Why do Dutch people use dietary supplements? Exploring the role of socio-cognitive and psychosocial determinants.

BACKGROUND: In the Netherlands, the prevalence of dietary supplement use has doubled (from 17 to 40 per cent) since the 1980s. Yet, limited data is available on which socio-cognitive factors are associated with dietary supplement use. Therefore, the purpose of the study is to explain dietary supplement use with determinants deriving from the Integrated Change Model (ICM) and from formative research. METHOD/DESIGN: Socio-cognitive and psychosocial factors were measured among users and non-users of dietary supplements in a longitudinal survey study, with measurements at baseline (N = 1448) and at one-month follow-up (N = 1161). Negative binomial regression analysis was applied to de data. RESULTS: Intention emerged as the main predictor of dietary supplement use (OR = 1.99). Further predictors of dietary supplement use with smaller effect-sizes were: health regulatory focus (promotion, OR = 1.46), social modelling (OR = 1.44), attitude (pros, OR = 1.37), attitude (cons, OR = 0.87), health locus of control (OR = 0.77), and risk perception (chance of getting ill, OR = 1.22). CONCLUSIONS: Individuals tend to use dietary supplements if they are promotion oriented, notice dietary supplement users in their social environment, estimate their chances of getting ill higher, and have positive attitudes towards dietary supplements. In contrast, non-users believe that external factors affect their health, and hold negative attitudes towards dietary supplements. PRACTICAL IMPLICATIONS: Mapping out individuals' socio-cognitive profile may contribute to the development of online health communication. Based on socio-cognitive and demographical factors, personalised advice can be given about dietary supplement use.

The Malnutrition Awareness Scale for community-dwelling older adults: Development and psychometric properties.

BACKGROUND & AIMS: Qualitative studies suggest that malnutrition awareness is poor in older adults. The aim of this study was to develop a questionnaire to quantitatively assess malnutrition awareness in community-dwelling older adults aged 60+ years. METHODS: The Malnutrition Awareness Scale (MAS) was developed based on the awareness phase of the Integrated-Change model, and included four domains: knowledge, perceived cues, risk perceptions, and cognizance. Twenty-six scale items were developed using results from mainly qualitative research and the expertise of the authors. Items were piloted in 10 Dutch older adults using the Thinking Aloud method to optimize wording. In a feasibility study, annoyance, difficulty and time to complete the MAS and its comprehensibility were tested. After final revisions, the MAS was applied to a large sample to test its psychometric properties (i.e., inter-item correlations, Cronbach's alpha, score distribution) and relevance of the items was rated on a 5-point scale by 12 experts to determine content validity. RESULTS: The feasibility study (n = 42, 55 % women, 19 % 80+ y) showed that the MAS took 12 ± 6 min to complete. Most participants found it not (at all) annoying (81 %) and not (at all) difficult (79 %) to complete the MAS, and found it (very) comprehensible (83 %). Psychometric analyses (n = 216, 63 % women, 28 % 80+ y) showed no redundant items, but two items correlated negatively with other items, and one correlated very low. After removal, the final MAS consists of 23 items with a min-max scoring range from 0 to 22 (with higher scores indicating higher awareness) and an overall Cronbach's alpha of 0.67. The mean MAS score in our sample (n = 216) was 14.8 ± 3.2. The lowest obtained score was 6 (n = 3) and the highest 22 (n = 1), indicating no floor or ceiling effects. Based on the relevance rating, the overall median across all 22 items was 4.0 with IQR 4.0-5.0. CONCLUSION: The Malnutrition Awareness Scale is a novel, feasible and reliable tool with good content validity to quantitively assess malnutrition awareness in community-dwelling older adults. The scale is now ready to identify groups with poor malnutrition awareness, as a basis to start interventions to increase malnutrition knowledge and awareness.