Associations of wheezing phenotypes in the first 6 years of life with atopy, lung function and airway responsiveness in mid-childhood

Background:

Patterns of wheezing during early childhood may indicate differences in aetiology and prognosis of respiratory illnesses. Improved characterisation of wheezing phenotypes could lead to the identification of environmental influences on the development of asthma and airway diseases in predisposed individuals.

Methods:

Data collected on wheezing at seven time points from birth to 7 years from 6265 children in a longitudinal birth cohort (the ALSPAC study) were analysed. Latent class analysis was used to assign phenotypes based on patterns of wheezing. Measures of atopy, airway function (forced expiratory volume in 1 s (FEV₁), mid forced expiratory flow (FEF_25-75)) and bronchial responsiveness were made at 7–9 years of age.

Results:

Six phenotypes were identified. The strongest associations with atopy and airway responsiveness were found for intermediate onset (18 months) wheezing (OR for atopy 8.36, 95% CI 5.2 to 13.4; mean difference in dose response to methacholine 1.76, 95% CI 1.41 to 2.12 %FEV₁ per μmol, compared with infrequent/never wheeze phenotype). Late onset wheezing (after 42 months) was also associated with atopy (OR 6.6, 95% CI 4.7 to 9.4) and airway responsiveness (mean difference 1.61, 95% CI 1.37 to 1.85 %FEV₁ per μmol). Transient and prolonged early wheeze were not associated with atopy but were weakly associated with increased airway responsiveness and persistent wheeze had intermediate associations with these outcomes.

Conclusions:

The wheezing phenotypes most strongly associated with atopy and airway responsiveness were characterised by onset after age 18 months. This has potential implications for the timing of environmental influences on the initiation of atopic wheezing in early childhood.

How to quantify coughing: correlations with quality of life in chronic cough

Different methods are used for quantifying coughing in sound recordings, but as yet no method has been shown to be more valid than any other. In the present study, the relationships between three different units of cough were examined and their ability to predict subjective ratings of cough and cough-related quality of life were evaluated. In total, 70 subjects (mean+/-SD age 55+/-11.7 yrs, 51 (73%) females) with chronic unexplained cough (median duration 4.8 yrs, interquartile range 2.5-10.1 yrs) performed fully ambulatory 24-h sound recordings, which were manually counted by trained observers and quantified by 1) explosive phases, 2) cough seconds and 3) cough epochs. Subjects also completed cough visual analogue scales (VAS) and the Leicester Cough Questionnaire (LCQ). All units of cough were strongly correlated; explosive phases and cough seconds correlated slightly more strongly than cough seconds with cough epochs or explosive phases with cough epochs. LCQ scores correlated moderately with explosive phases and seconds; epochs correlated slightly less well. Cough VAS scores showed a similar pattern. Explosive phases and seconds are interchangeable units of cough, moderately related to subjective measures and cough-related quality of life; epochs are a less satisfactory alternative.

Can lay people deliver asthma self-management education as effectively as primary care based practice nurses?

OBJECTIVES

To determine whether well trained lay people could deliver asthma self-management education with comparable outcomes to that achieved by primary care based practice nurses.

DESIGN

Randomised equivalence trial.

SETTING

39 general practices in West London and North West England.

PARTICIPANTS

567 patients with asthma who were on regular maintenance therapy. 15 lay educators were recruited and trained to deliver asthma self-management education.

INTERVENTION

An initial consultation of up to 45 min offered either by a lay educator or a practice based primary care nurse, followed by a second shorter face to face consultation and telephone follow-up for 1 year.

MAIN OUTCOME MEASURES

Unscheduled need for healthcare.

SECONDARY OUTCOME MEASURES

Patient satisfaction and need for courses of oral steroids.

RESULTS

567 patients were randomised to care by a nurse (n = 287) or a lay educator (n = 280) and 146 and 171, respectively, attended the first face to face educational session. During the first two consultations, management changes were made in 35/146 patients seen by a practice nurse (24.0%) and in 56/171 patients (32.7%) seen by a lay educator. For 418/567 patients (73.7%), we have 1 year data on use of unscheduled healthcare. Under an intention to treat approach, 61/205 patients (29.8%) in the nurse led group required unscheduled care compared with 65/213 (30.5%) in the lay led group (90% CI for difference -8.1% to 6.6%; 95% CI for difference -9.5% to 8.0%). The 90% CI contained the predetermined equivalence region (-5% to +5%) giving an inconclusive result regarding the equivalence of the two approaches. Despite the fact that all patients had been prescribed regular maintenance therapy, 122/418 patients (29.2%) required courses of steroid tablets during the course of 1 year. Patient satisfaction following the initial face to face consultation was similar in both groups.

