Hywel C. Williams

Worldwide time trends in the prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and eczema in childhood: ISAAC Phases One and Three repeat multicountry cross-sectional surveys

BACKGROUND Data for trends in prevalence of asthma, allergic rhinoconjunctivitis, and eczema over time are scarce. We repeated the International Study of Asthma and Allergies in Childhood (ISAAC) at least 5 years after Phase One, to examine changes in the prevalence of symptoms of these disorders. METHODS For the ISAAC Phase Three study, between 2002 and 2003, we did a cross-sectional questionnaire survey of 193,404 children aged 6-7 years from 66 centres in 37 countries, and 304,679 children aged 13-14 years from 106 centres in 56 countries, chosen from a random sample of schools in a defined geographical area. FINDINGS Phase Three was completed a mean of 7 years after Phase One. Most centres showed a change in prevalence of 1 or more SE for at least one disorder, with increases being twice as common as decreases, and increases being more common in the 6-7 year age-group than in the 13-14 year age-group, and at most levels of mean prevalence. An exception was asthma symptoms in the older age-group, in which decreases were more common at high prevalence. For both age-groups, more centres showed increases in all three disorders more often than showing decreases, but most centres had mixed changes. INTERPRETATION The rise in prevalence of symptoms in many centres is concerning, but the absence of increases in prevalence of asthma symptoms for centres with existing high prevalence in the older age-group is reassuring. The divergent trends in prevalence of symptoms of allergic diseases form the basis for further research into the causes of such disorders.

International Study of Asthma and Allergies in Childhood (ISAAC): rationale and methods.

The aetiology of asthma and allergic disease remains poorly understood, despite considerable research. The International Study of Asthma and Allergies in Childhood (ISAAC), was founded to maximize the value of epidemiological research into asthma and allergic disease, by establishing a standardized methodology and facilitating international collaboration. Its specific aims are: 1) to describe the prevalence and severity of asthma, rhinitis and eczema in children living in different centres, and to make comparisons within and between countries; 2) to obtain baseline measures for assessment of future trends in the prevalence and severity of these diseases; and 3) to provide a framework for further aetiological research into genetic, lifestyle, environmental, and medical care factors affecting these diseases. The ISAAC design comprises three phases. Phase 1 uses core questionnaires designed to assess the prevalence and severity of asthma and allergic disease in defined populations. Phase 2 will investigate possible aetiological factors, particularly those suggested by the findings of Phase 1. Phase 3 will be a repetition of Phase 1 to assess trends in prevalence.

The U.K. Working Party's Diagnostic Criteria for Atopic Dermatitis. I. Derivation of a minimum set of discriminators for atopic dermatitis.

A working party of 13 dermatologists, two family practitioners and a paediatrician was assembled, with the aim of developing a minimum list of reliable discriminators for atopic dermatitis. Each physician was asked to select 10 consecutive new cases of unequivocal mild to moderate atopic dermatitis and 10 controls with other inflammatory dermatoses. Each subject was examined by two independent observers, who were blind to the clinical diagnosis and study aim, with regard to 31 clinically useful diagnostic features for atopic dermatitis. Two hundred and twenty‐four patients were studied (120 cases and 102 controls). Using the key physicians clinical diagnosis as a gold standard, the sensitivity and specificity of each of the 31 diagnostic criteria were tested. Using multiple logistic regression techniques, a minimum set of diagnostic criteria for atopic dermatitis was derived. These were: history of flexural involvement, history of a dry skin, onset under the age of 2, personal history of asthma, history of a pruritic skin condition, and visible flexural dermatitis. Adjustment for age, sex, region, social class and ethnic group did not alter the choice of final criteria. The discriminatory value of these criteria was also satisfactory when tested against a further sample of 150 patients drawn from the community, who did not have skin disease.

Worldwide variations in the prevalence of symptoms of atopic eczema in the international study of asthma and allergies in childhood

BACKGROUND Little is known about the prevalence of atopic eczema outside Northern Europe. OBJECTIVES We sought to describe the magnitude and variation in the prevalence of atopic eczema symptoms throughout the world. METHODS A cross-sectional questionnaire survey was conducted on random samples of schoolchildren aged 6 to 7 years and 13 to 14 years from centers in 56 countries throughout the world. Those children with a positive response to being questioned about the presence of an itchy relapsing skin rash in the last 12 months that had affected their skin creases were considered to have atopic eczema. Children whose atopic eczema symptoms resulted in sleep disturbance for 1 or more nights per week were considered to have severe atopic eczema. RESULTS Complete data was available for 256,410 children aged 6 to 7 years in 90 centers and 458,623 children aged 13 to 14 years in 153 centers. The prevalence range for symptoms of atopic eczema was from less than 2% in Iran to over 16% in Japan and Sweden in the 6 to 7 year age range and less than 1% in Albania to over 17% in Nigeria for the 13 to 14 year age range. Higher prevalences of atopic eczema symptoms were reported in Australasia and Northern Europe, and lower prevalences were reported in Eastern and Central Europe and Asia. Similar patterns were seen for symptoms of severe atopic eczema. CONCLUSIONS Atopic eczema is a common health problem for children and adolescents throughout the world. Symptoms of atopic eczema exhibit wide variations in prevalence both within and between countries inhabited by similar ethnic groups, suggesting that environmental factors may be critical in determining disease expression. Studies that include objective skin examinations are required to confirm these findings.

