Table 4 Summary of the methods to assess occurrence of occupational asthma and excess public health burden from occupational or work-related asthma: the method, its advantages and limitations and recommended applications

Assessment of occurrence of diagnosed occupational asthma per se, e.g. registries

Data collection takes place as part of the routine health care practices

Influenced heavily by country-specific differences in diagnostic practices, health care system, workers' compensation system, reporting system

Can be used in countries with well-functioning occupational health services Suitable for assessing national or regional trends over time Not very useful for international comparisons

Assessment of occurrence (i.e. excess cases) based on population attributable fraction due to occupational exposures

Gives good and internationally comparable estimates of excess incidence attributable to occupational exposures Not much affected by country-specific practices or health care or compensation systems

Needs valid, high quality estimates of exposure prevalence, health effect of exposure, and incidence of adult-onset asthma

Works well at population level Suitable for assessing occurrence of occupational asthma for planning health care and health policies Suitable for international comparisons

Assessment of public health burden measured as excess DALYs and other disability indicators based on population attributable fraction due to occupational exposures

Gives good and internationally comparable estimates of burden attributable to occupational exposures Not much affected by country-specific practices or health care systems

Needs valid, high quality estimates of exposure prevalence, health effect of exposure, and total burden measured as DALYs and other disability indicators from asthma Assumes that severity related to occupational asthma is similar to severity related to adult-onset asthma in general, and that the severity of occupational asthma is comparable between countries

Works well at population level Suitable for assessing public health impact of occupational asthma for planning health care and health policies Suitable for international comparisons

Other methods to assess health care use, sickness absenteeism, unemployment and economic costs due to occupational exposures

Complement the assessment of burden to society from work- related asthma

Influenced heavily by country-specific differences in health care system, Workers' compensation

Suitable for assessing national or regional trends over time Gives complementary information on burden to society for planning health care and health policies Not very useful for international comparisons