A Non-parametric Frailty Model for Temporally Clustered Multivariate Failure Times

Abstract A model is introduced here for multivariate failure time data arising from heterogenous populations. In particular, we consider a situation in which the failure times of individual subjects are often temporally clustered, so that many failures occur during a relatively short age interval. The clustering is modelled by assuming that the subjects can be divided into ‘internally homogenous’ latent classes, each such class being then described by a time‐dependent frailty profile function. As an example, we reanalysed the dental caries data presented earlier in Härkänen et al. [Scand. J. Statist. 27 (2000) 577], as it turned out that our earlier model could not adequately describe the observed clustering.     

Motives for and barriers to physical activity among older adults with mobility limitations

The purpose of this study was to investigate what older adults with severe, moderate, or no mobility limitation consider motives for and barriers to engaging in physical exercise. Community-dwelling adults (N=645) age 75-81 years completed a questionnaire about their motives for and barriers to physical exercise and answered interview questions on mobility limitation. Those with severely limited mobility more often reported poor health, fear and negative experiences, lack of company, and an unsuitable environment as barriers to exercise than did those with no mobility limitation. They also accentuated disease management as a motive for exercise, whereas those with no or moderate mobility limitation emphasized health promotion and positive experiences related to exercise. Information about differences in motives for and barriers to exercise among people with and without mobility limitation helps tailor support systems that support engagement in physical activity among older adults.     

Stochastic complexity and the mdl principle

A Search for the stochastic complexity of the observed data, as the greates lower bound with which the data can be encoded, represents a global maximum likelihood principle, which permits comparison of models regardless of the number of parameters in them. For important special classes, such as the guassian and the multinomial models, formulas for the stochastic complexity give new and powerful model selection criteria,while in the general case approximations can be computed with the MDL principle. Once a model is found with which the stochastic complexity is reached, there is nothing further to learn from the data with the proposed models. The basic notions are reviewed and numerical examples are given.     

Progression of functional limitations in relation to physical activity: a life course approach

In this minireview, we summarize the research results to date on the progression of functional limitations and the role of physical activity during the life course in preventing risk factor accumulation. In addition, socioeconomic and health disparities play a role in the development process of functional limitation throughout life. We discuss the potential role of physical activity in alleviating this process. Functional limitations usually develop gradually over an extended period of time while the level of physical functioning varies greatly already from midlife onwards. Current research strongly suggests that physical activity has a beneficial effect on functional limitations at different life stages on the population level. However, the potential impact of physical activity in alleviating the effects caused by socioeconomic disparities is inconsistent. Research findings are also conflicting on the extent of the effect of physical activity among certain subsets of the population, such as obese persons. Although the benefits of physical activity on physical impairments and functioning among the adult population have been confirmed, the number of adults who are physically active is too low and, for the majority, physical activity declines with older age. Thus, detailed research evidence is needed for designing effective preventive interventions starting from earlier ages and continuing throughout the lifespan across different subgroups in the population.     

Patterns of conflict and enrichment in work-family balance: A three-dimensional typology

Abstract

A four-dimensional typology of work-family balance (WFB) that has previously been reported was tested in four samples: Finnish nurses (n=662), Slovenian nurses (n=667), Finnish health and social care workers (n=1493) and Finnish service sector employees (n=827). Latent profile analyses identified three rather than four types of WFB in each sample. In line with the four-dimensional typology, a Beneficial type (56% to 70% of the participants), experiencing high work-to-family and family-to-work enrichment (WFE and FWE) and low work-to-family and family-to-work conflict (WFC and FWC), and an Active type (15% to 20%), experiencing high WFC, FWC, WFE and FWE, emerged; however, the Harmful and Passive types were not identified. Instead, a Contradictory type (16% to 53%), experiencing high WFC and low WFE in combination with low FWC and high FWE, was found. The Beneficial type showed higher subjective well-being than the Contradictory and Active types, the latter showing higher vigour at work but also higher psychological strain and lower life satisfaction than the Contradictory type. These findings support the view that WFB is not a single state or continuum, but manifests itself in diverse combinations of WFC, FWC, WFE and FWE.     

Cash versus Child Care Services in Finland

In 1985 the Finnish Parliament passed a law which stipulated that all children under age three were to be guaranteed a day care place as from the beginning of the 1990s. The law was made possible by a political compromise in which the agrarian Centre Party won the backing it needed to push through a system of state subsidies for the home care of children. As an alternative to a day care place, parents were now given the option of taking a child home care allowance and using that allowance either for purposes of looking after their child themselves or for paying for a private place. Measured in terms of the number of users, the child home care allowance was a hugely successful innovation. Most parents of small children have used the allowance for at least some period of time. This was due above all to the size of the allowance compared with other social benefits. However, following cutbacks in allowance expenditure of more than 20 per cent from 1995, the use of home care allowances declined at almost the same rate as the allowances were reduced. This brought significant short-term savings to the Government and to local authorities, but in the longer term other costs have been rising. There has even been a sharp, unexpected decline in the birth rate. The case of Finland goes to show that, even in a country where wage-earning motherhood has become firmly established, income transfers through family policy can have a very significant influence on the numbers opting temporarily for homemaking.     

Interaction between employees' physical load factors and early support at the workplace

Physical workload is a continuous problem, even in modern workplaces. The purpose of the survey was to determine the effect of support on employees' physical load factors at workplaces. Training, guidance and support were the main focus areas of the early support intervention, which aimed to enable supervisors to find weak signals of impaired ergonomics.The survey was carried out in the form of a controlled longitudinal study, and the material was gathered via a questionnaire in both 2008 and 2010 from two co-operative trade groups. The final sample was 301 intervention subjects and 235 control subjects, and the response rate was 45% in both groups. We applied factor analysis to reduce the number of items. The physical load factors' sum score consisted of six items. We used logistic regression in the statistical analysis.Encouragement to improve processes at the workplace increased the probability of positive change (i.e. decrease) in physical load factors. The same applied to working pace, if individuals could control it themselves. In contrast, workload and the support of supervisors had a reversed impact on workers' physical load factors. Focusing on promoting workers' ergonomics is still important in workplaces when aiming to decrease physical load factors.     

Caries on Permanent Teeth: A Non-parametric Bayesian Analysis

Most earlier epidemiological investigations of dental caries have been based on cross-sectional data. Subject-specific information of dental caries in the past, and the duration of exposure of each tooth to the oral environment, are obviously important factors also influencing the presence of dental caries in the future. This has led us to consider multivariate survival models in which the information about the tooth eruption and failure times are combined to assess caries risk. A non-parametric Bayesian intensity model is presented, reflecting, on the one hand, the within subject and between subject sources of variability, and a corresponding split of variability when considering the 28 permanent teeth. We analyse a data set consisting of the dental history of 240 boys, where the observations are based on predetermined dental examinations taking place approximately once every year. Markov chain Monte Carlo integration techniques are applied in the numerical work.