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

Testing for sexually transmitted infections in the general population of the Rotterdam area:Who goes where?

The research described in this thesis aims to improve our understanding of sexually transmitted infection (STI) testing in the general population, focusing on the roles of general practitioners and sexual health centres. The study insights may contribute to improved STI testing policies

Testing for sexually transmitted infections in the general population of the Rotterdam area:Who goes where?

The research described in this thesis aims to improve our understanding of sexually transmitted infection (STI) testing in the general population, focusing on the roles of general practitioners and sexual health centres. The study insights may contribute to improved STI testing policies

Latent class analysis was accurate but sensitive in data simulations

Objectives: Latent class methods are increasingly being used in analysis of developmental trajectories. A recent simulation study by Twisk and Hoekstra (2012) suggested caution in use of these methods because they failed to accurately identify developmental patterns that had been artificially imposed on a real data set. This article tests whether existing developmental patterns within the data set used might have obscured the imposed patterns.&lt;p&gt;&lt;/p&gt; Study Design and Setting: Data were simulated to match the latent class pattern in the previous article, but with varying levels of randomly generated variance, rather than variance carried over from a real data set. Latent class analysis (LCA) was then used to see if the latent class structure could be accurately identified.&lt;p&gt;&lt;/p&gt; Results: LCA performed very well at identifying the simulated latent class structure, even when the level of variance was similar to that reported in the previous study, although misclassification began to be more problematic with considerably higher levels of variance.&lt;p&gt;&lt;/p&gt; Conclusion: The failure of LCA to replicate the imposed patterns in the previous study may have been because it was sensitive enough to detect residual patterns of population heterogeneity within the altered data. LCA performs well at classifying developmental trajectories.&lt;p&gt;&lt;/p&gt

The analysis of randomised controlled trial data with more than one follow-up measurement. A comparison between different approaches.

When more than one follow-up measurement is analysed in a randomized controlled trial, there is no consensus how to analyse the overall intervention effect in a proper way. Mostly, longitudinal analysis of covariance is used, because with this method a correction is made for possible regression to the mean. However, in this paper it is shown that this method (mostly) leads to an overestimation of the intervention effect. A possible solution is the use of autoregression, although this does not seem to be the best solution, because it leads to an overcorrection. Due to these flaws, in this paper a new approach is introduced in which a correction for the baseline value is made for the first follow-up, but no correction is made for the remaining follow-up measurements

Impact of time on improvement of outcome after stroke

Contains fulltext : 51306.pdf (publisher's version ) (Closed access)BACKGROUND AND PURPOSE: Longitudinal conducted studies show that neurologic and functional recovery show faster recovery in the first weeks poststroke. The aim of the present study was to study the effects of progress of time on observed improvements in motor strength, synergisms, and activities during the first 16 weeks poststroke. METHODS: Based on data from a previous study, 101 patients with first-ever ischemic middle cerebral artery strokes were prospectively investigated during the first 16 weeks after stroke. Progress of time was categorized into 8 biweekly time intervals and was used as the independent covariate in a first-order longitudinal regression model. The biweekly time change (progress of time) was related to improvement in upper and lower limb motor recovery assessed with Fugl-Meyer score and Motricity Index, reduction in visuospatial inattention based on the letter cancellation task, and improvement in walking ability, dexterity, and activities of daily living measured with the Functional Ambulation Categories, Action Research Arm test, and Barthel Index. RESULTS: Time explained a significant change of 8.4 (42%) measurement units on the Barthel Index for the first 10 weeks poststroke, 1.1 (22%) measurement units on Functional Ambulation Categories, and 19% on the Action Research Arm test for the first 6 and 8 weeks poststroke. Approximately 25% (for Fugl-Meyer-arm) to 26% (for Motricity Index-arm) of the significant change in measurements units was explained by time alone for the upper limb compared with 33% for Fugl-Meyer-leg and 39% for Motricity Index-leg of the lower limb. Time accounted for a reduction of 16% in the letter cancellation task. Observed associations did not change after controlling for covariates such as age, gender, hemisphere of stroke, type of stroke, or intervention. CONCLUSIONS: Progress of time is an independent covariate that reflects spontaneous recovery of body functions and activities explaining &16% to 42% of the observed improvements in the first 6 to 10 weeks after stroke onset

Predicting transitions in the use of informal and professional care by older adults

To prepare the care system for a rising population of older people, it is important to understand what factors predict the use of care. This paper reports a study of transitions in the use of informal and professional care using Andersen-Newman models of the predictive predisposing, enabling and need factors. The study has drawn on Longitudinal Ageing Study Amsterdam (LASA) data on the use of care and the contextual factors. The data were collected at three-yearly intervals from a random, sex- and age-stratified, population-based sample of adults aged 55-85 years. In summary, the findings for those who initially did not receive care were that almost one-third received some kind of care three years later, most of which was provided by informal care-givers. Need factors were important predictors of most transitions in care, and predisposing and enabling factors, such as age, partner status and income, also played a role. On the relationship between informal and professional care, evidence was found for both 'compensatory processes', i.e. informal care substitutes for professional care, and 'bridging processes', i.e. informal care facilitates professional care. In view of the increasing discrepancy between the demand for professional care and its supply, the significant impact of predisposing and enabling factors offers opportunities for intervention. © 2005 Cambridge University Press

The relationship between body composition and physical fitness in 14 year old adolescents residing within the Tlokwe local municipality, South Africa: The PAHL study

<p>Abstract</p> <p>Background</p> <p>Little is known about the relationship between body composition and physical fitness in 14 year-old high school adolescents of South Africa. Baseline data from a longitudinal study on physical activity and health (PAHLS) may provide valuable information for future studies, hence to inform public health policy makers. The objectives of this study are to determine the prevalence of underweight, normal weight and overweight among adolescents aged 14 years in the Tlokwe Local Municipality of the North West Province of South Africa, and to assess the association between physical fitness and body composition separately for boys and girls, adjusted for race and locality.</p> <p>Methods</p> <p>Body weight, height and triceps, and subscapular skinfolds of 256 adolescents (100 boys and 156 girls) aged 14 years were measured, and percentage body fat and body mass index (BMI) were calculated. BMI was used to determine underweight, normal weight and overweight based on the standard criterion. Physical fitness was assessed by standing broad jump, bent arm hang and sit-ups according to the EUROFIT fitness standard procedures. Multinomial logistic regression analyses stratified for gender and adjusted for race (black or white), and the locality (urban or township) of the schools were used to analyze the data.</p> <p>Results</p> <p>In the total group 35.9% were underweight and 13.7% overweight. Boys were more underweight (44%) than girls (30.7%). The prevalence of overweight was 8% in boys and 17.3% in girls. BMI was strongly (p = 0.01) related with percentage body fat. Strong and significant positive associations between physical fitness and BMI for the underweight girls with high physical fitness scores (OR, 10.69 [95%CI: 2.81-40.73], and overweight girls with high physical fitness scores (OR, 0.11 [95%CI: 0.03-0.50]) were found. Non-significant weaker positive relationship between physical fitness and BMI for the underweight boys with high physical fitness scores (OR, 1.80 [95%CI: 0.63-5.09]), and the overweight boys with high physical fitness scores (OR, 0.18 [95%CI: 0.02-1.78]) were found.</p> <p>Conclusion</p> <p>Both underweight and overweight among boys and girls in Tlokwe Local Municipality exist, and their effects on physical fitness performances were also noticed. As such, strategic physical activity, interventions or follow-up studies recognizing this relationship particularly in the overweight adolescents are needed. In addition, authorities in health and education departments dealing with adolescents should make use of this evidence base information in policies development.</p

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

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