Controlled manipulation of elastomers with radiation: Insights from multiquantum nuclear-magnetic-resonance data and mechanical measurements

Filled and cross-linked elastomeric rubbers are versatile network materials with a multitude of applications ranging from artificial organs and biomedical devices to cushions, coatings, adhesives, interconnects, and seismic-isolation, thermal, and electrical barriers. External factors such as mechanical stress, temperature fluctuations, or radiation are known to create chemical changes in such materials that can directly affect the molecular weight distribution (MWD) of the polymer between cross-links and alter the structural and mechanical properties. From a materials science point of view it is highly desirable to understand, affect, and manipulate such property changes in a controlled manner. Unfortunately, that has not yet been possible due to the lack of experimental characterization of such networks under controlled environments. In this work we expose a known rubber material to controlled dosages of γ radiation and utilize a newly developed multiquantum nuclear-magnetic-resonance technique to characterize the MWD as a function of radiation. We show that such data along with mechanical stress-strain measurements are amenable to accurate analysis by simple network models and yield important insights into radiation-induced molecular-level processes.

Prevalence and distribution of sensitization to foods in the European Community Respiratory Health Survey: a EuroPrevall analysis

BACKGROUND

Reports of adverse reactions to foods are increasing, but there is limited information on the comparative prevalence of sensitization to food allergens using standardized methods.

METHODS

Sera from the 'random sample' of young adults seen during the second phase of the European Community Respiratory Health Survey were analysed for IgE against 24 foods using ImmunoCAP. Sera were tested on five food mixes, and subsequently on individual foods in each positive mix.

RESULTS

Sera from 4522 individuals living in 13 countries were tested for at least one food allergen mix. Prevalence of sensitization to any of the 24 food allergens ranged from 24.6% in Portland (USA) to 7.7% in Reykjavik (Iceland). With few exceptions, the relative prevalence of sensitization to different foods was similar in all countries. Sensitization rates to egg, fish and milk were each less than 1%, and the most common sensitizations are not represented in current commercial mixes. The prevalence of sensitization to foods was not related to that of sensitization to aeroallergens but was related to the geometric mean total IgE for the country.

CONCLUSIONS

Sensitization to foods is common but highly variable. The relative prevalence of sensitization to different foods is more consistent than would be expected by chance, suggesting that quantity of consumption of specific foods does not determine prevalence. The aetiology of food sensitization is only partly similar to that for aeroallergens but is related to local levels of total IgE. This may provide an important clue to the origins of food sensitization.

Relationship between oxidative stress-related biomarkers and antioxidant status with asthma and atopy in young adults: a population-based study

BACKGROUND AND AIM

Enhanced oxidative stress has been described in adults who suffer from symptoms of asthma and poor lung function. This study assessed the relation between markers of oxidative stress and antioxidant status and lung function, symptoms of asthma, atopy and bronchial hyperresponsiveness (BHR) in young adults.

METHODS

A sub-sample of 589 individuals aged 22-28 years, selected from a total of 1232 included in a survey assessing early and current risk factors for chronic diseases, participated in the study. Participants were from an agricultural area of Chile, responded to a Spanish version of the European Community Respiratory Health Survey questionnaire, were skin tested to eight allergens, and challenged with methacholine to assess BHR. Five hundred and eighty-five individuals had measures of plasma biomarkers ferric reducing ability of plasma, uric acid, protein carbonyls and 564 had 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) assessed.

RESULTS

All participants had detectable plasma 8-iso-PGF(2alpha) and carbonyl levels. There was no indication for an association between markers of antioxidant status or oxidative stress with any of the outcomes studied.

CONCLUSION

The levels of oxidative stress-related biomarkers and antioxidant status in plasma may not be related to asthma in the general population in the absence of more severe symptoms or exacerbations.

Eczema, atopy and allergen exposure in adults: a population-based study

BACKGROUND

There are few published studies on geographical variation in prevalence of eczema in adults or its association with recognised risk factors for allergic disease.

OBJECTIVE

To describe the geographical variation in prevalence of eczema in adults, assess the associations with sociodemographic risk factors, serum-specific IgE and IgG, and exposure to allergen.

METHODS

A community-based sample of 8206 adults aged 27-56 years, in 25 European centres and Portland, USA, provided questionnaire information on symptoms of eczema. Serum-specific IgE to house dust mite (HDM), cat, grass and Cladosporium, and IgG and IgG4 to HDM and cat were measured. Mattress levels of mite and cat allergen were assessed.

RESULTS

Overall prevalence of eczema was 7.1% (range between countries of 2.2-17.6%). Eczema was associated with female gender [odds ratio (OR) 1.25; 95% confidence interval (CI) (1.01-1.55)], family history of atopic disease (OR 1.43; 95% CI 1.18-1.74), IgE sensitization to at least one allergen (OR 1.50; 95% CI 1.19-1.90), particularly Cladosporium (OR 3.65; 95% CI 1.81-7.37), and total IgE. Eczema was negatively associated with age and no clear associations were observed with sibship size, mattress mite and cat allergen levels or with cat and HDM-specific IgG or IgG4.

CONCLUSIONS

There is geographical variation in the prevalence of eczema in adults both within and between countries. Although the disease is associated with IgE sensitization, in this study it was not related to mattress mite or cat allergen levels.

Geographical variation in the prevalence of positive skin tests to environmental aeroallergens in the European Community Respiratory Health Survey I

BACKGROUND

Many studies have reported the prevalence of sensitization using skin prick tests. However, comparisons between studies and between regions are difficult because the number and the type of allergens tested vary widely. Using the European Community Health Respiratory Survey I data, the geographical variation of sensitization to environmental allergen as measured by skin tests was established.

METHODS

Adults aged 20-44 years, living in 35 centres in 15 developed countries, underwent skin tests for allergy to nine common aeroallergens: Dermatophagoides pteronyssinus, timothy grass, cat, Cladosporium herbarium, Alternaria alternata, birch, Olea europea, common ragweed and Parietaria judaica. The age-sex standardized prevalence of sensitization was determined and centres with high (95% confidence interval above and excluding study median) and low prevalence (95% confidence interval below and excluding study median) of sensitization to each allergen and to any of the nine allergens were identified.

RESULTS

There was substantial geographical variation in the prevalence of sensitization to each of the nine allergens tested and in the prevalence of sensitization to any allergen (lowest 17.1%, median 36.8% and highest 54.8%). Sensitization to D. pteronyssinus, grass pollen and cat were usually the most prevalent (median between centre 21.7%, 16.9% and 8.8%, respectively). Timothy grass sensitization was higher than that for any other pollen species.

CONCLUSIONS

As expected, geographical variations of sensitization to environmental allergen were observed across centres. These findings were compatible for those observed with serum-specific IgE. Skin tests can be used to assess the geographical distribution of allergens in a multicentric epidemiological survey.