CONCLUSIONS

It is possible to recruit and train lay educators to deliver a discrete area of respiratory care, with comparable outcomes to those seen by nurses.

Quantification of atopy and the probability of rhinitis in preschool children: a population-based birth cohort study

BACKGROUND

Atopy quantification using IgE levels/skin test diameter (SPT-MWD) may better predict the expression of rhinitis than using atopy as a dichotomous variable.

OBJECTIVE

To investigate the association between the presence, temporal pattern and severity of rhinitis in preschool children and specific IgE levels/SPT-MWDs.

METHODS

Children were followed prospectively to age 5 years in a whole-population birth cohort study. We administered questionnaires (n = 815), skin prick tested children (n = 717) and measured specific serum IgE (n = 478) to inhalant and food allergens. Main outcomes were current rhinitis (CR) and current rhinoconjunctivitis (CRC).

RESULTS

The prevalence of CR and CRC was 26.1% and 12.1%, respectively. The risk of CR and CRC increased significantly with increasing IgE to grass, mite and cat; CRC was also associated with increasing IgE to dog and peanut. Similarly, increasing SPT-MWDs to inhalant allergens were significantly associated with CR and CRC. This association was also shown for grass within the group of atopic children. Perennial and seasonal rhinitis were associated with increasing IgE/SPT-MWD to mite and grass, respectively. Moderate/severe rhinitis was associated with increasing IgE/SPT-MWD to grass. In a multivariate analysis, increasing levels of IgE/SPT-MWD to grass were the strongest independent predictors of both CR (for IgE: OR 1.42, 95% CI 1.23-1.64, P < 0.001) and CRC (for IgE: 1.51, 1.30-1.76, P < 0.001).

CONCLUSION

The probability of CR/CRC increases with increasing specific IgE levels or SPT-MWD. With respect to allergic rhinitis, the absolute levels of specific IgE antibody or the size of SPT wheal offer more information than just the presence/absence of sensitization.

Extent of satisfaction with tablets and food-timing in sulphonylurea-treated diabetes

This study measured patient views about following tablet-taking and food-timing recommendations in Type 2 diabetes. Two new questionnaires were validated. Outpatients with Type 2 diabetes treated with sulphonylurea agents (n=131) completed the seven-item Diabetes Tablet Treatment Questionnaire (DTTQ) and nine-item Diabetes Food Timing Questionnaire (DFTQ). Mean glycosylated haemoglobin (HbA1c) was 7.8% (S.D. 1.8%). At least 74% had optimal DTTQ item scores for tablet-taking as recommended, difficulty taking tablets, side effects, perceived hypoglycaemia and willingness to continue current tablets, but 71% scored sub-optimally regarding recent hyperglycaemia. Under half scored optimally on DFTQ items concerning eating at recommended times, difficulty with food-timing, denying oneself food and guilt about eating. Principal components and reliability analyses identified a two-item tablet problem scale within the DTTQ (alpha 0.72) and a seven-item food-timing problem scale in the DFTQ (alpha 0.77). Satisfaction and adherence were not closely related to glycaemic control. Only scores for perceived hyperglycaemia (r=0.38), perceived hypoglycaemia (r=-0.24) and satisfaction to continue current tablets (r=-0.20) correlated significantly with HbA1c. Clinicians found that the DTTQ helped to raise tablet-taking issues otherwise missed in consultations. Both questionnaires can be used to guide the need for focussed discussion, educational intervention and/or treatment change and to evaluate their impact.

