Trynke Hoekstra

Why don't young people volunteer to give blood? An investigation of the correlates of donation intentions among young nondonors.

BACKGROUND: In the past decade, the number of blood donors has steadily declined in the Netherlands, and young adults are underrepresented among registered donors. An understanding of the correlates of donation intentions among nondonors could facilitate targeting psychological prerequisites of donation decisions in recruitment campaigns.

Outcome of depression in later life in primary care: longitudinal cohort study with three years' follow-up

Objectives To study the duration of depression, recovery over time, and predictors of prognosis in an older cohort (≥55 years) in primary care. Design Longitudinal cohort study, with three years’ follow-up. Setting 32 general practices in West Friesland, the Netherlands. Participants 234 patients aged 55 years or more with a prevalent major depressive disorder. Main outcome measures Depression at baseline and every six months using structured diagnostic interviews (primary care evaluation of mental disorders according to diagnoses in Diagnostic and Statistical Manual of Mental Disorders, fourth edition) and a measure of severity of symptoms (Montgomery Åsberg depression rating scale). The main outcome measures were time to recovery and the likelihood of recovery at different time points. Multivariable analyses were used to identify variables predicting prognosis. Results The median duration of a major depressive episode was 18.0 months (95% confidence interval 12.8 to 23.1). 35% of depressed patients recovered within one year, 60% within two years, and 68% within three years. A poor outcome was associated with severity of depression at baseline, a family history of depression, and poorer physical functioning. During follow-up functional status remained limited in patients with chronic depression but not in those who had recovered. Conclusion Depression among patients aged 55 years or more in primary care has a poor prognosis. Using readily available prognostic factors (for example, severity of the index episode, a family history of depression, and functional decline) could help direct treatment to those at highest risk of a poor prognosis.

Progression and Regression: Distinct Developmental Patterns of Diabetic Retinopathy in Patients With Type 2 Diabetes Treated in the Diabetes Care System West-Friesland, the Netherlands

OBJECTIVE To identify distinct developmental patterns of diabetic retinopathy (DR) and assess the risk factor levels of patients in these clusters. RESEARCH DESIGN AND METHODS A cohort of 3,343 patients with type 2 diabetes mellitus (T2DM) monitored and treated in the Diabetes Care System West-Friesland, the Netherlands, was followed from 2 to 6 years. Risk factors were measured, and two-field fundus photographs were taken annually and graded according to the EURODIAB study group. Latent class growth modeling was used to identify distinct developmental patterns of DR over time. RESULTS Five clusters of patients with distinct developmental patterns of DR were identified: A, patients without any signs of DR (88.9%); B, patients with a slow regression from minimal background to no DR (4.9%); C, patients with a slow progression from minimal background to moderate nonproliferative DR (4.0%); D, patients with a fast progression from minimal or moderate nonproliferative to (pre)proliferative or treated DR (1.4%); and E, patients with persistent proliferative DR (0.8%). Patients in clusters A and B were characterized by lower risk factor levels, such as diabetes duration, HbA1c, and systolic blood pressure compared with patients in progressive clusters (C–E). CONCLUSIONS Clusters of patients with T2DM with markedly different patterns of DR development were identified, including a cluster with regression of DR. These clusters enable a more detailed examination of the influence of various risk factors on DR.

Defining discriminative pain trajectories in hip osteoarthritis over a 2-year time period

Background Although pain due to osteoarthritis (OA) generally deteriorates over time, there is a large individual variation in the course of pain. This study examines the different longitudinal trajectories of patients with hip pain due to OA. Methods Data from a previously performed randomised controlled trial were used to investigate the course of pain over 2 years in 222 patients with clinically and radiographically determined hip OA. Pain was measured with a visual analogue scale (0–100). Latent class growth analysis was used to determine the number of trajectories of patients with hip pain due to OA. Results Analyses yielded five trajectories of pain due to hip OA. Trajectory 1 (‘mild pain’; n=69) consists of patients with stable mild pain. Patients in trajectory 2 (‘moderate pain’; n=31) fluctuated slightly between moderate and severe pain levels. Trajectory 3 (‘always pain’; n=32) consists of patients with severe pain. Patients in trajectory 4 (‘regularly progressing’; n=48) started with mild pain and progressed slowly to moderate pain. Trajectory 5 (‘highly progressing’; n=42) patients also started with mild pain but quickly progressed to severe pain over 2 years. Compared with the ‘mild pain’ group, patients in the ‘always pain’ group had more severe radiographic hip OA, morning stiffness and decreased range of motion. The ‘highly progressing’ group had more severe radiographic hip OA and morning stiffness. Conclusions Latent class growth analysis applied to longitudinal data of patients with hip OA identified five distinct trajectories of pain. More studies are needed to externally validate these findings.

Cohort profile: The Amsterdam Growth and Health Longitudinal Study

The Amsterdam Growth and Health Longitudinal Study (AGHLS) is a unique, multidisciplinary cohort study that was initially set up to examine growth and health among teenagers. Throughout the years, the AGHLS has aimed to answer research questions dealing with the relationships between the (natural) development of anthropometry, lifestyle and health from adolescence into adulthood. The AGHLS specifically focuses on anthropometrics, physical activity and fitness, cardiovascular disease risk, lifestyle, musculoskeletal health, psychological health and well-being. Besides this, many methodological issues related to the analysis of longitudinal data were also explored within the framework of the AGHLS. In 1976, students from two secondary schools from the greater Amsterdam area were included in the study. Between 1976 and 2006, 10 rounds of measurement were performed covering an age range between 13 and 43 years. The huge database collected so far has been primarily used to answer relevant research questions regarding the longitudinal relationship between lifestyle and health. Further information about the study can be obtained from the principal investigator Jos Twisk (jwr.twisk@vumc.nl), and up-to-date information on AGHLS can be found by visiting the website www.aggo.nl.

