Liesbeth Mercken

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The co-evolution of adolescents' friendship networks and their smoking behavior is examined in a large sample across six European countries. Selection and influence processes are disentangled using new methods of social network analysis that enable alternative selection mechanisms to be controlled for. The sample consisted of 7704 adolescents participating(More)
OBJECTIVE To examine whether smoking onset in young adolescents is predicted by peer or parental smoking. DESIGN Longitudinal design with one pretest and one follow-up at 12 months. SETTING Schools in Finland, Denmark, the Netherlands, the United Kingdom, Spain and Portugal. PARTICIPANTS 7102 randomly selected adolescents from six countries. Mean age(More)
OBJECTIVE Similarity in alcohol consumption among adolescent friends could be caused by the influence of friends or by the selection of friends who consume similar levels of alcohol. This article aims to disentangle influence and selection processes while specifically examining changes over time in these processes and possible differences between reciprocal(More)
The aim of this study was to explore subgroup effects by high and low socioeconomic position (SEP) of three previously conducted, effective European interventions. Reanalyses stratified by SEP were conducted by the research groups of each study. All studies were school-based: two multi-component interventions targeting intake of fat or fruit and vegetables(More)
The aim was to study whether physical activity (PA) interventions in European teenagers are equally effective in adolescents of low versus high socio-economic status (SES). Based on a systematic review (Project TEENAGE), three school-based studies for secondary analyses were selected. SES stratified analyses were run in: (i) a Belgian multi-component(More)
BACKGROUND Smoking prevalence is higher among low socio-economic status (LSES) groups, and this difference may originate from a higher intention to smoke in childhood. This study aims to identify factors that explain differences in intention to smoke between children living in high socio-economic status (HSES) and LSES neighbourhoods. METHODS(More)
OBJECTIVE This study examined the impact of future friends and the contribution of different social influence and selection processes in predicting adolescents' smoking behaviour by extending the theory of planned behaviour (TPB). We investigated the impact of previous smoking, direct pressure from friends, descriptive norms of present and future friends,(More)
BACKGROUND Compared to other European countries, the Netherlands score among the highest of binge drinking rates of 16 to 18 year old adolescents. Dutch adolescents aged 16 are legally allowed to buy and consume low strength alcoholic beverages. This study focused on determinants of binge drinking in such a permissive environment from the perspectives of(More)
BACKGROUND Early adolescent alcohol use is a major public health challenge. Without clear guidance on the causal pathways between peers and alcohol use, adolescent alcohol interventions may be incomplete. The objective of this study is to disentangle selection and influence effects associated with the dynamic interplay of adolescent friendships and alcohol(More)