Argumentation Analysis of Risk Assessments: The Case of Perfluorooctanoic Acid.

Risk assessment of chemicals can be based on toxicology and/or epidemiology. The choice of toxicological or epidemiological data can result in different health-based guidance values (HBGVs). Communicating the underlying argumentation is important to explain these differences to the public and policymakers. In this article, we explore the argumentation used to justify the use of toxicological or epidemiological data in the derivation of HBGVs in four different risk assessments for the chemical Perfluorooctanoic acid (PFOA). The pragma-dialectical argumentation theory (PDAT) is hereby applied. The argumentations to select relevant health endpoints or certain studies to infer causality appeared mainly based on "symptomatic relations," that is, study results are used as characteristic of what was claimed to be a causal relation without delving into the actual causal argumentation that preceded it. Starting points that are at the basis of the chain of arguments remained implicit. Argumentation to use epidemiological and/or toxicological data was only briefly mentioned and the underlying argumentative foundation that led to the conclusion was seldom found or not addressed at all. The decision to include/exclude information was made based on the availability of data, or the motives for the choice remained largely unclear. We conclude that more depth in argumentation and a subordinative chain of arguments is needed to better disclose the underlying reasoning leading to a certain health-based guidance value (HBGV). More explicit identification and discussion of starting points could be a valuable addition to general risk assessment frameworks for maximum use of toxicological and epidemiological data and shared conclusions of the assessment.

Individual variation in temporal relationships between exposure to radiofrequency electromagnetic fields and non-specific physical symptoms: A new approach in studying 'electrosensitivity'.

BACKGROUND: Everyday exposure to radiofrequency electromagnetic fields (RF-EMF) emitted from wireless devices such as mobile phones and base stations, radio and television transmitters is ubiquitous. Some people attribute non-specific physical symptoms (NSPS) such as headache and fatigue to exposure to RF-EMF. Most previous laboratory studies or studies that analyzed populations at a group level did not find evidence of an association between RF-EMF exposure and NSPS. OBJECTIVES: We explored the association between exposure to RF-EMF in daily life and the occurrence of NSPS in individual self-declared electrohypersensitive persons using body worn exposimeters and electronic diaries. METHODS: We selected seven individuals who attributed their NSPS to RF-EMF exposure. The level of and variability in personal RF-EMF exposure and NSPS were determined during a three-week period. Data were analyzed using time series analysis in which exposure as measured and recorded in the diary was correlated with NSPS. RESULTS: We found statistically significant correlations between perceived and actual exposure to wireless internet (WiFi - rate of change and number of peaks above threshold) and base stations for mobile telecommunications (GSM + UMTS downlink, rate of change) and NSPS scores in four of the seven participants. In two persons a higher EMF exposure was associated with higher symptom scores, and in two other persons it was associated with lower scores. Remarkably, we found no significant correlations between NSPS and time-weighted average power density, the most commonly used exposure metric. CONCLUSIONS: RF-EMF exposure was associated either positively or negatively with NSPS in some but not all of the selected self-declared electrohypersensitive persons.

The impact of body mass index in old age on cause-specific mortality.

OBJECTIVES: To assess the association between Body Mass Index (BMI) and cause-specific mortality in older adults and to assess which BMI was associated with lowest mortality. DESIGN: Prospective study. SETTING: European towns. PARTICIPANTS: 1,980 older adults, aged 70-75 years from the SENECA (Survey in Europe on Nutrition and the Elderly: a concerted action) study. MEASUREMENTS: BMI, examined in 1988/1989, and mortality rates and causes of death during 10 years of follow-up. RESULTS: Cox proportional hazards model including both BMI and BMI², accounting for sex, smoking status, educational level and age at baseline showed that BMI was associated with all-cause mortality (p<0.01), cardiovascular mortality (p<0.01) and mortality from other causes (p<0.01), but not with cancer or respiratory mortality (p>0.3). The lowest all-cause mortality risk was found at 27.1 (95%CI 24.1, 29.3) kg/m², and this risk was increased with statistical significance when higher than 31.4 kg/m² and lower than 21.1 kg/m². The lowest cardiovascular mortality risk was found at 25.6 (95%CI 17.1, 28.4) kg/m², and was increased with statistical significance when higher than 30.9 kg/m². CONCLUSION: In this study, BMI was associated with all-cause mortality risk in older people. This risk was mostly driven by an increased cardiovascular mortality risk, as no association was found for mortality risk from cancer or respiratory disease. Our results indicate that the WHO cut-off point of 25 kg/m² for overweight might be too low in old age, but more studies are needed to define specific cut-off points.