Airway abnormalities at flexible bronchoscopy in patients with chronic cough

The algorithms utilised in the diagnosis of chronic cough advocate sequential investigations and treatment trials for asthma-like syndromes, post-nasal drip and gastro-oesophageal reflux disease; however, the role of bronchoscopy is unclear. In the present authors' specialist clinic (North West Lung Centre Cough Clinic, Manchester, UK), flexible bronchoscopy is included in the diagnostic work-up of patients with chronic unexplained cough. In a retrospective review, the authors report on their experiences. Over an 18-month period, patients followed a diagnostic algorithm that included: chest radiography; pulmonary function; methacholine challenge; ear, nose and throat examination; and empirical reflux treatment. Where diagnosis remained elusive, bronchoscopy was performed. A total of 82 bronchoscopies were carried out for the sole indication of chronic cough. Patient age (mean+/-SD) was 54.9+/-11.22 yrs, with a median (range) cough duration of 5 (0.5-30) yrs. In nine (11%) subjects, a diagnosis was made on inspection or biopsy. These included seven cases of tracheobronchopathia osteochondroplastica (TPO), one case of elongated uvula and one case of endobronchial amyloidosis. All TPO patients had early changes, with a typical nodular appearance to the tracheal cartilage, without significant airway obstruction. These subtle changes could not have been predicted from less invasive procedures and would have been missed without bronchoscopy. Flexible bronchoscopy is indicated in persistent unexplained cough and may reveal contributing pathology.

Ergonomics, education and children: a personal view

Educational ergonomics - the teaching of ergonomics and the design of environments where ergonomics teaching and learning might occur - has received little attention from ergonomists. This paper first describes the roots of the author's interest and research in educational ergonomics; second it provides a personal view of the opportunities and challenges posed by the two streams of educational ergonomics; and lastly it considers the implications of teaching ergonomics to children in terms of their personal development, the design of schools and the impact such initiatives might have on wider societal problems.

Fecal microbiota in sensitized wheezy and non-sensitized non-wheezy children: a nested case-control study

BACKGROUND

It has been suggested that intestinal microbiota of allergic and non-allergic children differs in composition, and that microbiota-immune system interactions may predispose children to develop sensitization. Previous studies have examined fecal microbiota of allergic children with atopic dermatitis, but little is known about that of atopic wheezy children.

OBJECTIVE

To investigate the composition of the fecal microbiota of young sensitized wheezy and non-sensitized non-wheezy children, using molecular methods.

METHODS

Within the context of a prospective birth cohort, we carried out a nested case-control study of sensitized wheezy children (cases) and non-sensitized non-wheezy controls. Cases and controls were matched for age, sex, parental atopy, allergen exposure, and pet ownership. We evaluated the composition of fecal microbiota by nucleic acid-based methods (PCR combined with denaturing gradient gel electrophoresis and quantification of bifidobacteria by fluorescent in situ hybridization).

RESULTS

Thirty-three case-control pairs (mean age 4.4 years) provided stool samples. Comparison of total bacterial community profiles showed that each child had a unique fecal microbiota (mean Dice's similarity coefficient 22%, range 3.3-60.8%). There was no difference between the groups in prevalence of Lactic Acid bacteria (12/33 vs. 11/33, P=0.8) or bifidobacteria (30/33 vs. 31/33, P=1.00, cases vs. controls). The bifidobacterial species detected were similar in both groups. The percentage of bifidobacteria in total fecal microflora was no different between cases (median 1.7%, range 0-20.8%) and controls (1.9%, 0-18.2%, P=0.7). However, cases with eczema had significantly fewer bifidobacteria (median 1.6%, range 0-4.8%) than their controls (4.0%, 1.9-18.2%, P=0.05).

CONCLUSION

We found no differences in fecal microbiota composition between sensitized wheezy and non-sensitized, non-wheezy children aged 3-5 years using nucleic acid-based methods. Differences appear to be isolated to those allergic children with eczema.

Effect of age related macular degeneration on the Eger macular stressometer photostress recovery time

AIM

To assess the repeatability of Eger macular stressometer (EMS) measures of photostress recovery and determine their association with other measures of visual function.

METHODS

EMS photostress recovery time was measured in 90 patients with bilateral exudative age related macular degeneration (AMD), 19 with bilateral atrophic AMD and 47 with both forms of the condition (mean age 79 (SD 13) years). Measurements were made on two occasions separated by 1 year. Intrasession repeatability was assessed by repeating the measures after a 10 minute recovery period at the first visit. Distance visual acuity was measured with a logMAR chart, near visual acuity with a MNRead chart at 25 cm, contrast sensitivity with a Pelli-Robson chart, and the presence of central visual disturbance assessed with an Amsler grid. A questionnaire was used to assess self reported difficulties with glare recovery.

