World Health Organization Concept Research Articles

POPULATION ATTRIBUTABLE FRACTION FOR LUNG CANCER DUE TO RESIDENTIAL RADON IN SWITZERLAND AND GERMANY

Studies on miners as well as epidemiological studies in the general population show an increased lung cancer risk after exposure to radon and its progeny. The European pooled analysis of indoor radon studies estimates an excess relative risk of 8% (16% after correction for measurement uncertainties) per 100 Bq m(-3) indoor radon concentration. Here, we determine the population attributable fraction (PAF) for lung cancer due to residential radon based on this risk estimate for Switzerland and Germany. Based on regionally stratified radon data, the PAF was calculated following the World Health Organization concept of global burden of disease, compared to a realistic baseline radon concentration equal to the outdoor concentration. Lifetable approaches were used taking smoking and sex into account. Measurement error corrections were applied to both risk estimates and the radon distribution. In Switzerland, the average indoor radon concentration is 78 Bq m(-3), resulting in a PAF of 8.3%. Therefore, 169 male lung cancer deaths and 62 deaths in women can be attributed to residential radon per year. For Germany, the average indoor radon concentration is 49 Bq m(-3), corresponding to a PAF of 5.0% (1,422 male and 474 female deaths annually). In both countries, a large regional variation in the PAF was observed due to regional differences in radon concentrations and population structure. Both calculations show a strong dependency on the risk model used. Risk models based on miner studies result in higher PAF estimates than risk models based on indoor radon studies due to different assumptions regarding exposures received more than 35 years ago. The use of a non-zero baseline radon concentration also contributes to the lower PAF estimates reported here. Although the estimates of the population attributable fraction of residential radon presented here are lower than previously reported estimates, the risk is still one of the most widespread environmental hazards. Radon monitoring and radon reduction programs are therefore important issues for environmental public health management.

Definition and classification of GP: medical-legal and service implications

The implications of a revised definition and classification system for cerebral palsy (CP) obviously extend well beyond clinical care and research. My commentary will focus on two disparate areas of concern: specific topics related to medicallegal issues and brief comments concerning potential effects on service provision. Important issues from the medical-legal perspective include the definition itself and issues relevant to causation in the classification section, specifically neuroimaging and etiological understanding. For nearly 150 years, causation theories for CP have been linked to intraparturn events. Despite decades of epidemiological research to the contrary, the causal connection in the public mind between CP: ‘brain damage’, and obstetrical misadventure continues to encourage litigation with highly significant professional and economic implications for health care and society.24 Consensus publications identify spastic quadriplegic and/or dyskinetic CP as an essential criterion for consideration of intraparturn hypoxic-ischemic injury as the cause of later disab i l i t~ .~ .~ The revised definition does not affect this perspective. Despite initial concerns that the new term ‘disturbances’ might broaden the concept of CP to include children with developmental coordination or dyspraxic conditions, the full document clearly specifies patterns of motor disability as spastic, dyskinetic, or ataxic and thereby preserves the traditional designations and relationship between CP pattern and potential etiologies. In the Classification section, the brief comments on neuroimaging are noteworthy. The committee correctly notes that the classification of CP by imaging criteria is still in development but forcefully endorses the previous recommendation of the American Academy of Neurology on the importance of such testing whenever feasible.’ This statement cannot be over-emphasized in the medical-legal context. Currently, allegations of ‘brain injury’ do not require the demonstration of such injury or in fact, any anatomic abnormality. This unfortunately permits CP and other impairments to be presented as evidence of ‘brain injury’ a seriously uninformed perspective. Such a view fails to acknowledge the value of MRI in identifying injury patterns, and even more importantly, overlooks the significance of brain malformations and genetic/ metabolic disorders in producing the CP phenotype. The critical issues of causation and timing are also addressed directly in the revision document. The annotation on the definition states that ‘a full understanding of causal pathways and mechanisms leading to CP remains elusive’ and then amplifies this perspective in the section on Cause and Timing. In discussing causation, the current understanding of the importance of multiple interacting risk factors, the lack of a specific etiological relationship between adverse circumstances and CE and the absence of a known cause in many cases are stated explicitly. This section concludes with the important caveat that, ‘clinicians should avoid making the assumption that adverse events in the prenatal, perinatal, and postnatal life of a child with CP [are] sufficient to permit an etiological classification that implies a causal role for these events in the genesis of CP’. In summary, the committee’s statements provide an authoritative reminder about what is actually known and not known about causation and will be useful to those who are asked to render legal opinions in cases involving CP. With respect to service provision, the diagnosis of CP is generally understood to indicate the presence of significant motor impairments which require educational and community-based services. The new definition maintains the central position of motor impairment but expands the focus considerably by emphasizing the importance of associated neurodevelopmental and musculoskeletal complications. The revision also places these impairments in a functional context by adopting the World Health Organization concept of ‘activity limitation’ as a defining criterion.8 These are significant modifications of the traditional focus on motor impairments alone and should have a major impact on services for those with CI! Care providers, educational institutions, advocacy groups, policy makers and others will need to adapt current approaches by placing increased emphasis on associated impairments as they consider the multiplicity of challenges facing individuals with CP. Such an expansion of the core concept of CP is likely to challenge current systems of care. Carried to their logical extent these changes in definition present rather daunting challenges and are likely to require significant modifications in the application of economic and manpower resources. Despite these practical difficulties, the revised definition presents a welcome opportunity to broaden the focus on CP. I believe that the net effect will be to stimulate progress on multiple fronts including neurobiological understanding, management approaches, and societal participation.

