Dietary intake, physical activity, body mass index, and childhood asthma in the Third National Health And Nutrition Survey (NHANES III)

The association of objectively measured sedentary time with asthma in US youth: A glimpse into the connection between obesity and asthma

BACKGROUND

Evidence suggests that asthma and obesity may share a common pathway, possibly through an increase in inflammation. Sedentary time is thought to promote both inflammation and obesity and previous studies have found a relationship between self-reported sedentary and asthma. However, the relationship between objectively measured sedentary time and asthma is not well described. We hypothesized that the association between asthma and sedentary time would not be present when physical activity was measured objectively, nor would objectively-measured sedentary time play an important role in the relationship between asthma and obesity.

OBJECTIVE

To determine if there is an association between asthma and objectively measured sedentary time in a large, nationally representative sample of the United States youth.

METHODS

Using the National Health and Nutrition Examination Survey 2003-2006, we assessed the relationship between asthma and sedentary time using objectively measured and self-reported measures of sedentary time, in 6-19 years-old subjects with available accelerometry data. We used multivariate logistic regression analysis to determine associations between the risk of asthma and sedentary time controlling for accelerometer wear time, gender, age, race/ethnicity, body mass index percentile, and moderate-to-vigorous physical activity (MVPA).

RESULTS

In this cohort, youth with asthma self-reported more time in sedentary behavior, specifically computer time, than those without asthma (p = 0.01). However, when sedentary time was measured objectively by accelerometry, sedentary time did not differ between youth with and without asthma (421 min [standard deviation 4.2] versus. 414 min [standard deviation 7.8] [p = 0.38]). Controlling for measures of activity, such as MVPA, or time spent in long versus short bouts of sedentary time did not modify our results.

CONCLUSIONS

Differences in sedentary time by self-report between those with and without asthma were not born out by examining sedentary time using objective measures. Further work is necessary to examine the complex interaction among inactivity, obesity, and asthma over time, specifically focusing on whether the type of sedentary activity (e.g., computer vs. television time) is important.

The Role of Nutritional Factors in Asthma: Challenges and Opportunities for Epidemiological Research

The prevalence of asthma has nearly doubled over the last decades. Twentieth century changes in environmental and lifestyle factors, including changes in dietary habits, physical activity and the obesity epidemic, have been suggested to play a role in the increase of asthma prevalence and uncontrolled asthma worldwide. A large body of evidence has suggested that obesity is a likely risk factor for asthma, but mechanisms are still unclear. Regarding diet and physical activity, the literature remains inconclusive. Although the investigation of nutritional factors as a whole (i.e., the “diet, physical activity and body composition” triad) is highly relevant in terms of understanding underlying mechanisms, as well as designing effective public health interventions, their combined effects across the life course has not received a lot of attention. In this review, we discuss the state of the art regarding the role of nutritional factors in asthma, for each window of exposure. We focus on the methodological and conceptual challenges encountered in the investigation of the complex time-dependent interrelations between nutritional factors and asthma and its control, and their interaction with other determinants of asthma. Lastly, we provide guidance on how to address these challenges, as well as suggestions for future research.

Obesity in young children and its relationship with diagnosis of asthma, vitamin D deficiency, iron deficiency, specific allergies and flat-footedness: A systematic review and meta-analysis

There is evidence that a number of medical conditions and co-morbidities are associated with obesity in young children. This review explored whether there is evidence of associations with other conditions or co-morbidities. Observational studies of young children (mean age < 10 years) were identified using electronic searches of five databases (MEDLINE, Embase, CINAHL, AMED and SPORTDiscus). Of 27 028 studies screened, 41 (comprising 44 comparisons) met the inclusion criteria. These studies provided data on five distinct diseases/conditions: asthma (n = 16), vitamin D deficiency (n = 10), iron deficiency (n = 10), allergies (n = 4) and flat-footedness (n = 4). Thirty-two studies were appropriate for meta-analysis using random-effects models, and revealed obesity was significantly associated with having asthma (OR 1.5, 95% CI 1.3-1.7), vitamin D deficiency (OR 1.9, 95% CI 1.4-2.5) and iron deficiency (OR 2.1, 95% CI 1.4-3.2). Heterogeneity (I2 ) ranged from 57% to 61%. Narrative synthesis was conducted for all studies. There was no evidence of a consistent association between obesity in young children and eczema, dermatitis or rhinitis due to the low number of studies. However, there was an association with flat-footedness. These results have implications for health policy and practice and families. Further research leading to a greater understanding of the associations identified in this review is suggested.

A computer-based incentivized food basket choice tool: Presentation and evaluation

Objective

To develop and evaluate a low-cost computer-based tool to elicit dietary choices in an incentive compatible manner, which can be used on-line or as part of a laboratory study.

Methods

The study was conducted with around 255 adults. Respondents were asked to allocate a fixed monetary budget across a choice of around a hundred grocery items with the prospect of receiving these items with some probability delivered to their home by a real supermarket. The tool covers a broad range of food items, allows inference of macro-nutrients and calories, and allows the researcher to fix the choice set participants can choose from. We compare the information derived from our incentivized tool, and compare it to alternative low-cost ways of measuring dietary intake, namely the food frequency questionnaire and a one-shot version of the 24-hour dietary recall, which are both based on self-reports. We compare the calorie intake indicators derived from each tool with a number of biometric measures for each subject, namely weight, body-mass-index (BMI) and waist size.