Effect of the choice of food composition table on nutrient estimates: a comparison between the British and American (Chilean) tables

Objective:

To determine the level of agreement between the American (Chilean) and British food composition tables in estimating intakes of macronutrients and antioxidants.

Results:

Mean differences between the two tables of food composition ranged from 5.3% to 8.9% higher estimates when using the American (Chilean) table for macronutrients. For micronutrients, a bias towards a higher mean was observed for vitamin E, iron and magnesium when the American (Chilean) table was used, but the opposite was observed for vitamin A and selenium. The intra-class correlation coefficient (ICC) ranged from 0.86 (95% confidence interval (CI) 0.81–0.91) to 0.998 (95% CI 0.995–1.00), indicating high to excellent agreement. LOAs for macronutrients and vitamins A and C were satisfactory, as they were sufficiently narrow. There was more uncertainty for other micronutrients.

Conclusion:

The American table gives relative overestimates of macronutrients in comparison to the British table, but the relative biases for micronutrients are inconsistent. Estimates of agreement between the two food composition tables provide reassurance that results are interchangeable for the majority of nutrients.

Changes in active and passive smoking in the European Community Respiratory Health Survey

The aim of the present investigation was to study changes and determinants for changes in active and passive smoking. The present study included 9,053 adults from 14 countries that participated in the European Community Respiratory Health Survey II. The mean follow-up period was 8.8 yrs. Change in the prevalence of active and passive smoking was expressed as absolute net change (95% confidence interval) standardised to a 10-yr period. Determinants of change were analysed and the results expressed as adjusted hazard risk ratio (HRR) or odds ratio (OR). The prevalence of active smoking declined by 5.9% (5.1-6.8) and exposure to passive smoking in nonsmokers declined by 18.4% (16.8-20.0). Subjects with a lower educational level (HRR: 0.73 (0.54-0.98) and subjects living with a smoker (HRR: 0.45 (0.34-0.59)) or with workplace smoking (HRR: 0.69 (0.50-0.95)) were less likely to quit. Low socio-economic groups were more likely to become exposed (OR: 2.21 (1.61-3.03)) and less likely to cease being exposed to passive smoking (OR: 0.48 (0.37-0.61)). In conclusion, the quitting rate was lower and the risk of exposure to passive smoking higher among subjects with lower socio-economic status. Exposure to other peoples smoking decreased quitting rates and increased the risk of starting to smoke.

Sources of variation in forced expiratory volume in one second and forced vital capacity

Published prediction equations for lung function differ considerably, but the components of population variation responsible for the differences are unknown. Data were analysed for 6,323 never-smoking adults who did not report wheeze or asthma, from 42 centres participating in the European Community Respiratory Health Survey. Means and components of variance were estimated for males and females aged 20-24 yrs, and the relationships with age and height were examined in those aged 25-44 yrs. Mean lung function for those aged 20-24 yrs differed between centres, but variation could not be wholly attributed to differences in population or equipment. The maximum difference in means by equipment type was 101 mL for FVC in males. Equipment differences were not statistically significant adjusted for country, but differences in mean forced expiratory volume in one second and forced vital capacity by country, adjusted for instrument, were statistically significant in males. Differences between centres in relation to age and height had less influence on predicted values. In conclusion, there are unexplained differences in lung function between ethnically similar nonsmoking symptom-free populations. Neither national reference curves nor those based on the same ethnic group can be guaranteed to give accurate norms of lung health.

Optimum expression of adult lung function based on all-cause mortality: results from the Reykjavik study

A variety of reference curves are used to derive predicted values for adult lung function, even within ethnically similar populations. Alternatives to percentage predicted value are sometimes used to allow for height in research. Strength of association with total mortality can be used to choose the optimal expression, between forced expiratory volume in 1s (FEV(1)) divided by height(2), FEV(1)/height(3), FEV(1)% predicted and difference from predicted. Data from the Reykjavik Study cohort, 1976-2002, included 5544 men and 8062 women randomly selected from the population. Total mortality was analysed by Cox proportional hazards regression in relation to each height-adjusted measure, allowing for age group, period of recruitment and body mass index, and smoking before or at baseline. FEV(1)/height(2) and FEV(1)/height(3) had stronger associations with mortality than FEV(1)% predicted and difference from predicted in men and in women. There were similar findings for forced vital capacity (FVC) in non-smokers and in women. FEV(1)/height(2) was slightly better predictive than FEV(1)/height(3) in men, but distributions of FEV(1)/height(3) in men and women were closer than those of FEV(1)/height(2). Clinical practise and epidemiological research would benefit from agreement on how to adjust lung function for height. Replication of these analyses in other cohort studies would inform the choice between FEV(1)/height(2) and FEV(1)/height(3).

Incidence of asthma and net change in symptoms in relation to changes in obesity

The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males.

Definitions of childhood obesity: current practice

OBJECTIVE

To review current practice in the definition of childhood obesity based on body mass index (BMI), in order to understand why the recommendations of the International Task Force on Obesity (IOTF) have not been fully adopted.

DESIGN

Literature search using MEDLINE to identify papers on childhood obesity published in the first 4 months of 2005, and a cited reference search on the recommendations of the IOTF.

RESULTS

Citations of the IOTF definition have increased since publication, but less than half of papers on childhood obesity published in the period used the definition. Most used the 95th centile of a national distribution to define obesity.

CONCLUSIONS

Reasons for using centiles of a national distribution included the need for z-scores or centiles to define underweight or extreme obesity, not available in conjunction with the IOTF definition, inclusion of children under 2 years, and concerns about over- or underestimation of the prevalence of obesity. None of these preclude use of the principle underlying the IOTF definition, that of continuity with the adult definition of BMI of 30 kg/m2 or more. Adoption of either the IOTF definition or corresponding centiles of a national distribution would enable comparisons of prevalence between countries and over time.

Overweight and obesity trends from 1974 to 2003 in English children: what is the role of socioeconomic factors?

AIMS

To examine the childhood overweight and obesity prevalence trends between 1974 and 2003 and to assess whether these trends relate to parental social class and household income.

METHODS

A school based and a general population health survey: the National Study of Health and Growth in 1974, 1984, and 1994, and the Health Survey for England, yearly from 1996 to 2003. Participants were 14,587 white boys and 14,014 white girls aged 5-10 years. Overweight and obesity prevalence were calculated using UK specific as well as international body mass index (kg/m2) cut-offs. Socioeconomic status was measured using the Registrar General's social class; household income (1997 onwards only) was adjusted for household size.

