Biomedical subjects

M A Pols

Publications and source records attributed to M A Pols.

10 recordsLinked to original sources

PubMed2000

Factors predicting survival for HIV-infected patients with respiratory failure.

BACKGROUND: Despite improved treatment modalities, the mortality of HIV infected patients admitted to the intensive care unit with respiratory failure remains high. To help ICU physicians in advising HIV infected patients whether to undergo mechanical ventilation, we retrospectively investigated prognostic factors predicting hospital outcome for HIV-infected patients, admitted to a medical intensive care unit with respiratory failure before the era of highly-active anti-retroviral therapy. METHODS: A retrospective chart review was carried out of all HIV-infected patients with respiratory failure admitted to the medical ICU of a Dutch University Hospital between 1991 and 1997. RESULTS: In the six year period, 29 HIV-infected patients were admitted to the ICU for respiratory failure. Mechanical ventilation, CD4 cell count, APACHE II score, APACHE III score, ARDS and length of ICU stay all differed significantly between survivors and non-survivors. However, a multivariate analysis only showed the need for mechanical ventilation as an independent risk factor for mortality. The only combination of factors able to accurately predict mortality for the individual patient was the development of ARDS and the requirement of mechanical ventilation. CONCLUSIONS: The combination of mechanical ventilation and ARDS accurately predicts hospital outcome in HIV-infected patients presenting with respiratory failure before the HAART era.

AIDS-Related Opportunistic Infections↗

PubMed1998

Methodological aspects of physical activity assessment in epidemiological studies.

A range of epidemiological studies conducted over the past decades has produced strong support for the view that lack of physical activity is associated with increased risks of several chronic diseases, such as cardiovascular disease, diabetes mellitus, cancer, etc. Much is still unknown about the type and degree of activity that is required to influence the risk of specific diseases. Furthermore, physical activity can act as a confounder in relationships between other exposure variables (e.g. diet) and disease. Thus, the measurement of physical activity in epidemiological studies is of great importance. The questionnaire is the most frequently used method in epidemiological research. Before using a questionnaire on a large scale, validity and reproducibility should be assessed in a representative population. Some practical and methodological aspects of physical activity validation studies are described, together with the possible implications of the results.

Epidemiologic Methods↗

PubMed1997

Physical activity and cardiovascular disease risk profile in women.

In a population of 4,576 Dutch women aged 49-70 years who participated in the European Prospective Investigation into Cancer and Nutrition (EPIC) in 1993-1995, the relation between physical activity and the presence of cardiovascular disease risk indicators was assessed cross-sectionally. Physical activity was determined from a self-administered questionnaire, while blood pressure, heart rate, body mass index, waist/hip ratio, and waist circumference were measured at the study center. Mean risk indicator levels were calculated for different activity categories. Blood pressure was most clearly associated with time spent in sports (mean systolic blood pressure, adjusted for age, level of education, and smoking, 128.9 mmHg in the highest sports tertile, and 132.1 mmHg in the lowest sports tertile; mean diastolic blood pressure, 77.8 mmHg and 79.0 mmHg, respectively). Body mass index, waist/hip ratio, and waist circumference showed an inverse relation with cycling, gardening, do-it-yourself-activities, and sports. In this population, leisure-time activity was inversely related to cardiovascular disease risk indicators, but work activity and housework were not. The authors conclude that if investigators wish to measure physical activity in women over age 50 years with the aim to identify high- and low-risk groups for cardiovascular disease, they should consider not only housework activity, but also leisure-time activities such as cycling, sports, and do-it-yourself activities.

Aged↗

PubMed1997

Estimation of reproducibility and relative validity of the questions included in the EPIC Physical Activity Questionnaire.

BACKGROUND: The EPIC core questionnaire on lifestyle contains a number of questions on physical activity designed to rank subjects according to level of physical activity (short PA questionnaire). These questions are based on a more extensive questionnaire designed to measure absolute total energy expenditure (extensive PA questionnaire), that was validated in a pilot study preceding EPIC. Reproducibility and relative validity of the short PA questionnaire were estimated by selecting, from the pilot study data, the answers to a number of questions from the extensive questionnaire that resembled those actually included in the short version. METHODS: The population of the pilot study consisted of 126 men and women aged between 20 and 70 years. Reproducibility was estimated by administering the extensive questionnaire three times: at baseline, and after 5 and 11 months. In order to determine the relative validity of the extensive questionnaire, a 3-day activity diary, repeated four times, was used as the reference method. RESULTS: Over the study period (13 months), mean absolute energy expenditure, estimated from the questions included in the short questionnaire, was fairly constant in men but not in women. REPRODUCIBILITY: Spearman correlation coefficients ranged from 0.47 to 0.89 in men, and from 0.49 to 0.81 in women. RELATIVE VALIDITY: Spearman correlation coefficients between the short questionnaire and the diary were between 0.32 and 0.81 for men, and between 0.28 and 0.72 for women. CONCLUSIONS: The questions selected for the short questionnaire are not suitable for estimating energy expenditure at an absolute level. Reproducibility and relative validity of the ranking of subjects seemed satisfactory and comparable to the extensive questionnaire. The results imply that the short questionnaire is suitable for ranking subjects in the EPIC study.

