Repeatability and validity of IUATLD Respiratory Questionnaire responses as a measure of asthma in an Ethiopian population

OBJECTIVE

To assess the repeatability and validity of the IUATLD respiratory symptoms questionnaire in relation to exercise-induced bronchoconstriction or bronchodilator responses in a community in southern Ethiopia.

DESIGN

A case-control study.

SETTING

Rural and small town setting in southern Ethiopia, April to May 2006.

SUBJECTS

Two hundred and forty seven adults and children who previously reported wheeze in the past year, and 174 who did not.

INTERVENTIONS

Administered IUATLD bronchial symptoms questionnaire; standardised free-running exercise test or (for those with airflow obstruction) assessment of bronchodilator response to inhaled salbutamol.

RESULTS

Kappa values for four-week repeatability for the wheeze and asthma questions were 0.61 (95% CI 0.52 to 0.70) and 0.75 (0.63 to 0.87), respectively. Of the 58 people who reported wheeze in 2003 and in April 2006, only five had a positive exercise test or bronchodilator challenge (Positive Predictive Value (PPV) 0.09, 95% CI 0.01 to 0.22). Of the 12 who reported asthma in 2003 and April 2006, three had a positive result to either to exercise test or bronchodilator challenge test (PPV 0.25, 95% CI 0.05 to 0.50).

CONCLUSION

Our findings suggest that self-reported wheeze and asthma have good short-term repeatability, but do not closely reflect exercise-induced bronchospasm or bronchodilator responsiveness. The validity of questionnaire methods of studying asthma epidemiology in developing countries needs further investigation.

Safety of hookworm infection in individuals with measurable airway responsiveness: a randomized placebo-controlled feasibility study

Background

Epidemiological evidence suggests that hookworm infection protects against asthma. However, for ethical and safety reasons, before testing this hypothesis in a clinical trial in asthma it is necessary to establish whether experimental hookworm infection might exacerbate airway responsiveness during larval lung migration.

Objective

To determine whether hookworm larval migration through the lungs increases airway responsiveness in allergic individuals with measurable airway responsiveness but not clinical asthma, and investigate the general tolerability of infection and effect on allergic symptoms.

Methods

Thirty individuals with allergic rhinoconjunctivitis and measurable airway responsiveness to adenosine monophosphate (AMP) but not clinically diagnosed asthma were randomized, double-blind to cutaneous administration of either 10 hookworm larvae or histamine placebo, and followed for 12 weeks. The primary outcome was the maximum fall from baseline in provocative dose of inhaled AMP required to reduce 1-s forced expiratory volume by 10% (PD₁₀AMP) measured at any time over the 4 weeks after active or placebo infection. Secondary outcomes included peak flow variability in the 4 weeks after infection, rhinoconjunctivitis symptom severity and adverse effect diary scores over the 12-week study period, and change in allergen skin test responses between baseline and 12 weeks.

Results

Mean maximum change in PD₁₀AMP from baseline was slightly but not significantly greater in the hookworm than the placebo group (−1.67 and −1.16 doubling doses; mean difference −0.51, 95% confidence interval −1.80 to 0.78, P=0.42). Symptom scores of potential adverse effects were more commonly reported in the hookworm group, but infection was generally well tolerated. There were no significant differences in peak-flow variability, rhinoconjunctivitis symptoms or skin test responses between groups.

Conclusion

Hookworm infection did not cause clinically significant exacerbation of airway responsiveness and was well tolerated. Suitably powered trials are now indicated to determine the clinical effectiveness of hookworm infection in allergic rhinoconjunctivitis and asthma.

High-fidelity transport of trapped-ion qubits through an X-junction trap array

We report reliable transport of (9)Be(+) ions through an "X junction" in a 2D trap array that includes a separate loading and reservoir zone. During transport the ion's kinetic energy in its local well increases by only a few motional quanta and internal-state coherences are preserved. We also examine two sources of energy gain during transport: a particular radio-frequency noise heating mechanism and digital sampling noise. Such studies are important to achieve scaling in a trapped-ion quantum information processor.

