Biomedical subjects

Jacob D van Klaveren

Publications and source records attributed to Jacob D van Klaveren.

3 recordsLinked to original sources

PubMed2005

Calculations of dietary exposure to acrylamide.

In this paper we calculated the usual and acute exposure to acrylamide (AA) in the Dutch population and young children (1-6 years). For this AA levels of different food groups were used as collected by the Institute for Reference Materials and Measurements (IRMM) of the European Commission's Directorate General Joint Research Centre (JRC) from April 2003 up to May 2004. This database contained about 3500 AA levels received from mainly Germany, The Netherlands, Ireland, Greece, Austria, UK and from food industry. Food consumption levels used were derived from the Dutch National Food Consumption Survey of 1997/1998 (n=6250 of which 530 children aged 1-6 years). The exposure was estimated using the probabilistic approach. The results of the exposure calculations are discussed in relation to different methodological aspects of AA exposure calculations and possible uncertainties related to this. The items discussed include quality of the AA levels measured in food items, the allocation of AA levels to food categories, the quality of food consumption levels, and relevant exposure model in relation to reported toxicity of AA. Furthermore, we demonstrate that scenario studies and probabilistic modelling of exposure are potential useful tools to evaluate the effect of processing techniques to reduce AA levels in food on AA exposure. The scenarios studied reduced total AA exposure ranging from <1% up to 17%.

Acrylamide↗

PubMed2005

Risk assessment of dietary exposure to pesticides using a Bayesian method.

Risk assessment of pesticides can be a statistically difficult problem because pesticides occur only occasionally, but they may occur on multiple components in the diet. A Bayesian statistical model is presented which incorporates multivariate modelling of food consumption and modelling of pesticide measurements which are for a large part below a measurement threshold. It is shown that Bayesian modelling is feasible for a limited number of food components, and that in a data-rich situation the model compares well with an empirical Monte Carlo modelling.

Bayes Theorem↗

PubMed2003

Using a correction factor to correct for overreporting in a food-frequency questionnaire does not improve biomarker-assessed validity of estimates for fruit and vegetable consumption.

To correct for overreporting of fruit and vegetable (FV) consumption in a food-frequency questionnaire, summary questions about consumption of main FV groups are often used to calculate correction factors. This study compared the ability to rank people according to their FV intake of those summary questions and the sum of questions on individual FV items within categories, and of corrected or uncorrected estimates of specific sorts of FV. Healthy middle-age women (n = 161) completed a food-frequency questionnaire about FV consumption during the previous month and gave a single fasting blood sample. Correction factors were calculated as the reported frequency on a summary question divided by the summed frequencies of all items in a category. Plasma carotenoids and vitamin C served as biomarkers of FV consumption. Significant correlations between FV consumption and biomarkers were observed (e.g., Spearman's correlation coefficient r with total carotenoids/vitamin C: 0.32/0.34 for vegetables, 0.30/0.25 for fruits). Summary estimates of cooked, raw and total vegetable consumption correlated higher with biomarkers than sum estimates. For fruits no differences in correlations between sum and summary estimates were observed. Applying a correction factor on the consumption of carrots and total cabbage resulted in lower correlations with relevant biomarkers. For broccoli/cauliflower, Brussels sprouts and citrus fruits, correlations with biomarkers did not change after correction. We conclude that summary questions may suffice to rank individuals according to their intake of main FV categories, and that correction for overreporting of individual FV items is probably not advisable when ranking individuals according to intake of these items.

Adult↗