The U.K. Working Party's Diagnostic Criteria for Atopic Dermatitis. III. Independent hospital validation.

In order to qualify as a case of atopic dermatitis, we propose that an individual must have an itchy skin condition plus three or more of the following: history of flexural involvement, a history of asthma/hay fever, a history of a generalized dry skin, onset of rash under the age of 2 years, or visible flexural dermatitis. When tested in an independent sample of 200 consecutive dermatology outpatients of all ages, this arrangement of the diagnostic criteria achieved 69% sensitivity and 96% specificity when validated against physicians diagnosis. Based on the findings of this first exercise, minor modifications in the wording of the criteria were undertaken, and these were tested on a sample of 114 consecutive children attending out‐patient paediatric dermatology clinics. Overall discrimination improved, with a sensitivity of 85% and specificity of 96%. The simplified criteria are easy to use, take under 2 min per patient to ascertain, and do not require subjects to undress. These two independent validation studies suggest that the newly proposed criteria for atopic dermatitis perform reasonably well in hospital out‐patient patients. Further validation in community settings and in developing countries is needed.

Worldwide variations in prevalence of symptoms of allergic rhinoconjunctivitis in children: the International Study of Asthma and Allergies in Childhood (ISAAC).

Background: As part of the International Study of Asthma and Allergies in Childhood (ISAAC), prevalence surveys were conducted among representative samples of school children from locations in Europe, Asia, Africa, Australasia, North and South America.

Topical corticosteroid phobia in patients with atopic eczema

Topical corticosteroids are widely prescribed by dermatologists caring for patients with atopic eczema. Patients’ fears about using topical corticosteroids may have important implications for compliance with treatment. We carried out a questionnaire‐based study of 200 dermatology outpatients with atopic eczema (age range 4 months−67·8 years) to assess the prevalence and source of topical corticosteroid phobia. We also questioned patients on their knowledge of the potencies of different topical corticosteroids. Overall, 72·5% of people worried about using topical corticosteroids on their own or their child’s skin. Twenty‐four per cent of people admitted to having been non‐compliant with topical corticosteroid treatment because of these worries. The most frequent cause for concern was the perceived risk of skin thinning (34·5%). In addition, 9·5% of patients worried about systemic absorption leading to effects on growth and development. The most commonly used topical corticosteroid was hydrocortisone, yet 31% of patients who used this preparation classified it as either strong, very strong or did not know the potency. Only 62·5% of the 48 patients who had used both Dermovate® (Glaxo) and hydrocortisone in the past were able to correctly grade Dermovate® as being more potent than hydrocortisone. The most common source of patient information regarding topical corticosteroid safety was the general practitioner. Although skin thinning and systemic effects can develop very occasionally in people using topical corticosteroids, the concern expressed by people using them seems out of proportion in relation to the evidence of harm. This study highlights the need for provision of better information and education to patients and possibly general practitioners regarding the safety, potency and appropriate use of topical corticosteroids.

