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Biomedical subjects

A Kroke

Publications and source records attributed to A Kroke.

At least 19 recordsLinked to original sources
PubMed2006

The influence of habitual protein intake in early childhood on BMI and age at adiposity rebound: results from the DONALD Study.

OBJECTIVE: To analyse the influence of habitual protein intake in early childhood on age and body mass index (BMI) at adiposity rebound (AR), a potential critical period for the development of obesity. SUBJECTS: A total of 313 children (161 boys, 152 girls) participating in the Dortmund Nutritional and Anthropometric Longitudinally Designed Study. METHODS: Weighted summary indices were created reflecting habitual, energy-adjusted protein intake (expressed as % of energy) and protein intake per kg reference body weight per day (g/kg RBW/day) between the age of 12 and 24 months. Body mass index standard deviation scores (BMI-SDS), age at AR and covariates (mother's BMI, gestational age, breastfeeding and siblings) were included in the final models. RESULTS: After adjusting for potential confounders, girls in the highest tertile (T3) of habitual energy-adjusted protein intake had a significantly higher BMI-SDS at AR than those in T1 (T1: -0.61 (95% CI: -0.90; -0.31), T2: -0.49 (-0.79; -0.20), T3: -0.08 (-0.36; 0.20), P for difference=0.01). A comparable association existed with habitual protein intake expressed as g/kg RBW/day (T1: -0.64 (-0.93; -0.36), T2: -0.22 (-0.52; 0.09), T3: -0.25 (-0.54; 0.04), P=0.04). In boys, there were no differences in BMI-SDS at AR between tertiles of habitual protein intake (% of energy or g/kg RBW/day) (P>0.05). Boys in the lowest tertile of habitual energy-adjusted protein intake tended to experience a later AR (T1: 6.0 (5.6; 6.4), T2: 5.5 (5.1; 5.9), T3: 5.4 (5.0; 5.9) years, P=0.07). But neither in girls nor in boys was age at AR significantly different between tertiles of habitual protein intake (% of energy or g/kg RBW/day) (P>0.05). CONCLUSION: A higher habitual protein intake between the age of 12 and 24 months was associated with a higher BMI-SDS at AR in girls, but not in boys. There was no consistent relation between habitual protein intake in early childhood and timing of AR.

Adiposity↗
PubMed2006

A comparative evaluation of two different approaches to estimating age at adiposity rebound.

OBJECTIVE: To compare different approaches (visual estimation of individual BMI curves with polynomial models) to estimate age at adiposity rebound (AR), as different approaches might lead to different results. AR has been suggested as a critical period between intra-uterine life and early adulthood, and recent data showed that early age at AR is associated with higher body mass later in life. METHODS: Longitudinal anthropometric data from the DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study were used to obtain individual BMI growth curves. We then compared the visual estimation approach to polynomial models in three different scenarios reflected by different data sets: an idealistic, an realistic, and a realistic scenario with imputed values. RESULTS: In all three scenarios, the visual estimation yielded significantly higher estimates than the polynomial models of 2nd or 3rd order. Cross-tabulations of groups of age at AR (early, medium, and late) showed that truly concordant classification was low, ranging only from 51 to 63%. A closer examination of the data indicated that the differences in estimates were mainly due to differences in the underlying definitions: the polynomial models select the nadir in the growth curve as the age at AR, whereas the visual estimation deviates from this concept in those cases where there is plateau in the growth curve. In the latter instance, the turning point of the growth curve before its increase is selected as the age at rebound. CONCLUSIONS: Estimating AR with the visual approach appears to best reflect the physiological basis of the AR, and is also preferable, because it resulted in the lowest number of children with missing estimates for age at AR. Only when the underlying criteria for the estimation of AR with the visual approach were modified, could concordant results between the two approaches be obtained. Considering the underlying physiological basis, it became clear that approaches which determine AR by simply identifying the nadir in the BMI curve do not reflect AR appropriately. This refers to those cases in which the nadir in the growth curve and the turning point at the onset of the adiposity increase are not identical.

Adipose Tissue↗
PubMed2005

Differences between recumbent length and stature measurement in groups of 2- and 3-y-old children and its relevance for the use of European body mass index references.