Results

The results show that the dietary information collected is only weakly correlated across the three methods. We find that only the calorie intake measure from our incentivized tool is positively and significantly related to each of the biometric indicators. Specifically, a 10% increase in calorie intake is associated with a 1.5% increase in BMI. By contrast, we find no significant correlations for either of the two measures based on self-reports.

Conclusion

The computer-based tool is a promising new, low-cost measure of dietary choices, particularly in one-shot situations where such behaviours are only observed once, whereas other tools like 24-hour dietary recalls and food frequency questionnaires may be more suited when they are administered repeatedly. The tool may be useful for research conducted with limited time and budget.

Time-Dependent Associations Between Body Composition, Physical Activity, and Current Asthma in Women: A Marginal Structural Modeling Analysis

The role of obesity in adult asthma is well-known and has been partly attributed to a confounding role of physical inactivity. However, the interrelationships between obesity, physical activity, and asthma have been incompletely addressed, probably because their time-dependent and bidirectional nature represents a methodologically challenging research question. We aimed to estimate the independent causal effects of body mass index (BMI; weight (kg)/height (m)2) and physical activity on current asthma using marginal structural models (MSMs). MSMs were applied to 15,353 adult women from a 2011 case-control study of asthma (Asthma-E3N) nested within the French E3N study (Etude Epidémiologique auprès de Femmes de la Mutuelle Générale de l'Education Nationale). Three time periods (1997-2000-2002, 2000-2002-2005, and 2002-2005-2011) were defined, where exposures (BMI and physical activity) were measured at time t, outcome (current asthma) was measured at time t + 1, and covariates were measured at time t - 1 or at baseline. A strong significant and positive dose-response relationship between BMI and current asthma was observed (odds ratios were 0.90 (95% confidence interval (CI): 0.79, 1.03), 1.29 (95% CI: 1.17, 1.42), and 1.87 (95% CI: 1.60, 2.18) for the BMI groups <20.0, 25.0-29.9, and ≥30.0, respectively, versus the normal-weight group (BMI 20.0-24.9)). We found no association between physical activity and current asthma. Our results suggest an independent causal deleterious effect of overweight and obesity on current asthma, whereas no independent causal effect of physical activity was found.

Obesity, Asthma, and Exercise in Child and Adolescent Health

Obesity increases the risk of asthma throughout life but the underlying mechanisms linking these all too common threats to child health are poorly understood. Acute bouts of exercise, aerobic fitness, and levels of physical activity clearly play a role in the pathogenesis and/or management of both childhood obesity and asthma. Moreover, both obesity and physical inactivity are associated with asthma symptomatology and response to therapy (a particularly challenging feature of obesity-related asthma). In this article, we review current understandings of the link between physical activity, aerobic fitness and the asthma-obesity link in children and adolescents (e.g., the impact of chronic low-grade inflammation, lung mechanics, and direct effects of metabolic health on the lung). Gaps in our knowledge regarding the physiological mechanisms linking asthma, obesity and exercise are often compounded by imprecise estimations of adiposity and challenges of assessing aerobic fitness in children. Addressing these gaps could lead to practical interventions and clinical approaches that could mitigate the profound health care crisis of the increasing comorbidity of asthma, physical inactivity, and obesity in children.

Childhood asthma and physical activity: a systematic review with meta-analysis and Graphic Appraisal Tool for Epidemiology assessment

BACKGROUND

Childhood asthma is a global problem affecting the respiratory health of children. Physical activity (PA) plays a role in the relationship between asthma and respiratory health. We hypothesized that a low level of PA would be associated with asthma in children and adolescents. The objectives of our study were to (1) summarize the evidence available on associations between PA and asthma prevalence in children and adolescents and (2) assess the role of PA in new-onset or incident asthma among children and adolescents.

METHODS

We searched Medline, the Cochrane Library, and Embase and extracted data from original articles that met the inclusion criteria. Summary odds ratios (ORs) and confidence intervals (CIs) were used to express the results of the meta-analysis (forest plot). We explored heterogeneity using funnel plots and the Graphic Appraisal Tool for Epidemiology (GATE).

RESULTS

We retrieved 1,571 titles and selected 11 articles describing three cohort and eight cross-sectional studies for inclusion. A meta-analysis of the cohort studies revealed a risk of new-onset asthma in children with low PA (OR [95 % CI] 1.32 [0.95; 1.84] [random effects] and 1.35 [1.13; 1.62] [fixed effects]). Three cross-sectional studies identified significant positive associations between childhood asthma or asthma symptoms and low PA.

