Tracking of fruit and vegetable consumption from adolescence into adulthood and its longitudinal association with overweight.

The objective of the present study was to assess to what extent fruit and vegetable intakes track over a 24-year time period and to assess longitudinal associations between fruit and vegetable intakes and (change in) BMI and sum of skinfolds. Dietary intake and anthropometrics were repeatedly assessed for 168 men and women between the ages of 12 and 36 years. Linear general estimating equations analyses were applied (1) to estimate tracking coefficients, (2) to estimate predictability for meeting the national recommendation for fruit and vegetable intake and for being in the highest quartile for fruit and vegetable intake, and (3) to estimate the association between fruit and vegetable intake and BMI and sum of skinfolds. We found that tracking coefficients were 0.33 (P<0.001) for fruit intake and 0.27 (P<0.001) for vegetable intake. Mean fruit intake decreased over a 24-year period. For fruit intake, predictability was higher in men than in women (OR 6.02 (P<0.001) and 2.33 (P=0.001) for meeting the recommendation for men and women respectively). After adjustment, fruit intake was not associated with BMI, but being in the lowest quartile of fruit intake was significantly associated with a lower sum of skinfolds. Women in the lowest quartiles of vegetable intake had significantly higher BMI and sum of skinfolds and also greater positive changes in these parameters. In conclusion, tracking and predictability for fruit and vegetable intake appear to be low to moderate, which might indicate that fruit and vegetable promotion should be started at an early age and continued into adulthood. Despite the fact that we only observed beneficial weight- maintaining effects of vegetable intake in women, promoting vegetables is important for both sexes because of other positive properties of vegetables. No evidence was found for promoting fruit intake as a means of weight maintenance. © The Authors 2007

Why item response theory should be used for longitudinal questionnaire data analysis in medical research

Background Multi-item questionnaires are important instruments for monitoring health in epidemiological longitudinal studies. Mostly sum-scores are used as a summary measure for these multi-item questionnaires. The objective of this study was to show the negative impact of using sum-score based longitudinal data analysis instead of Item Response Theory (IRT)-based plausible values. Methods In a simulation study (varying the number of items, sample size, and distribution of the outcomes) the parameter estimates resulting from both modeling techniques were compared to the true values. Next, the models were applied to an example dataset from the Amsterdam Growth and Health Longitudinal Study (AGHLS). Results The results show that using sum-scores leads to overestimation of the within person (repeated measurement) variance and underestimation of the between person variance. Conclusions We recommend using IRT-based plausible value techniques for analyzing repeatedly measured multi-item questionnaire data

Self-management abilities and frailty are important for healthy aging among community-dwelling older people; A cross-sectional study

__Abstract__ Background: This study aimed to identify the relationships of self-management abilities and frailty to perceived poor health among community-dwelling older people in the Netherlands while controlling for important individual characteristics such as education, age, marital status, and gender. Methods. The cross-sectional study sample consisted of 869/2212 (39% response rate) independently living older adults (aged ≥70 years) in 92 neighborhoods of Rotterdam. In the questionnaires we assessed self-rated health, frailty using the Tilburg Frailty Indicator (TFI) and self-management abilities with the short version of the Self-Management Ability Scale (SMAS-S). We first used descriptive analysis to identify those in poor and good health. Differences between groups were established using chi-squared and t-tests. Relationships between individual characteristics, frailty, self-management abilities and poor health were investigated with correlation analyses. Multilevel logistic regression analyses were than performed to investigate the relationships of self-management abilities and frailty to health while controlling for age, gender, education, and marital status. The results of the multilevel regression analyses are reported as odd ratios. Results: Respondents in poor health were older than those in good health (78.8 vs. 77.2; p ≤.001). A significantly larger proportion of older people in poor health were poorly educated (38.4% vs. 19.0%; p ≤.001) and fewer were married (33.6% vs. 46.3%; p ≤.001). Furthermore, older people in poor health reported significantly lower self-management abilities (3.5 vs. 4.1; p ≤.001) and higher levels of frailty (6.9 vs. 3.3; p ≤.001). Correlation analyses showed significant relationships between frailty, self-management abilities and poor health. Multilevel analyses showed that, after controlling for background characteristics, self-management abilities were negatively associated with poor health (p ≤.05) and a positive relationship was found between frailty and poor health (p ≤.05) among older people in the community. Conclusions: Self-management abilities and frailty are important for healthy aging among community-dwelling older people in the Netherlands. Pa

Should we use logistic mixed model analysis for the effect estimation in a longitudinal RCT with a dichotomous outcome variable?