Smoking in Ghana: a review of tobacco industry activity

Background:

African countries are a major potential market for the tobacco industry, and the smoking epidemic is at various stages of evolution across the continent. Ghana is an African country with a low prevalence of smoking despite an active tobacco industry presence for over 50 years. This study explores potential reasons for this apparent lack of industry success.

Objective:

To explore the history of tobacco industry activity in Ghana and to identify potential reasons for the current low prevalence of smoking.

Methods:

A search was made of tobacco industry archives and other local sources to obtain data relevant to marketing and consumption of tobacco in Ghana.

Findings:

British American Tobacco, and latterly the International Tobacco Company and its successor the Meridian Tobacco Company, have been manufacturing cigarettes in Ghana since 1954. After an initial sales boom in the two decades after independence in 1957, the sustained further increases in consumption typical of the tobacco epidemic in most countries did not occur. Possible key reasons include the taking of tobacco companies into state ownership and a lack of foreign exchange to fund tobacco leaf importation in the 1970s, both of which may have inhibited growth at a key stage of development, and the introduction of an advertising ban in 1982. BAT ceased manufacturing cigarettes in Ghana in 2006.

Conclusion:

The tobacco industry has been active in Ghana for over 50 years but with variable success. The combination of an early advertising ban and periods of unfavourable economic conditions, which may have restricted industry growth, are likely to have contributed to the sustained low levels of tobacco consumption in Ghana to date.

Do helminth parasites protect against atopy and allergic disease?

Allergic diseases are rare in areas with high helminth parasite exposure and common where helminth exposure is lacking or significantly reduced, such as urban areas of developing countries and industrialized nations. Studies suggest that helminths induce a systemic immuno-modulatory network, including regulatory T cells and anti-inflammatory IL-10, which might play a key role in the protection against the allergic phenotype. Here, we review the current cross-sectional, birth cohort, and intervention study evidence for a protective effect of helminth infection on allergy. There is increasing evidence for a causal relationship between helminth infection and reduced skin prick test responsiveness to allergens. Cross-sectional studies have shown a consistent negative relationship, and these results have been confirmed in several, although not all, intervention studies. The immunological basis for this protective effect is less clear. Recent studies do not support the mast-cell IgE saturation hypothesis, but suggest that protection is associated with IL-10 production. As for allergic disease, cross-sectional studies support a negative relationship between clinical asthma and infection with some helminth species, particularly hookworm, but more studies are required to draw conclusions for eczema and rhinitis. In addition, none of the few intervention studies to date have demonstrated an increase in clinical allergy after helminth treatment, and further studies are needed. Furthermore, we are only beginning to understand the host genetic factors that are potentially involved. A genetically predetermined T-helper type 2 cell-dominated cytokine milieu reduces parasite burden and may enhance host survival in an environment where helminth parasites are prevalent. Lack of parasite exposure in such hosts might lead to hypersensitivity to seemingly minor environmental allergen stimuli. Large birth cohort studies in helminth-endemic areas that use epidemiological, genetic, and immunological tools are required to further examine how helminth parasites affect the development of atopy and allergic disease. Intervention studies with hookworm in parasite-naïve allergic individuals are currently ongoing in the United Kingdom to test the above hypotheses further.

Environmental tobacco smoke and fetal health: systematic review and meta-analysis

OBJECTIVE

To determine the effects of environmental tobacco smoke (ETS) exposure on birth outcomes.

DESIGN

A systematic review and meta-analysis was performed in accordance with MOOSE guidelines. MEDLINE, EMBASE, CINAHL and LILACS (up to October 2007), were searched and also reviews and reference lists from publications, with no language restrictions. Pooled mean differences and odds ratios (ORs) with 95% confidence intervals were estimated using data extracted from papers, based on random effect models.

SETTING

Comparative epidemiological studies.

PATIENTS

Pregnant women or women who have given birth.

EXPOSURES

Maternal exposure to ETS during pregnancy.

MAIN OUTCOME MEASURES

Mean birth weight and proportion of premature infants.