Maintenance of weight loss after lifestyle interventions for overweight and obesity, a systematic review.

Lifestyle interventions can reduce body weight, but weight regain is common and may particularly occur with higher initial weight loss. If so, one may argue whether the 10% weight loss in clinical guidelines is preferable above a lower weight loss. This systematic review explores the relation between weight loss during an intervention and weight maintenance after at least 1 year of unsupervised follow-up. Twenty-two interventions (during at least 1 month) in healthy overweight Caucasians were selected and the mean percentages of weight loss and maintenance were calculated in a standardized way. In addition, within four intervention groups (n > 80) maintenance was calculated stratified by initial weight loss (0-5%, 5-10%, >10%). Overall, mean percentage maintenance was 54%. Weight loss during the intervention was not significantly associated with percentage maintenance (r = -0.26; P = 0.13). Percentage maintenance also not differed significantly between interventions with a weight loss of 5-10% vs. >10%. Consequently, net weight loss after follow-up differed between these categories (3.7 vs. 7.0%, respectively; P < 0.01). The analyses within the four interventions confirmed these findings. In conclusion, percentage maintenance does not clearly depend on initial weight loss. From this perspective, 10% or more weight loss can indeed be encouraged and favoured above lower weight loss goals.

Relationship between costs of lifestyle interventions and weight loss in overweight adults.

Lifestyle interventions in a healthcare setting are effective for weight loss, but it is unclear whether more expensive interventions result in more weight loss. Our objective was to explore the relationship between intervention costs and effectiveness in a systematic review of randomized trials. Intervention studies were selected from 14 reviews and from a systematic MEDLINE-search. Studies had to contain a dietary and a physical activity component and report data on measured weight loss in healthy Caucasian overweight adults. Intervention costs were calculated in a standardized way. The association between costs and percentage weight loss after 1 year was assessed using regression analysis. Nineteen original studies describing 31 interventions were selected. The relationship between weight loss and intervention costs was best described by an asymptotic regression model, which explained 47% of the variance in weight loss. A clinically relevant weight loss of 5% was already observed in interventions of approximately euro110. Results were similar in an intention-to-treat analysis. In conclusion, lifestyle interventions in health care for overweight adults are relatively cheap and higher intervention costs are associated with more weight loss, although the effect of costs on weight loss levels off with growing costs.

Explaining fruit and vegetable consumption: the theory of planned behaviour and misconception of personal intake levels.

The influence of individuals' misconceptions in assessing fruit and vegetable consumption on the ability of the theory of planned behaviour to explain variance in the consumption of these foods was studied. Dutch women (mean age 41, n=159) completed a questionnaire assessing the theory's constructs with regard to the daily consumption of at least two pieces of fruit and 200 gram of vegetables. Consumption was assessed using a self-rated measure and more objectively with a food-frequency questionnaire. Both measures were combined to classify participants according to the accuracy of their self-assessed intake levels ('realists' vs. 'overestimators'). The model explained variation in objective fruit and vegetable intake much better among realists (R2 = 45% for fruits and 39% for vegetables) than among overestimators (R2 = 18% and 5%, respectively). Perceived behavioural control was the strongest predictor of intentions and behaviour. When plasma vitamin C and carotenoid concentrations were used as objective indicators for fruit and vegetable intake, the explanatory value of the model was lower, but again more variance was explained among realists than among overestimators. We conclude that awareness of personal behaviour should be taken into account when applying the theory of planned behaviour to explain dietary behaviours as well as to design health education interventions.