Michael Leslie Burr

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.

Changes in asthma prevalence: two surveys 15 years apart.

In 1973 a survey was conducted among 12 year old children living in a defined area of South Wales. In 1988 the survey was repeated in the same area, again among 12 year old children. Questionnaires were completed for all 965 children in the population sample; peak expiratory flow rates were performed on them all, and repeated (except for five children) after an exercise provocation test. The prevalence of a history of wheeze at any time had increased from 17% to 22%, while that of a history of asthma at any time had increased from 6% to 12%. Current asthma had increased from 4% to 9%, but wheezing in the past year not attributed to asthma had remained at 6%. The exercise provocation tests suggested that both mild and severe asthma had become more common. Increases had also occurred in the frequencies of a history of eczema (from 5% to 16%) and of hay fever (from 9% to 15%). It seems that the prevalence of asthma has risen, and that this cannot be wholly explained by a greater readiness to diagnose the disease.

A Randomized Controlled Trial of Acetyl Salicyclic Acid in the Secondary Prevention of Mortality from Myocardial Infarction

The results of a randomized controlled trial of a single daily dose of acetyl salicylic acid (aspirin) in the prevention of reinfarction in 1,239 men who had had a recent myocardial infarct were statistically inconclusive. Nevertheless, they showed a reduction in total mortality of 12% at six months and 25% at twelve months after admission to the trial. Further trials are urgently required to establish whether or not this effect is real.

Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies

We combined data from 5 prospective studies to compare the death rates from common diseases of vegetarians with those of nonvegetarians with similar lifestyles. A summary of these results was reported previously; we report here more details of the findings. Data for 76172 men and women were available. Vegetarians were those who did not eat any meat or fish (n = 27808). Death rate ratios at ages 16-89 y were calculated by Poisson regression and all results were adjusted for age, sex, and smoking status. A random-effects model was used to calculate pooled estimates of effect for all studies combined. There were 8330 deaths after a mean of 10.6 y of follow-up. Mortality from ischemic heart disease was 24% lower in vegetarians than in nonvegetarians (death rate ratio: 0.76; 95% CI: 0.62, 0.94; P<0.01). The lower mortality from ischemic heart disease among vegetarians was greater at younger ages and was restricted to those who had followed their current diet for >5 y. Further categorization of diets showed that, in comparison with regular meat eaters, mortality from ischemic heart disease was 20% lower in occasional meat eaters, 34% lower in people who ate fish but not meat, 34% lower in lactoovovegetarians, and 26% lower in vegans. There were no significant differences between vegetarians and nonvegetarians in mortality from cerebrovascular disease, stomach cancer, colorectal cancer, lung cancer, breast cancer, prostate cancer, or all other causes combined.

Dietary habits and mortality in 11 000 vegetarians and health conscious people: results of a 17 year follow up

Abstract Objective: To investigate the association of dietary habits with mortality in a cohort of vegetarians and other health conscious people. Design: Observational study. Setting: United Kingdom. Subjects: 4336 men and 6435 women recruited through health food shops, vegetarian societies, and magazines. Main outcome measures: Mortality ratios for vegetarianism and for daily versus less than daily consumption of wholemeal bread, bran cereals, nuts or dried fruit, fresh fruit, and raw salad in relation to all cause mortality and mortality from ischaemic heart disease, cerebrovascular disease, all malignant neoplasms, lung cancer, colorectal cancer, and breast cancer. Results: 2064 (19%) subjects smoked, 4627 (43%) were vegetarian, 6699 (62%) ate wholemeal bread daily, 2948 (27%) ate bran cereals daily, 4091 (38%) ate nuts or dried fruit daily, 8304 (77%) ate fresh fruit daily, and 4105 (38%) ate raw salad daily. After a mean of 16.8 years follow up there were 1343 deaths before age 80. Overall the cohort had a mortality about half that of the general population. Within the cohort, daily consumption of fresh fruit was associated with significantly reduced mortality from ischaemic heart disease (rate ratio adjusted for smoking 0.76 (95% confidence interval 0.60 to 0.97)), cerebrovascular disease (0.68 (0.47 to 0.98)), and for all causes combined (0.79 (0.70 to 0.90)). Conclusions: In this cohort of health conscious individuals, daily consumption of fresh fruit is associated with a reduced mortality from ischaemic heart disease, cerebrovascular disease, and all causes combined. Key messages This study examined dietary factors associated with mortality among 11 000 health conscious people followed for an average of 17 years. After smoking was adjusted for, daily consumption of fresh fruit was associated with a 24% reduction in mortality from ischaemic heart disease, a 32% reduction in mortality from cerebrovascular disease, and a 21% reduction in all cause mortality compared with less frequent consumption.