RESULTS

58 studies were included; 53 used cohort designs, 23 ascertaining ETS exposure prospectively and 30 retrospectively; 5 used case-control designs. In prospective studies, ETS exposure was associated with a 33 g (95% CI 16 to 51) reduction in mean birth weight, and in retrospective studies a 40 g (95% CI 26 to 54) reduction. ETS exposure was also associated with an increased risk of low birth weight (birth weight <2500 g; prospective studies: OR 1.32, 95% CI 1.07 to 1.63; retrospective studies: OR 1.22, 95% CI 1.08 to 1.37). The risk of small for gestational age (<10th centile) birth was significantly associated with ETS exposure only in retrospective studies (OR 1.21, 95% CI 1.06 to 1.37). There was no effect of ETS exposure on gestational age.

CONCLUSIONS

Exposure of non-smoking pregnant women to ETS reduces mean birth weight by 33 g or more, and increases the risk of birth weight below 2500 g by 22%, but has no clear effect on gestation or the risk of being small for gestational age.

Vagus nerve stimulation for epilepsy: is output current correlated with acute response?

OBJECTIVES

Vagus nerve stimulation (VNS) is an effective treatment for intractable epilepsy. It is unknown whether acute response is correlated with the amplitude of output current. The purpose of this study was to determine if the output current of VNS is correlated with percent reductions in seizure frequency and response.

MATERIALS AND METHODS

Retrospective analysis of a multicenter randomized trial of three unique paradigms of VNS was carried out in patients with intractable partial onset epilepsy. Output current at 1 and 3 months was correlated with percent reduction in seizure frequency and response rates.

RESULTS

Sixty-one subjects were enrolled and completed the study. Output current, ranging from 0.25 to 1.5 mA, was not correlated with reductions in seizure frequency, or with > or = 50% reduction in seizures. Six of seven initial non-responders did experience > or = 50% reductions in seizures after current was increased.

CONCLUSIONS

The output current is not a major determinant of acute response to VNS for epilepsy. Many patients respond to low current (<1 mA). Some (20%) initial non-responders may respond to an increase in output current.

Passive cooling of a micromechanical oscillator with a resonant electric circuit

We cool the fundamental mode of a miniature cantilever by capacitively coupling it to a driven rf resonant circuit. Cooling results from the rf capacitive force, which is phase shifted relative to the cantilever motion. We demonstrate the technique by cooling a 7 kHz cantilever from room temperature to 45 K, obtaining reasonable agreement with a model for the cooling, damping, and frequency shift. Extending the method to higher frequencies in a cryogenic system could enable ground state cooling and may prove simpler than related optical experiments in a low temperature apparatus.

The relation between dietary intake of individual fatty acids, FEV1 and respiratory disease in Dutch adults

BACKGROUND

A reduced dietary intake of n-3 fatty acids, in association with increased n-6 fatty acid intake, has been proposed as a potential aetiological factor for chronic obstructive pulmonary disease (COPD) and asthma. However, the relative importance of individual fatty acids within the n-3 and n-6 categories on this effect has not been widely investigated. We have studied the relation between individual fatty acid intakes, lung function and self-reported respiratory symptoms and diagnoses in a representative sample of more than 13,000 Dutch adults.

METHODS

Intake of individual fatty acids was estimated by a food frequency questionnaire and analysed in relation to measures of forced expiratory volume in 1 s (FEV1) and to questionnaire reported wheeze, asthma and COPD symptoms.

RESULTS

After adjusting for confounding, we found no protective association between individual n-3 fatty acid intakes and FEV1. Higher intakes of some n-6 fatty acids were associated with lower FEV1, this effect being most marked for c22:4 n-6 docosatetraenoic acid (reduction in FEV1 between the highest and lowest quintile of intake 54.5 ml (95% CI -81.6 to -27.4)). Most of the n-6 fatty acid effects interacted significantly with smoking, their effects being strongest in current smokers. Individual n-3 fatty acid intakes were generally associated with a higher risk of wheeze in the past year, but otherwise there was little or no association between fatty acid intake and wheeze, doctor diagnosed asthma or other respiratory symptoms.

CONCLUSIONS

A high intake of n-3 fatty acids does not appear to protect against COPD or asthma, but a high intake of several n-6 fatty acids is associated with a significant reduction in FEV1, particularly in smokers. These findings indicate that high dietary intake of n-6 fatty acids, rather than reduced n-3 intake, may have an adverse effect on lung health.