OBJECTIVE: To compare length and stature measurements of young children and to examine the relevance of any difference for comparison with body mass index (BMI) references designed for use from birth to adulthood. SUBJECTS: A total of 426 2-y-old and 525 3-y-old children included in the Dortmund Nutritional and Anthropometrical Longitudinally Designed (DONALD) Study. DATA ANALYSIS: Length and stature were measured to the nearest millimetre using a stadiometre. Agreement between both measurements at age 2 and 3 y, respectively, was determined by mean differences and by comparison with the German BMI reference. RESULTS: The average length of 2-y-old girls and boys was 88.3 (3.1) and 89.9 (3.2) cm, mean differences (stature minus length) were -0.47 (0.65) and -0.45 (0.64) cm. The corresponding BMI values were 16.18 (1.3) and 16.46 (1.2) kg/m2, with mean differences of +0.17 (0.24) and +0.16 (0.23). According to stature, 9.4% of the girls and 10.8% of the boys were overweight (>90th percentile), while length classified 7.1 and 9.4% as overweight. Similar mean differences between length and stature were observed at age 3 y: -0.53 (0.62) and -0.47 (0.65) cm in height and +0.17 (0.20) and +0.14 (0.20) kg/m2 in the BMI of girls and boys, respectively. According to stature, 7.6 and 7.3% were overweight as opposed to 5.4 and 4.8% using length. The observed differences increased with higher BMI levels. CONCLUSION: Changing measurements from length to stature results in an upward shift of BMI, not reflected in current European BMI references. This small but systematic error may result in misinterpretation of individual BMI levels or trend observations.

Anthropometry↗
PubMed2005

Associations of short-term weight changes and weight cycling with incidence of essential hypertension in the EPIC-Potsdam Study.

The aim of this study was to examine the relationships of short-term weight gain, weight loss, and weight cycling on the odds of developing hypertension. Normotensive middle-aged German men and women (n=12,362) of the European Prospective Investigation into Cancer and Nutrition-Potsdam Study were assigned to categories of 2-year short-term weight changes that were self-reported to have occurred prior to recruitment into the study (gain only, loss only, weight cycling, stable). After 2 years of follow-up after recruitment, 180 cases of incident essential hypertension were identified. In logistic regression models, odds ratios were estimated for the associations between short-term weight changes and risk of developing hypertension. Obesity status (BMI>or=30 or BMI<30 kg/m2) modified the associations between short-term weight change and incidence of diagnosed hypertension. Among obese individuals, short-term weight gain occurring during the 2 years prior to recruitment (OR=2.79, 95% CI 1.19-6.56), weight loss (OR=6.74, 95% CI 2.58-17.6) and weight cycling (OR=4.29, 95% CI 1.55-11.9) were strongly positively associated with incident hypertension, adjusted for age and gender, compared to obese individuals with short-term stable weight. No significant associations between short-term weight changes and risk of diagnosed hypertension were detected among non-obese individuals. Short-term weight changes appeared to present strong risk factors for developing hypertension among obese individuals. The effect seen for weight cycling supports the hypothesis that weight cycling increases the risk of hypertension. The finding for short-term weight loss may be explained by subsequent weight regain and needs further investigation.

Adult↗
PubMed2004

[Nutrition of children and adolescents. Results of the DONALD Study].

In this paper, the actual diet of children and adolescents is characterized by food group intake. Age-dependent dietary patterns and long-term dietary trends are described and commented on against the background of the optimized mixed diet, a preventive total diet concept for German children and adolescents. Dietary intake data come from 3-day dietary records obtained in the DONALD Study (Dortmund Nutritional and Anthropometrical Longitudinally Designed Study), an ongoing mixed longitudinal cohort study conducted at the Research Institute of Child Nutrition since 1985. The actual diet of the observed children and adolescents differed to some extent from the optimized mixed diet. For example, the intake of vegetables was lower and the intake of meat/sausage and confectionary was higher than recommended. The three rules for food selection of the optimized mixed diet (consume plant foods and beverages liberally, animal foods moderately, and high-fat, high-sugar foods occasionally) show a practical way to improve unfavorable dietary habits of children and adolescents without fundamental changes of food intake patterns and taste properties of the actual diet. The partly favorable and partly unfavorable dietary trends observed in the DONALD Study should continue to be critically considered.

Adolescent↗
PubMed2004

Letter.

Explore the source record for details and available documents.

Energy Intake↗
PubMed2004

[The problem of response in epidemiological studies in Germany (part I)].