RESULTS

The average EMS recovery time was 11.0 (SD 8.9) seconds, decreasing by 1.6 (5.2) seconds on repeated measurement (p<0.05). EMS photostress recovery was not correlated with visual function measures or subjective difficulties with lights (p>0.05). EMS photostress recovery time did not predict those whose vision decreased over the following year compared with those among whom it remained stable.

CONCLUSIONS

The EMS test is not a useful tool in determining the severity or progression of AMD.

Dietary intake in sensitized children with recurrent wheeze and healthy controls: a nested case-control study

BACKGROUND

The rising prevalence of asthma and allergic disease remains unexplained. Several risk factors have been implicated including diet, in particular poly-unsaturated fats and antioxidant intake.

METHODS

A nested case-control study comparing the dietary intake of sensitized children with recurrent wheeze (age 3-5 years) and nonsensitized children who had never wheezed was carried out within an unselected population-based cohort. Cases and controls were matched for age, sex, parental atopy, indoor allergen exposure and pet ownership. Dietary intake was assessed using a validated semi-quantitative food frequency questionnaire and nutrient analysis program.

RESULTS

Thirty-seven case-control pairs (23 male, mean age 4.4 years) participated. Daily total polyunsaturated fat intake was significantly higher in sensitized wheezers (g/day, geometric mean, 95% confidence intervals: 7.1, 6.4-7.9) compared with nonsensitized nonwheezy children (5.6, 5.0-6.3, P = 0.003). Daily omega-3 and omega-6 fat intakes were not significantly different between the two groups. No significant differences were found in intake of any antioxidant or antioxidant cofactors between the groups.

CONCLUSIONS

Young sensitized wheezy children had a significantly higher total polyunsaturated fat intake compared with nonsensitized nonwheezy children. However, we were unable to distinguish a significant difference in specific poly-unsaturated fat intakes. Otherwise the children in both groups had a very similar nutritional intake.

Objective measurement of cough during pulmonary exacerbations in adults with cystic fibrosis

BACKGROUND

Little is known about cough frequency in adults with cystic fibrosis (CF). This study aimed to determine (1) daytime and overnight cough rates in patients with CF at the beginning and end of a course of antibiotics for treatment of an exacerbation; (2) the relationship between cough frequencies and standard clinical measures of disease; and (3) the relationship between objective cough rates and the subjective assessment of cough.

METHODS

Nineteen adult patients admitted with a pulmonary exacerbation performed daytime and overnight sound recordings on admission; 13 had repeat recordings prior to discharge. Coughs were manually quantified in cough seconds (time spent coughing). Patients subjectively scored their cough using a visual analogue scale (VAS) and numerical score. Lung function, C-reactive protein (CRP) levels, and sputum weights were recorded.

RESULTS

Cough rates fell substantially with treatment; median fall in cough rate was 51.3% (IQR 32.3-77.5) (p<0.001) for daytime and 72.2% (28.6-90.1) (p = 0.049) for overnight. Multivariate regression analyses showed that forced expiratory volume in 1 second and CRP levels predicted overnight cough rates on admission. On discharge, sputum volume predicted daytime cough rates. Only the change in overnight VAS correlated with the change in objective cough rates.

CONCLUSIONS

The cough rate significantly decreases with treatment of a pulmonary exacerbation in adults with CF. Lung function, sputum volume, and CRP influences the cough rate, with the effects differing from day to night and between admission and discharge. Subjective reporting of a nocturnal cough may indicate a pulmonary exacerbation of CF in adults.

High-efficiency vacuum cleaners increase personal mite allergen exposure, but only slightly

BACKGROUND

High-efficiency particulate-arrest-filter vacuum cleaners are recommended to allergy sufferers although their use increases personal cat allergen exposure. We aimed to measure personal mite allergen exposure during vacuum cleaning by nasal air sampling and to compare exposures while vacuuming and emptying the vacuum cleaner bag.