Does participation in a population-based dietary intervention scheme have a lasting impact on fruit intake in young children?

BACKGROUND

The National Schools Fruit Scheme (NSFS) is intended to improve fruit intake in young children by providing free daily fruit at school.

METHODS

We used a parentally completed questionnaire for three consecutive years to study fruit intake in young children before, during and after participation in the NSFS compared with a control region.

RESULTS

In 2003, 2004 and 2005, a total of 224, 220 and 179 schools, respectively, were studied with responses from 5,606, 5,111 and 3,382 children for each survey. Between 2003 and 2004, individual fruit consumption in the intervention region increased by more (from a median of 7.5 to 14.0 pieces/week) than in the control region (from a median of 9.2-11.0 pieces/week), resulting in a difference (P < 0.001) between the two regions in 2004. However, after ceasing to be eligible for the NSFS, fruit intake in children in the intervention region fell to a median of 12 pieces per week, lower than that in the control region (median value of 14 pieces per week, P = 0.02).

CONCLUSIONS

School-based fruit distribution schemes providing free fruit at school appear to be an effective means of increasing dietary fruit intake in young children, including those who live in relatively socio-economically deprived areas. However, this approach does not influence fruit intake after the provision of free fruit ends, so schemes may need to be sustained to provide the maximum benefit to young children.

MRI of the foetal brain

Ultrasound examinations for foetal brain abnormalities have been a part of the routine antenatal screening programme in the UK for many years. In utero brain magnetic resonance imaging (MRI) is now being used increasingly successfully to clarify abnormal ultrasound findings, often resulting in a change of diagnosis or treatment plan. Interpretation requires an understanding of foetal brain development, malformations and acquired diseases. In this paper we will outline the technique of foetal MRI, relevant aspects of brain development and provide illustrated examples of foetal brain pathology.

Prevalence, diagnosis and relation to tobacco dependence of chronic obstructive pulmonary disease in a nationally representative population sample

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the fourth most common cause of death worldwide. It is caused primarily by cigarette smoking. Given its importance, it is remarkable that reliable national prevalence data are lacking for most countries. This study provides estimates of the national prevalence of COPD in England, the extent of under-detection of the disorder, and patterns of cigarette smoking, dependence, and motivation to stop smoking in those with the disease.

METHODS

Data from 8215 adults over the age of 35 who participated in the Health Survey for England were analysed. Information was obtained on self-reported and cotinine validated smoking status, cigarette dependence, motivation to stop smoking, COPD defined by spirometry using joint American Thoracic Society and European Respiratory Society criteria, and self-reports of diagnosis with respiratory disorders.

RESULTS

Spirometry-defined COPD was present in 13.3% (95% CI 12.6 to 14.0) of participants, over 80% of whom reported no respiratory diagnosis. Even among people with severe or very severe COPD by spirometric assessment, only 46.8% (95% CI 39.1 to 54.6) reported any diagnosed respiratory disease. A total of 34.9% (95% CI 32.1 to 37.8) of people with spirometry-defined COPD were smokers compared with 22.4% (95% CI 21.4 to 23.4) of those without, and smoking prevalence increased with disease severity. Smokers with spirometry-defined COPD were more cigarette dependent but had no greater desire to quit than other smokers.

CONCLUSION

COPD is common among adults in England and is predominantly undiagnosed. In smokers it is associated with higher degrees of cigarette dependence but not with a greater motivation to stop smoking.

Experimental purification of two-atom entanglement

Entanglement is a necessary resource for quantum applications--entanglement established between quantum systems at different locations enables private communication and quantum teleportation, and facilitates quantum information processing. Distributed entanglement is established by preparing an entangled pair of quantum particles in one location, and transporting one member of the pair to another location. However, decoherence during transport reduces the quality (fidelity) of the entanglement. A protocol to achieve entanglement 'purification' has been proposed to improve the fidelity after transport. This protocol uses separate quantum operations at each location and classical communication to distil high-fidelity entangled pairs from lower-fidelity pairs. Proof-of-principle experiments distilling entangled photon pairs have been carried out. However, these experiments obtained distilled pairs with a low probability of success and required destruction of the entangled pairs, rendering them unavailable for further processing. Here we report efficient and non-destructive entanglement purification with atomic quantum bits. Two noisy entangled pairs were created and distilled into one higher-fidelity pair available for further use. Success probabilities were above 35 per cent. The many applications of entanglement purification make it one of the most important techniques in quantum information processing.