Measurement Invariance of the Perceived Stress Scale and Latent Mean Differences across Gender and Time

Measurement invariance of the 2-factor model of the Perceived Stress Scale--10-item version (Cohen & Williamson, 1988) was tested across men and women at two time points and in the combined total sample over a 2-year time frame (n = 871). Measurement invariance results indicated that the scale measured the latent factors, stress and counter-stress, equivalently in men and women and over time. With measurement invariance demonstrated, differences in latent means were tested. Results indicated that men had lower levels of frequencies of stressors, and at one time point, higher levels of counter-stress, when compared with women. When examining change in frequencies of stressors and counter-stress over 2 years with the combined male and female sample, stressors remained stable, yet counter-stress increased over time. These findings may aid in the interpretation of results when examining stressors and counter-stress in clinical samples where one would expect stress to increase, whereas positive psychological states decrease.

Law Enforcement Officer Versus Non–law Enforcement Officer Status as a Longitudinal Predictor of Traditional and Emerging Cardiovascular Risk Factors

Objective: To determine whether law enforcement officer (LEO) status and perceived stress are longitudinal predictors of traditional and inflammatory cardiovascular (CV) risk factors. Method: Linear hierarchical regression was employed to investigate the longitudinal (more than 7 years) relationship between occupational category (LEO vs non-LEO) and perceived stress scale scores, and traditional and inflammatory CV risk factors in an all-male sample of 105 LEOs and 65 non-LEOs. Results: The occupational status of LEOs, compared with that of non-LEOs, predicted higher levels of C-reactive protein, systolic blood pressure, body mass index, and waist circumference. Perceived stress across occupational categories was directly associated with diastolic blood pressure and waist circumference and inversely with fibrinogen. Perceived stress did not interact with occupational category to predict any risk factor. Conclusion: Traditional and inflammatory risk factors, but not perceived stress, appear to contribute to elevated CV risk among LEOs.

The Longitudinal Relation between Smoking and Muscle Strength in Healthy Adults

Aim: To assess longitudinally whether smoking tobacco is related to muscle strength in healthy adults and to assess the influence of lifestyle covariates on this relation. Methods: Data were obtained from the observational Amsterdam Growth and Health Longitudinal Study, with four repeated measurements at the ages of 21 (n = 181), 27 (n = 144), 32 (n = 426) and 36 (n = 373) years. Knee muscle strength (KMS) was measured at an angle of 300° per second. Smoking and the covariates physical activity and dietary intake were assessed with a questionnaire. Other covariates included physical fitness and body fat percentage. Cardiopulmonary fitness was assessed with a maximal running test and body fatness with skinfold measurements. Sex-specific longitudinal analyses were carried out using generalized estimating equations. Results: In men and women, an inverse relationship between smoking tobacco and KMS was found. Smoking 100 g of tobacco a week resulted in a reduction of 2.9% in KMS in men and a reduction of 5.0% in women. This relation existed largely independently of lifestyle covariates. Conclusion: This study indicates that smoking is inversely related to skeletal muscle strength in healthy adults.

Inflammation Markers are Associated with Cardiovascular Diseases Risk in Adolescents: The Young Hearts Project 2000

Purpose The traditional approach for identifying subjects at risk from cardiovascular diseases (CVD) is to determine the extent of clustering of biological risk factors adjusted for lifestyle. Recently, markers of endothelial dysfunction and low grade inflammation, including high sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion molecules (sICAM), and soluble vascular adhesion molecules (sVCAM), have been included in the detection for high risk individuals. However, the relationship of these novel biomarkers with CVD risk in adolescents remains unclear. The purpose of this study, therefore, was to establish the association of hsCRP, sICAM, and sVCAM with CVD risk in an adolescent population. Methods Data from the Young Hearts 2000 cross-sectional cohort study, carried out in 1999–2001, were used. From a total of 2,017 male and female participants, 95 obese subjects were identified and matched according to age, sex, and cigarette smoking, with 95 overweight and 95 normal-weight adolescents. Clustered CVD risk was computed using a sum of Z-scores of biological risk factors. The relationship was described using multiple linear regression analyses. Results hsCRP, sICAM, and sVCAM showed significant associations with CVD risk. hsCRP and sICAM had a positive relation with CVD risk, whereas sVCAM showed an inverse relationship. In this study, lifestyle factors showed no relation with CVD risk. Conclusion The results fit the hypothesized role of low grade inflammation and endothelial dysfunction in CVD risk in asymptomatic adolescents. The inverse relationship of VCAM, however, is hard to explain and indicates the complex mechanisms underlying CVD. Further research is needed to draw firm conclusions on the biomarkers used.

Seasonal influences on hemoglobin levels and deferral rates in whole-blood and plasma donors

BACKGROUND: Indications exist that deferral rates in blood donors are highest in summer. However, a detailed quantitative analysis is not available. The association between Hb values, deferral rates, and daily temperatures was investigated in a large data set of blood donors.