METHODS

Five brand new high-efficiency vacuum cleaners were selected. An old, previously used vacuum cleaner with its original microfilter in situ was used as a control. Nasal air samples were taken prior to and during vacuum cleaning in 10 homes. Samples were processed by HALOgen assay. Personal mite and cat allergen exposure was measured as the dust compartments were emptied.

RESULTS

There was an increase in personal mite allergen exposure with vacuum cleaning, which approached significance (P = 0.058). There was no difference between the high-efficiency vacuum cleaners and the control vacuum cleaner (P = 0.141). When the dust compartments were emptied, personal mite and cat allergen exposure increased (P < 0.02). CONCLUSIONS. The increase in personal mite allergen exposure while vacuum cleaning in an area with mild to moderate mite allergen exposure is small. High-efficiency vacuum cleaners confer no benefit and cannot currently be recommended to allergy sufferers as a means of reducing personal mite allergen exposure.

Study of modifiable risk factors for asthma exacerbations: virus infection and allergen exposure increase the risk of asthma hospital admissions in children

BACKGROUND

Asthma exacerbation is the most common cause of hospital admission in children. A study was undertaken to investigate the importance of allergen exposure in sensitised individuals in combination with viral infections and other potentially modifiable risk factors precipitating asthma hospital admission in children.

METHODS

Eighty four children aged 3-17 years admitted to hospital over a 1 year period with an acute asthma exacerbation (AA) were matched for age and sex with two control groups: stable asthmatics (SA) and children admitted to hospital with non-respiratory conditions (IC). Risk factors were assessed by questionnaires and determination of allergen sensitisation, home allergen exposure, pollen exposure, and respiratory virus infection.

RESULTS

Several non-modifiable factors (atopy, duration of asthma) were associated with increased risk. Among the modifiable factors, pet ownership, housing characteristics, and parental smoking did not differ between the groups. Regular inhaled corticosteroid treatment was significantly less common in the AA group than in the SA group (OR 0.2, 95% CI 0.1 to 0.6; p = 0.002). A significantly higher proportion of the AA group were virus infected (44%) and sensitised and highly exposed to sensitising allergen (76%) compared with the SA (18% and 48%) and IC groups (17% and 28%; both p<0.001). In a multiple conditional logistic regression (AA v SA), allergen sensitisation and exposure or virus detection alone were no longer independently associated with hospital admission. However, the combination of virus detection and sensitisation with high allergen exposure substantially increased the risk of admission to hospital (OR 19.4, 95% CI 3.7 to 101.5, p<0.001).

CONCLUSIONS

Natural virus infection and real life allergen exposure in allergic asthmatic children increase the risk of hospital admission. Strategies for preventing exacerbations will need to address these factors.

The information needs and preferred roles in treatment decision-making of parents caring for infants with atopic dermatitis: a qualitative study

BACKGROUND

Information needs and preferences in treatment decision-making of parents caring for infants with atopic dermatitis (AD) are unknown, despite emphasis on quality information-giving and involvement of health-care users in treatment decisions.

OBJECTIVE

To explore information needs and decisional role-preferences of parents caring for infants with AD.

METHODS

Qualitative study. Purposive sample: 31 parents caring for infants with AD. Tape-recorded focussed conversation-style interviews. Interview topic-guide literature-derived. Control Preferences Scale (5 sort-card vignettes 'very active' to 'very passive' role) adapted for use with parents; used to facilitate discussion. Thematic analysis of verbatim transcripts.

RESULTS

Nine core information needs identified: AD-causation, role of diet, medication-use, medication-side-effects, exacerbating factors, new/alternative medication, nonpharmacological treatments, AD-prevention, AD and other atopic conditions. Parents desired verbal and written information. Many felt their baby's condition was not taken seriously, leading to delayed diagnosis and treatment. They had to be more active than they wished to obtain information/treatment. Parents preferred sharing decisions with their doctor.

CONCLUSIONS

Parents caring for infants with AD have clearly defined, unmet information needs, forcing them into more active roles in the treatment decision-making process than they desire. The study-findings may inform the development of written information specifically for these parents and improve partnership during consultations.