Microfabricated surface-electrode ion trap for scalable quantum information processing

Individual laser-cooled 24Mg+ ions are confined in a linear Paul trap with a novel geometry where gold electrodes are located in a single plane and the ions are trapped 40 microm above this plane. The relatively simple trap design and fabrication procedure are important for large-scale quantum information processing (QIP) using ions. Measured ion motional frequencies are compared to simulations. Measurements of ion recooling after cooling is temporarily suspended yield a heating rate of approximately 5 motional quanta per millisecond for a trap frequency of 2.83 MHz, sufficiently low to be useful for QIP.

Use and misuse of aspirin in rural Ethiopia

OBJECTIVES

To investigate ability to distinguish simple analgesics, to document misconceptions about aspirin use, and to identify strategies to diminish potentially harmful aspirin use in Ethiopia.

DESIGN

Qualitative study (eight focus group discussions) used to inform cross-sectional survey.

SETTING

Butajira, a small town in southern Ethiopia, and surrounding rural areas.

PARTICIPANTS

Purposively selected informants for focus groups; random sample of urban and rural residents for cross-sectional survey.

MAIN OUTCOME MEASURES

Ability to distinguish aspirin from paracetamol; proportion using aspirin; proportion aware of common risks of aspirin.

RESULTS

Questionnaires were completed by 204 of the 250 residents sampled (82% response). Three-quarters of survey participants knew the difference between aspirin and paracetamol. Aspirin was used by 7.3% of respondents, and was mainly taken for headache and fever. In focus group discussions there was a suggestion that aspirin was considered particularly useful for children. There was very low awareness of the risks of using aspirin in children (2.5% unprompted, 18.6% prompted) or in people with asthma (1% unprompted, 5.9% prompted). Aspirin is cheap and widely available in urban and rural areas.

CONCLUSION

Awareness of the risks of aspirin use by children and in asthma is extremely low in this rural Ethiopian setting. Medications are purchased with minimal packaging by a population with low literacy. Drug dispensers and vendors must be trained to convey simple verbal warnings about aspirin use.

Use of nicotine replacement therapy and the risk of acute myocardial infarction, stroke, and death

OBJECTIVE

To determine whether nicotine replacement therapy (NRT) is associated with an increased risk of acute myocardial infarction, acute stroke, or death.

DESIGN

Self control case series analysis of data from The Health Improvement Network (THIN) to estimate the relative incidence of myocardial infarction and stroke in four 14 day periods before and after the first prescription for NRT.

SETTING

THIN is a computerised general practice database.

SUBJECTS

Patients contributing data to THIN.

INTERVENTIONS

Observational study of NRT.

MAIN OUTCOMES

Acute myocardial infarction, acute stroke, and death.

RESULTS

33,247 individuals had been prescribed NRT, of whom 861 had had a myocardial infarction and 506 a stroke. There was a progressive increase in the incidence of first myocardial infarction in the 56 days leading up to the first NRT prescription (overall incidence ratio 5.55, 95% confidence interval (CI) 4.42 to 6.98), but the incidence fell after this time and was not increased in the 56 days after starting NRT (incidence ratio 1.27, 95% CI 0.82 to 1.97). The results were similar for second myocardial infarction and stroke, and for subgroups of people with pre-existing angina and hypertension. There were 960 deaths in our cohort during a mean follow up period of 2.6 years after starting NRT, with no evidence of an increased mortality in the 56 days after the NRT prescription (incidence ratio 0.86, 95% CI 0.60 to 1.23).

CONCLUSIONS

The use of NRT is not associated with any increase in the risk of myocardial infarction, stroke, or death.