RESULTS

The prevalence of obesity (UK specific definition) in boys increased from 1.2% in 1984 to 3.4% in 1996-97 and 6.0% in 2002-03. In girls, obesity increased from 1.8% in 1984 to 4.5% in 1996-97 and 6.6% in 2002-03. Obesity prevalence has been increasing at accelerating rates in the more recent years. Children from manual social classes had marginally higher odds (OR 1.14, 95% CI 0.98 to 1.33) and children from higher income households had lower odds (OR 0.74, 95% CI 0.61 to 0.89) to be obese than their peers from non-manual class, and lower income households, respectively.

CONCLUSION

Childhood obesity is increasing rapidly into the 2000s in England and these increases are more marked among children from lower socioeconomic strata. There is an urgent need for action to prevent further increase in obesity among children.

Indoor nitrous acid and respiratory symptoms and lung function in adults

BACKGROUND

Nitrogen dioxide (NO2) is an important pollutant of indoor and outdoor air, but epidemiological studies show inconsistent health effects. These inconsistencies may be due to failure to account for the health effects of nitrous acid (HONO) which is generated directly from gas combustion and indirectly from NO2.

METHODS

Two hundred and seventy six adults provided information on respiratory symptoms and lung function and had home levels of NO2 and HONO measured as well as outdoor levels of NO2. The association of indoor HONO levels with symptoms and lung function was examined.

RESULTS

The median indoor HONO level was 3.10 ppb (IQR 2.05-5.09), with higher levels in homes with gas hobs, gas ovens, and in those measured during the winter months. Non-significant increases in respiratory symptoms were observed in those living in homes with higher HONO levels. An increase of 1 ppb in indoor HONO was associated with a decrease in forced expiratory volume in 1 second (FEV1) percentage predicted (-0.96%; 95% CI -0.09 to -1.82) and a decrease in percentage FEV1/forced vital capacity (FVC) (-0.45%; 95% CI -0.06 to -0.83) after adjustment for relevant confounders. Measures of indoor NO2 were correlated with HONO (r = 0.77), but no significant association of indoor NO2 with symptoms or lung function was observed. After adjustment for NO2 measures, the association of HONO with low lung function persisted.

CONCLUSION

Indoor HONO levels are associated with decrements in lung function and possibly with more respiratory symptoms. Inconsistencies between studies examining health effects of NO2 and use of gas appliances may be related to failure to account for this association.

Reproducibility of non-specific bronchial challenge in adults: implications for design, analysis and interpretation of clinical and epidemiological studies

BACKGROUND

Poor reproducibility of an outcome measure reduces power and, in an independent variable, biases results. The intraclass correlation coefficient measures loss of power and degree of bias. Information is lacking on the intraclass correlation coefficient for bronchial responsiveness and factors affecting reproducibility.

METHODS

Papers containing information on reproducibility of bronchial responsiveness were identified using a Medline search and citations. Within and between person components of variance of PD20 or PC20 were expressed in doubling dose or concentration units, and the intraclass correlation coefficient calculated when not reported.

RESULTS

Results were extracted from 32 papers. Intraclass correlation coefficients were over 0.9 in short term studies of highly selected asthmatic patients, but larger and most long term studies had lower intraclass correlation coefficients, less than 0.5 in some cases, due to greater within person or lower between person variation. Reproducibility of dose or concentration-response slope was generally higher, but still less than that of forced expiratory volume in 1 second.

CONCLUSIONS

Information is available to calculate sample size for studies with bronchial responsiveness as the outcome, but results when bronchial responsiveness is an explanatory variable may be misleading.

Intraclass correlation coefficient and outcome prevalence are associated in clustered binary data

BACKGROUND AND OBJECTIVE

To describe the association between values for a proportion and the intraclass correlation coefficient (ICC).

METHODS

Analysis of data obtained from the General Practice Research Database (GPRD) for variation between United Kingdom general practices and results from a Health Technology Assessment (HTA) review for a range of outcomes in community and health services settings.

RESULTS

There were 188 ICCs from the GPRD, the median prevalence was 13.1% (interquartile range IQR 3.5 to 28.4%) and median ICC 0.051 (IQR 0.011 to 0.094). There were 136 ICCs from the HTA review, with median prevalence 6.5% (IQR 0.4 to 20.7%) and median ICC 0.006 (IQR 0.0003 to 0.036). There was a linear association of log ICC with log prevalence in both datasets (GPRD, regression coefficient 0.61, 95% confidence interval 0.53 to 0.69, P < 0.001; HTA, 0.91, 0.81 to 1.01, P < 0.001). When the prevalence was 1% the predicted ICC was 0.008 from the GPRD or 0.002 from the HTA, but when the prevalence was 40% the predicted ICC was 0.075 (GPRD) or 0.046 (HTA).

CONCLUSION

The prevalence of an outcome may be used to make an informed assumption about the magnitude of the intraclass correlation coefficient.

The association of hepatitis A and Helicobacter pylori with sensitization to common allergens, asthma and hay fever in a population of young British adults

BACKGROUND

A negative association of oro-faecally spread infection with serological markers of sensitization and allergic disease has been reported.

METHOD

Previous infection with hepatitis A and Helicobacter pylori was assessed in a community-based sample of young British adults and associations with serum-specific IgE to environmental allergens, asthma-like symptoms and hay fever were examined.

RESULTS

There was no association of previous infection with hepatitis A or H. pylori with wheeze or hay fever. There was no evidence of an association of infection with either agent and sensitization except for the isolated finding of a lower prevalence of sensitization to grass in those with IgG antibodies to H. pylori (OR 0.65, 95% CI 0.43-0.99). This association did not explain the negative association of family size with sensitization to grass.

CONCLUSION

In this population, there was no evidence that infection with hepatitis A or H. pylori was associated with lower levels of IgE sensitization, asthma or hay fever except for an isolated finding of a negative association of H. pylori infection with sensitization to grass.

Increase in diagnosed asthma but not in symptoms in the European Community Respiratory Health Survey

BACKGROUND

Information on the epidemiology of asthma in relation to age is limited and hampered by reporting error. To determine the change in the prevalence of asthma with age in young adults we analysed longitudinal data from the European Community Respiratory Health Survey.

METHODS

A self-administered questionnaire was completed by 11 168 randomly selected subjects in 14 countries in 1991-3 when they were aged 20-44 years and 5-11 years later from 1998 to 2003. Generalised estimating equations were used to estimate net change in wheeze, nocturnal tightness in chest, shortness of breath, coughing, asthma attacks in the last 12 months, current medication, "diagnosed" asthma, and nasal allergies.

RESULTS

Expressed as change in status per 10 years of follow up, subjects reporting asthma attacks in the previous 12 months increased by 0.8% of the population (95% CI 0.2 to 1.4) and asthma medication by 2.1% (95% CI 1.6 to 2.6), while no statistically significant net change was found in reported symptoms. Reported nasal allergies increased, especially in the youngest age group.