CONCLUSIONS

Children and adolescents with low PA levels had an increased risk of new-onset asthma, and some had a higher risk of current asthma/or wheezing; however, there was some heterogeneity among the studies. This review reveals a critical need for future longitudinal assessments of low PA, its mechanisms, and its implications for incident asthma in children. The systematic review was prospectively registered at PROSPERO (registration number: CRD42014013761; available at: http://www.crd.york.ac.uk/PROSPERO [accessed: 24 March 2016]).

Promoting an obesity education program among minority patients in a single urban pediatric Emergency Department (ED)

Background

The purpose of this study was to assess the feasibility of the Emergency Department (ED) as a place for obesity education and to evaluate its impact on patient’s lifestyle modification.

Methods

In this study, children between 8 and 18 years of age, who presented to the ED for non-urgent reasons in a single urban hospital, were enrolled. Parents’ perception of their child’s diet and exercise were assessed prior to the intervention. Both parents and children attended a brief audio-visual presentation that provided educational information on age-appropriate diet and exercise. Following the intervention, the participants were asked about their impressions regarding the ED as a place to receive obesity education and whether they plan to make any changes in diet and exercise.

Results

One hundred children and their parents participated in this study. Of these, 76 were Latino and 21 were African-Americans. The mean age was 14 years, and the mean body mass index (BMI) was 25.6. Following the intervention, 21 (100 %) of the African-American parents and 73 (98.6 %) of the Latino parents felt that the ED should provide obesity education. Eighteen (85.7 %) of the African-American parents and 72 (97.3 %) of the Latino parents planned to make changes in their child’s diet and exercise. Among the children, 21 (100 %) of African-American participants and 76 (100 %) of Latino participants reported that they found the audio-visual useful. Seventeen (81.0 %) of the African-American children and 73 (96.1 %) of Latino children stated learning new information from the intervention program.

Conclusions

This study suggests the ED may have a role in primary health promotion and obesity prevention. An ED-based intervention may be used to provide education about obesity prevention and has the potential to impact life style modifications, including diet and exercise.

The association of sedentary lifestyle with childhood asthma. The role of nurse as educator

BACKGROUND

To provide a summary of the existing published knowledge on the association between sedentary lifestyle and childhood asthma. Twelve years ago, the first longitudinal studies carried out in children showed a relationship between physical activity and asthma. Several epidemiological studies confirmed these findings, with sedentary lifestyle predicting the onset of asthma.

METHODS

A systematic review of epidemiological studies was conducted within the MEDLINE database. Epidemiological studies on children subjects, published in English were included in the review. A comprehensive literature search yielded 50 studies for further consideration. Following the application of the eligibility criteria, we identified 11 studies.

RESULTS

A positive association and an excess risk of asthma during childhood were revealed to sedentary lifestyle. The findings proved the association between childhood asthma and sedentary lifestyle. The correlation between bronchial asthma and sedentary life during childhood and identifying whether preventable or treatable risk factors exist needs to be determined. Further research on the topic is essential for safer and standardised conclusions.

CONCLUSIONS AND PRACTICE IMPLICATION

Asthma can be controlled when managed properly. The role of the nurse as an educator should establish and maintain a relationship with patients in order to help them manage their disease. The steps towards asthma management will help paediatric patients to guide their approach to the condition.

Associations between sedentary behaviour and physical activity in children and adolescents: a meta-analysis

Physical activity and sedentary behaviour are associated with metabolic and mental health during childhood and adolescence. Understanding the inter-relationships between these behaviours will help to inform intervention design. This systematic review and meta-analysis synthesized evidence from observational studies describing the association between sedentary behaviour and physical activity in young people (<18 years). English-language publications up to August 2013 were located through electronic and manual searches. Included studies presented statistical associations between at least one measure of sedentary behaviour and one measure of physical activity. One hundred sixty-three papers were included in the meta-analysis, from which data on 254 independent samples was extracted. In the summary meta-analytic model (k = 230), a small, but significant, negative association between sedentary behaviour and physical activity was observed (r = -0.108, 95% confidence interval [CI] = -0.128, -0.087). In moderator analyses, studies that recruited smaller samples (n < 100, r = -0.193, 95% CI = -0.276, -0.109) employed objective methods of measurement (objectively measured physical activity; r = -0.233, 95% CI = -0.330, -0.137) or were assessed to be of higher methodological quality (r = -0.176, 95% CI = -0.215, -0.138) reported stronger associations, although effect sizes remained small. The association between sedentary behaviour and physical activity in young people is negative, but small, suggesting that these behaviours do not directly displace one another.

Physical fitness and amount of asthma and asthma-like symptoms from childhood to adulthood

OBJECTIVE

The potential benefits of physical activity on the development of respiratory symptoms are not well known. The present study investigated the longitudinal association between physical fitness and the development of asthma-like symptoms from childhood to adulthood in a longitudinal community-based study.

METHODS

Participants were assessed at ages 9, 15, 20 and 29 years. Asthma-like symptoms and physical fitness was assessed at each age.

RESULTS

Tracking for physical fitness was high from age 9 to 29 years. Using logistic regression, high physical fitness at age 9 predicted a lower prevalence of asthma-like symptoms at ages 9, 20 and 29 years. Asthma at age 9 and female sex and smoking at any age were also independently associated with the presence of asthma-like symptoms. Our findings suggest that the risk for the development of asthma is reduced by 3% and of asthma-like symptoms reduced by 2% from early adolescence to young adulthood (ages 9-29 years) by increasing the maximal workload with 1 W/kg.

