PubMed Health⌕ Search

Biomedical subjects

M A de Ridder

Publications and source records attributed to M A de Ridder.

At least 19 recordsLinked to original sources
PubMed2001

Prognosis of Alzheimer's disease: the Rotterdam Study.

The aim of this study was to construct a prognostic model to predict the progression of Alzheimer's disease (AD). Prevalent and incident cases with AD came from the Rotterdam Study, a population-based prospective cohort study of persons aged 55 years and older, including those living in institutions. Rate of cognitive decline, as measured by the Mini Mental State Examination (MMSE score), was predicted by a random effects model. Risk of institutionalization and death were estimated with polytomous logistic regression analysis. At baseline, 306 subjects were diagnosed with prevalent AD and had complete data on living conditions and cognitive function. After a mean follow-up of 2.1 years, 95 subjects with incident AD had been diagnosed. Prevalent patients showed a slower decline in cognitive function than incident patients (p = 0.004). For prevalent and incident AD patients, high age and low cognitive performance were the strongest predictors for institutionalization and death. These prognostic risk functions can provide information on the decline of Alzheimer patients and might be used to better evaluate the effect of treatments for AD.

Activities of Daily Living↗
PubMed2000

[Prevalence of sexually transmitted diseases (STD) and HIV-infection among attendees of STD Outpatient Clinic, Dijkzigt University Hospital in Rotterdam; comparative analysis of years 1993 and 1998].

OBJECTIVE: To gain an impression as to the possible trends in the prevalence of VD and HIV between 1993 and 1998. DESIGN: Retrospective. METHOD: Data of age, gender, ethnic background, sexual preference, intravenous drug use and a diagnosis of VD or HIV infection for persons attending the VD Outpatient Clinic of the Department of Dermato-Venereology of the Dijkzigt University Hospital in Rotterdam, the Netherlands, for the first time were compared for the years 1993 and 1998. RESULTS: The number of patients examined was 3099 (1894 men and 1205 women) in 1993 and 3696 (1878 men and 1818 women) in 1998. No diagnosis of venereal disease was made in 58.9% and 56.2% of them, respectively. The prevalence of HIV infection decreased from 1.3% in 1993 to 0.6% in 1998. This was caused mainly by a decline in the prevalence of HIV-antibodies among men with homosexual contacts. In the total population, the prevalence of Neisseria gonorrhoeae and Chlamydia trachomatis decreased significantly (from 5.4% to 2.5% and from 9.3% to 7.5%, respectively), but there was no similar decrease among the men with homosexual contacts.

Comorbidity↗
PubMed2000

Human fetal pulmonary artery velocimetry: repeatability and normal values with emphasis on middle and distal pulmonary vessels.

OBJECTIVES: To establish the nature and gestational age dependency of flow velocity waveforms from fetal middle and distal arterial pulmonary branches in the second half of normal pregnancy and to determine repeatability and inter-relationship of flow velocity waveform recordings from proximal, middle and distal arterial pulmonary branches. DESIGN: Cross-sectional study. SUBJECTS/METHODS: A total of 111 singleton normal pregnancies between 20 and 40 weeks of gestation were studied using a color-coded Doppler ultrasound system. Pulmonary waveforms were obtained at the level of the fetal cardiac four-chamber view. Repeatability was tested from two recordings at 15 min time-intervals in 25 separate normal pregnancies. RESULTS: Acceptable repeatability of flow velocity waveforms from fetal arterial pulmonary branches was established with coefficients of variation below 15%. The nature of middle arterial pulmonary flow velocity waveforms was similar to that of proximal waveforms and showed a gestational age-related change for diastolic velocity parameters, peak systolic/peak diastolic ratio and pulsatility index. The distal arterial pulmonary branch displayed a monophasic forward flow velocity profile throughout the cardiac cycle. All velocity parameters of the distal branch remained unchanged with advancing gestation, with the exception of the pulsatility index. Significant inter-pulmonary changes were found for all pulmonary arterial waveform parameters. CONCLUSIONS: Alteration in pulmonary vascular resistance may play a role in gestational age-related changes, whereas changes in vessel branching/diameter and in the distance between the heart and more distal arterial pulmonary vessels may cause inter-pulmonary differences.

Blood Flow Velocity↗
PubMed2000

Contribution of adverse drug reactions to hospital admission of older patients.