Effect of Mycobacterium vaccae on cytokine responses in children with atopic dermatitis

The increasing prevalence of atopic diseases over the last few decades is thought to be due to reduced exposure to environmental microbes that normally down-regulate allergic responses (hygiene hypothesis). We have shown previously that administration of the environmental microbe Mycobacterium vaccae ameliorates atopic dermatitis in school-age children at 3 months post-treatment. The present study tested the hypothesis that M. vaccae suppresses Th2-type cytokine activity and increases transforming growth factor (TGF)-beta(1) immunomodulatory activity in these children. Interleukin (IL)-4, IL-5, TGF-beta(1) and interferon (IFN)-gamma activity were assessed in resting and stimulated peripheral blood mononuclear cells (PBMC) isolated from 12 of the children who received M. vaccae in our original clinical trial. A cDNA expression array was used to examine a broader range of cytokine pathway transcripts. There were no significant changes in either Th2-type or TGF-beta(1) activity. A 5- to 10-fold increase in Th1-type activity was found at 1 month post-M. vaccae administration (P < 0.05), but it had returned to baseline by 3 months. The results do not support the hypothesis that M. vaccae reduces Th2-type or increases TGF-beta(1) activity of PBMC isolated from children with atopic dermatitis. The transient surge in IFN-gamma at 1 month is unlikely to explain any improvement in eczema score at 3 months.

Involvement in treatment decisions: what do adults with asthma want and what do they get? Results of a cross sectional survey

BACKGROUND

Current healthcare policy advocates patient participation in treatment decision making. However, in asthma there is little evidence regarding patients' views on such involvement. This study explored the preferred and perceived level of involvement in treatment decisions, rationales for role preference, perceived facilitators of/barriers to involvement, and the interrelationship of role preference and demographic variables in a sample of patients with asthma.

METHODS

A cross sectional survey was performed of 230 adults with clinician diagnosed asthma from 10 primary care sites and one specialist respiratory centre in north-west England. Preferred role in treatment decisions was assessed using the Control Preferences Scale.

RESULTS

Fifty five (23.9%) preferred an active role, 82 (35.7%) a collaborative role, and 93 (40.4%) a passive role; 19 (8.2%) perceived their role as active compared with 45 (19.6%) collaborative and 166 (72.2%) passive. Only 33.5% (n = 77) of respondents attained their most preferred role; 55.2% (n = 127) were less involved than they preferred. Patient related, professional related, and organisational factors, especially quality and duration of consultations, facilitated or hampered involvement. Role preferences were not strongly associated with demographic variables or asthma severity.

CONCLUSIONS

This study in patients with asthma highlights the fact that there is a need for professional and patient education regarding partnership working, skilful communication, and innovative approaches to service delivery.

Relationship between exposure to domestic allergens and bronchial hyperresponsiveness in non-sensitised, atopic asthmatic subjects

BACKGROUND

The effect of exposure to allergens not causing sensitisation in atopic asthmatic subjects has not previously been studied. A study was undertaken to assess the degree of asthma severity (measured by spirometry, airway reactivity and exhaled nitric oxide) in atopic asthmatic patients not sensitised to the domestic allergen to which they were exposed.

METHODS

Dust samples were collected from the living room carpet and mattress in the homes of 248 subjects and dust mite, cat and dog allergen concentrations were measured. Spirometry, non-specific bronchial reactivity (BR), and exhaled nitric oxide (eNO) were ascertained. Patients' sensitisation status was assessed by skin prick testing.

RESULTS

Adult atopic asthmatics not sensitised to mite but exposed to high levels of mite allergen had significantly more severe BR than subjects not exposed to high levels of mite (PD(20), geometric mean (GM) 0.21 mg (95% CI 0.09 to 0.47) v 0.86 mg (95% CI 0.44 to 1.67), mean ratio difference 4.1 (95% CI 1.5 to 11.4), p=0.008). Subjects not sensitised but exposed to high levels of dog allergen also had significantly more severe BR than subjects not exposed (PD20 GM 0.16 v 0.52 mg, mean ratio difference 3.3 (95% CI 1.2 to 9.2), p=0.01). The differences in BR between these groups were still significant after adjusting for confounding factors. This effect of greater airway reactivity was not seen in subjects exposed but not sensitised to cat allergens.

CONCLUSION

Atopic asthmatic subjects who are exposed to high levels of dust mite or dog allergens but not sensitised to these allergens have evidence of increased airway reactivity.