Within-person association of volitional factors and physical activity: Insights from an ecological momentary assessment study.

OBJECTIVE: Current health behavior models of physical activity (PA) suggest that not all PA intentions are translated into actual PA behavior, resulting in a significant intention-behavior gap (IBG) of almost 50%. These models further suggest that higher self-efficacy and specific planning can aid in decreasing this gap. However, as most evidence stems from between-person (trait level), questionnaire-based research, it is unclear how large short-term IBGs are, how self-efficacy and planning covary within-persons across time and whether they similarly predict smaller IBGs. It is likely that day-to-day changes in circumstances and barriers affect these variables thus the applicability of theoretical models is uncertain. Here, within-person prospective analyses of ecological momentary assessment (EMA) data can provide insights. METHODS: 35 healthy participants (aged 23-67) completed four EMA-based questionnaires every day for three weeks. Each prompt assessed PA (retrospectively, "since the last EMA prompt"); PA intentions, planning specificity, self-efficacy, and intrinsic motivation (prospectively, "until the next EMA prompt") and momentary affect. Generalized logistic mixed-effect modeling was used to test predictors of PA. RESULTS: Across the 2341 answered EMA prompts, PA intentions were not enacted in 25% of the episodes (IBG). In episodes with given intentions, PA likelihood increased with higher levels of self-efficacy, planning specificity, and intrinsic motivation. The latter two also positively predicted PA duration and intensity. CONCLUSIONS: Short-term intention behavior gaps seem to be smaller than what is known from more long-term studies, most likely as individuals can anticipate the actual circumstances of PA. Further, current health behavior models show validity in explaining within-person dynamics in IBGs across time. Knowing the relevance of planning specificity, self-efficacy and intrinsic motivation for day-to-day variations in PA enactment can inform respective real-time mHealth interventions for facilitating PA.

Multivariate permutation tests for two sample testing in presence of nondetects with application to microarray data.

Very often, data collected in medical research are characterized by censored observations and/or data with mass on the value zero. This happens for example when some measurements fall below the detection limits of the specific instrument used. This type of left censored observations is called "nondetects". Such a situation of an excessive number of zeros in a data set is also referred to as zero-inflated data. In the present work, we aim at comparing different multivariate permutation procedures in two-sample testing for data with nondetects. The effect of censoring is investigated with regard to the different values that may be attributed to nondetected values, both under the null hypothesis and under alternative. We motivate the problem using data from allergy research.

Association of Antidementia Drugs and Mortality in Community-Dwelling Frail Older Patients With Dementia: The Role of Mortality Risk Assessment.

OBJECTIVE: To evaluate whether treatment with antidementia drugs is associated with reduced mortality in older patients with different mortality risk at baseline. DESIGN: Retrospective. SETTING: Community-dwelling. PARTICIPANTS: A total of 6818 older people who underwent a Standardized Multidimensional Assessment Schedule for Adults and Aged Persons (SVaMA) evaluation to determine accessibility to homecare services or nursing home admission from 2005 to 2013 in the Padova Health District, Italy were included. MEASUREMENTS: Mortality risk at baseline was calculated by the Multidimensional Prognostic Index (MPI), based on information collected with the SVaMA. Participants were categorized to have mild (MPI-SVaMA-1), moderate (MPI-SVaMA-2), and high (MPI-SVaMA-3) mortality risk. Propensity score-adjusted hazard ratios (HR) of 2-year mortality were calculated according to antidementia drug treatment. RESULTS: Patients treated with antidementia drugs had a significant lower risk of death than untreated patients (HR 0.82; 95% confidence interval [CI] 0.73-0.92 and 0.56; 95% CI 0.49-0.65 for patients treated less than 2 years and more than 2 years treatment, respectively). After dividing patients according to their MPI-SVaMA grade, antidementia treatment was significantly associated with reduced mortality in the MPI-SVaMA-1 mild (HR 0.71; 95% CI 0.54-0.92) and MPI-SVaMA-2 moderate risk (HR 0.61; 95% CI 0.40-0.91, matched sample), but not in the MPI-SVaMA-3 high risk of death. CONCLUSIONS: This large community-dwelling patient study suggests that antidementia drugs might contribute to increased survival in older adults with dementia with lower mortality risk.