Do smoking and fruit and vegetable intake mediate the association between socio-economic status and plasma carotenoids?

BACKGROUND: The aim was to study whether the association between educational attainment and antioxidant status is mediated by smoking and fruit and vegetable intake. METHODS: Cross-sectional analyses of the Oslo Youth Study 2006 wave were carried out. Information about education, smoking habits and diet was collected by questionnaire for 261 subjects (142 women and 119 men aged 38-42 years). Blood samples, height and weight measurements were taken by the participants' General Practitioner. Blood were analysed for plasma carotenoids. Linear regression analyses were used to examine whether smoking and fruit and vegetable intake mediate the association between education and plasma carotenoids. RESULTS: Educational level was positively associated with ß-cryptoxanthin, α-carotene and lutein/zeaxanthin, but not with total carotenoids, ß-carotene or lycopene. Education was negatively associated with smoking and positively associated with fruit and vegetable intake. Smoking was negatively associated with ß-cryptoxanthin, and fruit and vegetable intake was positively associated with ß-cryptoxanthin (adjusted for educational level). Moreover, cigarette consumption mediated the association between education and ß-cryptoxanthin by 37%, while fruit and vegetable intake mediated this association by 18%. The total mediation effect was 55%. CONCLUSION: Smoking seemed to be more important as a mediator between education and plasma levels of ß-cryptoxanthin than the intake of fruit and vegetables, but more studies are needed to establish the relative importance of smoking and diet as mediators of the association between education and antioxidant status.

Are screen-based sedentary behaviors longitudinally associated with dietary behaviors and leisure-time physical activity in the transition into adolescence?

BACKGROUND: There is a need for more longitudinal studies investigating the associations between screen-based sedentary behaviors (SB), dietary behaviors and leisure-time physical activity (PA). METHODS: In the HEIA cohort study, 908 children were followed from age 11 to age 13 (September 2007-May 2009). The children self-reported their intake of fruits, vegetables, soft drinks with sugar and snacks. TV/DVD use, computer/game use and leisure-time PA were also self-reported. Multilevel generalized linear mixed model analysis was used to assess longitudinal associations between the screen-based SB and each of the two other behaviors. RESULTS: Twenty-month changes in TV/DVD use and computer/game use were positively associated with changes in the consumption of soft drinks with sugar and unhealthy snacks in the same period; and inversely associated with change in vegetable consumption. Change in computer/game use was also inversely related to change in fruit consumption. An inverse but non-substantive association was found between change in TV/DVD use and change in leisure-time PA. Change in computer/game use was not significantly associated with change in leisure-time PA. CONCLUSIONS: Changes in screen-based SB were associated with multiple unfavorable changes in dietary habits, although the associations were weak. These associations need to be further investigated in intervention/experimental studies, to assess whether changing screen-based SB will result in clinically relevant changes in dietary behaviors. However, the findings of this study suggest that screen-based SB and leisure-time PA are largely independent behaviors which should be addressed separately in health promotion activities.

Adolescents' prospective screen time by gender and parental education, the mediation of parental influences.

BACKGROUND: The present study investigated associations in gender dyads of parents' and adolescents' time spent on television and video viewing (TV/DVD), and computer and electronic game use (PC/games) at the ages of 11 and 13 years. Possible mediating effects of parental modelling and parental regulation in the relationship between parental education and adolescents' prospective TV/DVD and PC/game time were further examined. METHODS: A total of 908 adolescents, participating at both ages 11 and 13 years in the Norwegian HEalth In Adolescents (HEIA) cohort study (2007-2009), were included in the analyses. Data on adolescents', mothers' and fathers' self reported time spent on TV/DVD and PC/games were measured at both time points by questionnaires. Correlation coefficients were used to examine gender dyads of parents' and adolescents' reports. Mediation analyses using linear regression investigated possible mediation effects of parental modelling and parental regulation in the prospective relationship between parental education and adolescents' time spent on TV/DVD and PC/games between the ages of 11 and 13 years. RESULTS: Correlations of screen time behaviours in gender dyads of parents and adolescents showed significant associations in time spent on TV/DVD at the age of 11 and 13 years. Associations between mothers and sons and between fathers and daughters were also observed in time spent on PC/games at the age of 11 years. Maternal and paternal modelling was further found to mediate the relationship between parental education and adolescents' prospective TV/DVD time between the ages of 11 and 13 years. No mediation effect was observed for parental regulation, however a decrease in both maternal and paternal regulation at the age of 11 years significantly predicted more TV/DVD time among adolescents at the age of 13 years. CONCLUSION: Cross-sectional and longitudinal relationships were observed in gender dyads of parents' and adolescents' screen time behaviours at the ages of 11 and 13 years, and further studies including both parents and their children should be emphasized. Moreover, maternal and paternal modelling were found to be important target variables in interventions aiming to reduce social differences by parental education in adolescents' prospective time spent on TV/DVD.