To achieve high response rates in German epidemiological studies is growing more difficult. Low response in epidemiological studies may decrease the acceptance of the results. Response, however, is not identical with the quality of a study. In the first part of this paper various definitions of response (contact, cooperation, response, recruitment proportions) are introduced and discussed in the context of different study designs with reference to practical examples. A population-based survey such as the Study of Health in Pomerania (SHIP) investigates the distribution of risk factors and health-related endpoints. Surveys should yield representative results which can be generalised to apply to the entire population (external validity). This study design usually requires large participitation proportions. In a prospective cohort study such as the European Investigation into Cancer and Nutrition (EPIC) the emphasis is on internal validity. A stable study population willing to participate in regular follow-ups is a primary recruitment goal. If the response in a case-control study such as the Northern Germany Leukaemia and Lymphoma Study (NLL) is low, the priority is to achieve approximately equal response proportions for cases and controls. Simultaneous public relation and media activities can improve participitation in a study. Multidimensional strategies combining public communications, cooperation with local and regional officials and frequent press and media coverage are emphasised. The second part of this paper will discuss methods to quantify the effects of the response proportions on the validity of the study results.

Adult↗
PubMed2004

History of the concept of 'levels of evidence' and their current status in relation to primary prevention through lifestyle interventions.

Primary prevention is a major option to reduce the burden of chronic disease in populations. Because lifestyle interventions have proved to be effective, lifestyle recommendations including nutritional advice are made abundantly. However, both their credibility and their effectiveness are often considered not to be high. Therefore, scientific evidence should form the basis of recommendations and, as in clinical medicine, a rational approach should be followed for the evaluation of evidence. In this paper, the development and current concepts of 'levels of evidence' as they are applied in clinical medicine are outlined and their impact on evidence-based recommendations is discussed. Next, the question is raised as to how far the existing schemes are applicable to the evaluation of issues pertaining to primary prevention through lifestyle changes. Current schemes were developed mainly for clinical research questions and therefore place major emphasis on randomised controlled trials as the main and most convincing evidence in the evaluation process. These types of study are rarely available for lifestyle-related factors and might even not be feasible to obtain. Arguments are advanced to support the notion that a modification of currently existing 'levels of evidence' as developed for clinical research questions might be necessary. Thereby, one might be able to accommodate the specific aspects of evidence-related issues of recommendations for primary prevention through lifestyle changes, like dietary changes.

Diet↗
PubMed2004

The bone mass concept: problems in short stature.

Bone densitometry is currently one of the mainstays in the evaluation of systemic bone diseases in adults and is also increasingly used to assess primary or secondary bone disorders in children and adolescents. The purpose of carrying out densitometric studies in such circumstances is to measure the densitometric indicators of bone stability. Following procedures which were established for diagnosing adult osteoporosis, a decrease in densitometric surrogates of bone stability is usually interpreted as indicating increased fracture risk. The most basic densitometric parameter is bone mineral content (BMC), which can be measured with most densitometric techniques. BMC is either defined as the mass of mineral contained in an entire bone or as the mass of mineral per unit bone length. While mineral mass can be expected to be a good surrogate for bone stability, BMC is obviously a size-dependent parameter, since small bones weigh less than big bones. This is a drawback in paediatric use, since many children and adolescents who are examined by densitometry suffer from chronic disorders and are small-for-age. Short children will have a lower BMC than their healthy age-matched peers, even if their (smaller) bones are otherwise completely normal.

Adolescent↗
PubMed2003

Time trends in cigarette smoking in two German cohorts--results from EPIC Germany.

Smoking prevention is less advanced in Germany compared with other European and North American countries, and fewer data exist, especially on the consumption habits at the individual level over time. EPIC Germany, which is part of a European multicentre study on diet and cancer, collected data on individual smoking behaviour and allows for consideration of the changing consumption pattern for both centres and different age groups. Within EPIC 25 546 and 27 548 participants, respectively, were recruited in Heidelberg and Potsdam. Data on smoking habits were collected by means of a computer-guided interview during the baseline examination between 1994 and 1998. For each birth cohort smoking prevalence and mean number of cigarettes smoked per day at different ages were calculated. Additionally, the prevalence of non-filter cigarette smoking was computed. Smoking prevalence in the 1990s was still higher among men (Heidelberg 16.3-32.3%; Potsdam 18.2-29.3%) than among women (Heidelberg 12.8-32.0%; Potsdam 10.4-27.8%). However, the percentage of women smokers was still increasing. Filter cigarettes comprised a growing percentage of the cigarettes smoked, but especially among men differences between both German cohorts can still be seen: depending on age, 10.0-12.7% of men in the Heidelberg cohort smoked non-filter cigarettes, but only 1.1-2.3% in the Potsdam cohort. The quantity smoked was higher in the Heidelberg than in the Potsdam cohort with respect to the mean number of cigarettes smoked per day as well as the pack-years of smoking. In conclusion, smoking habits in the Potsdam and the Heidelberg cohorts did not strongly differ by smoking prevalence. However, they did differ according to the quantity and quality of smoking. These differences, as well as the changes over the last 40 years may contribute to a changing pattern of diseases in different groups of the German population.

