Electrolytes in early primary hypertension : an epidemiological approach

The studies presented in this thesis were conducted in a population of young, non-hospitalized subjects. This opportunity was presented by the availability of a large cohort of children and young adults that had been followed up for more than seven years as part of the Epidemiologic Preventive Organization zoetermeer {EPOZ study), and of which a large body of data on blood pressure and other characteristics could be used. The basic theme of the studies was to elucidate mechanisms involved hypertension, with special electrolytes. (chapter 1) in the early pa~hogenesis emphasis on the role of of primary dietary The effect of changes in electrolyte intake in youngsters elevated blood pressure was studied in two randomized trials. with The scientific concept in evaluating the of the randomized trial is of primary importance effect of a certain characteristic, like electrolyte intake, on another characteristic, like blood Randomization garantuees internal validity of a study with pressure. regard to potential sources of bias. In addition, blinding of participants and investigators for the type of intervention during the trial reduces the possibility of distortion of the results by information bias. Randomization may be accomplished by random assignment of individuals to a certain treatment, the parallel-group design, or by randomization of treatment periods within an individual, the crossover design. Both methods were applied in studies presented in this thesis. (chapter 2

Prospective cohort study of routine use of risk assessment scales for prediction of pressure ulcers

Objective To evaluate whether risk assessment scales can be used to identify patients who are likely to get pressure ulcers.Design Prospective cohort study.Setting Two large hospitals in the Netherlands.Participants 1229 patients admitted to the surgical, internal, neurological, or geriatric wards between January 1999 and June 2000.Main outcome measure Occurrence of a pressure ulcer of grade 2 or worse while in hospital.Results 135 patients developed pressure ulcers during four weeks after admission. The weekly incidence of patients with pressure ulcers was 6.2% (95% confidence interval 5.2% to 7.2%). The area under the receiver operating characteristic curve was 0.56 (0.51 to 0.61) for the Norton scale, 0.55 (0.49 to 0.60) for the Braden scale, and 0.61 (0.56 to 0.66) for the Waterlow scale; the areas for the subpopulation, excluding patients who received preventive measures without developing pressure ulcers and excluding surgical patients, were 0.71 (0.65 to 0.77), 0.71 (0.64 to 0.78), and 0.68 (0.61 to 0.74), respectively. In this subpopulation, using the recommended cut­off points, the positive predictive value was 7.0% for the Norton, 7.8% for the Braden, and 5.3% for the Waterlow scale.Conclusion Although risk assessment scales predict the occurrence of pressure ulcers to some extent, routine use of these scales leads to inefficient use of preventive measures. An accurate risk assessment scale based on prospectively gathered data should be developed

Higher usual dietary intake of phytoestrogens is associated with lower aortic stiffness in postmenopausal women

Objective¿ Phytoestrogens have been postulated to protect against cardiovascular diseases, but few studies have focused on the effect of Western dietary phytoestrogen intake. Methods and Results¿ Four hundred three women with natural menopause either between 1987 and 1989 or between 1969 and 1979 were selected from the baseline data of the PROSPECT study (n=17 395). Isoflavone and lignan intake was calculated from a food-frequency questionnaire. Aortic stiffness was noninvasively assessed by pulse-wave velocity measurement of the aorta. Linear regression analysis was used. After adjustment for age, body mass index, smoking, physical activity, mean arterial pressure, follow-up time, energy intake, dietary fiber intake, glucose, and high density lipoprotein cholesterol, increasing dietary isoflavone intake was associated with decreased aortic stiffness: -0.51 m/s (95% CI -1.00 to -0.03, fourth versus first quartile, P for trend=0.07). Increasing dietary intake of lignans was also associated with decreased aortic pulse-wave velocity: -0.42 m/s (95% CI -0.93 to 0.11, fourth versus first quartile, P for trend=0.06). Results were most pronounced in older women: for isoflavones, -0.94 m/s (95% CI -1.65 to -0.22, P for trend=0.02), and for lignans, -0.80 m/s (95% CI -1.85 to -0.05), fourth versus first quartile. Conclusions¿ The results of our study support the view that phytoestrogens have a protective effect on the risk of atherosclerosis and arterial degeneration through an effect on arterial walls, especially among older wome

A nested case-control study on mortality in uses of ibopamine

Background: A recent interim analysis of the PRIME II placebo-controlled study showed a significantly higher mortality in the group treated with ibopamine than in the control group. The objective was to study mortality in patients on ibopamine, and to assess risk factors for death. Methods: All 2147 drug-dispensing outlets (DDO) in the Netherlands were asked to provide a printout of the complete medication history of users of ibopamine. A reaction was received from 92% of the DDO. From the 14,024 identified former or current users of ibopamine, a sample of 3148 patients (22%) was enrolled in the follow-up study. All general practitioners (GP) of these patients received an enquiry pertaining to the vital status of their patient, cause of death, primary cause and NYHA classification of heart failure, echo- and electrocardiographic data, serum creatinine, admissions and the effects of ibopamine. Cases were defined as patients who died during the follow-u

Common carotid intima-media thickness and risk of stroke and myocardial infarction: the Rotterdam Study

BACKGROUND: Noninvasive assessment of intima-media thickness (IMT) is widely used in observational studies and trials as an intermediate or proxy end point for cardiovascular disease. However, data showing that IMT predicts cardiovascular disease are limited. We studied whether common carotid IMT is related to future stroke and myocardial infarction. METHODS AND RESULTS: We used a nested case-control approach among 7983 subjects aged > or =55 years participating in the Rotterdam Study. At baseline (March 1990 through July 1993), ultrasound images of the common carotid artery were stored on videotape. Determination of incident myocardial infarction and stroke was predominantly based on hospital discharge records. Analysis (logistic regression) was based on 98 myocardial infarctions and 95 strokes that were registered before December 31, 1994. IMT was measured from videotape for all case subjects and a sample of 1373 subjects who remained free from myocardial infarction and stroke during follow-up. The mean duration of follow-up was 2.7 years. Results were adjusted for age and sex. Stroke risk increased gradually with increasing IMT. The odds ratio for stroke per standard deviation increase (0.163 mm) was 1.41 (95% CI, 1.25 to 1.82). For myocardial infarction, an odds ratio of 1.43 (95% CI, 1.16 to 1.78) was found. When subjects with a previous myocardial infarction or stroke were excluded, odds ratios were 1.57 (95% CI, 1.27 to 1.94) for stroke and 1.51 (95% CI, 1.18 to 1.92) for myocardial infarction. Additional adjustment for several cardiovascular risk factors attenuated these associations: 1.34 (95% CI, 1.08 to 1.67) and 1.25 (95% CI, 0.98 to 1.58), respectively. CONCLUSIONS: The present study, based on a short follow-up period, provides evidence that an increased common carotid IMT is associated with future cerebrovascular and cardiovascular events