Background: Within epidemiology both mixed model analysis and Generalised Estimating Equations (GEE analysis) are frequently used to analyse longitudinal RCT data. With a continuous outcome, both methods lead to more or less the same results, but with a dichotomous outcome the results are totally different. The purpose of the present study is to evaluate the performance of a logistic mixed model analysis and a logistic GEE analysis and to give an advice which of the two methods should be used. Methods: Two real life RCT datasets with and without missing data were used to perform this evaluation. Regarding the logistic mixed model analysis also two different estimation procedures were compared to each other. Results: The regression coefficients obtained from the two logistic mixed model analyses were different from each other, but were always higher then the regression coefficients derived from a logistic GEE analysis. Because this also holds for the standard errors, the corresponding p-values were more or less the same. It was further shown that the effect estimates derived from a logistic mixed model analysis were an overestimation of the ‘real’ effect estimates. Conclusions: &nbsp;Although logistic mixed model analysis is widely used for the analysis of longitudinal RCT data, this article shows that logistic mixed model analysis should not be used when one is interested in the magnitude of the regression coefficients (i.e. effect estimates)

Carotid stiffness in young adults: a life-course analysis of its early determinants The Amsterdam Growth and Health Longitudinal Study

Cardiovascular risk factors affecting arterial stiffness in adulthood may develop at different critical periods earlier in life. We examined whether the trajectories, from adolescence to young adulthood, of blood pressure, body fatness and fat distribution, blood lipids, cardiorespiratory fitness, and heart rate determined levels of arterial stiffness in young adults. We investigated 373 apparently healthy adults in whom cardiovascular risk factors were repeatedly examined between the ages of 13 and 36 years and carotid stiffness estimates were obtained at the age of 36 years. Differences in the mean levels and the trajectories of risk factors throughout the 24-year longitudinal period between subjects with different levels of carotid stiffness at age 36 years were analyzed with generalized estimating equations. Compared with individuals with less stiff carotid arteries, those with stiffer carotid arteries at the age of 36 years were characterized from ages 13 to 36 years by greater levels of and steeper increases in blood pressure and central fatness, independently of each other and other risk factors. These increases were already present in adolescence, preceded the development of poorer levels of blood lipids, cardiorespiratory fitness, and heart rate, which were evident during adulthood only, and explained to a great extent the deleterious association between these risk factors and carotid stiffness at the age of 36 years. Multiple and intertwined mechanisms involved in the pathogenesis of arterial stiffness have their origins in early life. Blood pressure and central fatness have a pivotal role herein and should be specifically targeted to prevent arterial stiffening and its cardiovascular sequelae

Strategy for finding occupational health survey participants at risk of long-term sickness absence

BACKGROUND: When resources are limited, occupational health survey participants are usually invited to consultations based on an occupational health provider's subjective considerations. This study aimed to find health survey participants at risk of long-term (i.e., ≥ 42 consecutive days) sickness absence (LTSA) for consultations with occupational health providers (OHPs). METHODS: The data of 64 011 non-sicklisted participants in occupational health surveys between 2010 and 2015 were used for the study. In a random sample of 40 000 participants, 27 survey variables were included in decision tree analysis (DTA) predicting LTSA at 1-year follow-up. The decision tree was transferred into a strategy to find participants for OHP consultations, which was then tested in the remaining 24 011 participants. RESULTS: In the development sample, 1358 (3.4%) participants had LTSA at 1-year follow-up. DTA produced a decision tree with work ability as first splitting variable; company size and sleep problems were the other splitting variables. A strategy differentiating by company size would find 75% of the LTSA cases in small (≤99 workers) companies and 43% of the LTSA cases in medium-sized (100-499 workers) companies. For large companies (≥500 workers), case-finding was only 25%. CONCLUSIONS: In small and medium-sized companies, work ability and sleep problems can be used to find occupational health survey participants for OHP consultations aimed at preventing LTSA. Research is needed to further develop a case-finding strategy for large companies

Glutamine-enriched enteral nutrition in very low birth weight infants. Design of a double-blind randomised controlled trial [ISRCTN73254583]

