Familial influences on adolescence smoking - parental smoking, home smoking ban and home-based sourcing of tobacco

Tupakoimattomien perheiden osuus kaksinkertaistui 1970-luvulta 2000-luvulle. Tupakoimattomassa perheessä sekä lapsi että molemmat vanhemmat ovat olleet tupakoimattomia koko lapsen elämänkaaren ajan. Molempien vanhempien polttaessa, lapsen todennäköisyys ryhtyä tupakoimaan on 8 kertaa suurempi kuin tupakoimattomien vanhempien lapsella. Tämä vanhempien tupakoinnin voimakas vaikutus lasten tupakointiin on säilynyt muuttumattomana 30 vuoden ajan. Lasten tupakointi oli yleisempää, jos kodin sisätiloissa sai tupakoida. Tärkeä tulos oli, että tupakointikielto kodin sisätiloissa vähensi lasten tupakointia jopa niissä perheissä, joissa molemmat vanhemmista olivat tupakoitsijoita. Tupakointikiellot olivat keskimääräistä yleisempiä niissä perheissä, joissa vanhemmilla oli korkea koulutus, vanhemmat olivat tupakoimattomia ja lapsi asui molempien vanhempiensa kanssa. Päivittäin tupakoivista nuorista suuri osa, yli 40 %, sai tupakkaa vanhemmiltaan tai sisaruksiltaan tai oli ottanut tupakkaa kotoa viimeisen kuukauden aikana. Joka viides päivittäin tupakoiva nuori sai tupakkaa vanhemmiltaan. Tutkimuksen tulokset osoittavat, että vanhempien tupakoimattomuus ja kodin tupakointikiellot ovat keinoja, joilla perhe voi merkittävästi ehkäistä lasten tupakointia. Lasten tupakoinnin ehkäisyn kannalta merkitystä on myös sillä, että vanhemmat eivät anna tupakkaa lapsilleen tai jätä niitä kotona vapaasti lasten saataville. TtM Susanna Rainion väitöskirjassa tutkittiin eri perhetekijöiden merkitystä lasten tupakoinnissa. Aineistoina olivat valtakunnallisen Nuorten terveystapatutkimuksen aineistot vuosilta 1977 2007 sekä vuosilta 2000 2005 kootut kansainväliset ja vuosilta 1962 2004 kootut suomalaiset tutkimusjulkaisut vanhempien ja perheen merkityksestä lasten tupakointiin.The overall aim of this dissertation was to increase the knowledge and understanding of the role of familial influences in adolescent smoking. This was first examined in the light of the published literature, followed by three separate studies utilizing data from a Finnish nationwide monitoring system of adolescent health and health behaviors, the Adolescent Health and Lifestyle Survey (AHLS). The AHLS is a mailed survey conducted biennially since 1977 among representative samples of 12-18-year-olds. In the first study (I), the current state of knowledge regarding familial influences on adolescent smoking from international and Finnish studies was reviewed. Parents and siblings smoking and negligent parental attitude towards smoking emerged as the strongest predictors for smoking initiation and continuation in children. The importance of more common familial influences such as parenting or interactions within the family in shaping adolescents smoking behavior has not yet been fully established. However, family structure has been clearly shown to be associated with adolescents smoking, being lowest among adolescents living in two biological parent families. The first study further revealed that familial influences on smoking in adolescence have been insufficiently studied in Finland, although the association between parental and child smoking has been well-documented for decades. Based on eleven cross-sectional surveys using nationally representative samples of 14-18-year-old adolescents, the results from the second study (II) provided unique knowledge for the field of adolescent tobacco research by examining the evolution of the association between parental smoking and child smoking over time (1977-2005). A novel finding was that this association persisted strong and similar between 1977 and 2005. Furthermore, this study explored family smoking trends in the corresponding time period. An important finding was that the proportion of never-smoking families in which neither parents nor child had ever smoked increased substantially from 9% in 1977 to 18% in 2005 while the proportion of smoking families only slightly increased (3.8% vs. 5.5%). The third study (III) examined home smoking bans and associated family factors, as well as associations of home smoking bans with experimental and daily smoking among the adolescents. A remarkable proportion of 12-18-year old Finns live in homes where no total ban on smoking is in place. The prevalence of total home smoking ban varied according to the sociodemographic characteristics of adolescents families. The factors contributed to an increase in the prevalence of total home smoking ban were: having non-smoking parents, having parents with higher education and living in a two biological parent family. The result further showed that the absence of a total home smoking ban independently contributes to a high likelihood of adolescent daily smoking. A noteworthy finding was that this persisted even when the parents themselves smoked. In the fourth study (IV), use of home-based sources of tobacco (from parents, from siblings, taking tobacco from home), and associated family factors among adolescent smoking population were investigated. To summarize the main findings from this study, home-based sourcing was fairly common among adolescent daily smokers, although other social sources and commercial sources were mostly used. The majority of the experimental and occasional smokers got their tobacco from other social sources, mostly friends. Of family factors associated with home-based sourcing, parents smoking and absence of a home smoking ban increased home-based sourcing among adolescent daily smokers. As a conclusion, the importance of several family factors in smoking and smoking-related behaviors of adolescents is underscored by this study. Several valuable contributions to the adolescent tobacco research literature and for future research and practice can also be made. According to the main results of this dissertation, being a non-smoking role model, imposing a total ban on smoking in the home and limiting adolescents access to tobacco through home-based sources provide invaluable tools for parents in adolescent smoking prevention. Smoking prevention work would benefit from investigating family-focused intervention strategies. The issues that could also be looked further are home smoking policies