Adult↗
PubMed2002

Recent weight changes and weight cycling as predictors of subsequent two year weight change in a middle-aged cohort.

OBJECTIVE: To evaluate the influence of recent weight changes (weight gain, loss and cycling) on subsequent weight changes. DESIGN: Prospective cohort study with 2 y of follow-up. Data analysis with a polytomous logistic regression model. SUBJECTS: A total of 18 001 non-smoking subjects, 6689 men and 11 312 women, from the general population. MEASUREMENTS: Body height and weight measurements and interview data on lifestyle habits and medical history at baseline. For follow-up, self-administered questionnaires for assessment of body weight and incident diseases. RESULTS: Recent changes in body weight, that is weight gain, weight loss and weight cycling, were significant predictors of subsequent weight changes in both men and women after controlling for age, baseline BMI and several lifestyle and behavioural characteristics as potential confounding factors. Weight cycling before baseline was the strongest predictor of subsequent large weight gain (> or =2 kg) with an odds ratio (OR) of 4.84 (95% confidence interval (CI) 3.34-7.02) in men. In women, prior weight loss was the strongest predictor of subsequent large weight gain (OR 4.77; 95% CI 3.63-6.03), followed by weight cycling (OR 3.02; 95% CI 2.15-4.25). CONCLUSION: These data indicate the need for thorough weight history assessment to identify those who are most likely to gain weight. Effective weight control before the development of obesity or after intentional weight loss due to obesity should be a primary goal in the management of obesity.

Adolescent↗
PubMed2002

[Biological markers in epidemiology: concepts, applications, perspectives (part I)].

The inclusion of biomarkers in epidemiological research provides new possibilities for exposure assessment and the study of early structural or functional changes and pre-clinical stages of diseases. At the same time issues of validity, reliability, and quality control as well as logistics require special attention. Usually epidemiological studies become more expensive with regard to time and cost. Interdisciplinary collaboration between epidemiology, basic research, and laboratory research is crucial. A prerequisite for this collaboration are agreements on definitions, methods and procedures. The definition of "biomarker" and a description of previous uses of biomarkers in epidemiological studies are presented in the first part of this paper. The second part addresses genetic markers and markers of individual sensitivity and susceptibility. We will end with a discussion about the possible future of biomarkers in epidemiology.

Biomarkers↗
PubMed2002

[Biological Markers in Epidemiology: Concepts, applications, Perspectives (Part II)].

The first part of this paper outlined terms and definitions in the context of the application of biological markers in epidemiological studies. Cardiovascular epidemiology served as an example for their historical development. The second part focusses on DNA-based biomarkers, practical and methodological dimensions of the use of biomarkers in analytic epidemiological studies as well as requirements in respect of validity and quality assurance. Most genetic polymorphisms have no impact on health. However, some can be used as biomarkers for individual sensitvity to exposures and susceptibility for specific diseases. The Human Genome Project has brought about a quantum leap in the development of genetic markers. The practical implications cannot presently be assessed with certainty. However, present and future research programmes of gene-environment interactions depend on "traditional" epidemiological study designs, methods, and concepts. Ethical principles and data protection requirements apply equally to genetic and molecular epidemiology as do the "Guidelines for Good Epidemiological Practice".

Biomarkers↗
PubMed2002

European Prospective Investigation into Cancer and Nutrition (EPIC) calibration study: rationale, design and population characteristics.

