Differential pulse oximetry readings between ethnic groups and delayed transfer to intensive care units.

BACKGROUND: Pulse oximeters are widely used to monitor blood oxygen saturations, although concerns exist that they are less accurate in individuals with pigmented skin. AIMS: This study aimed to determine if patients with pigmented skin were more severely unwell at the period of transfer to intensive care units (ICUs) than individuals with White skin. METHODS: Using data from a large teaching hospital, measures of clinical severity at the time of transfer of patients with COVID-19 infection to ICUs were assessed, and how this varied by ethnic group. RESULTS: Data were available on 748 adults. Median pulse oximetry demonstrated similar oxygen saturations at the time of transfer to ICUs (Kruskal-Wallis test, P = 0.51), although median oxygen saturation measurements from arterial blood gases at this time demonstrated lower oxygen saturations in patients classified as Indian/Pakistani ethnicity (91.6%) and Black/Mixed ethnicity (93.0%), compared to those classified as a White ethnicity (94.4%, Kruskal-Wallis test, P = 0.005). There were significant differences in mean respiratory rates in these patients (P < 0.0001), ranging from 26 breaths/min in individuals with White ethnicity to 30 breaths/min for those classified as Indian/Pakistani ethnicity and 31 for those who were classified as Black/Mixed ethnicity. CONCLUSIONS: These data are consistent with the hypothesis that differential measurement error for pulse oximeter readings negatively impact on the escalation of clinical care in individuals from other than White ethnic groups. This has implications for healthcare in Africa and South-East Asia and may contribute to differences in health outcomes across ethnic groups globally.

Access to a piped water supply is positively associated with haemoglobin levels in females living in rural Maharashtra State, India.

OBJECTIVES: There is a high prevalence of anaemia in individuals living in rural India, which may be modified by a number of environmental factors. The association between access to water, toileting facilities and healthcare services with the prevalence of anaemia was explored to determine potentially modifiable community-level risk factors. STUDY DESIGN: This was a cross-sectional survey. METHODS: Data were collected from adolescent females (aged 13-17 years) living in 34 villages in rural areas of the Maharashtra state of India on measures of sanitation facilities and access to health care along with haemoglobin measurements. Linear and logistic regression analyses were conducted to investigate associations between environmental (community) factors and adolescent haemoglobin levels and anaemia, respectively. RESULTS: Data were available from 1010 individuals, which represented a response rate of over 97% of those who were approached for the study. The prevalence of anaemia was very high (87%) when measured using haemoglobin levels. Access to a piped water supply was associated with 0.59 g/dL of increase in haemoglobin levels (95% confidence interval: 0.10-1.09). Associations between access to communal toilets, travel time to the hospital, health centres or nurses and haemoglobin levels or anaemia were not statistically significant. CONCLUSIONS: Anaemia prevalence was very high in our study population. Simple improvements such as provision of regular piped water is associated with an increase in haemoglobin levels in rural Indian females. These are consistent with the hypothesis that chronic exposure to higher levels of microbes in the living environment contributes to the risk of anaemia.

Mortality rates immediately after severe hurricanes in Cuba have decreased over the past three decades.

OBJECTIVES: The objective of this study is to understand how Cuba responds to extreme weather events, which can help identify and disseminate good public health practice. STUDY DESIGN: The study design of this study is an observational study using routinely collected mortality data. METHODS: National daily mortality counts after severe hurricanes arrived on the Cuba landmass since 1990 were compared with baseline values. Incidence rate ratios of mortality during the hurricane and for the four weeks afterwards were calculated for four eligible hurricanes: Georges (1998), Dennis (2005), Ike (2008) and Irma (2017). RESULTS: Mortality rates decreased over time (P < 0.001 for interaction), and no excess mortality counts were observed after Hurricane Irma in 2017. CONCLUSIONS: Mortality rates for severe hurricanes that have made landfall in Cuba have decreased over three decades, despite the most recent hurricane (Irma) being one of the strongest observed in recent decades. This suggests that the Cuban public health preparations and responses to recent severe hurricanes are probably contributing to this mitigation in national mortality rates during these periods.