The relationship between parental education and adolescents' soft drink intake from the age of 11-13 years, and possible mediating effects of availability and accessibility.

The present study examined the prospective relationship between parental education and adolescents' soft drink intake over 20 months, and possible mediating effects of adolescents' availability and accessibility of soft drinks at home. A total of 866 adolescents, with data on two time points in the Norwegian HEalth In Adolescents (HEIA) cohort study (2007-9), were included in the analyses. Data on intake and determinants of soft drinks were collected from adolescents and both parents by questionnaires. Mediation analyses using linear regression investigated the total and direct effects of parental education on adolescents' soft drink intake from the age of 11-13 years. In order to investigate prospective relationships, two models were set up to measure the (1) prediction and (2) change in consumption over 20 months. Possible mediation effects of availability and perceived accessibility at home were further examined in both models. The results showed that a lower level of parental education predicted a higher intake of soft drinks among adolescents after 20 months, and that higher perceived accessibility of soft drinks reported by adolescents and mothers explained 39 % of the total effect. No relationship was observed between parental education and the change in adolescents' intake of soft drinks over 20 months. Interventions aimed at families with low parental education should target the perceived accessibility of soft drinks at home in order to diminish social differences in adolescents' soft drink consumption.

Does tracking of dietary behaviours differ by parental education in children during the transition into adolescence?

OBJECTIVE: The present study investigates the changes and tracking of dietary behaviours in Norwegian 11-year-olds and examines the association between parental education and dietary tracking over a time period of 20 months. DESIGN: Longitudinal data from the Norwegian HEalth In Adolescents (HEIA) cohort study followed up at three time points (2007-2009). SETTING: Intakes of fruits, vegetables and snacks were assessed by frequency and intakes of sugar-sweetened soft drinks and squash were assessed by frequency and amount. Tracking of dietary behaviours was assessed by adolescents' relative position in rank over time and Cohen's kappa was used to measure tracking coefficients. Multinomial logistic regression analyses were performed to assess the association between parental education and the tracking of dietary behaviours. SUBJECTS: In total, 885 adolescents from the HEIA cohort study participated by answering Internet-based questionnaires at three time points. RESULTS: The results indicated that boys and girls maintained their relative position in rank of dietary intake over time, when grouped by baseline consumption. Fair to moderate tracking coefficients of dietary variables were observed. An inverse association was found between parental education and stability of soft drink and squash consumption during the 20 months. CONCLUSIONS: The observed tracking pattern indicates the importance of promoting healthy dietary behaviours at an even earlier age. Furthermore, interventions should focus particularly on adolescents from families with low parental education and their consumption of sugar-sweetened beverages.

Does the school food environment influence the dietary behaviours of Norwegian 11-year-olds? The HEIA study.

AIMS: The aim of the study is to investigate the influence of the school food environment on the dietary behaviours of 11-year-old Norwegian children in elementary schools. METHODS: Baseline data from a school-based intervention study: the Health In Adolescents study was used. A total of 1425 11-year-old children from 35 schools from the eastern part of Norway were included. School administrators provided information on the physical, political, and sociocultural school food environment and students reported their intake of fruits, vegetables, sugar-sweetened beverages (SSB), and snacks. Multilevel modelling was used to assess the school-level variance in dietary behaviours and to investigate the association of school food environmental factors with these dietary behaviours. RESULTS: After adjustment for student characteristics, the school level accounted for a small proportion (1.1%-3.0%) of the variance in the dietary behaviours investigated. None of the investigated school food environmental factors were found to be related to the children's reported intake of fruits, vegetables, snacks or SSB. CONCLUSIONS: Most of the variance in the dietary behaviours investigated was at the personal level. Thus in this sample, the investigated school-level factors do not appear to exert a strong influence on the dietary behaviours of children. Longitudinal studies using validated measures of the school food environment are needed.

Stability and change in screen-based sedentary behaviours and associated factors among Norwegian children in the transition between childhood and adolescence.