CONCLUSIONS

As this cohort of young adults has aged, there has been an increase in the proportion treated for asthma but not in the proportion of those reporting symptoms suggestive of asthma. Either increased use of effective treatments has led to decreased morbidity among asthmatic subjects or those with mild disease have become more likely to label themselves as asthmatic.

Parental smoking in childhood and adult obstructive lung disease: results from the European Community Respiratory Health Survey

BACKGROUND

Early exposure to parental smoking appears to influence the development of the airways and predispose to respiratory symptoms. A study was undertaken to determine whether the consequences of parental smoking could be traced in adulthood.

METHODS

Information from interviewer-led questionnaires was available for 18 922 subjects aged 20-44 years from random population samples in 37 areas participating in the European Community Respiratory Health Survey. Lung function data were available for 15,901 subjects.

RESULTS

In men, father's smoking in childhood was associated with more respiratory symptoms (ORwheeze 1.13 (95% CI 1.00 to 1.28); never smokers: ORwheeze 1.21 (95% CI 0.96 to 1.50)) and there was a dose-dependent association between number of parents smoking and wheeze (one: OR 1.08 (95% CI 0.94 to 1.24); both: OR 1.24 (95% CI 1.05 to 1.47); ptrend = 0.010). A reduced ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) was related to father's smoking (-0.3% (95% CI -0.6 to 0)) and number of parents smoking (ptrend <0.001) among men. In women, mother's smoking was associated with more respiratory symptoms and poorer lung function (ORwheeze 1.15 (95% CI 1.01 to 1.31), never smokers: ORwheeze 1.21 (95% CI 0.98-1.51); FEV1 -24 ml (95% CI -45 to -3); FEV1/FVC ratio -0.6% (95% CI -0.9 to -0.3)). These effects were possibly accounted for by maternal smoking in pregnancy (ORwheeze 1.39 (95% CI 1.17 to 1.65); FEV1 -23 ml (95% CI -52 to 7); FEV1/FVC ratio -0.9% (95% CI -1.3 to -0.4)) as there was no association with paternal smoking among women (interaction by sex, p<0.05). These results were homogeneous across centres.

CONCLUSION

Both intrauterine and environmental exposure to parental tobacco smoking was related to more respiratory symptoms and poorer lung function in adulthood in this multicultural study. The age window of particular vulnerability appeared to differ by sex, postnatal exposure being important only in men and a role for prenatal exposure being more evident in women.

Is Methicillin-Resistant Staphylococcus aureus More Virulent than Methicillin-Susceptible S. aureus? A Comparative Cohort Study of British Patients with Nosocomial Infection and Bacteremia

Staphylococcus aureus is the most common cause of hospital-acquired bacteremia. From 1995 through 2000, data on age, sex, patient specialty at time of first bacteremia, primary and secondary sites of infection, delay in initiating antimicrobial therapy, and patient outcome were prospectively recorded for 815 patients with nosocomial S. aureus bacteremia. The proportion of patients whose death was attributable to methicillin-resistant S. aureus (MRSA) was significantly higher than that for methicillin-susceptible S. aureus (MSSA) (11.8% vs. 5.1%; odds ratio [OR], 2.49; 95% confidence interval [CI], 1.46-4.24; P<.001). After adjustment for host variables, the OR decreased to 1.72 (95% CI, 0.92-3.20; P=.09). There was no significant difference between rates of disseminated infection (7.1% vs. 6.2% for MRSA-infected patients and MSSA-infected patients, respectively; P=.63), though the rate of death due to disseminated infection was significantly higher than death due to uncomplicated infection (37% vs. 10% for MRSA-infected patients [P<.001] and 37% vs. 3% for MSSA-infected patients [P<.001]). There was a strong statistical trend toward death due to nosocomial MRSA infection and bacteremia, compared with MSSA.

Social inequalities and children's height in Trinidad and Tobago

OBJECTIVE

The aim of the study was to report the association of socio-economic factors with child's height.

DESIGN

Cross-sectional study based on a representative national sample of government schools.

SETTING

Trinidad and Tobago in 1999.

SUBJECTS

A total of 2608 boys and girls mean age 5.8 y, range 4.38-6.99 y and 3080 mean age 8.6 y, range 7.00-10.44 y olds.

OUTCOME

Measurement of height and a questionnaire completed by parents. In the analysis height was expressed as standard deviation scores (s.d.s.) based on the British height curves (1990) or height below -1.5 s.d.s.

RESULTS

Ethnicity, parental heights, birthweight, maternal age at child's birth and number of children in the family were the main factors associated with children's height. Lack of piped water supply in the home was the only socio-economic factor consistently associated with height (mean difference in s.d.s. adjusted only for age group, gender and ethnicity -0.192, 95% CI -0.257 to -0.127 and in addition adjusted for the variables listed above -0.080, 95% CI -0.141 to -0.019). Parental education, household overcrowding and employment status were weakly associated with height in the partially adjusted model only. Analysis of severe growth failure gave similar results.

CONCLUSION

The impact of socio-economic factors on height is marginal in Trinidad and Tobago. As socio-economic factors may have an impact on a broad range of health indicators, height and rates of undernutrition should not be used as sole criteria for assessing progress in decreasing health differentials caused by social inequalities.

Relation of bronchial responsiveness to body mass index in the ECRHS. European Community Respiratory Health Survey

BACKGROUND

There is substantial evidence for an association between symptoms of asthma and overweight or obesity. However, a study that reported no association between bronchial responsiveness (BHR) and body mass index (BMI) suggested that the relation of symptoms to obesity was due to increased diagnosis of asthma. The relation of BHR to BMI was therefore investigated in a large multicentre study.

METHODS

Data were obtained for 11,277 participants in stage II of the European Community Respiratory Health Survey (ECRHS). BHR to methacholine was analysed in relation to BMI adjusted for a number of factors known to be associated with BHR, including baseline lung function and allergen sensitisation, and combined across 34 centres using random effects meta-analysis.

RESULTS

BHR increased with increasing BMI in men (ECRHS slope changed by -0.027 for each unit increase in BMI, 95% confidence interval -0.044 to -0.010, p=0.002), but the relation in women was weak (-0.014, 95% CI -0.033 to 0.005, p=0.14). There was no evidence for an interaction of sex with BMI (p=0.41).

CONCLUSIONS

BHR is related to BMI in the ECRHS. This suggests that the association is not due to greater diagnosis or perception of symptoms in obese people compared with those of normal weight. The data do not support the finding by some studies of a relation between asthma and obesity in women but not in men.

Specific sensitization to common allergens and pulmonary function in the European Community Respiratory Health Survey

BACKGROUND

The role of atopy in the evolution to chronic obstructive disease remains controversial.

AIM

We aimed to assess the association between individual sensitization to common allergens and lung function.