BACKGROUND: Enteral feeding of very low birth weight (VLBW) infants is a challenge, since metabolic demands are high and administration of enteral nutrition is limited by immaturity of the gastrointestinal tract. The amino acid glutamine plays an important role in maintaining functional integrity of the gut. In addition, glutamine is utilised at a high rate by cells of the immune system. In critically ill patients, glutamine is considered a conditionally essential amino acid. VLBW infants may be especially susceptible to glutamine depletion as nutritional supply of glutamine is limited in the first weeks after birth. Glutamine depletion has negative effects on functional integrity of the gut and leads to immunosuppression. This double-blind randomised controlled trial is designed to investigate the effect of glutamine-enriched enteral nutrition on feeding tolerance, infectious morbidity and short-term outcome in VLBW infants. Furthermore, an attempt is made to elucidate the role of glutamine in postnatal adaptation of the gut and modulation of the immune response. METHODS: VLBW infants (gestational age <32 weeks and/or birth weight <1500 g) are randomly allocated to receive enteral glutamine supplementation (0.3 g/kg/day) or isonitrogenous placebo supplementation between day 3 and 30 of life. Primary outcome is time to full enteral feeding (defined as a feeding volume ≥ 120 mL/kg/day). Furthermore, incidence of serious infections and short-term outcome are evaluated. The effect of glutamine on postnatal adaptation of the gut is investigated by measuring intestinal permeability and determining faecal microflora. The role of glutamine in modulation of the immune response is investigated by determining plasma Th1/Th2 cytokine concentrations following in vitro whole blood stimulation

Children's physical activity levels during school recess: a quasi-experimental intervention study

Background : Recess provides a daily opportunity for children to engage in moderate-to-vigorous (MVPA) and vigorous physical activity (VPA). Limited research has investigated the effects of recess-based interventions on physical activity using large sample sizes whilst investigating variables that may influence the intervention effect. The aim of the study was to investigate the short-term effects of a playground markings and physical structures intervention on recess physical activity. A secondary aim was to investigate the effects of covariates on the intervention.Methods : 150 boys and 147 girls were randomly selected from 26 elementary schools to wear uni-axial accelerometers that quantified physical activity every 5 seconds during recess. Fifteen schools located in deprived areas in one large urban city in England received funding through a national initiative to redesign the playground environment. Eleven schools served as matched socioeconomic controls. Data were collected at baseline and 6-weeks following playground intervention. Recess MVPA and VPA levels adjusted for pupil- and school-level covariates (baseline physical activity, age, gender, recess length, body mass index) were analysed using multilevel analyses.Results : Positive but non-significant intervention effects were found for MVPA and VPA when confounding variables were added to the model. Gender was a significant predictor of recess physical activity, with boys engaging in more MVPA and VPA than girls. Significant interactions for MVPA revealed that the intervention effect was stronger for younger elementary aged school children compared to older children, and the intervention effect increased as daily recess duration increased.Conclusion : The playground redesign intervention resulted in small but non-significant increases in children\u27s recess physical activity when school and pupil level variables were added to the analyses. Changing the playground environment produced a stronger intervention effect for younger children, and longer daily recess duration enabled children to engage in more MVPA following the intervention. This study concludes that the process of increasing recess physical activity is complex when school and pupil-level covariates are considered, though they should be taken into account when investigating the effects of playground intervention studies on children\u27s physical activity during recess.<br /

Development of Prediction Models for Sickness Absence Due to Mental Disorders in the General Working Population

PurposeThis study investigated if and how occupational health survey variables can be used to identify workers at risk of long-term sickness absence (LTSA) due to mental disorders.MethodsCohort study including 53,833 non-sicklisted participants in occupational health surveys between 2010 and 2013. Twenty-seven survey variables were included in a backward stepwise logistic regression analysis with mental LTSA at 1-year follow-up as outcome variable. The same variables were also used for decision tree analysis. Discrimination between participants with and without mental LTSA during follow-up was investigated by using the area under the receiver operating characteristic curve (AUC); the AUC was internally validated in 100 bootstrap samples.Results30,857 (57%) participants had complete data for analysis; 450 (1.5%) participants had mental LTSA during follow-up. Discrimination by an 11-predictor logistic regression model (gender, marital status, economic sector, years employed at the company, role clarity, cognitive demands, learning opportunities, co-worker support, social support from family/friends, work satisfaction, and distress) was AUC = 0.713 (95% CI 0.692-0.732). A 3-node decision tree (distress, gender, work satisfaction, and work pace) also discriminated between participants with and without mental LTSA at follow-up (AUC = 0.709; 95% CI 0.615-0.804).ConclusionsAn 11-predictor regression model and a 3-node decision tree equally well identified workers at risk of mental LTSA. The decision tree provides better insight into the mental LTSA risk groups and is easier to use in occupational health care practice