OBJECTIVE: To describe the severity of adverse drug reactions as a factor in hospital admission of older patients, and to identify risk indicators for severe adverse drug reactions in these patients. DESIGN: Observational cross-sectional study. SETTING: Five wards in a university hospital in The Netherlands. SUBJECTS: Patients aged 70 and over admitted to general medical wards. METHODS: Use of statistical comparison and Kramer's algorithm. RESULTS: A severe adverse drug reaction was present in 25 (24%) of 106 patients. Thirteen patients (12%; 95% confidence interval 6.1-18.6%) were admitted probably because of an adverse drug reaction. Risk indicators for a severe adverse drug reaction were a fall before admission (odds ratio 51.3, P = 0.006), gastrointestinal bleeding or haematuria (odds ratio 19.8, P < 0.001) and the use of three or more drugs (odds ratio 9.8, P = 0.04). CONCLUSION: Adverse drug reactions are an important cause of hospital admissions in older people. A fall before admission may indicate a severe adverse drug reaction.

Accidental Falls↗
PubMed2000

Do older hospital patients recognize adverse drug reactions?

OBJECTIVE: To establish the relationship between subjective complaints of side effects of drugs and the objective presence of adverse drug reactions in older patients. DESIGN: Observational cross-sectional study. SETTING: Five medical wards at the University Hospital Rotterdam Dijkzigt. SUBJECTS: Patients aged 70 and over admitted to the general medical wards over a 3-month period. METHODS: Statistical comparison and Kramer's algorithm. RESULTS: Of 106 patients, 102 used medication, and 93 of these were able to report whether they believed they were experiencing drug side effects. Thirty-six [39% (95% confidence interval 28.8-48.6)] believed that they were experiencing side effects and the number of diagnoses per patient and the proportion of patients with chronic obstructive pulmonary disease was higher in these 36 'complainers' than in the group of the 'non-complainers'. We found a correct opinion (true positive and negative) about the objective presence or absence of mild or severe adverse drug reactions in 79% (95% confidence interval 70.2-86.8). Asking the patient about side effects of drugs had a sensitivity of 0.70 and a specificity of 0.85 patients. The severe adverse drug reactions in 21 patients were not recognized by 14 of them. CONCLUSION: At hospital admission, older patients should be asked about drug side effects because they are often correct in recognizing them. However, severe adverse drug reactions are not easily recognized.

Adverse Drug Reaction Reporting Systems↗
PubMed1998

G-estimation of causal effects: isolated systolic hypertension and cardiovascular death in the Framingham Heart Study.

Time-dependent covariates are often both confounders and intermediate variables. In the presence of such covariates, standard approaches for adjustment for confounding are biased. The method of G-estimation allows for appropriate adjustment. Previous studies applying the G-estimation method have addressed effects on all-cause mortality rather than on specific causes of death. In the present study, a method to adjust for censoring by competing risks is presented. The authors used the approach to estimate the causal effect of isolated systolic hypertension on cardiovascular mortality in the Framingham Heart Study, with a 10-year follow-up using data from 1956 to 1970. Arterial rigidity is a major determinant of isolated systolic hypertension and may be a confounder of the relation between isolated systolic hypertension and cardiovascular death. Conversely, isolated systolic hypertension may by itself contribute to stiffening of the vessel wall, and arterial rigidity may therefore also be an intermediate variable in the causal pathway from isolated systolic hypertension to cardiovascular death. While controlling for arterial rigidity and other baseline and time-dependent covariates, isolated systolic hypertension decreased the time to cardiovascular death by 45% (95% confidence interval 3-69).

Adult↗
PubMed1998

A rebreathing method to determine carbon monoxide diffusing capacity in children: reference values for 6- to 18-year-olds [corrected] and validation in adult volunteers.

The diffusing capacity of carbon monoxide (D(L,CO)) and its value normalized to alveolar volume (D(L,CO)/V(A)) are usually estimated with the single breath method at total lung capacity (TLC). Severely ill patients and small children are not able to deliver a satisfactory vital capacity (VC) or hold their breath for 10 s at TLC. The aim of this study was to develop a rebreathing procedure in which diffusing capacity can be determined during spontaneous tidal breathing. The conventional rebreathing method during hyperventilation was modified so that rebreathing volume and gas concentrations were kept constant by CO2 absorption and O2 supplementation. In adult healthy volunteers and in patients who were able to perform both tests, the diffusion indices obtained with this rebreathing method during resting ventilation were compared with those obtained by the single breath method. Predicted (reference) values for rebreathing D(L,CO) and D(L,CO)/V(A) for children were determined. D(L,CO)/V(A) decreased with alveolar volume (V(A)) and increased with alveolar ventilation (V'(A)). In adults at V'(A) above 35 L x min(-1) rebreathing D(L,CO)/V(A) was similar to single breath D(L,CO)/V(A) at similar alveolar volumes. The D(L,CO)/V(A) relative to their corresponding reference values were the same for both methods in adult patients, irrespective of ventilation distribution disturbances. In children the newly described diffusing capacity obtained by the rebreathing method during resting ventilation can serve as a valuable index to assess and follow a diffusion disorder.