Cost effectiveness of an outpatient multidisciplinary pulmonary rehabilitation programme

BACKGROUND Pulmonary rehabilitation programmes improve the health of patients disabled by lung disease but their cost effectiveness is unproved. We undertook a cost/utility analysis in conjunction with a randomised controlled clinical trial of pulmonary rehabilitation versus standard care. METHODS Two hundred patients, mainly with chronic obstructive pulmonary disease, were randomly assigned to either an 18 visit, 6 week rehabilitation programme or standard medical management. The difference between the mean cost of 12 months of care for patients in the rehabilitation and control groups (incremental cost) and the difference between the two groups in quality adjusted life years (QALYs) gained (incremental utility) were determined. The ratio between incremental cost and utility (incremental cost/utility ratio) was calculated. RESULTS Each rehabilitation programme for up to 20 patients cost £12 120. The mean incremental cost of adding rehabilitation to standard care was £ –152 (95% CI –881 to 577) per patient, p=NS. The incremental utility of adding rehabilitation was 0.030 (95% CI 0.002 to 0.058) QALYs per patient, p=0.03. The point estimate of the incremental cost/utility ratio was therefore negative. The bootstrapping technique was used to model the distribution of cost/utility estimates possible from the data. A high likelihood of generating QALYs at negative or relatively low cost was indicated. The probability of the cost per QALY generated being below £0 was 0.64. CONCLUSIONS This outpatient pulmonary rehabilitation programme produces cost per QALY ratios within bounds considered to be cost effective and is likely to result in financial benefits to the health service.

Prevalence of asthma symptoms, diagnosis, and treatment in 12–14 year old children across Great Britain (international study of asthma and allergies in childhood, ISAAC UK)

Objective: To investigate variations in the prevalence of self reported symptoms, diagnosis, and treatment of asthma in 12–14 year old children. Design: Self completion questionnaire. Setting: Great Britain. Subjects: All pupils aged 12–14 years in a stratified cluster sample of 93 large mixed secondary schools in 1995. Main outcome measures: Self reported prevalence of symptoms, diagnosis, and treatment of asthma at four geographical levels. Results: 27 507 questionnaires were completed (85.9% response rate). The national 12 month prevalence of any wheezing, speech limiting wheeze, four or more attacks of wheeze, and frequent night waking with wheeze was 33.3% (n=9155), 8.8% (2427), 9.6% (2634), and 3.7% (1023) respectively. The prevalence of ever having had a diagnosis of asthma was 20.9% (5736). In total, 19.8% (5438/27 507) of pupils reported treatment with anti-asthma drugs in the past year, but, of pupils reporting frequent nocturnal wheeze in the past year, 33.8% (342/1012) had no diagnosis of asthma and 38.6% (395/1023) denied receiving inhaler therapy. The 12 month prevalence of wheeze was highest in Scotland (36.7%, 1633/4444), but in England and Wales there was no discernible north-south or east-west gradient. Wheeze prevalence was slightly higher in non-metropolitan areas (35.0%, 6155/17 605) than in metropolitan areas (30.3%, 3000/9902). The prevalence of self reported asthma diagnosis and inhaler use showed no discernible national, regional, north-south, or east-west geographical pattern but was higher in non-metropolitan areas. Conclusion: Prevalence of self reported symptoms, diagnosis, and treatment of asthma was high among 12–14 year olds throughout Great Britain with little geographical or urban-rural variation. Underdiagnosis and undertreatment were substantial. Key messages We investigated the prevalence of self reported symptoms, diagnosis, and treatment of asthma in 12–14 year old children in Great Britain A third of subjects reported wheezing in the past year, and a fifth reported ever having had a diagnosis of asthma—higher prevalences than reported previously Prevalences of symptoms generally varied by a factor of 1.3 or less across Great Britain but, in contrast to previous reports, were significantly higher in Scotland than England and in non-metropolitan areas than metropolitan ones Asthma may still be undiagnosed and undertreated—4% of pupils reported having had a diagnosis of asthma but were still experiencing moderate or greater disruption of their lives, while 1-3.4% reported moderate to severe symptoms but were undiagnosed and untreated The limited geographical variation in prevalences of symptoms and diagnosis of asthma suggests that the causes of asthma are widely distributed in Great Britain and that factors which do vary geographically—such as climate, diet, and outdoor environment—are not the main determinants of prevalence.