CONCLUSION

This finding provide further evidence of a possible beneficial effect of physical activity in childhood on the development of respiratory symptoms in adulthood and supports the notion that the lower levels of physical activity in recent decades may have contributed to an increase in the prevalence of asthma and asthma-like symptoms.

Physical activity and respiratory symptoms in children: the Generation R Study

BACKGROUND

To assess the relationship between physical activity in second year of life and respiratory symptoms during the pre-school period.

METHODS

This study was embedded in the Generation R Study, a large prospective birth-cohort study in Rotterdam, the Netherlands. Physical activity was measured in the second year of life by an Actigraph accelerometer in a subgroup of 347 children (182 boys, 165 girls; mean age 25.1 months) and data were expressed as counts per 15 sec in categories: light activity (302-614 counts/15 sec), moderate activity (615-1,230 counts/15 sec), and vigorous activity (≥1,231 counts/15 sec). Respiratory symptoms were assessed by the International Study of Asthma and Allergies in Childhood Questionnaire in the third and fourth year of life.

RESULTS

Physical activity levels were not associated with wheezing symptoms in the third and fourth year of life (OR: 0.98; 95% CI: 0.92-1.05 and OR: 0.99; 95% CI: 0.92-1.07 for total activity, respectively), nor associated with shortness of breath symptoms (OR: 0.98; 95% CI: 0.92-1.05 and OR 1.03; 95% CI: 0.96-1.11 for total activity, respectively).

CONCLUSION

These results suggest that physical activity may not play an important role in the development of respiratory symptoms in pre-school children.

Assessing the relationship between obesity and asthma in adolescent patients: a review

The parallel rise in the prevalence of obesity and asthma over the last several decades has led to an extensive line of investigation into the relationship between these two conditions. This review will discuss evidence from laboratory-based studies, observational clinical studies, and clinical trials that suggests that obesity adversely influences asthma through multiple mechanisms. The effect of obesity on asthma during adolescence, including asthma incidence, the severity and control of existing asthma, lung function, and exacerbations, will be reviewed.

Physical activity and asthma: a systematic review and meta-analysis

INTRODUCTION

This review aims to give an overview of available published evidence concerning the association between physical activity and asthma in children, adolescents and adults.

METHODS

We included all original articles in which both physical activity and asthma were assessed in case-control, cross-sectional or longitudinal (cohort) studies. Excluded were studies concerning physical fitness, studies in athletes, therapeutic or rehabilitation intervention studies such as physical training or exercise in asthma patients. Methodological quality of the included articles was assessed according to the Newcastle-Ottawa Scale (NOS).

RESULTS

A literature search was performed until June 2011 and resulted in 6,951 publications derived from PubMed and 1,978 publications from EMBASE. In total, 39 studies met the inclusion criteria: 5 longitudinal studies (total number of subjects n = 85,117) with physical activity at baseline as exposure, and asthma incidence as outcome. Thirty-four cross-sectional studies (n = 661,222) were included. Pooling of the longitudinal studies showed that subjects with higher physical activity levels had lower incidence of asthma (odds ratio 0.88 (95% CI: 0.77-1.01)). When restricting pooling to the 4 prospective studies with moderate to good study quality (defined as NOS≥5) the pooled odds ratio only changed slightly (0.87 (95% CI: 0.77-0.99)). In the cross-sectional studies, due to large clinical variability and heterogeneity, further statistical analysis was not possible.

CONCLUSIONS

The available evidence indicates that physical activity is a possible protective factor against asthma development. The heterogeneity suggests that possible relevant effects remain hidden in critical age periods, sex differences, or extremes of levels of physical activity (e.g. sedentary). Future longitudinal studies should address these issues.

Associations of intake of antioxidant vitamins and fatty acids with asthma in pre-school children

OBJECTIVE

Increasing childhood asthma rates may be due to changing dietary lifestyle. We investigated the association of dietary intake of antioxidant vitamins and fatty acids with asthma in Japanese pre-school children.

DESIGN

Cross-sectional study.

SETTING

School-based survey on lifestyle/diet and health status in children in Japan.

SUBJECTS

Parents of 452 children aged 3-6 years completed a questionnaire on the children's and parents’ lifestyle and demographics. Children were classified into asthma cases and non-asthma cases in accordance with the ATS-DLD(American Thoracic Society and Division of Lung Diseases of the National Heart, Lung, and Blood Institute) questionnaire. Children's diet was assessed using a 3 d dietary record completed by parents. Children's age, sex, BMI, history of food allergy, maternal age, parental history of allergy, maternal education,family size and second-hand smoking were included as covariates. Logistic regression models were used to examine the association between children's diet and asthma.

RESULTS

Compared with children with the lowest intake tertile for vitamin C and vitamin E, those in the highest were significantly inversely associated with asthma; adjusted OR (95% CI) were 0?35 (0?14, 0?88) and 0?32 (0?12, 0?85),respectively. A statistically significant trend was also observed. Fruit intake showed an inverse but insignificant association with asthma. There were no associations of any type of fatty acids with asthma.

