Acceptable risk of contact allergy in the general population assessed by CE–DUR – A method to detect and categorize contact allergy epidemics based on patient data

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Abstract

Over the 20th century, several contact allergy epidemics arose in Western Europe. Today, industries use various assays to determine the sensitization potential of new ingredients and thereby prevent new contact allergy outbreaks. This study debates acceptable risk of sensitization in the general population by using a new epidemiological tool. The clinical epidemiology (CE) and drug utilization research (DUR) method recently estimated the 10-year contact allergy prevalence in the general population in Germany and Denmark based on patch test reading data in combination with an estimate of the number of persons eligible for patch testing each year based on patch test sales data. A reverse CE–DUR was performed to make delineations between the 10-year prevalence of contact allergy in the general population and the corresponding theoretical prevalences of contact allergy observed among patients with dermatitis in Denmark and Germany. Results indicated that if 1/100 subjects in the general population in Denmark and Germany had contact allergy; dermatologists would observe a prevalence of contact allergy among dermatitis patients was between 4.5–8.0% and 2.5–10.4%, respectively. The reverse CE–DUR approach can be used to alert public health authorities if the estimated number of sensitized persons in the general population is above a certain threshold.

Introduction

Over the 20th century, several contact allergy epidemics arose in Western Europe. The epidemics affected workers and consumers, and were in several cases efficiently addressed by dermatologists and policy makers (Thyssen et al., 2007a). Today, industries may use various assays to determine the sensitization potential of new ingredients and thereby prevent new contact allergy outbreaks (Basketter et al., 2005, Api et al., 2008, Safford, 2008). In an effort to achieve a more accurate pre-marketing risk assessment, Safford recently introduced the “dermal sensitization threshold” (DST). Briefly, this mathematical approach seeks to establish a safe-limit for ingredients below which there is no appreciable risk of sensitization (even for untested ingredients) (Safford, 2008). However, we only have relatively slow and inefficient epidemiological tools to detect new as well as established contact allergy epidemics once such toxicological tools fail. Thus, there is a clear need for initiatives that will enhance the identification and categorization of contact allergy epidemics.

We set out to discuss acceptable risk of sensitization in the general population. By using the clinical epidemiology (CE) and drug utilization research (DUR) method (Schnuch et al., 2002, Thyssen et al., 2007b) in a reverse manner, this study delineates between various prevalences of contact allergy in the general population (i.e., both subjects that are exposed to a particular contact allergen and those who are not exposed) and the corresponding estimated prevalences of contact allergy observed among patients with dermatitis. This approach was chosen as dermatologists and administrators may easily recognize and relate to prevalences of contact allergy among patients with dermatitis, and since this could potentially be an easy way to recognize and monitor future epidemics. Although other epidemiological approaches may provide superior validity and precision compared to the CE–DUR method, it does serve as a rapid way to grossly estimate contact allergy prevalence in the general population, and to approach and discuss “acceptable risk” on this level.

Section snippets

Basic principles of the CE–DUR method

The CE–DUR method has previously been detailed as it was used to assess the 10-year prevalence of contact allergy in the general populations in Germany and Denmark (Schnuch et al., 2002, Thyssen et al., 2007b). The method was based on the DUR method, defined by the World Health Organization as research addressing “the marketing, distribution, prescription, and use of drugs in a society, with special emphasis on the resulting medical, social and economic consequences” (Lunde et al., 1987). The

Results

The Danish population had 5,400,000 inhabitants, and the number of subjects eligible for patch testing was 67,290 (1.2%), 87,750 (1.6%), and 118,750 (2.2%) according to the best, medium and worst case scenarios, respectively (Thyssen et al., 2007b). The German population had 82,000,000 inhabitants, and the number of subjects eligible for patch testing was 786,000 (1.0%), 1,360,000 (1.7%), and 3,240,000 (3.9%) according to the best, medium and worst case scenarios, respectively (Schnuch et al.,

Discussion

This study used the CE–DUR method in a reverse manner to relate various pre-defined prevalences of contact allergy in the general population with corresponding prevalences of contact allergy among patients with dermatitis in Germany and Denmark (Table 2, Table 3). It is essential to discuss briefly the validity of these calculations before their application to the concept of “acceptable risk” in the general population is addressed. The backward CE–DUR tool is different from the normal CE–DUR

Funding sources

None.

Conflict of interest

The authors declare that there are no conflicts of interest.

Prior presentations

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