Vagus nerve stimulation for epilepsy: randomized comparison of three stimulation paradigms

Vagus nerve stimulation (VNS) is an effective adjunctive treatment for intractable epilepsy. However, the optimal range of device duty-cycles [on/(on + off times)] is poorly understood. The authors performed a multicenter, randomized trial of three unique modes of VNS, which varied primarily by duty-cycle. The results indicate that the three duty-cycles were equally effective. The data support the use of standard duty-cycles as initial therapy.

Creation of a six-atom 'Schrödinger cat' state

Among the classes of highly entangled states of multiple quantum systems, the so-called 'Schrödinger cat' states are particularly useful. Cat states are equal superpositions of two maximally different quantum states. They are a fundamental resource in fault-tolerant quantum computing and quantum communication, where they can enable protocols such as open-destination teleportation and secret sharing. They play a role in fundamental tests of quantum mechanics and enable improved signal-to-noise ratios in interferometry. Cat states are very sensitive to decoherence, and as a result their preparation is challenging and can serve as a demonstration of good quantum control. Here we report the creation of cat states of up to six atomic qubits. Each qubit's state space is defined by two hyperfine ground states of a beryllium ion; the cat state corresponds to an entangled equal superposition of all the atoms in one hyperfine state and all atoms in the other hyperfine state. In our experiments, the cat states are prepared in a three-step process, irrespective of the number of entangled atoms. Together with entangled states of a different class created in Innsbruck, this work represents the current state-of-the-art for large entangled states in any qubit system.

Lung function and blood levels of copper, selenium, vitamin C and vitamin E in the general population

BACKGROUND

Increased dietary intake of antioxidants has been associated with higher lung function, but few studies have used biological markers of antioxidant intake.

OBJECTIVE

This study aimed to determine if antioxidant status, as measured by blood levels, influences lung function.

DESIGN

Using a random subsample of 479 participants, aged 18-65 y old, from a larger cross-sectional observational study, the association of forced expiratory volume in 1 s (FEV1) with plasma copper, vitamin C, vitamin E and serum selenium was assessed.

RESULTS

An s.d. increase in blood copper level was associated with a difference in FEV1 of -48 ml (95% confidence intervals: -95, -2 ml, P = 0.04), vitamin C +49 ml (+4, +94, P = 0.03), vitamin E -15 ml (-62, +32, P = 0.53) and selenium +52 ml (+7, +96, P = 0.02). The sizes of association were not appreciably altered in a mutually adjusted model.

CONCLUSIONS

Higher levels of serum vitamin C and selenium appear to be associated with higher FEV1. The association between higher serum copper and lower FEV1 requires further study in view of the ubiquitous exposure to this mineral.

Smoking cessation treatment in primary care: prospective cohort study

OBJECTIVE

To compare the characteristics of smokers who do and do not receive smoking cessation treatment in primary care.

DESIGN

Prospective cohort study using practices registered with the pilot QRESEARCH database.

SETTING

156,550 patients aged 18 years and over from 39 general practices located within four strategic health authorities, representing the former Trent Region, UK.

SUBJECTS

Patients registered with practices between 1 April 2001 and 31 March 2003 aged 18 years and over who were identified as smokers before the two year study period.

OUTCOME

Prescription for smoking cessation treatment (nicotine replacement therapy (NRT) or bupropion) in the two year study period.

VARIABLES

Age, sex, deprivation score, co-morbidity.

RESULTS

Of the 29,492 patients recorded as current smokers at the start of the study period 1892 (6.4%) were given prescriptions for smoking cessation treatment during the subsequent two years. Of these, 1378 (72.8%) were given NRT alone, 406 (21.5%) bupropion alone, and 108 (5.7%) both treatments. Smokers were more likely to receive smoking cessation treatment if they lived in the most deprived areas (odds ratio (OR) for the most relative to the least deprived fifth, adjusted for sex, age, and co-morbidity, 1.50, 95% confidence interval (CI) 1.26 to 1.78), and if they were aged 25-74 years compared to 18-24 years or 75 and over. Smokers with co-morbidity were also more likely to receive smoking cessation treatment. Smokers were less likely to receive smoking cessation treatment if they were male (adjusted OR 0.68, 95% CI 0.62 to 0.75).

CONCLUSION

The low proportion of smokers being prescribed these products strongly suggests that a major public health opportunity to prevent smoking related illness is being missed.