CONCLUSIONS

These data suggest that children with high intakes of vitamins C and E may be associated with a reduced prevalence of asthma.

The Relationship between Asthma and Obesity in Urban Early Adolescents

Asthma and obesity, which have reached epidemic proportions, impact urban youth to a great extent. Findings are inconsistent regarding their relationship; no studies have considered asthma management. We explored the association of obesity and asthma-related morbidity, asthma-related health care utilization, and asthma management in urban adolescents with uncontrolled asthma. We classified 373 early adolescents (mean age=12.8 years; 82% Hispanic or Black) from New York City public middle schools into 4 weight categories: normal (body mass index [BMI]<85th percentile); overweight (85th percentile≤BMI<95th percentile); obese (95th percentile≤BMI<97th percentile); and very obese (BMI≥97th percentile). We compared sample obesity prevalence to national estimates, and tested whether weight categories predicted caregiver reported asthma outcomes, adjusting for age and race/ethnicity. Obesity prevalence was 37%, with 28% of the sample being very obese; both rates were significantly higher than national estimates. We found no significant differences in asthma-related health care utilization or asthma management between weight categories, and a few differences in asthma-related morbidity. Relative to normal weight and obese youth, overweight youth had higher odds of never having any days with asthma-related activity limitations. They also had higher odds of never having asthma-related school absences compared with obese youth. Overweight youth with asthma-related activity limitations had more days with limitations compared with normal weight youth. Overweight, but not obese youth, missed more school due to asthma than normal weight youth. Overweight and obesity prevalence was very high in urban, Hispanic, and Black adolescents with uncontrolled asthma, but not strongly associated with asthma-related morbidity, asthma-related health care utilization, or asthma management practices.

Confounding and effect modification in studies of diet and childhood asthma and allergies

OBJECTIVE

To propose a comprehensive set of confounders and effect modifiers that should be considered in epidemiologic investigations.

METHODS

Two reviewers independently critiqued studies included in a recent systematic review and extracted data on the confounders and effect modifiers that were considered and the approaches used to justify inclusion.

RESULTS

Of the 62 studies reviewed, 20 were cohort, 16 case-control, 25 cross-sectional studies, and one ecologic study. All cohort, cross-sectional, and ecologic studies had some adjustment for confounding or consideration of effect modification, but this was only the case for 7/16 (44%) case-control studies. Of the 53 studies that considered confounding or effect modification, 39/53 (74%) gave no justification for the inclusion of the variables considered. Studies that justified the inclusion of the variables did so based on empirical evidence (n = 10), conceptual justification (n = 7), or a combination of the two (n = 3). Confounding was handled mainly by using regression modeling, but some case-control studies utilized matching and anova. Ten studies handled effect modification by stratification, eight tested for interaction, and five used both strategies.

CONCLUSIONS

We have found substantial shortcomings in the handling of confounding and effect modification in studies of diet and development of childhood asthma/allergies. Selection of variables should be based on conceptual considerations and empirical evidence. Using this approach, we have proposed a comprehensive set of confounders and effect modifiers that need to be considered in future studies.

The moderating influence of asthma diagnosis on biobehavioral health characteristics of women of reproductive age

Promoting healthy behaviors to improve pregnancy outcomes requires an understanding of the factors influencing health behaviors among at-risk populations. We hypothesized that women with an asthma diagnosis would have poorer biobehavioral health risk factors and pregnancy outcomes compared to women without an asthma diagnosis. The Central Pennsylvania Women's Health Study (CePAWHS) included a population-based survey examining health status indicators, risk factors and outcomes, and detailed pregnancy histories among 2,002 women (ages 18-45). 213 asthmatics were identified. Compared with Non-asthmatic women (NA), Asthmatic (A) women reported lower rates of excellent health status (45% A vs. 65% NA, P < 0.001), were more likely to be overweight or obese (68% A vs. 50% NA, P < 0.001), and were more likely to have smoked cigarettes during their first pregnancy (25% A vs. 17% NA, P < 0.01). Psychological measures (psychosocial hassles, low self-esteem, depression) were reported more often in asthmatics than non-asthmatics. Also, asthmatics reported a higher incidence of gestational diabetes (10% A vs. 6% of NA, P = 0.05), preterm births (25% A vs. 16% NA, P < 0.01), and had a higher proportion of low birth weight infants (20% A vs. 13% NA, P = 0.03) compared with non-asthmatics. As predicted, asthmatics had poorer biobehavioral risk factors and outcomes compared to non-asthmatics. These findings illustrate the need to target asthmatic women of reproductive age, particularly in this largely rural setting, with interventions to reduce biobehavioral risk factors as part of a strategy to improve pregnancy outcomes.