Two measures of systemic inflammation are positively associated with haemoglobin levels in adolescent girls living in rural India: a cross-sectional study.

OBJECTIVE: This study tested the hypothesis that systemic inflammation is inversely associated with haemoglobin levels in adolescent girls in India. METHODS: The study population consisted of adolescent girls aged between 10 and 19 years living in a remote rural region in Maharashtra State, India. Data were collected on anthropometric measures, and a venous blood sample was taken and tested for complete blood count and C-reactive protein (CRP). RESULTS: Of 679 individuals who were invited to the research site to participate, data were available from 401 participants giving a response rate of 59%. Median blood CRP was 1.26 mg/l (Range 0.00 to 26.33), and 167 (41.6%) participants had CRP level < 1.0 mg/l. The mean haemoglobin was 12.24 g/dl (standard deviation [SD] 1.51), and the mean total white blood cells (WBC) count was 9.02 × 103 /µl (SD 2.00). With each g/dl increase in blood haemoglobin, the risk of having an elevated CRP of ≥ 1 mg/l increased with an odds ratio of 1.16 (95% CI 1.01 to 1.33, P = 0.03). Total WBC count was also positively associated with blood haemoglobin, increasing by 0.24 × 103 /µl (95% CI 0.11 to 0.37, P < 0.001) per g/dl increase in haemoglobin. Both analyses were adjusted for age. CONCLUSIONS: In this population, blood haemoglobin levels were positively associated with two measures of systemic inflammation, contrary to the primary hypothesis being tested. Other unmeasured environmental exposures may modify haemoglobin levels in this population. Understanding this observation may help design better public health interventions to improve the well-being of adolescent girls in India.

OBJECTIF: Cette étude a testé l'hypothèse selon laquelle l'inflammation systémique est inversement associée aux taux d'hémoglobine chez les adolescentes en Inde. MÉTHODES: La population étudiée était composée d'adolescentes âgées de 10 à 19 ans vivant dans une région rurale éloignée de l'Etat du Maharashtra, en Inde. Les données ont été collectées sur des mesures anthropométriques et un échantillon de sang veineux a été prélevé et testé pour la formule globulaire complète et la protéine C-réactive (CRP). RÉSULTATS: Sur 679 personnes qui ont été invitées au site de recherche à participer, des données étaient disponibles pour 401 participantes, soit un taux de réponse de 59%. La CRP sanguine médiane était de 1,26 mg/L (intervalle de 0,00 à 26,33) et 167 participantes (41,6%) avaient un taux de CRP <1,0 mg/L. L'hémoglobine moyenne était de 12,24 g/dL (écart-type [ET] 1,51), et le nombre moyen total de globules blancs (GB) était de 9,02 x103 /µL (ET 2,00). Avec chaque augmentation par g/dL de l'hémoglobine sanguine, le risque d'avoir une CRP élevée ≥1 mg/L augmentait avec un rapport de cotes de 1,16 (IC95%: 1,01 à 1,33, p = 0,03). La numération totale des GB était également positivement associée à l'hémoglobine sanguine, augmentant de 0,24 x103 /µL (IC95%: 0,11 à 0,37, p <0,001) par g/dL d'augmentation de l'hémoglobine. Les deux analyses ont été ajustées en fonction de l'âge. CONCLUSIONS: Dans cette population, les taux d'hémoglobine sanguine étaient positivement associés à deux mesures de l'inflammation systémique, contrairement à l'hypothèse principale testée. D'autres expositions environnementales non mesurées peuvent modifier les taux d'hémoglobine dans cette population. Comprendre cette observation peut aider à concevoir de meilleures interventions de santé publique pour améliorer le bien-être des adolescentes en Inde.

Patients' attitudes towards cost feedback to doctors to prevent unnecessary testing: a qualitative focus group study.

