Accumulating evidence suggests that fruit and vegetable intake (FVI) plays a protective role against major diseases. Despite this protective role and the obesity pandemic context, populations in Western countries usually eat far less than five servings of fruits and vegetables per day. In order to increase the efficiency of interventions, they should be tailored to the most important determinants or mediators of FVI. The objective was to systematically review social cognitive theory-based studies of FVI and to identify its main psychosocial determinants.

The aim of this study was to identify the psychosocial and socio-demographic determinants of physical activity maintenance (PAM) among adults by examining baseline differences between individuals who did and did not maintain physical activity participation over time (Part-I) and by examining how well combinations of psychosocial constructs and socio-demographic characteristics predict PAM (Part-II). Longitudinal and experimental studies (sample mean age 18–64 years) published between 1980 and 2010 were included. Independent data extraction was performed by two reviewers. All pooled effect sizes were calculated with the inverse-variance method under the random-effects model assumption. A total of 31 and 22 studies met all inclusion criteria and were included in Part-I and Part-II meta-analysis, respectively. Maintainers had higher [standard mean difference (95%CI)] self-efficacy (0.62 [0.49, 0.76]) and intention (0.65 [0.52, 0.79]) compared with relapsers. Health status directly affected PAM and moderated the relationship between BMI, education as well as perceived negative consequences and PAM. The overall model adjusted R ² [95%CI] for the prediction of PAM was 0.20 [0.14, 0.27]. The present findings suggest that beliefs about capabilities and motivation and goals are among the strongest variables associated with PAM. However, other variables rarely investigated so far (e.g., post-intentional constructs/self-regulatory processes) may also influence PAM.

Objective.: To identify the determinants of influenza vaccination and the moderators of the intention-behavior relationship among healthcare workers (HCWs).Design.: Prospective survey with 2-month follow-up.Setting.: Three university-affiliated public hospitals.Participants.: Random sample of 424 HCWs.Methods.: The intention of an HCW to get vaccinated against influenza was measured by means of a self-administered questionnaire based on an extended version of the theory of planned behavior. An objective measure of behavior was extracted 2 months later from the vaccination database of the hospitals.Results.: Controlling for past behavior, we found that the determinants of influenza vaccination were intention (odds ratio [OR], 8.32 [95% confidence interval {CI}, 2.82–24.50]), moral norm (OR, 3.01 [95% CI, 1.17–7.76]), anticipated regret (OR, 2.33 [95% CI, 1.23–4.41]), and work status (ie, full time vs part time; OR, 1.99 [95% CI, 1.92–3.29]). Moral norm also interacted with intention as a significant moderator of the intention-behavior relationship (OR, 0.09 [95% CI, 0.03–0.30]). Again, apart from the influence of past behavior, intention to get vaccinated was predicted by use of the following variables: attitude (ß = .32;P< .001), professional norm (β = .18;P< .001), moral norm (β = .18;P< .001), subjective norm (ß = .09;P< .001), and self-efficacy (ß = .08;P< .001). This latter model explained 89% of the variance in HCWs' intentions to get vaccinated against influenza during the next vaccination campaign.Conclusions.: Our study suggests that influenza vaccination among HCWs is mainly a motivational issue. In this regard, it can be suggested to reinforce the idea that getting vaccinated can reduce worry and protect family members.

Objective: To verify the efficacy of school-based interventions aimed at reducing sugar-sweetened beverage (SSB) consumption among adolescents in order to develop or improve public health interventions.Design: Systematic review of interventions targeting adolescents and/or the school environment.Setting: The following databases were investigated: MEDLINE/PubMed, PsycINFO, CINAHL and EMBASE. Proquest Dissertations and Theses was also investigated for unpublished trials.Subjects: Adolescents were defined as individuals between the ages of 12 and 17 years.Results: A total of thirty-six studies detailing thirty-six different interventions tested among independent samples (n152 001) were included in the review. Twenty interventions were classified as educational/behavioural and ten were classified as legislative/environmental interventions. Only six interventions targeted both individuals and their environment. Over 70 % of all interventions, regardless of whether they targeted individuals, their environment or both, were effective in decreasing SSB consumption. Legislative/environmental studies had the highest success rate (90·0 %). Educational/behavioural interventions only and interventions that combined educational/behavioural and legislative/environmental approaches were almost equally effective in reducing SSB consumption with success rates of 65·0 and 66·7 %, respectively. Among the interventions that had an educational/behavioural component, 61·5 % were theory-based. The behaviour change techniques most frequently used in interventions were providing information about the health consequences of performing the behaviour (72·2 %), restructuring the physical environment (47·2 %), behavioural goal setting (36·1 %), self-monitoring of behaviour (33·3 %), threat to health (30·6 %) and providing general social support (30·6 %).Conclusions: School-based interventions show promising results to reduce SSB consumption among adolescents. A number of recommendations are made to improve future studies.