Adult↗

PubMed1997

The Dutch EPIC food frequency questionnaire. I. Description of the questionnaire, and relative validity and reproducibility for food groups.

BACKGROUND: A self-administered food frequency questionnaire was developed for the Dutch cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC). Habitual consumption of 178 food items can be calculated from the questionnaire data. METHODS: Reproducibility and relative validity for food group intake were investigated in a population of 121 Dutch men and Women. The questionnaire was administered three times at 6-month intervals in order to determine the reproducibility. To assess the relative validity 12 monthly 24-hour recalls served as the reference method. RESULTS: Spearman rank order correlation coefficients between estimates of food group intake assessed by repeated questionnaires ranged from 0.45 to 0.92. For men, Spearman correlation coefficients between estimates of food group intake based on the questionnaire and those based on 24-hour recalls ranged from 0.21 for cooked vegetables to 0.78 for sugar and sweet products, with a range of 0.61. For women the median was 0.53, with a minimum of 0.31 for vegetables and a maximum of 0.87 for alcoholic beverages. The photographs in the questionnaire for the estimation of portion sizes contributed little to the relative validity of the ranking of subjects. However, on the group level most median food group estimates based on photographic portion sizes were closer to the median intakes as assessed by 24-hour recalls than those based on standard portion sizes. CONCLUSIONS: The questionnaire seems adequate for ranking Dutch EPIC subjects according to intake of most food groups, although the relative validity for some food groups, such as vegetables and fish, remains of concern.

Adult↗

PubMed1997

The Dutch EPIC food frequency questionnaire. II. Relative validity and reproducibility for nutrients.

BACKGROUND: A self-administered semi-quantitative food frequency questionnaire (FFQ) was developed for the Dutch cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: The reproducibility and relative validity of nutrient intake as assessed by this questionnaire were investigated in a population of 121 men and women. To assess the relative validity, 12 monthly 24-hour recalls served as reference method, together with four determinations of 24-hour urinary nitrogen excretion, predicted basal metabolic rate, and serum beta-carotene and alpha-tocopherol levels. RESULTS: Protein and among women, energy intake were underestimated by the questionnaire compared to urinary nitrogen excretion and the basal metabolic rate, respectively. The underestimation for protein decreased with increasing protein intake. Pearson correlation coefficients between nutrient intakes assessed by repeated questionnaires ranged from 0.70 to 0.94 among men and from 0.59 to 0.94 among women. Correlation coefficients between nutrient intakes assessed by the questionnaire and 24-hour recalls ranged from 0.26 to 0.83 for men and from 0.35 to 0.90 for women, with medians of 0.59 and 0.58, respectively. Correlation coefficients between 0.2 and 0.5 were observed for beta-carotene and vitamin C for men and for beta-carotene and vitamin E for women. Associations with serum beta-carotene (r = -0.16 for men; 0.13 for women) and alpha-tocopherol (0.23 and 0.15, respectively) were much poorer than those obtained with 24-hour recalls. Correlations between protein intake and 24-hour urinary nitrogen excretion were 0.47 and 0.53, respectively. CONCLUSIONS: The FFQ seems adequate for ranking subjects according to intake of energy, macronutrients, dietary fibre and retinol, but it does not yield such good results for beta-carotene, vitamin C for men, vitamin E for women.

Adult↗

PubMed1996

Repeatability and relative validity of two physical activity questionnaires in elderly women.