Absorption↗
PubMed1998

An estimate of fetal autonomic state by spectral analysis of human umbilical artery flow velocity waveforms.

OBJECTIVE: Determination of gestational age-related fluctuations in heart rate in the umbilical artery of the early human fetus. METHODS: Doppler velocity recordings from human umbilical artery were obtained, in a cross-sectional study design in 137 singleton pregnancies at 10-20 weeks of gestation. After exclusion criteria were applied, data on 117 normal pregnancies were available and subdivided into group I: 10-12 weeks (n = 49); group II: 13-16 weeks (n = 43); and group III: 17-20 weeks (n = 25). Blood flow velocity waveforms were reconstructed from Doppler audio signals. Variability in heart rate was calculated using Fast Fourier Transforms (FFT). Individual heart rate variability power spectra were subdivided into frequency bands. RESULTS: Fetal heart rate variability decreases at 10-20 weeks and demonstrates a shift to lower frequencies at 17-20 weeks. CONCLUSIONS: Fetal heart rate variability is related to gestational age and shows a shift to lower frequencies which may reflect autonomic functional development.

Adolescent↗
PubMed1998

Effects of environmental exposure to polychlorinated biphenyls and dioxins on birth size and growth in Dutch children.

Lower birth weight and growth retardation has been found in studies with laboratory animals, in children born of mothers exposed to accidental high levels of polychlorinated biphenyls (PCBs) and related compounds, and in children born of mothers who consumed PCB-contaminated fish. The effect of background exposure to PCBs and dioxins on birth size and growth in human newborns, however, is still unknown. This study examined birth size and postnatal growth of term newborns in relation to their background PCB and dioxin exposure. Birth weight and weight, length, and head circumference were measured at 10 d and 3, 7, 18, and 42 mo of age in 207 children, of whom 105 were breast-fed and 102 were formula-fed during infancy. The effect of in utero exposure to PCBs on birth size, assessed by cord and maternal plasma PCB levels, was investigated in the whole group. The effect of prenatal PCB exposure on postnatal growth was studied in the formula-fed group, whereas the effect of prenatal as well as lactational exposure to PCBs and dioxins on postnatal growth was studied in the breast-fed group. After adjustment for covariates, cord and maternal plasma PCB levels where both negatively associated with birth weight. Infants with high cord plasma PCB levels (P90 = 0.80 microL) weighed 165 g less compared with infants with low cord plasma PCB levels (P10 = 0.20 microg/L). Cord and maternal plasma PCB levels where both significantly associated with lower growth rate, defined as change in SD score (SDS) of weight, length, and head circumference from birth to 3 mo in the formula-fed group (all p values <0.05). No negative effects of prenatal PCB exposure on growth rate were found from 3 to 42 months of age. Postnatal PCB and dioxin exposure was not negatively associated with growth rate in the breast-fed group. In utero exposure to environmental levels of PCBs is negatively associated with birth weight and postnatal growth until 3 mo of age. Although this growth delay was described in healthy term born infants, intrauterine and postnatal growth retardation are potentially harmful to the developing human and should be avoided by reducing maternal PCB and dioxin body burden, and consequently fetal exposure to these pollutants.

Adult↗
PubMed1997

Determinants of body composition measured by dual-energy X-ray absorptiometry in Dutch children and adolescents.