Lifestyle of young Australian adults with asthma

Asthma is a highly prevalent disease that may affect the lifestyle adopted by young adults. This study investigated whether asthma status influences fruit and vegetable consumption, physical activity level, tobacco smoking, and alcohol drinking behavior of young adults in Australia. Information of 2619 participants aged 18 to 29 years was extracted from the 2007-2008 Australian National Health Survey database. The level of physical activity and fruit consumption were found to be similar between young adults with and without asthma. Participants with asthma symptoms in the past 12 months were more likely to achieve the dietary recommendation for vegetable intake, but they tended to smoke tobacco and consume alcohol above safe levels. It may be necessary to develop prevention strategies targeting young adults with asthma that include screening for harmful use of substances.

Early childhood overweight and asthma and allergic sensitization at 8 years of age

OBJECTIVES

Our aim was to examine the associations between high BMI and changes in BMI status during the first 7 years of life and asthma and allergic sensitization at age 8 years.

METHODS

A birth cohort of newborn infants was followed for 8 years. Repeated parental questionnaires provided information on environmental exposures and health outcomes. Information on height and weight during childhood was retrieved from preschool and school health care records. The analyses included the 2075 children for whom information was available on weight and height, as well as on asthma, at age 8 years.

RESULTS

A high BMI (≥85th percentile) at age 1, 4, and/or 7 years was associated with an increased risk of asthma at age 8 years. However, no significant association was observed among children with high BMI at age 12 and/or 18 months (early age) or at age 4 years who developed a normal BMI by age 7 years. The risk was increased among children with high BMI at age 7 years, regardless of their earlier weight. Moreover, we observed an increased risk of sensitization to inhalant allergens among children with high BMI at age 7 years.

CONCLUSIONS

Our study indicates that high BMI during the first 4 years does not increase the risk of asthma at school age among children who have developed a normal weight by age 7 years. However, high BMI at age 7 years is associated with an increased risk of asthma and sensitization to inhalant allergens.

Prevalence, demographics, and health outcomes of comorbid asthma and overweight in urban children

BACKGROUND

Asthma and overweight are epidemic in urban children but the relationship between these conditions is not fully understood. This study presents demographic and risk profiles of comorbidity for overweight asthmatic children, characterizes morbidity by comparing health outcomes among overweight asthmatics and healthy weight asthmatics, and examines socioeconomic factors associated with comorbidity.

OBJECTIVE

To construct a demographic profile of overweight asthmatic children in an urban setting and identify factors that contribute to prevalence.

METHOD

Cross-sectional study of 5250 children in New York City public elementary schools using a parent-report questionnaire on body mass index, socioeconomic status, asthma, and asthma-related outcomes.

RESULTS

Prevalence of overweight (body mass index ≥ 85th percentile for age and gender) was 50.9%. The prevalence of overweight and ever being diagnosed with asthma was 10.9%. The prevalence of overweight with current asthma was 6.2%. Overweight current asthmatics had more night symptoms, missed school days, and asthma medication use than healthy weight asthmatics. Almost 50% of overweight current asthmatic children reported emergency department visits for asthma compared with 30% of healthy weight asthmatics. Comorbidity was most prevalent among males, Latinos, and children in low-income households, with the highest prevalence among Puerto Ricans. In multivariate analysis stratified by gender, the most significant factors associated with comorbidity among girls were low income and minority race/ethnicity, while among boys significant factors were parental education and parental history of asthma. Interestingly, there were few underweight children (7.8%) but they had high prevalence of asthma (13.8%).

CONCLUSIONS

The comorbidity of overweight and asthma has a large impact on urban populations, causing greater disease burden than asthma alone. Overweight asthmatics show more uncontrolled asthma, evidenced by emergency department visits, quick-relief medication use, and days with asthma symptoms. The relationship between socioeconomic factors and the asthma-obesity comorbidity may vary by gender and requires further study to identify successful interventions to reduce disease in children.

U-shaped association between body mass index and the prevalence of wheeze and asthma, but not eczema or rhinoconjunctivitis: the ryukyus child health study

BACKGROUND

Studies reporting on the association between obesity and allergies have mostly focused on asthma. Little is known about the relationship of obesity to other allergic diseases, and the information that is available has been inconsistent. We examined the association between body mass index (BMI) and the prevalence of wheeze, asthma, eczema, and rhinoconjunctivitis in Japanese schoolchildren.

METHODS

Study subjects were 24,399 children aged 6-15 years in Okinawa, Japan. Outcomes were based on diagnostic criteria from the International Study of Asthma and Allergies in Childhood. BMI was categorized into five groups; <5th, 5th to 35th, >35th to 65th, >65th to 95th, and >95th percentile groups. Adjustment was made for sex, age, region of residence, number of siblings, smoking in the household, physical activity, paternal and maternal history of allergic disorders, and paternal and maternal educational levels.

RESULTS

The prevalence values of wheeze, asthma, eczema, and rhinoconjunctivitis in the previous 12 months were 10.8%, 7.6%, 6.9%, and 7.6%, respectively. Compared with the referent category (>35th to 65th percentile group), higher percentile categories were positively associated with the prevalence of wheeze. A U-shaped relationship between BMI and asthma was observed. No material associations between BMI percentile categories and the prevalence of eczema or rhinoconjunctivitis were found.