OBJECTIVES: There is a need to improve efficiency in healthcare delivery without compromising quality of care. One approach is the development and evaluation of behavioural strategies to reduce unnecessary use of common tests. However, there is an absence of evidence on patient attitudes to the use of such approaches in the delivery of care. Our objective was to explore patient acceptability of a nudge-type intervention that aimed to modify blood test requests by hospital doctors. STUDY DESIGN: Single-centre qualitative study. METHODS: The financial costs of common blood tests were presented to hospital doctors on results reports for 1 year at a hospital. Focus group discussions were conducted with recent inpatients at the hospital using a semi-structured question schedule. Discussions were transcribed and analysed using qualitative content analysis to identify and prioritise common themes explaining attitudes to the intervention approach. RESULTS: Three focus groups involving 17 participants were conducted. Patients were generally apprehensive about the provision of blood test cost feedback to doctors. Attitudes were organised around themes representing beliefs about blood tests, the impact on doctors and their autonomy, and beliefs about unnecessary testing. Patients thought that blood tests were important, powerful and inexpensive, and cost information could place doctors under additional pressure. CONCLUSION: The findings identify predominantly positive beliefs about testing and negative attitudes to the use of financial costs in the decision-making of hospital doctors. Public discussion and education about the possible overuse of common tests may allow more resources to be allocated to evidence-based healthcare, by reducing the perception that such strategies to improve healthcare efficiency negatively impact on quality of care.

Prevalence of and factors associated with Helicobacter pylori infection in preschoolers in Havana, Cuba: A population-based study. / Prevalencia y factores asociados a infección por Helicobacter pylori en preescolares de La Habana, Cuba. Estudio de base poblacional.

INTRODUCTION: Helicobacter pylori (H. pylori) infection is usually acquired in childhood. In Cuba, its study in pediatric ages is a little explored field. AIM: To identify the prevalence of the infection and its associated risk factors in 3-year-old children in Havana. MATERIALS AND METHODS: An analytic, cross-sectional, epidemiologic analysis was conducted on 1,274 children belonging to the cohort of participants in the Natural History of Wheezing in Cuba study (HINASIC for its Spanish acronym) that were 3 years of age and provided a stool sample. H. pylori infection was identified by determining the H. pylori antigen (Ag) in stool, utilizing the commercial Spinreact kit, from Spain. The data were collected through a questionnaire applied by the researchers that included sociodemographic, environmental, and lifestyle variables, as well as infection from other parasites. Prevalence and the prevalence ratio with a 95% confidence interval were calculated and the dichotomous logistic regression analysis was employed. RESULTS: The prevalence of positive H. pylori Ag was 5%. Sleeping together was the risk factor found (PR:1.27; 95% CI: 1.03-1.50). Protective factors were drinking water from water delivery trucks (PR: 0.16; 95% CI: 0.04-0.72) and living in a nuclear family unit (PR: 0.94; 95% CI: 0.85-0.99). CONCLUSIONS: The prevalence of H. pylori infection in early childhood places Havana in an intermediate position at the international level. To control the infection, causal studies should be conducted and opportune interventions implemented.

Prevalence and risk factors for initiating tobacco and alcohol consumption in adolescents living in urban and rural Ethiopia.

OBJECTIVES: African countries are potential high growth markets for the alcohol and tobacco industries. This study aimed to identify exposures that are associated with initiating use of alcohol and tobacco products in young people living in Ethiopia. As televised football and Internet viewing are media through which products can be promoted to this population efficiently, these risk factors were of particular interest. STUDY DESIGN: This is a cross-sectional study. METHODS: Data were collected using a self-administered questionnaire of 3967 children aged 13-19 years in 20 high schools in urban and rural Ethiopia on consumption and risk factors for alcohol and tobacco use in 2016, as well as exposure to potential sources of advertising. RESULTS: Eight percent of respondents reported having ever smoked and 3% were current smokers. Twenty-nine percent reported ever having used alcohol, and 14% were current users. Risk factors for ever smoking included father smoking (odds ratio [OR] 1.95; 95% confidence interval [CI]: 1.21 to 3.15), mother smoking (OR 3.90; 95% CI: 1.63 to 9.33), best friend smoking (OR 5.86; 95% CI: 4.31 to 7.96) and home Internet access (OR 1.75; 95% CI: 1.35 to 2.27). There was a very strong positive association between ever having smoked cigarettes and ever having tried alcohol (P < 0.001). Risk factors for currently drinking alcohol included father drinking (OR 1.45; 95% CI: 1.05 to 2.01), mother drinking (OR 2.00; 95% CI: 1.44 to 2.77), home Internet access (OR 1.53; 95% CI: 1.24 to 1.90) and regular watching of televised football (OR 2.44 compared to those who do not; 95% CI: 1.58 to 3.78). CONCLUSIONS: As in rich countries, tobacco and alcohol use among Ethiopian teenagers increases among those exposed to family and peer use but are also more common among those accessing the Internet and, for alcohol, those watching televised football. The effect of watching televised football on alcohol use, at least, is likely to be due to exposure to advertising.