Knowledge about body composition is important in metabolic and nutritional studies. In this cross-sectional study the body composition of 403 healthy white Dutch children and adolescents was evaluated by using dual-energy X-ray absorptiometry (DXA). Possible determinants of body composition were analyzed. In 85 subjects the results of bioelectrical impedance analysis (BIA) were compared with DXA. Fat mass, lean tissue mass, and bone mineral content were greater in older boys and girls. Percentage body fat was greater in older girls but not in boys and it was higher in girls than in boys at all ages. From the age of 14 y boys had higher lean tissue mass and bone mineral content than girls. Tanner stage had a significant relation with body composition in both sexes. Percentage body fat was lower in boys in stage 4 than in stage 3 and was higher in consecutive Tanner stages in girls. After adjustment for age, Tanner stage was significantly positively related to lean tissue mass and bone mineral content in boys and girls and to percentage body fat and fat mass in girls. The profession of the parents and the education of the father had a significant negative correlation with percentage body fat and fat mass in girls (P < 0.01). Physical activity was related to lean tissue mass (P = 0.001) but not to fat mass in boys after adjustment for age. A high correlation and a small difference was found between lean body mass by BIA and lean tissue mass by DXA. Body composition in healthy Dutch children and adolescents is related to age, sex, Tanner stage, socioeconomic status, and physical activity.

Absorptiometry, Photon↗
PubMed1997

Doppler velocimetry in branch pulmonary arteries of normal human fetuses during the second half of gestation.

The objective of the present study was to determine the characteristics of Doppler flow velocity wave forms in branch pulmonary arteries in relation to gestational age. A total of 111 singleton normal pregnancies were studied during the second half of pregnancy using a combined color-coded Doppler and two-dimensional real-time ultrasound system. Pulsed Doppler measurements of the most proximal branch of the right or left pulmonary artery were attempted during fetal apnea from a transverse cross-section of the fetal chest at the level of the cardiac four-chamber view after visualization with color Doppler. The success rate in obtaining the pulmonary arterial wave form was 85%. The wave form displayed a rapid systolic velocity acceleration, followed by an initially rapid but then more gradual velocity deceleration which was interrupted in most cases by a short reversed flow interval at the beginning of the diastolic phase of the cardiac cycle. The diastolic phase was characterized by forward flow. Peak systolic, end-diastolic and time-averaged velocity, pulsatility index, and systolic integral remained constant during gestation. Changes in vessel diameter or compliance may play a role in this. A gestational age-dependent rise was established for peak diastolic velocity, diastolic integral, and early peak diastolic reverse flow, whereas a gestational age-determined decline was found for the peak systolic/peak diastolic ratio. Fetal heart rate demonstrated a statistically significant increase relative to gestational age. However, the observed relation between the flow velocity wave form parameters, pulsatility index calculations, and gestational age was independent of fetal heart rate. It is speculated that peak diastolic velocity, diastolic integral, and peak systolic/peak diastolic ratio rather than the pulsatility index are useful in detecting gestational age-related changes in human fetal pulmonary vascular resistance.

Adolescent↗
PubMed1997

Bone mineral density in children and adolescents: relation to puberty, calcium intake, and physical activity.

The association of height, weight, pubertal stage, calcium intake, and physical activity with bone mineral density (BMD) was evaluated in 500 children and adolescents (205 boys and 295 girls), aged 4-20 yr. The BMD (grams per cm2) of lumbar spine and total body was measured with dual energy x-ray absorptiometry. Lumbar spine volumetric BMD was calculated to correct for bone size. BMD and volumetric BMD increased with age. During puberty, the age-dependent increment was higher. After adjustment for age, the Tanner stage was significantly associated with all three BMD variables in girls and with spinal BMD in boys. In boys, positive correlations were found between BMD and both calcium intake and physical activity after adjustment for age. Stepwise regression analysis with weight, height, Tanner stage, calcium intake, and physical activity as determinants with adjustment for age resulted in a model with Tanner stage in girls and weight in boys for all three BMD variables. The major independent determinant of BMD was the Tanner stage in girls and weight in boys.

Adolescent↗
PubMed1997

Comparison of patients refusing with patients accepting unlinked anonymous HIV testing in an outpatient STD department in The Netherlands.

From 1 February 1993 to 1 February 1994 all new patients, known patients with new problems, and prostitutes attending the Outpatient Department of Sexually Transmitted Diseases (STD) of the University Hospital Rotterdam were asked to participate in unlinked anonymous human immunodeficiency virus (HIV) testing and to answer some questions. Data from the medical records of 300 patients refusing to participate were compared with self-reported data obtained from 2701 people accepting, to verify if the HIV seroprevalence among accepters could be representative for all STD department visitors. Men refusing were more often of foreign origin, had more often had more than one partner during the previous 6 months, more often attended the STD department for the first time, and more often had an STD diagnosed than men accepting. Women refusing were more often of foreign origin, had less often had more than one partner during the previous 6 months, and had more often used drugs intravenously than women accepting. Because most findings associated with refusing are also associated with being infected with HIV, the HIV seroprevalence among refusers is likely to be higher than among accepters. We therefore advise unlinked anonymous HIV testing of all patients visiting an STD department.