CONCLUSION

These findings suggested that being either underweight or overweight might increase the likelihood of asthma among Japanese schoolchildren.

Nutrients and foods for the primary prevention of asthma and allergy: systematic review and meta-analysis

BACKGROUND

Epidemiologic studies suggest that deficiencies of the nutrients selenium; zinc; vitamins A, C, D, and E; and low fruit and vegetable intake may be associated with the development of asthma and allergic disorders.

OBJECTIVES

To investigate the evidence that nutrient and food intake modifies the risk of children developing allergy.

METHODS

We systematically searched 11 databases. Studies were critically appraised, and meta-analyses were undertaken.

RESULTS

We identified 62 eligible reports. There were no randomized controlled trials. Studies used cohort (n = 21), case-control (n = 15), or cross-sectional (n = 26) designs. All studies were judged to be at moderate to substantial risk of bias. Meta-analysis revealed that serum vitamin A was lower in children with asthma compared with controls (odds ratio [OR], 0.25; 95% CI, 0.10-0.40). Meta-analyses also showed that high maternal dietary vitamin D and E intakes during pregnancy were protective for the development of wheezing outcomes (OR, 0.56, 95% CI, 0.42-0.73; and OR, 0.68, 95% CI, 0.52-0.88, respectively). Adherence to a Mediterranean diet was protective for persistent wheeze (OR, 0.22; 95% CI, 0.08-0.58) and atopy (OR, 0.55; 95% CI, 0.31-0.97). Seventeen of 22 fruit and vegetable studies reported beneficial associations with asthma and allergic outcomes. Results were not supportive for other allergic outcomes for these vitamins or nutrients, or for any outcomes in relation to vitamin C and selenium.

CONCLUSION

The available epidemiologic evidence is weak but nonetheless supportive with respect to vitamins A, D, and E; zinc; fruits and vegetables; and a Mediterranean diet for the prevention of asthma. Experimental studies of these exposures are now warranted.

Physical Activity in Childhood Asthma: Friend or Foe?

Physical activity has been considered as a double-edged sword for children with asthma. Children with asthma are recommended to participate in physical activities like their healthy nonasthmatic peers because regular physical activity positively affects psychological functioning, quality of life, morbidity, and aerobic fitness in children with asthma. However, uncontrolled asthma with ongoing exercise-induced bronchoconstriction may limit participation in sports, free play, and daily living. Observations also suggest that high-intensity exercise performed in cold air, seasonal allergens, pollutants, or respiratory virus infections may increase the risk for asthma in the highly active child. In contrast, a sedentary lifestyle has been highlighted as the explanation for the increased prevalence of asthma in the past decades. However, there is no consensus on whether a low level of physical activity increases the severity or risk of asthma. Use of asthma medications and good asthma control can make the conditions favorable for a physically active lifestyle and influence physical activity level and the level of aerobic fitness.

Essential role of vitamin C and zinc in child immunity and health

With the progressive elimination of dietary protein-energy deficits, deficiencies of micronutrients are emerging as the limiting factors in ensuring children's optimal health. Data from several countries in Asia and Latin America indicate that deficiencies of vitamin C and zinc continue to be at alarming levels. This article reviews the roles of vitamin C and zinc in supporting children's growth and development, with a particular focus on the complementary roles they play in supporting immune functions and combating infections. The contemporary relevance of vitamin C and zinc deficiency in the Asian and Latin American regions, both undergoing a rapid nutritional transition, are also discussed. Overall, there is increasing evidence that deficiency of vitamin C and zinc adversely affects the physical and mental growth of children and can impair their immune defences. Nutrition should be the main vehicle for providing these essential nutrients; however, supplementation can represent a valid support method, especially in developing regions.

Association of nutrient intake and wheeze or asthma in a Greek pre-school population

The rise of asthma prevalence in children observed the last years might be related to several dietary factors/components as suggested by several researchers. We aimed to evaluate the potential relationship between certain nutrients intake and asthma occurrence in a population of pre-school children. In the framework of the cross-sectional study 'Growth, Exercise and Nutrition Epidemiological Study In pre-schoolers', data were collected from 1964 children, aged 24-72 months, living in five different counties in Greece. The International Study of Asthma and Allergies in Childhood questionnaire was used to assess asthma related outcomes. Dietary intake was assessed with 3 days diet records. The prevalence of ever wheeze, current wheeze and diagnosed asthma was 37.7%, 27.5% and 10.5% respectively. Dietary intake of magnesium had a 0.5% and 0.6% increase in the reported risk of current wheeze and diagnosed asthma respectively. On the contrary a decrease in the prevalence of ever (OR: 0.997, 95% CI: 0.995-1.000) and current wheeze (OR: 0.996, 95% CI: 0.993-0.999) was associated with vitamin C intake. Calcium intake slightly decreased the risk of current wheeze (OR: 0.999, 95% CI: 0.998-0.999). An increase of 2% of the risk of reporting ever or current wheeze was associated with mono-unsaturated fatty acid intake. Magnesium intake was the only independent predictor for doctor's diagnosed asthma. We conclude that dietary intake of vitamin C and calcium seem to have a protective effect on the incidence of wheeze in pre-school children, whereas magnesium and mono-unsaturated fatty acid may have a harmful role.