BACKGROUND: In order to inform interventions to prevent sedentariness, more longitudinal studies are needed focusing on stability and change over time in multiple sedentary behaviours. This paper investigates patterns of stability and change in TV/DVD use, computer/electronic game use and total screen time (TST) and factors associated with these patterns among Norwegian children in the transition between childhood and adolescence. METHODS: The baseline of this longitudinal study took place in September 2007 and included 975 students from 25 control schools of an intervention study, the HEalth In Adolescents (HEIA) study. The first follow-up took place in May 2008 and the second follow-up in May 2009, with 885 students participating at all time points (average age at baseline = 11.2, standard deviation ± 0.3). Time used for/spent on TV/DVD and computer/electronic games was self-reported, and a TST variable (hours/week) was computed. Tracking analyses based on absolute and rank measures, as well as regression analyses to assess factors associated with change in TST and with tracking high TST were conducted. RESULTS: Time spent on all sedentary behaviours investigated increased in both genders. Findings based on absolute and rank measures revealed a fair to moderate level of tracking over the 2 year period. High parental education was inversely related to an increase in TST among females. In males, self-efficacy related to barriers to physical activity and living with married or cohabitating parents were inversely related to an increase in TST. Factors associated with tracking high vs. low TST in the multinomial regression analyses were low self-efficacy and being of an ethnic minority background among females, and low self-efficacy, being overweight/obese and not living with married or cohabitating parents among males. CONCLUSIONS: Use of TV/DVD and computer/electronic games increased with age and tracked over time in this group of 11-13 year old Norwegian children. Interventions targeting these sedentary behaviours should thus be introduced early. The identified modifiable and non-modifiable factors associated with change in TST and tracking of high TST should be taken into consideration when planning such interventions.

Gender-specific mediators of the association between parental education and adiposity among adolescents: the HEIA study.

Identifying the mechanisms behind socioeconomic inequalities in adiposity among youth is vital for efforts aimed at combating these inequalities. The study explored whether a broad range of behavioral and familial factors mediated the associations between parental education and indicators of adiposity among adolescents. Baseline data from a school-based intervention study conducted in 2007 among 11-year-old adolescents were used. Anthropometric outcomes, physical activity and sedentary time among adolescents were objectively measured. Other behavioral variables and parental waist circumference were self-reported. Mediation analyses were conducted. Among boys, maternal waist circumference (WC), paternal WC and TV viewing mediated 16%, 11.5% and 13% of the association between parental education and adolescent WC. The respective proportions when body fat percentage was used as the outcome variable were 22.5%, 16% and 21%. Among girls, maternal and paternal WC mediated 20% and 14% of the association between parental education and WC. The respective proportions when body fat percentage was used as the outcome variable were 14% and 10%. Other included variables did not play any mediating role. Parental WC was found to be a mediator of socioeconomic differences in adiposity in both genders; underlying mechanisms were however not investigated. Among boys, reducing TV time could contribute to the reduction of social inequalities in adiposity.

Changes in adolescents' and parents' intakes of sugar-sweetened beverages, fruit and vegetables after 20 months: results from the HEIA study - a comprehensive, multi-component school-based randomized trial.

BACKGROUND: Interventions conducted in school-aged children often involve parents, but few studies have reported effects on parents' own behaviour as a result of these interventions. OBJECTIVE: To determine if a multi-component, cluster randomized controlled trial targeting 11-13 year olds influenced their consumption of fruit, vegetables, sugar-sweetened soft drinks and fruit drinks, and to explore whether the results varied by gender, adolescent weight status or parental educational level. A final aim was to assess whether the parents' intakes were affected by the intervention. DESIGN: Participants were 1,418 adolescents, 849 mothers and 680 fathers. Baseline and post-intervention data from the 20 months intervention study HEIA (HEalth In Adolescents) were included. Data were collected assessing frequency (and amounts; beverages only). RESULTS: No significant differences were found at baseline between the intervention and control groups, except for the parental groups (educational level and intakes). At post-intervention, the adolescents in the intervention group consumed fruit more frequently (P<0.001) and had a lower intake of sugar-sweetened fruit drinks compared to the control group (P=0.02). The parental educational level moderated the effect on intake of sugar-sweetened fruit drinks in adolescents. The intake was less frequent in the intervention groups compared to the control groups (P=0.02) for those who had parents with low and medium educational level. Furthermore, the intervention may have affected mothers' fruit intake and the vegetable intake in higher educated fathers. CONCLUSION: Favourable effects in favour of the intervention group were found for intake of fruit and sugar-sweetened fruit drinks among the adolescents in the HEIA study. Our results indicate that it is possible to reduce adolescents' intake of sugar-sweetened fruit drinks across parental education, and potentially affect sub-groups of parents.