What is the association between price and economic activity with cigarette consumption in Cuba from 1980 to 2014?

OBJECTIVES: Cuba is a tobacco-producing country that has been economically isolated as a consequence of an embargo imposed by the USA. It has also experienced a severe economic depression in the 1990s after the withdrawal of support by the former Soviet Union. These characteristics provide a unique opportunity to study the relation between large changes in economic activity, cigarette price and demand for cigarettes in a relatively isolated socialist economy. STUDY DESIGN: This is an observational epidemiological study. METHODS: Data were obtained on the annual price of a packet of cigarettes and the mean number of cigarettes consumed per adult living in Cuba from 1980 to 2014. Descriptive and regression analysis were used to explore the relationship between cigarette consumption and price in Cuba. RESULTS: In 1980, the mean price of a packet of cigarettes was 1.53 Cuban peso (CUP) in 1997 prices and the mean annual per capita consumption was 2237 cigarettes. In 2014, the mean price had increased to 5.57 CUP (1997 prices) per packet of cigarettes, and consumption had fallen to 1527 cigarettes per capita. There were significant negative associations between annual cigarette consumption and both price and living through an economic depression. The elasticity was approximately -0.31 with price, and living through an economic depression was also associated with lower consumption of cigarettes (a reduction of 9%, 95% confidence intervals -0.18 to -0.001). CONCLUSIONS: Higher cigarette pricing, along with other public health interventions, are required to protect the national population from the adverse effects of tobacco smoke exposure.

Risk factors for maternal anaemia and low birth weight in pregnant women living in rural India: a prospective cohort study.

OBJECTIVE: The aim of this prospective study was to estimate the prevalence and risk factors for maternal anaemia and low birth weight (LBW) in pregnant women living in Maharashtra state, India. STUDY DESIGN: This is a prospective study. METHODS: Women between 3 and 5 months of pregnancy were recruited from 34 villages based in Maharashtra state. Baseline data collection, anthropometric measurements and blood investigations were performed. Participants were followed-up to record birth weight. RESULTS: In total, 303 women were eligible, and 287 (95%) provided data. 77% were anaemic, defined as haemoglobin less than 11.0 g/dl at the time of recruitment, with a mean corpuscular volume of 80.5 fl/cell (standard deviation: 7.22, range: 53.4-93.8). The increased risk of anaemia was seen in women with consanguineous marriages (odds ratio [OR]: 2.41, 95% confidence interval [CI]: 1.16-5.01, P = 0.01) after adjustment for potential confounding factors. Postdelivery data from full-term singleton live births demonstrated a 7% prevalence of LBW. Consanguineous marriage was a major risk factor for LBW (OR: 4.10, 95% CI: 1.25-13.41, P = 0.02). The presence of maternal anaemia during 3-5 months of pregnancy was associated with lower risk of LBW (unadjusted OR: 0.34, 95% CI: 0.13-0.92, P = 0.03). CONCLUSION: About 30% of our study participants were in a consanguineous marriage, which was identified as a potentially avoidable risk factor for both anaemia and LBW.

Household air pollution and lung function in Indian adults: a cross-sectional study.

Exposure to air pollution produced by cooking is common in developing countries, and represents a potentially avoidable cause of lung disease. Cross-sectional data were collected by the World Health Organization's Study on Global AGEing and Adult Health conducted in India between 2007 and 2010. Exposure to biomass cooking was also associated with a decrease in forced expiratory volume in 1 s (FEV1) (-70 ml, 95%CI -111 to -30) and FEV1/FVC (forced vital capacity) ratio (-0.025, 95%CI -0.035 to -0.015) compared to those who were not exposed. These associations were predominantly observed in males (P < 0.05 for interaction analyses). Intervention studies using non-biomass fuels in India are required to ascertain potential respiratory health benefits.

