cosmic rays; however, the main idea proposed to account for that constancy, namely that superbubbles are at the source of cosmic rays, encounters some serious difficulties. The best explanation for the mismatch between primordial Li and the observed "Spite-plateau" in halo stars appears to be depletion of Li in stellar envelopes, by some yet poorly understood mechanism. But this explanation impacts on the level of the recently discovered early ``Li-6 plateau'', which (if confirmed), seriously challenges current ideas of cosmic ray nucleosynthesis.Comment: 18 pages, 9 figs. Invited Review in "Symposium on the Composition of Matter", honoring Johannes Geiss on the occasion of his 80th birthday (Grindelwald, Switzerland, Sept. 2006), to be published in Space Science Series of ISS