METHOD

We analysed data from 12,687 subjects aged 20 to 44 years, from 34 centres in 15 countries participating in the European Community Respiratory Health Survey (ECRHS). Participants performed a blood test, lung function test, methacholine challenge, and answered an administered questionnaire. The relationships between specific IgE, FEV1 and FEV1/FVC ratio were assessed for each study centre stratified by sex, followed by random effects meta-analysis.

RESULTS

Asthmatics sensitized to house dust mite had a lower FEV1 (-119 mL in women and -112 mL in men) and FEV1/FVC ratio (-1.95%, and -2.48%) than asthmatics without sensitization. Asthmatics sensitized to cat had a lower FEV1 (statistically significant for women only) and a lower FEV1/FVC ratio. Asthmatic women sensitized to grass had a lower FEV1 and a lower ratio, and those sensitized to Cladosporium had a lower FEV1. A weak association was found with sensitization to cat and to Cladosporium among non-asthmatic women, which disappeared after adjusting for BHR.

CONCLUSION

We conclude that atopy was related to a lower lung function, which was only apparent among asthmatics. This relationship was explained by specific sensitization to cat and to house dust mite, the latter being homogeneous across areas.

Early exposure to children in family and day care as related to adult asthma and hay fever: results from the European Community Respiratory Health Survey

BACKGROUND

The literature indicates that early exposure to children in the family and to day care permanently influences the development of allergic disease. A study was undertaken to examine the associations of family size and day care with adult asthma and hay fever and to determine whether these associations are mediated through specific IgE production and whether they vary with allergic predisposition.

METHODS

18,530 subjects aged 20-44 years from 36 areas predominantly in the market economies participated in the European Community Respiratory Health Survey and provided information through interviewer-led questionnaires. 13,932 subjects gave blood samples for measurement of specific IgE.

RESULTS

Hay fever was less common in subjects with many siblings (OR=0.92; 95% CI 0.90 to 0.95 per sib). There was a U-shaped relationship between asthma and number of siblings (quadratic effect of siblings, pwheeze=0.014, pFEV(1)=0.016). In subjects without siblings but exposed to children in day care, hay fever was less common (OR=0.76; 95% CI 0.60 to 0.98) and asthma symptoms were more common (ORwheeze=1.48; 95% CI 1.12 to 1.95). Adjustment for specific IgEs did not alter these associations. The inverse association of hay fever with siblings was found in sensitised subjects (OR=0.89; 95% CI 0.84 to 0.94) and in those with parental allergy (OR=0.91; 95% CI 0.85 to 0.97), but not in subjects without such a predisposition (OR=1.02; 95% CI 0.97 to 1.09).

CONCLUSION

Subjects exposed to many children at home or in day care experienced less hay fever and more asthma in adulthood. Microbial challenge through children may contribute to a non-allergic immunological development giving less hay fever but more airways infections predisposing to asthma. These effects were not mediated through production of specific IgE. The protective effect of siblings on hay fever was particularly strong in those with an allergic predisposition.

Free school meals and children's social and nutritional status in Trinidad and Tobago

OBJECTIVE

To evaluate the provision of free school meals in Trinidad and Tobago in relation to children's social and nutritional status.

DESIGN AND METHODS

Cross-sectional survey of a nationally representative sample of 66 government schools, including children in the admissions classes (aged 4 to 7 years) and classes for 'rising nines' (aged 7-10 years). Data included questionnaire details of free school meals and children's social background, and measurements of children's heights, weights and skinfold thicknesses.

RESULTS

Of 6731 eligible children, data were analysed for 5688 (85%). There were 2386 (42%) children receiving free meals provided at school. At different schools the proportion of all children receiving free meals ranged from 20% to 100%, Receipt of free meals was associated with larger family size (one child, 32% received free meals; > or =6 children, 63%), lower paternal educational attainment (primary, 52% free; university, 30%), father's employment (employed, 39% free meals; unemployed >12 months, 59%) as well as maternal education and employment and household amenities. After adjusting for age, sex and ethnic group, children who received free meals were shorter (mean difference in height standard deviation score (SDS) -0.12, 95% confidence interval (CI) -0.17 to -0.06), lighter (body mass index SDS -0.21, -0.28 to -0.14) and thinner (subscapular skinfold SDS -0.13, -0.18 to -0.09).

CONCLUSIONS

Free school meals were widely available, with some targeting of provision to children with less favourable social and nutritional status. Greater universality would reduce inequity, but more stringent targeting and reduction of school-level variation would increase efficiency.

Association of body mass index with respiratory symptoms and atopy: results from the European Community Respiratory Health Survey

BACKGROUND

There are several reports showing that obese adults report more respiratory symptoms suggestive of asthma than those who are not obese.

OBJECTIVE

To determine the association of body mass index with respiratory symptoms and atopy in young adults

METHOD

Information collected from 15,454 participants in the European Community Respiratory Health Survey, a multicentre cross-sectional survey of young adults, was analysed to determine the association of body mass index with respiratory symptoms and atopy.

RESULTS

Men and women with a body mass index of greater than 30 were at an increased risk of wheeze with shortness of breath compared with those with a body mass of 20-24.99 (OR in men 1.85, 95% confidence interval 1.41-2.42; OR in women 2.03, 95% confidence interval 1.59-2.58). Similar associations were observed for other symptoms suggestive of asthma. Body mass index was not associated with 'hayfever or nasal allergies', specific IgE to house dust mite, grass or cat or with total IgE in men or women.

CONCLUSION

Reported associations of body mass index with symptoms suggestive of asthma are unlikely to be explained by a higher risk of atopy in the obese. Alternative explanations must be sought.

International definitions of overweight and obesity for children: a lasting solution?

BACKGROUND

Definitions of overweight and obesity for children were published in 2000, derived by averaging the centiles of six countries equivalent to body mass index (BMI) at age 18 years of 25 and 30. For use in the UK it is unclear whether these present an advantage over equivalent definitions based on UK data.

AIM

To compare the recently published international cut-off points for overweight and obesity in children with alternative cut-off points based on the UK 1990 reference data.

SUBJECTS AND METHODS

Around 6000 white children aged 4-11 years from primary schools in 22 areas in England were measured in two cross-sectional surveys, in 1984 and 1994. Measurements included height and weight, from which BMI was calculated. Each child was classified as overweight or obese according to each cut-off point.

RESULTS

The proposed international cut-off points exaggerate the difference in prevalence of overweight and obesity between English boys and girls in comparison to comparable measures based on UK data by up to 7%, and are not compatible with the UK reference charts for BMI. Using proposed UK cut-off points the prevalence of overweight in boys was 10.2% in 1984, rising to 13.8% in 1994, compared to 5.4 to 9.0% using the international definition.