Prevalence of iron-deficiency anaemia and risk factors in 1010 adolescent girls from rural Maharashtra, India: a cross-sectional survey.

OBJECTIVE: Iron-deficiency anaemia (IDA) is the most common nutritional disorder observed in adolescent girls in India. Our aim was to investigate the prevalence and risk factors associated with IDA in rural Maharashtra, India, to address current evidence gaps. STUDY DESIGN: Cross-sectional survey. METHODS: The study recruited 13- to 17-year-old adolescent girls living in 34 villages of Osmanabad district. Data were collected on individual health, dietary, sociodemographic factors, and anthropometric measurements were taken. Haemoglobin (Hb) levels were measured using Sahli's haemometer. Logistic and linear regressions were used to identify risk factors associated with IDA and Hb levels, respectively. RESULTS: Among 1010 adolescent girls (response rate 97.5%), the mean Hb was 10.1 g/dl (standard deviation = 1.3), and 87% had anaemia (Hb < 12 g/dl). The prevalence of mild (11.0-11.9 g/dl), moderate (8.0-10.9 g/dl) and severe (Hb ≤ 7.9 g/dl) anaemia was 17%, 65% and 5%, respectively. Anaemia likelihood increased significantly with age (odds ratio (OR): 1.41 per year, 95% confidence interval (CI): 1.17-1.70). Factors associated with decreased anaemia risk were mid-upper arm circumference (MUAC) ≥22 cm (OR: 0.51, 95% CI: 0.31-0.82), ≥3 days/week consumption of fruit (OR: 0.35, 95% CI: 0.23-0.54) or rice (OR: 0.39, 95% CI: 0.17-0.91), and incomplete schooling (OR: 0.47, 95% CI: 0.24-0.91). In the final model lower age, MUAC and fruit consumption were significantly associated with Hb level. CONCLUSION: Anaemia prevalence was extremely high among adolescent girls in rural areas of Maharashtra. Whilst we identified risk factors that could be used for targeting interventions, there is urgent need of comprehensive preventative interventions for the whole adolescent girl population.

What have studies of non-industrialized countries told us about the cause of allergic disease?

The increase in allergic diseases that was observed in countries that had experienced rapid economic growth since the mid-20th century initiated a search for environmental exposures that may explain these phenomena that continues to the present day. Societies that are in the earlier stages of the process of industrialization provide an opportunity to compare the initial stages of economic development and the lifestyle changes that may accompany this, with other communities whose way of life may not have changed appreciably for centuries. These studies have consistently demonstrated higher levels of allergic disease in the relatively affluent populations compared with those who maintain a more traditional lifestyle. Environmental changes that have emerged from these studies that may modify the risk of allergic disease include microbial exposures including parasite infection, pollution, diet and obesity. In addition, food and drug allergies represent a neglected area of research in these countries that may be causing a relatively high burden of disease.

The UK prevalence of hereditary haemorrhagic telangiectasia and its association with sex, socioeconomic status and region of residence: a population-based study.

BACKGROUND: Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant genetic disorder of aberrant blood vessel development characterised by arteriovenous malformations. HHT is associated with significant morbidity due to complications including epistaxis, gastrointestinal bleeding and stroke. We explored the hypothesis that a diagnosis of HHT is associated with sex, socioeconomic status and geographical location. METHODS: We used The Health Improvement Network, a longitudinal, computerised general practice database covering 5% of the UK population to calculate prevalence estimates for HHT stratified by age, sex, socioeconomic status and geographical location. RESULTS: The 2010 UK point prevalence for HHT was 1.06/10 000 person years (95% CI 0.95 to 1.17) or 1 in 9400 individuals. The diagnosed prevalence of HHT was significantly higher in women compared with men (adjusted prevalence rate ratio (PRR) 1.53, 95% CI 1.24 to 1.88) and in those from the most affluent socioeconomic group compared with the least (adjusted PRR 1.74, 95% CI 1.14 to 2.64). The PRR varied between different regions of the UK, being highest in the South West and lowest in the West Midlands (adjusted PRR for former compared with latter 1.86, 95% CI 1.61 to 2.15). CONCLUSIONS: HHT prevalence is more common in the UK population than previously demonstrated, though this updated figure is still likely to be an underestimate. HHT appears to be significantly under-diagnosed in men, which is likely to reflect their lower rates of consultation with primary care services. There is under-diagnosis in patients from lower socioeconomic groups and a marked variation in the prevalence of diagnosis between different geographical regions across the UK that requires further investigation.