Adult↗
PubMed1997

Plasma polychlorinated biphenyl levels in Dutch preschool children either breast-fed or formula-fed during infancy.

OBJECTIVES: This study examined the influence of lactational and in utero exposure to polychlorinated biphenyls (PCBs) on plasma PCB levels in children. METHODS: Plasma PCB levels were measured in 173 children at 3.5 years, of whom 91 were breast-fed and 82 were formula-fed in infancy. RESULTS: Median plasma PCB levels were 3.6 times higher in breast-fed children (0.75 microgram/L) than in their formula-fed peers (0.21 microgram/L). Breast-feeding period and breast-milk PCB levels were important predictors for PCB levels in the breast-fed group. For children in the formula-fed group, PCB levels were significantly related to their material plasma PCB levels. CONCLUSIONS: PCB levels in Dutch preschool children are related to transfer of maternal PCBs; therefore, strategies should be aimed at reducing maternal PCB body burden.

Adult↗
PubMed1996

Effects of polychlorinated biphenyl/dioxin exposure and feeding type on infants' mental and psychomotor development.

OBJECTIVE: To evaluate the effects of in utero and lactational exposure to polychlorinated biphenyls (PCBs) and dioxins on the mental and psychomotor development of infants. DESIGN: Prenatal PCB exposure was estimated from the levels in maternal plasma during the last month of pregnancy. Postnatal PCB and dioxin exposure of breastfed infants was calculated from levels in human milk samples and the duration of breastfeeding. Infants were examined at 3, 7, and 18 months of age with the Bayley Scales of Infant Development. SETTING: General community. PARTICIPANTS: Voluntary sample of 207 mother-infant pairs. One hundred five infants were breastfed and 102 were bottle-fed. INTERVENTIONS: None. RESULTS: Higher in utero exposure to PCBs was associated with lower psychomotor scores at 3 months of age: a doubling of the PCB load resulted in a decrease of 3 points. Breastfed infants scored significantly higher on the psychomotor score at 7 months of age, compared with formula-fed infants. However, when corrected for confounders, the psychomotor score of the 66% highest-exposed breastfed infants ( > 756 pg total PCB-dioxin toxic equivalent) was negatively influenced by this postnatal exposure to PCBs and dioxins, and was comparable to the psychomotor score of the formula-fed infants. Breastfed infants also scored higher on the mental scale at 7 months of age in a dose-dependent way. There was no significant influence of the perinatal PCB and dioxin exposure on the mental outcome at 3 and 7 months of age. At 18 months of age neither the mental nor the psychomotor score was related to perinatal PCB or dioxin exposure, nor to the duration of breastfeeding. CONCLUSIONS: Prenatal PCB exposure has a small negative effect on the psychomotor score at 3 months of age. PCB and dioxin exposure through breastfeeding has an adverse effect on the psychomotor outcome at 7 months of age. The mental outcome at 7 months of age is positively influenced by breastfeeding per se; the perinatal exposure to PCBs and dioxins does not influence this outcome. At 18 months of age the development is affected neither by PCB and dioxin exposure nor by feeding type.

Bottle Feeding↗
PubMed1995

Normal fetal pulmonary venous blood flow velocity.

Our objectives were to describe the normal pulmonary venous blood flow velocity waveform and to establish reference ranges for the second half of pregnancy in healthy human fetuses. A total of 123 women with uncomplicated pregnancies of between 20 and 40 weeks were examined, using a combined color-coded Doppler and two-dimensional real-time ultrasound system. Pulsed Doppler flow velocity waveforms of pulmonary venous drainage into the left atrium were obtained from a transverse cross section of the fetal chest at the level of the cardiac four-chamber view. All waveforms were obtained during fetal apnea. The success rate in obtaining the pulmonary venous waveform was 81%. The waveform displayed a biphasic forward flow profile with a systolic and diastolic component. Peak systolic, peak diastolic and time-averaged velocities demonstrated a gestational age-related rise, whereas the peak systolic/peak diastolic ratio showed a gestational age-related reduction. The nature of the fetal pulmonary venous flow velocity waveform pattern suggests positive pressure towards the left atrium throughout the cardiac cycle. We speculate that an increase in volume flow and the pulmonary venous pressure gradient play a role in the gestational age-related changes in pulmonary venous flow velocities.

Blood Flow Velocity↗