The European Prospective Investigation into Cancer and Nutrition (EPIC), which covers a large cohort of half a million men and women from 23 European centres in 10 Western European countries, was designed to study the relationship between diet and the risk of chronic diseases, particularly cancer. Information on usual individual dietary intake was assessed using different validated dietary assessment methods across participating countries. In order to adjust for possible systematic over- or underestimation in dietary intake measurements and correct for attenuation bias in relative risk estimates, a calibration approach was developed. This approach involved an additional dietary assessment common across study populations to re-express individual dietary intakes according to the same reference scale. A single 24-hour diet recall was therefore collected, as the EPIC reference calibration method, from a stratified random sample of 36 900 subjects from the entire EPIC cohort, using a software program (EPIC-SOFT) specifically designed to standardise the dietary measurements across study populations. This paper describes the design and populations of the calibration sub-studies set up in the EPIC centres. In addition, to assess whether the calibration sub-samples were representative of the entire group of EPIC cohorts, a series of subjects' characteristics known possibly to influence dietary intakes was compared in both population groups. This was the first time that calibration sub-studies had been set up in a large multi-centre European study. These studies showed that, despite certain inherent methodological and logistic constraints, a study design such as this one works relatively well in practice. The average response in the calibration study was 78.3% and ranged from 46.5% to 92.5%. The calibration population differed slightly from the overall cohort but the differences were small for most characteristics and centres. The overall results suggest that, after adjustment for age, dietary intakes estimated from calibration samples can reasonably be interpreted as representative of the main cohorts in most of the EPIC centres.

Adult↗
PubMed2002

Consumption of vegetables, fruit and other plant foods in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohorts from 10 European countries.

OBJECTIVE: To describe and compare the consumption of the main groups and sub-groups of vegetables and fruits (V&F) in men and women from the centres participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). DESIGN: Cross-sectional analysis. Dietary intake was assessed by means of a 24-hour dietary recall using computerised interview software and standardised procedures. Crude and adjusted means were computed for the main groups and sub-groups of V&F by centre, separately for men and women. Adjusted means by season, day of the week and age were estimated using weights and covariance analysis. SETTING: Twenty-seven centres in 10 European countries participating in the EPIC project. SUBJECTS: In total, 35 955 subjects (13 031 men and 22 924 women), aged 35-74 years, randomly selected from each EPIC cohort. RESULTS: The centres from southern countries had the highest consumption of V&F, while the lowest intake was seen in The Netherlands and Scandinavia for both genders. These differences were more evident for fruits, particularly citrus. However, slightly different patterns arose for some sub-groups of vegetables, such as root vegetables and cabbage. Adjustment for body mass index, physical activity, smoking habits and education did not substantially modify the mean intakes of vegetables and fruits. CONCLUSIONS: Total vegetable and fruit intake follows a south-north gradient in both genders, whereas for several sub-groups of vegetables a different geographic distribution exists. Differences in mean intake of V&F by centre were not explained by lifestyle factors associated with V&F intake.

Adult↗
PubMed2001

Assignment to menopausal status and estimation of age at menopause for women with missing or invalid data--a probabilistic approach with weighting factors in a large-scale epidemiological study.

OBJECTIVE: Gynaecologic surgeries and hormone medication increasingly interfere with the concept of determining menopausal status based on self-reported data about the last menstrual period-an approach frequently applied in epidemiological studies. This analysis compared different approaches of menopausal status determination, including a probabilistic approach that was developed to reduce misclassification of menopausal status. METHODS: Interview and questionnaire data relating to hormone status from about 16,000 German women were used to determine menopausal status using different approaches: menses based, age based, self-assessment based, and a probabilistic approach. RESULTS: Applying strict menses-based criteria, 29.1% of the women were found to be with undetermined menopausal status. The probabilistic approach was applied to determine menopausal status and age at menopause for these women. The proposed approach uses the current age of the women with undetermined menopausal status, and the relative age-dependent frequencies of pre- or postmenopausal status among those with natural menopausal status to calculate weighting factors, which represent the probabilities of being pre- and postmenopausal of each woman previously undetermined. Correspondingly, the missing age at menopause was estimated with the same probabilistic approach. Applying various approaches to determine menopausal status, the ratio of pre- to postmenopausal women differed considerably, ranging from 1.03 to 1.61. In addition, considerable differences were observed with respect to the number of missing values for both menopausal status and age at menopause. CONCLUSION: The probabilistic approach allowed to estimate menopausal status and age at menopause with the advantage that all available information from the entire study population and from the individual is used.

Adult↗