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Article: Explaining the effects of a 1-year intervention promoting a low fat diet in adolescent girls: A mediation analysis

TitleExplaining the effects of a 1-year intervention promoting a low fat diet in adolescent girls: A mediation analysis
Authors
KeywordsAdolescent health
Child behavior
Child nutrition
Environmental change
Fat intake
Issue Date2007
PublisherBioMed Central Ltd. The Journal's web site is located at http://www.ijbnpa.org/
Citation
International Journal Of Behavioral Nutrition And Physical Activity, 2007, v. 4 How to Cite?
AbstractBackground: Although it is important to investigate how interventions work, no formal mediation analyses have been conducted to explain behavioral outcomes in school-based fat intake interventions in adolescents. The aim of the present study was to examine mediation effects of changes in psychosocial determinants of dietary fat intake (attitude, social support, self-efficacy, perceived benefits and barriers) on changes in fat intake in adolescent girls. Methods: Data from a 1-year prospective intervention study were used. A random sample of 804 adolescent girls was included in the study. Girls in the intervention group (n = 415) were exposed to a multi-component school-based intervention program, combining environmental changes with a computer tailored fat intake intervention and parental support. Fat intake and psychosocial determinants of fat intake were measured with validated self-administered questionnaires. To assess mediating effects, a product-of-coefficient test, appropriate for cluster randomized controlled trials, was used. Results: None of the examined psychosocial factors showed a reliable mediating effect on changes in fat intake. The single-mediator model revealed a statistically significant suppression effect of perceived barriers on changes in fat intake (p = 0.011). In the multiple-mediator model, this effect was no longer significant, which was most likely due to changes in perceived barriers being moderately related to changes in self-efficacy (-0.30) and attitude (-0.25). The overall mediated-suppressed effect of the examined psychosocial factors was virtually zero (total mediated effect = 0.001; SE = 7.22; p = 0.992). Conclusion: Given the lack of intervention effects on attitudes, social support, self-efficacy and perceived benefits and barriers, it is suggested that future interventions should focus on the identification of effective strategies for changing these theoretical mediators in the desired direction. Alternatively, it could be argued that these constructs need not be targeted in interventions aimed at adolescents, as they may not be responsible for the intervention effects on fat intake. To draw any conclusions regarding mediators of fat-intake change in adolescent' girls and regarding optimal future intervention strategies, more systematic research on the mediating properties of psychosocial variables is needed. © 2007 Haerens et al; licensee BioMed Central Ltd.
Persistent Identifierhttp://hdl.handle.net/10722/137056
ISSN
2015 Impact Factor: 3.993
2015 SCImago Journal Rankings: 2.216
PubMed Central ID
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorHaerens, Len_HK
dc.contributor.authorCerin, Een_HK
dc.contributor.authorDeforche, Ben_HK
dc.contributor.authorMaes, Len_HK
dc.contributor.authorDe Bourdeaudhuij, Ien_HK
dc.date.accessioned2011-08-09T03:16:29Z-
dc.date.available2011-08-09T03:16:29Z-
dc.date.issued2007en_HK
dc.identifier.citationInternational Journal Of Behavioral Nutrition And Physical Activity, 2007, v. 4en_HK
dc.identifier.issn1479-5868en_HK
dc.identifier.urihttp://hdl.handle.net/10722/137056-
dc.description.abstractBackground: Although it is important to investigate how interventions work, no formal mediation analyses have been conducted to explain behavioral outcomes in school-based fat intake interventions in adolescents. The aim of the present study was to examine mediation effects of changes in psychosocial determinants of dietary fat intake (attitude, social support, self-efficacy, perceived benefits and barriers) on changes in fat intake in adolescent girls. Methods: Data from a 1-year prospective intervention study were used. A random sample of 804 adolescent girls was included in the study. Girls in the intervention group (n = 415) were exposed to a multi-component school-based intervention program, combining environmental changes with a computer tailored fat intake intervention and parental support. Fat intake and psychosocial determinants of fat intake were measured with validated self-administered questionnaires. To assess mediating effects, a product-of-coefficient test, appropriate for cluster randomized controlled trials, was used. Results: None of the examined psychosocial factors showed a reliable mediating effect on changes in fat intake. The single-mediator model revealed a statistically significant suppression effect of perceived barriers on changes in fat intake (p = 0.011). In the multiple-mediator model, this effect was no longer significant, which was most likely due to changes in perceived barriers being moderately related to changes in self-efficacy (-0.30) and attitude (-0.25). The overall mediated-suppressed effect of the examined psychosocial factors was virtually zero (total mediated effect = 0.001; SE = 7.22; p = 0.992). Conclusion: Given the lack of intervention effects on attitudes, social support, self-efficacy and perceived benefits and barriers, it is suggested that future interventions should focus on the identification of effective strategies for changing these theoretical mediators in the desired direction. Alternatively, it could be argued that these constructs need not be targeted in interventions aimed at adolescents, as they may not be responsible for the intervention effects on fat intake. To draw any conclusions regarding mediators of fat-intake change in adolescent' girls and regarding optimal future intervention strategies, more systematic research on the mediating properties of psychosocial variables is needed. © 2007 Haerens et al; licensee BioMed Central Ltd.en_HK
dc.languageeng-
dc.publisherBioMed Central Ltd. The Journal's web site is located at http://www.ijbnpa.org/en_HK
dc.relation.ispartofInternational Journal of Behavioral Nutrition and Physical Activityen_HK
dc.rightsThe International Journal of Behavioral Nutrition and Physical Activity. Copyright © BioMed Central Ltd.-
dc.subjectAdolescent health-
dc.subjectChild behavior-
dc.subjectChild nutrition-
dc.subjectEnvironmental change-
dc.subjectFat intake-
dc.titleExplaining the effects of a 1-year intervention promoting a low fat diet in adolescent girls: A mediation analysisen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1479-5868&volume=4, article no. 55&spage=55&epage=&date=2007&atitle=Explaining+the+effects+of+a+1-year+intervention+promoting+a+low+fat+diet+in+adolescent+girls:+a+mediation+analysis-
dc.identifier.emailCerin, E: ecerin@hku.hken_HK
dc.identifier.authorityCerin, E=rp00890en_HK
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1186/1479-5868-4-55en_HK
dc.identifier.pmid17996087-
dc.identifier.pmcidPMC2200660-
dc.identifier.scopuseid_2-s2.0-38349079858en_HK
dc.identifier.hkuros165032-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-38349079858&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume4en_HK
dc.identifier.spage55-
dc.identifier.epage55-
dc.identifier.isiWOS:000252412500001-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridHaerens, L=15135602200en_HK
dc.identifier.scopusauthoridCerin, E=14522064200en_HK
dc.identifier.scopusauthoridDeforche, B=6507791855en_HK
dc.identifier.scopusauthoridMaes, L=7005829786en_HK
dc.identifier.scopusauthoridDe Bourdeaudhuij, I=35510873600en_HK
dc.identifier.citeulike1895973-

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