Cross-validation and refinement of the Stoffenmanager as a first tier exposure assessment tool for REACH

Objectives: For regulatory risk assessment under REACH a tiered approach is proposed in which the first tier models should provide a conservative exposure estimate that can discriminate between scenarios which are of concern and those which are not. The Stoffenmanager is mentioned as a first tier approach in the REACH guidance. In an attempt to...

Multiple imputation of discrete and continuous data by fully conditional specification

The goal of multiple imputation is to provide valid inferences for statistical estimates from incomplete data. To achieve that goal, imputed values should preserve the structure in the data, as well as the uncertainty about this structure, and include any knowledge about the process that generated the missing data. Two approaches for imputing...

Nonresponse bias in a follow-up study of 19-year-old adolescents born as preterm infants

Objective. To assess the effect of demographic and neonatal risk factors and outcome at the last available assessment on the probability of full responders, postal responders (those who only responded to the mailed questionnaire), or nonresponders in a follow-up study of 19-year-old adolescents who were born as preterm infants. Design. The 19...

Hand wash and manual skin wipes

Hand wash and skin wipes are major techniques that have been used for dermal exposure sampling. Both techniques remove chemicals either deposited on or transferred to the skin contaminant layer by a combination of chemical and mechanical actions. The paper overviews identified methods and techniques, with emphasis on sampling parameters and...

Clothing evaporative heat resistance - Proposal for improved representation in standards and models

Clothing heat and vapour resistances are important inputs for standards and models dealing with thermal comfort, heat- and cold-stress. A vast database of static clothing heat resistance values is available, and this was recently expanded with correction equations to account for effects of movement and wind on the static value of heat resistance...

The effects of wind and human movement on the heat and vapour transfer properties of clothing

This paper integrates the research presented in the papers in this special issue of Holmer et al. and Havenith et al. [Holmer, I., Nilsson, H., Havenith, G., Parsons, K. C. (1999) Clothing convective heat exchange: proposal for improved prediction in standards and models. Annals of Occupational Hygiene, in press; Havenith, G., Holmer, I., den...

The impact of response bias on estimates of health care utilization in a metropolitan area: The use of administrative data

Background. Surveys among the general population are an important method for collecting epidemiological data on health and utilization of health care in that population. Selective non-response may affect the validity of these data. This study examines the impact of response bias on estimates of health care utilization and on risk estimates for...

Fat watch: A nationwide campaign in the Netherlands to reduce fat intake-effect evaluation

In the Netherlands, the nationwide Fat Watch campaign aiming at a reduction in fat consumption was organized from 1991 onwards. This study describes the effects of the first three consecutive campaign years on attention to fat, diet and health, attitudes, self-efficacy expectations and intentions related to dietary fat reduction, and self-rated...

Epidemiological studies on Brassica vegetables and cancer risk

This paper gives an overview of the epidemiological data concerning the cancer-preventive effect of brassica vegetables, including cabbage, kale, broccoli, Brussels sprouts, and cauliflower. The protective effect of brassicas against cancer may be due to their relatively high content of glucosinolates. Certain hydrolysis products of...

Reproducibility of a food frequency questionnaire and stability of dietary habits determined from five annually repeated measurements

Objectives: In studies on diet and cancer, diet assessment should address long-term intake. Therefore, the authors determined the 5-year reproducibility of a self-adminstered 150-item food frequency questionnaire (FFQ) used to assess dietary habits in the Netherlands Cohort Study on diet and cancer. Since the FFQ was repeated more than once, the...

Differential misclassification of alcohol and cigarette consumption by pregnancy outcome

Background. The validity of the results of studies using retrospectively collected information on exposures is often criticized, because cases may report differently from controls even if their true exposure status is the same. This study was performed to quantify the extent to which this effect (differential misclassification) may occur for...

Non-differential underestimation may cause a threshold effect of exposure to appear as a dose-response relationship

It is generally believed that non-differential misclassification will lead to a bias toward the null-value. However, using one graphical and one numerical example, we show that in situations where underestimation more than overestimation is the problem, non-differential misclassification may lead to a bias away from the null-value for...