CONCLUSION

The limitations of the international definitions, due to averaging data from different countries and the choice of reference age, need to be known. The UK cut-off points here presented are compatible with the current UK reference curves.

Critical illness in systemic lupus erythematosus and the antiphospholipid syndrome

OBJECTIVES

To investigate the causes, course, and outcome of critical illness requiring emergency admission to the intensive care unit (ICU) in patients with systemic lupus erythematosus (SLE) or the antiphospholipid syndrome (APS), or both.

METHODS

Critically ill patients with SLE or APS, or both, admitted to a London teaching hospital ICU over a 15 year period were studied. Demographic, diagnostic, physiological, laboratory, and survival data were analysed. Kaplan-Meier survival curves were constructed by age, time from first diagnosis of SLE, and time from first ICU admission. The log rank test and a backwards stepwise Cox regression were used to identify factors associated with reduced survival.

RESULTS

Sixty one patients with SLE alone (39%) and/or APS (61%) required 76 emergency admissions to the ICU. Patients had high severity of illness scores (median APACHE II 22 (range 8-45)) and multiorgan dysfunction. The primary diagnoses for patients admitted were infection in 31/76 (41%), renal disease in 16/76 (21%), cardiovascular disease in 12/76 (16%), and coagulopathies in 11/76 (14%). The commonest secondary diagnosis was renal dysfunction (49%). Factors associated with an increased risk of death were cyclophosphamide before admission, low white cell count, and high severity of illness score. Before adjustment for these factors renal disease had a strong adverse effect on long term survival (analysis by age at diagnosis p=0.005, analysis by time since first ICU admission, p=0.07). After adjustment, infection at admission to ICU was associated with an increased ICU mortality (p=0.02) and was the cause of death in 13/17 patients who died in the ICU. Similarly, after adjustment, APS was associated with reduced ICU survival (p=0.1) and reduced long term (p=0.03) survival. Seventeen patients (28%) died in the ICU, and 31 patients (51%) had died by the last follow up. Median time from ICU admission to death was four years. Overall five year survival from the first ICU admission was 43%.

CONCLUSION

Critical illness requiring ICU admission may occur in patients with SLE and APS. In this study, ICU survival was better than previously described, but long term survival was poor. Cyclophosphamide administration, low white cell count, and high severity of illness score were associated with reduced survival. Before adjustment for these factors, only renal disease had an adverse effect on outcome but after adjustment, infection and APS reduced survival.

Teleradiology in a military training area

A pilot teleradiology project was established for the medical service providers at the Pohakuloa Training Area (PTA) in Hawaii. It connected them with radiologists at Tripler Army Medical Center (TAMC) on the island of Oahu, approximately 400 km away. This involved changing the standard practice of sending soldiers from the PTA to a civilian hospital in Hilo for radiographs. These emergency trips to Hilo, 55 km away, were expensive, manpower intensive, and dangerous due to road and weather conditions. During 51 days of a training exercise involving 2600 personnel, 29 evacuations were avoided, which would have cost $36,569 in total. The expected savings during one year of training were $176,540. The cost of teleradiology during the first year, including the cost of the equipment, was $167,203. Over five years, the costs and savings were estimated to be $349,940 and $882,700, respectively.

Effect of passive smoking on respiratory symptoms, bronchial responsiveness, lung function, and total serum IgE in the European Community Respiratory Health Survey: a cross-sectional study

BACKGROUND

Passive smoking is widespread, and environmental tobacco smoke contains many potent respiratory irritants. This analysis aimed to estimate the effect of passive smoking on respiratory symptoms, bronchial responsiveness, lung function, and total serum IgE in the European Community Respiratory Health Survey.

METHODS

This analysis included data from 7882 adults (age 20-48 years) who had never smoked, from 36 centres in 16 countries. Information on passive smoking, respiratory symptoms, asthma, and allergic rhinitis was gathered through a structured interview. Spirometry and methacholine challenge were carried out, and total and specific IgE were measured. The effect of passive smoking was estimated by means of logistic and multiple linear regression for each country and combined across countries by random-effects meta-analysis.

FINDINGS

In 12 of the 36 centres, more than half the participants were regularly involuntarily exposed to tobacco smoke. The prevalence of passive smoking in the workplace varied from 2.5% in Uppsala, Sweden, to 53.8% in Galdakao, Spain. Passive smoking was significantly associated with nocturnal chest tightness (odds ratio 1.28 [95% CI 1.02 to 1.60]), nocturnal breathlessness (1.30 [1.01 to 1.67]), breathlessness after activity (1.25 [1.07 to 1.47]), and increased bronchial responsiveness (effect -0.18 [-0.30 to -.05]). Passive smoking in the workplace was significantly associated with all types of respiratory symptoms and current asthma (odds ratio 1.90 [95% CI 0.90 to 2.88]). No significant association was found between passive smoking and total serum IgE.

INTERPRETATION

Passive smoking is common but the prevalence varies widely between different countries. Passive smoking increased the likelihood of experiencing respiratory symptoms and was associated with increased bronchial responsiveness. Decreasing involuntary exposure to tobacco smoke in the community, especially in workplaces, is likely to improve respiratory health.

Does living on a farm during childhood protect against asthma, allergic rhinitis, and atopy in adulthood?

Recent studies of children suggest that factors encountered in a farm environment might protect against the development of allergy. However, it remains uncertain whether living on a farm in childhood is associated with a decreased risk of atopic diseases in adulthood. We analyzed data from 6,251 randomly selected adults 20 to 44 yr of age participating in the European Community Respiratory Health Survey (ECRHS). Subjects answered a detailed questionnaire and underwent specific IgE measurements to five allergens. After adjustment for potential confounders, including pet exposure in childhood, number of siblings, severe respiratory infection in childhood, and parental history of allergy, living on a farm in childhood was associated with a reduced risk of atopic sensitization in adulthood (OR = 0.76, CI 95% = 0.60-0.97). Compared with other adults, those who had lived on a farm as a child were less frequently sensitized to cat (OR = 0.63, CI 95% = 0.41-0.96) and to Timothy grass (OR = 0.68, CI 95% = 0.50-0.94), and were at lower risk of having nasal symptoms in the presence of pollen (OR = 0.80, CI 95% = 0.64-1.02). The protective effect of farming environment in childhood observed in this population-based sample of young adults provides evidence in favor of the hypothesis that environmental factors encountered in childhood may have a lifelong protective effect against the development of allergy.

Can the increase in body mass index explain the rising trend in asthma in children?

BACKGROUND

The reported association between asthma and obesity and the documented rise in each over time have led to suggestions that rising obesity might explain the increase in the prevalence of asthma. Trends in both in British children participating in the National Study of Health and Growth were marked from 1982 to 1994.

METHODS

Odd ratios for trends in asthma and symptoms in 8 and 9 year old children were calculated with and without adjustment for body mass index (BMI).