Quality of life: a deconstruction for clinicians

Quality of life has been an issue in medical research for more than twenty years1, and many authorities now regard it as a key measurement in clinical trials2,3. Yet the concept remains controversial. In the clinical world, scepticism is exemplified by a comment by Wulff in the JRSM: ‘Scientists may use rating scales and visual analogue scales to measure pain, and they may even invent scoring systems quantifying types of handicaps; but when they talk about measuring quality of life they have gone too far’4. This statement reflects a two-world model of medicine and of human experience in which objective facts are clearly distinguished from subjective values4,5. It can be seen as a reaction to the World Health Organization's concept of health and of quality of life that invites us to mix facts and values non-systematically: ‘Quality of life is defined as an individual's perception of their position in life in the context of the culture and value system in which they live and in relation to their goals, expectations and standards and concerns. It is a broad ranging concept affected in a complex way by the person's physical health, psychological state, level of independence, social relationships, and their relationship to salient features of their environment’6.

The subjective handicap of epilepsy. A new approach to measuring treatment outcome.

It is now widely acknowledged that the impact of epilepsy on the individual extends beyond the occurrence of seizures, and that there is a need for outcome measures sensitive to these consequences. Until now these instruments have largely been developed within a 'quality of life' framework. The technical and conceptual difficulties that arise with measuring quality of life have led us to develop a more focused measurement model, the 'Subjective Handicap of Epilepsy' (SHE) scale, based on the World Health Organization's concept of handicap. The scale contains 32 items in six subscales: 'Work and activities' (eight items), 'Social and personal' (four items), 'Self-perception' (five items), 'Physical' (four items), 'Life-satisfaction' (four items) and a 'Change' scale (seven items); and it takes on average < 10 min to complete. The scale's test-retest reliability was found to be satisfactory (intra-class correlation coefficient was 0.8-0.9 in 110 subjects). The test-retest interval (24 h to 8 weeks) had no influence on the reliability. The reliability was also not affected by minor recent fluctuations in seizure frequency. The internal consistency of the scales was 0.8-0.9 (Cronbach's alpha). The construct validity of the scale was examined in a sample of 287 clinic attendees at a university neurology clinic in the UK. The scales were highly sensitive to the handicapping effects of increasing seizure frequency, employment status, the impact of epilepsy on career choice and the subject's own opinion as to the major determinant of their quality of life. The scales were also sensitive, retrospectively, to the benefits of successful epilepsy surgery in a cohort of 105 patients. Scales focusing specifically on handicap were more sensitive to group differences in seizure frequency in the clinic population, and to outcome after epilepsy surgery, than the 'Life-satisfaction' scale and the Epilepsy Surgery Inventory 55 (ESI-55) scales. This supports the contention that measuring 'subjective handicap' may be a more sensitive, and more useful, approach to assessing the impact of interventions on the long-term consequences of epilepsy than current methods.

Neighbourhood support to families with a disabled child: observations on a coping strategy off caregivers in a Jamaican community‐based rehabilitation programme

In Jamaica, a low degree of practical helpfulness of neighbours of families with a disabled child has been described. This seems to cast doubt on the World Health Organization's concept of community-based rehabilitation which simply assumes that the community is a source of support. Our study tries to elucidate which reasons, in a Jamaican socio-cultural setting, make neighbours give support to or withhold it from disabled children and their caregivers. A concept of neighbourhood help is identified, according to which help is something to be asked for and provided under exceptional circumstances only. Caregivers claim to give and receive support in child rearing within the limits of this definition, generally irrespective of the presence of a disability. The impression that neighbours are unconcerned can arise when the support needed becomes too extensive to fit into the local definition of neighbourhood help--which is more likely in the case of disabled children.