UK health performance: findings of the Global Burden of Disease Study 2010

BACKGROUND The UK has had universal free health care and public health programmes for more than six decades. Several policy initiatives and structural reforms of the health system have been undertaken. Health expenditure has increased substantially since 1990, albeit from relatively low levels compared with other countries. We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2010 (GBD 2010) to examine the patterns of health loss in the UK, the leading preventable risks that explain some of these patterns, and how UK outcomes compare with a set of comparable countries in the European Union and elsewhere in 1990 and 2010. METHODS We used results of GBD 2010 for 1990 and 2010 for the UK and 18 other comparator nations (the original 15 members of the European Union, Australia, Canada, Norway, and the USA; henceforth EU15+). We present analyses of trends and relative performance for mortality, causes of death, years of life lost (YLLs), years lived with disability (YLDs), disability-adjusted life-years (DALYs), and healthy life expectancy (HALE). We present results for 259 diseases and injuries and for 67 risk factors or clusters of risk factors relevant to the UK. We assessed the UKs rank for age-standardised YLLs and DALYs for their leading causes compared with EU15+ in 1990 and 2010. We estimated 95% uncertainty intervals (UIs) for all measures. FINDINGS For both mortality and disability, overall health has improved substantially in absolute terms in the UK from 1990 to 2010. Life expectancy in the UK increased by 4·2 years (95% UI 4·2-4·3) from 1990 to 2010. However, the UK performed significantly worse than the EU15+ for age-standardised death rates, age-standardised YLL rates, and life expectancy in 1990, and its relative position had worsened by 2010. Although in most age groups, there have been reductions in age-specific mortality, for men aged 30-34 years, mortality rates have hardly changed (reduction of 3·7%, 95% UI 2·7-4·9). In terms of premature mortality, worsening ranks are most notable for men and women aged 20-54 years. For all age groups, the contributions of Alzheimers disease (increase of 137%, 16-277), cirrhosis (65%, ?15 to 107), and drug use disorders (577%, 71-942) to premature mortality rose from 1990 to 2010. In 2010, compared with EU15+, the UK had significantly lower rates of age-standardised YLLs for road injury, diabetes, liver cancer, and chronic kidney disease, but significantly greater rates for ischaemic heart disease, chronic obstructive pulmonary disease, lower respiratory infections, breast cancer, other cardiovascular and circulatory disorders, oesophageal cancer, preterm birth complications, congenital anomalies, and aortic aneurysm. Because YLDs per person by age and sex have not changed substantially from 1990 to 2010 but age-specific mortality has been falling, the importance of chronic disability is rising. The major causes of YLDs in 2010 were mental and behavioural disorders (including substance abuse; 21·5% [95 UI 17·2-26·3] of YLDs), and musculoskeletal disorders (30·5% [25·5-35·7]). The leading risk factor in the UK was tobacco (11·8% [10·5-13·3] of DALYs), followed by increased blood pressure (9·0 % [7·5-10·5]), and high body-mass index (8·6% [7·4-9·8]). Diet and physical inactivity accounted for 14·3% (95% UI 12·8-15·9) of UK DALYs in 2010. INTERPRETATION The performance of the UK in terms of premature mortality is persistently and significantly below the mean of EU15+ and requires additional concerted action. Further progress in premature mortality from several major causes, such as cardiovascular diseases and cancers, will probably require improved public health, prevention, early intervention, and treatment activities. The growing burden of disability, particularly from mental disorders, substance use, musculoskeletal disorders, and falls deserves an integrated and strategic response. FUNDING Bill & Melinda Gates Foundation.

Strengthening the Reporting of Observational Studies in Epidemiology (STROBE)

Much medical research is observational. The reporting of observational studies is often of insufficient quality. Poor reporting hampers the assessment of the strengths and weaknesses of a study and the generalisability of its results. Taking into account empirical evidence and theoretical considerations, a group of methodologists, researchers, and editors developed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) recommendations to improve the quality of reporting of observational studies. The STROBE Statement consists of a checklist of 22 items, which relate to the title, abstract, introduction, methods, results and discussion sections of articles. Eighteen items are common to cohort studies, case-control studies and cross-sectional studies and four are specific to each of the three study designs. The STROBE Statement provides guidance to authors about how to improve the reporting of observational studies and facilitates critical appraisal and interpretation of studies by reviewers, journal editors and readers. This explanatory and elaboration document is intended to enhance the use, understanding, and dissemination of the STROBE Statement. The meaning and rationale for each checklist item are presented. For each item, one or several published examples and, where possible, references to relevant empirical studies and methodological literature are provided. Examples of useful flow diagrams are also included. The STROBE Statement, this document, and the associated Web site (http://www.strobe-statement.org/) should be helpful resources to improve reporting of observational research.

Global variations in prevalence of eczema symptoms in children from ISAAC Phase Three

BACKGROUND In 1999, The International Study of Asthma and Allergies in Childhood (ISAAC) Phase One reported the prevalence of eczema symptoms in 715,033 children from 154 centers in 56 countries by using standardized epidemiologic tools. OBJECTIVE To update the world map of eczema prevalence after 5 to 10 years (ISAAC Phase Three) and include additional data from over 100 new centers. METHODS Cross-sectional surveys using the ISAAC questionnaire on eczema symptoms were completed by adolescents 13 to 14 years old and by parents of children 6 to 7 years old. Current eczema was defined as an itchy flexural rash in the past 12 months and was considered severe eczema if associated with 1 or more nights per week of sleep disturbance. RESULTS For the age group 6 to 7 years, data on 385,853 participants from 143 centers in 60 countries showed that the prevalence of current eczema ranged from 0.9% in India to 22.5% in Ecuador, with new data showing high values in Asia and Latin America. For the age group 13 to 14 years, data on 663,256 participants from 230 centers in 96 countries showed prevalence values ranging from 0.2% in China to 24.6% in Columbia with the highest values in Africa and Latin America. Current eczema was lower for boys than girls (odds ratio, 0.94 and 0.72 at ages 6 to 7 years and 13 to 14 years, respectively). CONCLUSION ISAAC Phase Three provides comprehensive global data on the prevalence of eczema symptoms that is essential for public health planning. New data reveal that eczema is a disease of developing as well as developed countries.