In a population of 33 women aged 51-71 yr, two physical activity questionnaires (a modified Baecke questionnaire and the pre-EPIC questionnaire) were tested for repeatability (5 and 11 months). For assessment of relative validity, the questionnaires were compared with a physical activity diary (12 d) as the main reference method, a single 24-h Caltrac accelerometer score, and energy intake estimated from a 24-h dietary recall repeated 12 times. Repeatability of the questionnaires at 5 months was 0.82 (Baecke) and 0.42 (pre-EPIC), at 11 months 0.73 and 0.60, respectively. Correlation with the activity diary was 0.51 for the Baecke and 0.64 for the pre-EPIC questionnaire. Correlation with the Caltrac was 0.22 for both questionnaires, and with energy intake -0.21 and 0.43, respectively. Factor analysis suggested that the questionnaires and the diary measured a common aspect of activity, which could be interpreted as "reported normal physical activity." Women who reported sweating or breathlessness during the past week scored significantly higher only on the Baecke questionnaire. It was concluded that the two questionnaires seemed to be able to rank older women according to physical activity in epidemiological studies.

Aged↗

PubMed1995

Validity and repeatability of a modified Baecke questionnaire on physical activity.

BACKGROUND: In a pilot study for the European Prospective Investigation into Cancer and Nutrition (EPIC) a modification of the Baecke questionnaire on physical activity was tested for repeatability and relative validity in a population of 134 men and women aged 20-70 years. METHODS: For the assessment of repeatability Pearson's correlation coefficients and percentages of agreement after classification in tertiles were computed between administrations of the questionnaire at baseline, and after 5 and 11 months. Relative validity was determined by comparing the questionnaire to a four times repeated 3-day activity diary. RESULTS: Repeatability after 5 and 11 months was good, with test-retest correlation coefficients between 0.65 and 0.89 for main sections of the questionnaire. The percentages of agreement, exceeding chance (Cohen's kappa) were 57% and 56% for men (at 5 and 11 months respectively) and 41% and 46% for women. The correlations with the diaries were 0.56 in men and 0.44 in women. Agreement apart from chance between classification in tertiles for both methods was 35% for men and 10% for women. CONCLUSIONS: These data show that repeatability is good and relative validity as compared to an activity diary is moderate but well within the range of values found in other studies. The questionnaire is more valid in men than in women.

Adult↗

PubMed1990

The plain abdominal radiograph in the assessment of constipation.

To investigate the value of the plain abdominal radiograph in the assessment of constipation we prospectively studied 30 patients (20 females, 10 males, mean age 48.6 years, range 21-76 years). These patients underwent the following tests: plain abdominal radiograph in supine position, measurement of stool weight (mean of 5 days) and whole gut transit time (20 radioopaque pellets, fluoroscopy of stools). All patients completed a questionnaire regarding their defaecation characteristics (a.o. average defaecation frequency and faecal consistency). The abdominal films were coded and independently scored for the degree of faecal stasis in ascending, transverse, descending colon and rectosigmoid by four gastroenterologists. To each of these parts of the colon a score of 1 (no faeces) to 4 (loaded with faeces) was assigned. The film scores given by the four observers were significantly correlated (p less than 0.001). Significant correlations were found between the radiograph scores and frequency of defaecation, faecal consistency and stool weight. The strength of these correlations were of the same order of magnitude as those between the other subjective and objective defaecation variables. The scores for the left colon (descending colon and rectosigmoid) showed a better correlation with the other defaecation parameters than the scores for the right colon. It is concluded that in the assessment of constipation a simple plain abdominal radiograph is as reliable as measurement of faecal weight or marker transit and can thus be advocated as the first procedure. When an abdominal radiograph is used for this purpose the stasis in the descending and sigmoid colon provides most information.

Adult↗

PubMedDate not supplied

Relative validity and repeatability of a new questionnaire on physical activity.

BACKGROUND: A physical activity questionnaire was developed with the aim to estimate usual individual daily energy expenditure. The questionnaire focused on the number of hours usually spent on various activities. In a pilot study it was tested for repeatability and validity in a population of 126 Dutch adults (64 men, 62 women). METHODS: For assessment of repeatability the questionnaire was administered three times during the course of 1 year. A four-times-repeated 3-day activity diary was used as a reference instrument to evaluate validity. RESULTS: Differences in mean energy expenditure among repeated administrations of the questionnaire were small and not significant. Spearman's test-retest correlation coefficients for total energy expenditure for men were 0.76 [95% confidence interval (CI) 0.63-0.85] and 0.70 (95% CI 0.54-0.81) at 5 and 11 months, respectively, and for women were 0.58 (95% CI 0.36-0.74) and 0.71 (95% CI 0.54-0.82). There was a significant trend showing increasing mean diary energy expenditure for successive tertiles of questionnaire energy expenditure. The correlation between the questionnaire and the diary was 0.66 (95% CI 0.49-0.78) for men and 0.43 (95% CI 0.18-0.63) for women. CONCLUSIONS: It was concluded that this questionnaire is a useful tool for estimating energy expenditure in epidemiological studies.

Adult↗