Biomedical subjects

A Kroke

Publications and source records attributed to A Kroke.

41 records · Page 3Linked to original sources

PubMed1998

Blood pressure measurement in epidemiological studies: a comparative analysis of two methods. Data from the EPIC-Potsdam Study. European Prospective Investigation into Cancer and Nutrition.

OBJECTIVE: To investigate the impact of a device replacement in blood pressure measurement in epidemiological studies on comparison and interpretation of epidemiological data by replacing traditional aneroid manometry with automated oscillometric devices. DESIGN: Within the context of a continuing epidemiological study (EPIC-Potsdam Study), blood pressure measurements were performed simultaneously with an aneroid sphygmomanometer and an automated oscillometric device for each subject. We randomly selected 400 men and women from the main study population and one observer performed three consecutive blood pressure measurements for each subject according to a standardized procedure. In total, 10 oscillometric devices of the same type were used. Demographic and anthropometric data for each subject were obtained by trained interviewers. RESULTS: The mean difference between the aneroid and the oscillometric measurements of systolic blood pressure was 0.2 +/- 5.6 mmHg (aneroid value greater, NS), whereas the mean difference in diastolic blood pressure, 0.5 +/- 3.5 mmHg (aneroid value smaller), attained statistical significance (P = 0.0001). Estimates of prevalence for hypertension differed by 0.4% for women, and by 2.9% for men. Associations with the differences between methods were observed with age, blood pressure, lean body mass, upper arm circumference and specific devices without indicating a strong and consistent pattern. CONCLUSIONS: The use of automated oscillometric devices in epidemiological studies introduces a bias of very small magnitude compared with use of the aneroid method. The effect of the change to this automated measurement procedure on prevalence estimates is small but might affect comparability of data. Minor differences in measurement performance between devices of one type might affect population parameters.

Adult↗

PubMed1997

Determination of total energy expenditure, resting metabolic rate and physical activity in lean and overweight people.

A new 2H/1H and 18O/16O equilibration device was tested, standardized and employed for the determination of total energy expenditure. It was shown that overweight men and women have increased resting metabolic rate as well as increased total energy expenditure when compared to their lean counterparts. The physical activity level (PAL)index was slightly decreased which possibly suggests a decreased physical activity in obese people.

Adult↗

PubMed1997

Obesity as a major determinant of underreporting in a self-administered food frequency questionnaire: results from the EPIC-Potsdam Study.

The phenomenon of underreporting of dietary intake has been observed previously in many epidemiologic studies. In this study it was investigated whether dependencies exist between energy intake obtained by a semi-quantitative, self-administered food frequency questionnaire and lifestyle or anthropometric factors, particularly obesity. The study population consisted of 2,531 subjects, men aged 40 to 64 years and women aged 35 to 64 years from the general population of Potsdam and the surrounding areas. First, subjects were allocated into quintiles of the ratio 'reported energy intake (EI)' to 'calculated basal metabolic rate (BMR)' as a measure of age and weight adjusted energy intake. No apparent dependencies between socio-economic variables and the ratio EI/BMR were observed. Among anthropometric variables, BMI and related measures of obesity were inversely related to the ratio EI/BMR in men and women. While dietary intake was directly related to the ratio EI/BMR in absolute quantities, energy adjusted intake of fat, protein, carbohydrate, and alcohol was found to be independent of this ratio. Energy adjusted food group consumption was also found to be independent of the ratio EI/BMR, showing only slightly increasing trends across quintiles of EI/BMR for cereals and fats, and a slightly decreasing trend for sweet foods in women. When subjects were classified into three categories of BMI, reported energy intake decreased across categories. Estimated energy expenditure based on BMR was increasing with BMI categories. A close direct relationship was observed between BMI categories and the difference between reported energy intake and estimated energy expenditure. It is concluded that obesity is a major determinant of under-reporting. Energy adjusted dietary variables were found to be largely independent of such methodological influences.

Adult↗

PubMedDate not supplied

Arterial hypertension and glycemia in non-diabetic subjects: is there an association independent of obesity?

BACKGROUND: A possible association of glycemia with arterial hypertension has been suggested by the frequent co-occurrence of impaired glucose tolerance or Type 2 diabetes mellitus with arterial hypertension. The objective was to examine the relationship of glycated hemoglobin (HbA1c) concentration with arterial hypertension status in non-diabetic subjects. METHODS: A cross-sectional analysis of baseline data from the EPIC-Potsdam Cohort Study, Germany, was performed. The study population comprised 1846 non-diabetic subjects, 772 men and 1074 women, age 35-65. Blood pressure was measured three times consecutively. Level of HbA1c was determined by an assay based on monoclonal antibodies. Body height, weight and circumferences were obtained. Arterial hypertension status was either determined through blood pressure measurement (blood pressure > or = 160/95 mmHg) or based on antihypertensive drug use. HbA1c was divided into sex-specific quintiles and logistic regression was used to estimate the odds of being hypertensive and the corresponding confidence intervals. RESULTS: The highest compared to the lowest quintiles of HbA1c were in univariate analysis associated with being hypertensive. Adjustment for age and body mass index completely removed any significant association with arterial hypertension status. The odds ratio in men was 1.1 (95% CI 0.7-1.8), and in women it was 0.9 (95% CI 0.5-1.4). Repeating the analysis with systolic and diastolic blood pressure among untreated hypertensives yielded similar results. CONCLUSION: Unlike previous studies, our data do not support an association of HbA1c with arterial hypertension that is statistically independent of age and body mass index. Whether these established arterial hypertension risk factors are truly confounders of the HbA1c-arterial hypertension association or rather potentially antecedent factors requires further study.

Adult↗

PubMedDate not supplied

[The problem of response in epidemiologic studies in Germany (Part II)].

The first part of this paper introduced various definitions of response and discussed their significance in the context of different study types. This second part addresses incentives as a method to increase response and evaluates the impact of non response or delayed response on the validity of the study results. Recruitment aims at minimising the proportion of refusal. To achieve this, incentives can be used and potential participants can be contacted in a sequence of increasing intensity. The effectiveness of different incentives was investigated within the pretest of the German survey on children and adolescents by the Robert Koch Institute. A low response is often interpreted in terms of non-response bias. This assumption, however, is as incorrect as would be opposite conclusion, that a high response guarantees valid results. Any study of the influence of nonresponse requires information on non-responders. The comparison between early and late responders as an indirect method to evaluate systematic differences between participants and non-participants by wave analysis is demonstrated within the Northern Germany Leukaemia and Lymphoma study (NLL). The German guidelines for Good Epidemiologic Practice recommend to solicit a minimum of information on the principal hypotheses of a study from non-participants. The example of a population-based health survey (Cooperative Health Research in the Region of Augsburg, KORA) illustrates how information on non-responders within a quantitative non-responder analysis can be achieved and used for the estimation of prevalences. Recommendations how to deal with the response in epidemiological studies in Germany are suggested.

Adolescent↗