RESULTS

In a representative sample of white children the odds ratio per year for asthma was 1.09 (95% CI 1.07 to 1.11) before and after adjustment for BMI for boys and 1.09 (95% CI 1.07 to 1.12) and 1.09 (95% CI 1.05 to 1.12), respectively, for girls. Unadjusted and adjusted odds ratios were also virtually identical for wheeze and "asthma or bronchitis". The lack of effect of adjustment was due to a change in the association between BMI and symptoms with time.

CONCLUSIONS

Trends in overweight and obesity do not explain the increase in asthma. The evidence points towards the association between asthma and obesity being of recent origin. This may be explained by obesity being a marker of recent lifestyle differences now associated with both asthma and overweight.

Overweight, obesity and skinfold thicknesses of children of African or Indian descent in Trinidad and Tobago

BACKGROUND

To evaluate distribution of body mass index (BMI) and subcutaneous fat in children of African or Indian subcontinent descent living in Trinidad and Tobago.

METHODS

A cross-sectional survey was carried out in a nationally representative sample of 66 government schools. Measurements were made of children's heights, weights, triceps and subscapular skinfold thicknesses. Data were analysed by sex and ethnic group and comparison was made with international standards for overweight and obesity and with British (1990) reference curves for BMI.

RESULTS

Data were analysed for 5688/6731 (85%) eligible children including 1934 Afro-Trinidadian, 1689 Indo-Trinidadian, and 1794 of mixed ethnicity. Afro-Trinidadian and mixed children were taller, but Indo-Trinidadian children were shorter than reference. Values for BMI were lower than reference: mean standard deviation score (SDS), (95% confidence interval) Afro-Trinidadian -0.34 (-0.39 to -0.28), Indo-Trinidadian -1.32 (-1.39 to -1.25), mixed -0.67 (-0.74 to -0.61). Overall 486 (8.5%, 7.8 to 9.3%) of children were overweight and 138 (2.4%, 2.0 to 2.9%) were obese. Triceps skinfold thickness values were lower than reference (-0.45, -0.48 to -0.42 SDS) but subscapular skinfold thicknesses were higher (0.45, 0.43 to 0.47 SDS). Higher BMI were associated with higher BMI in the child's parents, higher reported birthweight, older age of the child's mother, smaller family size, and with higher maternal educational attainment.

CONCLUSIONS

Overweight was prevalent and distribution of subcutaneous fat was central. Work is needed to determine whether these findings are associated with adult patterns of fat distribution and metabolic abnormalities.

Determinants of cough in young adults participating in the European Community Respiratory Health Survey

Cough is a common symptom that affects a large proportion of the general population. The aim of this investigation was to identify determinants of nocturnal, nonproductive and productive cough in population samples from different countries. In a cross-sectional international population survey, 18,277 subjects (20-48 yrs) from 16 countries answered an interview-led questionnaire. Total and specific immunoglobulin-E was measured and spirometry was performed. Three types of cough were defined: nocturnal, nonproductive and productive cough. The relation of the independent variables to cough was estimated by means of logistic regression for each centre or country and combined across centre or country by random-effects meta-analysis. The median prevalence of nocturnal, nonproductive and productive cough in the different centres was 30.7%, 10.2% and 10.2%, respectively. Nocturnal and nonproductive cough were related to female sex (adjusted odds ratio (OR)=2.08 and 1.27, respectively), while nocturnal and productive cough were related to rhinitis (OR=1.46 and 1.61, respectively). All three types of cough were related to asthma, tobacco smoking, environmental tobacco smoke and obesity. Females are more likely to report nocturnal and nonproductive cough than males. Cough was related to treatable disorders, like asthma and rhinitis, as well as avoidable factors, such as tobacco smoking and environmental tobacco smoke.

The European Community Respiratory Health Survey: what are the main results so far? European Community Respiratory Health Survey II

The European Community Respiratory Health Survey (ECRHS) was the first study to assess the geographical variation in asthma and allergy in adults using the same instruments and definitions. The database of the ECRHS includes information from approximately 140,000 individuals from 22 countries. The aim of this review is to summarize the results of the ECRHS to date. The ECRHS has shown that there are large geographical differences in the prevalence of asthma, atopy and bronchial responsiveness, with high prevalence rates in English speaking countries and low prevalence rates in the Mediterranean region and Eastern Europe. Analyses of risk factors have highlighted the importance of occupational exposure for asthma in adulthood. The association between sensitization to individual allergens and bronchial responsiveness was strongest for indoor allergens (mite and cat). Analysis of treatment practices has confirmed that the treatment of asthma varies widely between countries and that asthma is often undertreated. In conclusion, the European Community Respiratory Health Survey has shown that the prevalence of asthma varies widely. The fact that the geographical pattern is consistent with the distribution of atopy and bronchial responsiveness supports the conclusion that the geographical variations in the prevalence of asthma are true and most likely due to environmental factors.

Symptoms of asthma, bronchial responsiveness and atopy in immigrants and emigrants in Europe. European Community Respiratory Health Survey

Migration studies on asthma may provide information on its environmental causes. The European Community Respiratory Health Survey has potential advantages due to the number of countries involved, standardized collection of information, assessment of directionality of migration, and availability of physiological data on bronchial responsiveness and atopy. Prevalence rates of symptoms associated with asthma were compared for immigrants, emigrants and nonmigrants living in centres mostly in western Europe. Similar analyses were carried out for bronchial responsiveness (provocative concentration causing a 20% fall in forced expiratory volume in one second and slope) and atopy. Medication and use of health services were also explored. Overall, 1,678 (8.6%) of 19,516 participants were immigrants in the 18 countries participating in the study, of whom 581 were emigrants from one of the participating countries. Rates of asthma symptoms were higher in immigrants (odds ratio (OR): 1.21, 95% confidence interval (CI): 1.00-1.51) and emigrants (OR: 1.31, 95% CI: 0.96-1.51) compared to nonmigrants after controlling for area, sex, age and smoking status. However, bronchial responsiveness and atopy were equally distributed between immigrants, emigrants and nonmigrants. Use of health services was observed to be similar in migrants and nonmigrants with asthma. In the European Community Respiratory Health Survey, migrants reported more asthma symptoms, but had similar bronchial responsiveness, atopy, and use of health services when compared with the nonmigrant population.