Diet and asthma, allergic rhinoconjunctivitis and atopic eczema symptom prevalence: an ecological analysis of the International Study of Asthma and Allergies in Childhood (ISAAC) data. ISAAC Phase One Study Group.

Several studies have suggested that the increasing prevalence of symptoms of asthma, rhinitis and eczema, could be associated with dietary factors. In the present paper, a global analysis of prevalence rates of wheeze, allergic rhinoconjunctivitis and atopic eczema was performed in relation to diet, as defined by national food intake data. Analyses were based on the International Study of Asthma and Allergies in Childhood (ISAAC) data for 6-7 and 13-14 yr old children. Symptoms of wheeze, allergic rhinoconjunctivitis and atopic eczema symptom prevalence were regressed against per capita food intake, and adjusted for gross national product to account for economic development. Dietary data were based on 1995 Food and Agriculture Organisation of the United Nations data for 53 of the 56 countries that took part in ISAAC phase I (1994/1995). The 13-14 year age group showed a consistent pattern of decreases in symptoms of wheeze (current and severe), allergic rhinoconjunctivitis and atopic eczema, associated with increased per capita consumption of calories from cereal and rice, protein from cereals and nuts, starch, as well as vegetables and vegetable nutrients. The video questionnaire data for 13-14 yr olds and the ISAAC data for 6-7 yr olds showed similar patterns for these foods. A consistent inverse relationship was seen between prevalence rates of the three conditions and the intake of starch, cereals, and vegetables. If these findings could be generalised, and if the average daily consumption of these foods increased, it is speculated that an important decrease in symptom prevalence may be achieved.

House dust mite control measures in the management of asthma: meta-analysis

Abstract Objective To determine whether patients with asthma who are sensitive to mites benefit from measures designed to reduce their exposure to house dust mite antigen in the home. Design Meta-analysis of randomised trials that investigated the effects on asthma patients of chemical or physical measures to control mites, or both, in comparison with an untreated control group. All trials in any language were eligible for inclusion. Subjects Patients with bronchial asthma as diagnosed by a doctor and sensitisation to mites as determined by skin prick testing, bronchial provocation testing, or serum assays for specific IgE antibodies. Main outcome measures Number of patients whose allergic symptoms improved, improvement in asthma symptoms, improvement in peak expiratory flow rate. Outcomes measured on different scales were combined using the standardised effect size method (the difference in effect was divided by the standard deviation of the measurements). Results 23 studies were included in the meta-analysis; 6 studies used chemical methods to reduce exposure to mites, 13 used physical methods, and 4 used a combination. Altogether, 41/113 patients exposed to treatment interventions improved compared with 38/117 in the control groups (odds ratio 1.20, 95% confidence interval 0.66 to 2.18). The standardised mean difference for improvement in asthma symptoms was −0.06 (95% confidence interval −0.54 to 0.41). For peak flow rate measured in the morning the standardised mean difference was −0.03 (−0.25 to 0.19). As measured in the original units this difference between the treatment and the control group corresponds to −3 l/min (95% confidence interval −25 l/min to 19 l/min). The results were similar in the subgroups of trials that reported successful reduction in exposure to mites or had long follow up times. Conclusion Current chemical and physical methods aimed at reducing exposure to allergens from house dust mites seem to be ineffective and cannot be recommended as prophylactic treatment for asthma patients sensitive to mites.

Helicobacter pylori infection rates in relation to age and social class in a population of Welsh men.

The seroprevalence of IgG antibodies to Helicobacter pylori was determined using a standard enzyme linked immunosorbent assay in a population of 749 randomly selected men, aged 30-75 years, from Caerphilly, South Wales. The overall prevalence of H pylori was 56.9%, increasing sharply in middle age from 29.8% in those aged 30-34 to over 59% in those aged 45 or older (p less than 0.0001). Age standardised seroprevalence rates were lowest in combined social class categories I and II (49.2%), intermediate in categories IIIN and M (57.5%), and highest in categories IV and V (62.2%) (p = 0.01). In those aged 30-34 years, the prevalence rate for those in combined social class categories IV and V was 57.9% - double the rate for social class categories IIIM and N (28.3%) and five times the prevalence rate in those in social class categories I and II (11.1%). These differences in the infection patterns of H pylori by social class are consistent with patterns of peptic ulcer disease and gastric cancer.