Risk factors for wheezing in infants born in Cuba.

BACKGROUND: Cuba is a unique country, and despite limited economic development, has an excellent health system. However, the prevalence of asthma symptoms in children in Havana, Cuba, is unusually high. AIM: As early life exposures are critical to the aetiology of asthma, we have studied environmental influences on the risk of wheezing in Cuban infants. DESIGN: Cross-sectional study. METHODS: A random sample of 2032 children aged 12-15 months living in Havana was selected for inclusion in the cohort. Data were collected using questionnaires administered by researchers. RESULTS: Of 2032 infants invited to participate, 1956 (96%) infants provided data. The prevalence of any wheeze was 45%, severe wheeze requiring use of emergency services was 30% and recurrent wheeze on three or more occasions was 20%. The largest adjusted risk factors for any wheeze were presence of eczema [odds ratio (OR) 2.09; 95% confidence interval (CI) 1.48-2.94], family history of asthma (OR 2.05; 95% CI 1.60-2.62), poor ventilation in the house (OR 1.99; 95% CI 1.48-2.67), attendance at nursery (OR 1.78; 95% CI 1.24-2.57), male sex (OR1.52; 95% CI 1.19-1.96) and the number of smokers in the house (P < 0.03 for trend), OR 1.64 (95% CI 1.17-2.31) for three or more smokers in the house compared to no smokers in the household. CONCLUSION: We have identified several risk factors for any wheeze in young infants living in modern day Cuba. As the prevalence of smoking in the house is high (51%), intervention studies are required to determine effective strategies to improve infant health.

A natural experiment on the impact of fruit supplementation on asthma symptoms in children.

A high fruit intake may reduce the risk of asthma. The English National School Fruit Scheme was introduced in the East Midlands region of the UK in June 2003 and in the Eastern region in September 2004. Questionnaires were distributed to children aged 4-6 yrs in schools in May 2003. This was repeated in May 2004 when those in the East Midlands had received free fruit for 1 yr and those in the Eastern region had not. Responses were obtained in 2004 for 4,971 (53%) and 5,770 (54%) children in the intervention and control regions, respectively. Despite an increase in fruit consumption in the intervention compared with the control region between 2003 and 2004, there was no difference between the two regions in the prevalence or severity of asthma symptoms after 1 yr of fruit supplementation (odds ratio for wheeze in the past 12 months in intervention compared with control region 1.00, 95% confidence interval 0.88-1.14). Providing free fruit at school for 1 yr does not have any immediate effect on prevalence or severity of asthma in young children, although these data do not refute the hypothesis that a higher increase in fruit intake improves measures of asthma control.

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.

Secondhand smoke, dietary fruit intake, road traffic exposures, and the prevalence of asthma: a cross-sectional study in young children.

The authors have investigated the independent effects of exposure to secondhand smoke, road vehicle traffic, and dietary fruit intake in a cross-sectional study of asthma in young children. They surveyed all children aged 4-6 years in 235 schools in the East Midlands and East of England regions of the United Kingdom in 2003. Data on respiratory symptoms, diagnoses and treatment, smoking in the home, and dietary fruit intake were collected by parental questionnaire. A geographic information system was used to map postcodes and determine the distance of the home from the nearest main road. Responses were obtained from 11,562 children. Wheeze in the past year and physician-diagnosed asthma were reported by 14.1% and 18.2%, respectively. Both of these outcomes were more common in children who lived with a smoker, and the prevalence of asthma increased with the number of smokers in the home. Asthma prevalence was not associated with proximity of the home to a main road or with dietary fruit intake. The authors conclude that, of the potential risk factors considered in this study, preventing secondhand smoke exposure may be the most effective way of preventing asthma.