Extracorporeal photopheresis in Sézary syndrome: hematologic parameters as predictors of response

Data were analyzed from 23 patients with Sézary syndrome (defined by erythroderma, more than 10% circulating atypical mononuclear cells, and peripheral blood T-cell clone) undergoing monthly extracorporeal photopheresis as the sole therapy for up to 1 year. The cohort showed a significant reduction of skin scores during treatment (P =.001). Thirteen patients (57%) achieved a reduction in skin score greater than 25% from baseline at 3, 6, 9, or 12 months (responders). Reduction in skin score correlated with reduction in the Sézary cell count as a percentage of total white cell count (P =.03). Responders and nonresponders were compared. None of the measured parameters was significantly different between the 2 groups. It was assessed whether any of the baseline parameters predicted outcome. A higher baseline lymphocyte count was significantly associated with a decrease in skin score at 6 months (P <.05). A higher baseline Sézary cell count as a percentage of total white cell count predicted a subject was more likely to be a responder after 6 months of treatment (P =.021). No other parameters predicted responder status. These data show that the modest falls in CD4, CD8, and Sézary cell counts were seen in all patients and might have resulted from lymphocyte apoptosis. This mechanism could explain the more favorable response seen in patients with higher percentages of Sézary cells in the peripheral blood. Alternatively, minimum tumor burden might be required for the induction of a cytotoxic response. Analysis of tumor-specific cytotoxic T cells is needed to investigate these possibilities further.

Reduced incidence of retinopathy of prematurity

AIM

To audit the prevalence of retinopathy of prematurity (ROP) in a level 2 status neonatal unit.

METHODS

Data were collected prospectively over 9 years from September 1989 to September 1998. Preterm infants were examined according to the Royal College of Ophthalmologists' guidelines and retinopathy graded following the International Classification of ROP. ROP 3-5 was analysed using logistic regression in relation to time, and to gestational age and birth weight.

RESULTS

383 babies were examined. Mean gestational age fell over the 9 year period (p=0.051) as did mean birth weight (p<0.001). There was a decrease in the number of infants with ROP grades 3-5 over the 9 years (p=0.045 and, when adjusted for gestational age and birth weight, the decrease in ROP 3-5 was significant (p=0.03).

CONCLUSIONS

This study found a significant reduction in the incidence of ROP during the 9 years of the study period, despite a decrease in mean gestational age of and birth weight. The reduced incidence of ROP is attributed to improvements in ventilation techniques and overall care of the neonate, in particular the use of prenatal steroids and surfactant.

Statistics for the European Respiratory Journal

This review summarizes statistical methods likely to be needed by researchers. It is not a replacement for a statistics book, and almost no symbols or mathematics are used. It seeks to guide researchers to the appropriate methods and to make them aware of some common pitfalls. Sections deal with methods for quantitative outcomes, both basic and more advanced, and parallel methods for qualitative or categorical outcomes. Reference is made to papers using the more advanced methods in the European Respiratory Journal in order that their relevance may be appreciated. The paper seeks to improve the quality of papers submitted to the European Respiratory Journal, to reduce the revisions to papers required of authors, and to enable readers of the journal to gain more insight into the interpretation of results.

Developing a strategy to define the effects of insulin-like growth factor-1 on gene expression profile in cardiomyocytes

Insulin-like growth factor (IGF)-1 activates intracellular signaling pathways and regulates myocardial structure and function. This study used DNA microarray to define the effects of IGF-1 on gene expression in cardiomyocytes. Despite DNA microarray becoming a popular tool for profiling gene expression, the specificity of DNA microarray results is rarely addressed. Our data showed that the specificity of a DNA microarray study can be increased by repetitive experiments and by excluding minimally expressed genes. In this study, the false-positive rates were reduced to <0.2%. Future DNA microarray studies should incorporate a proper strategy to minimize false-positive results. IGF-1 modulates the expression of genes in 17 functional categories, but most genes clustered around the regulation of intracellular signaling, cell cycle, transcription/translation, cellular respiration and mitochondrial function, cell survival, ion channels and calcium signaling, and humoral factors. To further explore whether extracellular signal-regulated kinase (ERK) and phosphatidylinositol (PI) 3 kinase specifically regulate different sets of genes, the effects of IGF-1 were inhibited with PD98059 or LY294002. The results showed that the majority of genes regulated by IGF-1 required activation of both ERK and PI 3 kinase. Thus, PI 3 kinase and ERK coordinately mediate the transcriptional regulatory effects of IGF-1 in cardiac muscle cells. These findings provide novel insight into how IGF-1 signaling modulates the programming of cardiac muscle gene expression.

Association between obesity and asthma in 4-11 year old children in the UK

BACKGROUND

There is evidence of a positive association between asthma and obesity in adults and in children. We investigated, in a large sample of English and Scottish primary school children, whether there is a consistent association between fatness and asthma symptoms in Britain.

METHODS

A cross sectional analysis was made of 18 218 children aged 4-11 years who participated in the 1993 or 1994 surveys of the National Study of Health and Growth (NSHG). Children belonged either to English or Scottish representative samples, or an English inner city sample. Asthma attacks in the previous year, occasional wheeze, or persistent wheeze were the symptoms used in the analysis. Body mass index (BMI) and the sum of triceps and subscapular skinfolds converted to standard deviation scores (SDS) were used to assess levels of fatness.

RESULTS

A total of 14 908 children (81.8%) were included in the analysis. In the multiple logistic analysis BMI and asthma (asthma attacks or wheeze) were associated in the representative sample (OR for the comparison of the 10th and 90th centiles of BMI 1.28, 95% CI 1.11 to 1.48), but sum of skinfolds was unrelated to asthma symptoms in most analyses. The association between asthma and BMI was stronger in girls than in boys in the inner city sample, but less convincingly in the representative sample.

CONCLUSIONS

Levels of obesity are associated with asthma symptoms regardless of ethnicity. The association is more consistent for BMI than for sum of skinfolds, partly because obese children are more advanced in their maturation than other children. There is some evidence that, as in adults, the association is stronger in girls than in boys, but only in the multiethnic inner city sample.

Changing frequency of thiuram allergy in healthcare workers with hand dermatitis

BACKGROUND

Healthcare workers (clinical, allied/paramedical professions and ancillary workers) may have prolonged contact with natural rubber latex devices, particularly in the form of natural rubber latex gloves.

OBJECTIVES

To examine the changing frequency of type IV thiuram allergy in healthcare workers with hand dermatitis over a 16-year period.

METHODS

During the study period, 450 healthcare workers (352 women and 98 men) with hand dermatitis were investigated, and their patch test results were analysed retrospectively.

RESULTS

On average, a thiuram-positive patch test was noted in 12% of individuals, with a peak incidence of 27% of the patients patch tested in 1994. Comparison of results between 1983--88 and 1989--93 showed a statistically significant increase in the incidence of thiuram-positive patch tests (odds ratio 2.55, 95% confidence interval 1.25--5.20, P = 0.01).

CONCLUSIONS

We have documented a changing frequency of thiuram-positive patch tests in healthcare workers with hand dermatitis since 1983. This may reflect changes in degree of exposure to thiurams in medical gloves during this period.