Obesity, inflammation, and asthma severity in childhood: data from the National Health and Nutrition Examination Survey 2001-2004

BACKGROUND

The prevalences of asthma and obesity in children have increased significantly during the past 2 decades. The basis for the relationship between pediatric asthma and obesity is not well established.

OBJECTIVES

To explore the association between obesity and asthma severity in children and adolescents and to test whether obesity-induced inflammation, as characterized by serum C-reactive protein (CRP), is associated with increased severity of asthma.

METHODS

Retrospective cohort analysis of interview, physical examination, and laboratory test data from participants younger than 20 years in 2 rounds of the National Health and Nutrition Examination Survey (2001-2002 and 2003-2004). We also performed generalized ordered logistic regression to evaluate the effect of body mass index (BMI) z score and CRP level on asthma severity, controlling for the impact of age, sex, race, income, insurance, and tobacco smoke exposure.

RESULTS

Of the 77 million individuals younger than 20 years represented by this weighted sample, 19% met the study-defined criteria for asthma; most cases were defined as mild (11%) or moderate (6%); 2% had severe asthma. In multivariable models, elevated BMI z scores (odds ratio, 1.12; 95% confidence interval, 1.05-1.21) were associated with worse asthma severity. Elevated CRP level was associated with obesity (P < .001) and asthma severity (odds ratio, 1.33; 95% confidence interval, 1.16-1.52).

CONCLUSIONS

Higher BMI z scores and elevated serum CRP levels are associated with increased asthma severity. These findings highlight the importance of controlling for inflammation when considering the role of obesity and provide support for the hypothesis that obesity-induced inflammation may contribute to greater asthma severity.

Indoor environmental risk factors and seasonal variation of childhood asthma

Seasonality of asthma may result from varying exposures. This cross-sectional study was designed to examine the relationship between indoor environmental factors and seasonal childhood asthma. Study subjects were participants from the International Study of Asthma and Allergies in Childhood (ISAAC) in 2004, a population-based surveillance, which included school children aged 6-15 yr in south Taiwan. Cases included 1725 children who experienced asthma symptoms in the past 12 months and the references consisted of 19,646 children who reportedly have no asthma history. By using a moving average and principal component analysis, asthmatic children were grouped into four asthma subtypes: winter, spring, summer/fall, and perennial. Multivariate logistic regression was used to evaluate the effect of indoor environmental factors on seasonality of childhood asthma. For all asthma prevalence, a peak occurred in the winter and a nadir appeared in summer. Contributing factors of asthma for children, regardless of seasonality, included younger age, parental atopy, maternal smoking during pregnancy, breast feeding, and perceived air pollution. After adjusted for salient risk factors, water damage was significantly associated with all subtypes of asthma. Presence of cockroaches was related to the summer/fall asthma (adjusted odds ratio [aOR] = 1.65, 95% confidence interval [CI] = 1.12-2.55). Visible mold on the walls was associated with an increased occurrence of winter and spring asthma (aOR = 1.53, 95% CI = 1.26-1.85 and aOR = 1.34, 95% CI = 1.10-1.62, respectively). Passive smoking was shown to be related to spring and summer/fall asthma. Water damage is a possible risk for childhood asthma year-round. Cockroaches and visible mold on the walls may play essential roles for seasonality of childhood asthma in Taiwan. Plausible mechanisms and allergic effects should be further determined. Elimination of these allergens is necessary to help prevent the development of asthma.

Obesity and obesity related co-morbidities in a referral population of children with asthma

OBJECTIVE

Although there is mounting evidence that childhood obesity is a risk factor for incident asthma, it remains unclear if there is a distinct "asthma-obesity" phenotype. This study characterized body composition, obesity related co-morbidities, and traditional risk factors for asthma in a cohort of children referred for asthma management in a pulmonary clinic. We hypothesized that children with asthma and obesity would have distinct risk factors and co-morbidities, particularly with respect to metabolic and sleep abnormalities.

PARTICIPANTS AND METHODS

One hundred sixteen asthmatic children ages 4-18 years underwent comprehensive measurements of common asthma risk factors as well as measurements of obesity-related morbidities, including lung function tests, atopy, and assessments of sleep (overnight oximetry and actigraphy), physical activity (accelerometry), and metabolism. Characteristics of children who were obese (BMI > or =95th percentile) were compared to those who were not obese (BMI <95th percentile).

RESULTS

Obesity was present in 44% of participants. Obese participants had similar rates of atopy and family history of atopy, lung function, and asthma control at enrolment as their non-obese peers. A significantly higher proportion of obese participants had metabolic syndrome (23% vs. 0%) and habitual snoring (60% vs. 33%) compared to non-obese participants; insufficient sleep and nocturnal desaturations tended to be more prevalent among obese subjects.

CONCLUSIONS

Obesity and obesity related co-morbidities were common in a referral population of children with asthma. The specific influence of metabolic abnormalities on asthma morbidity and management is still uncertain and likely will need to be addressed in prospective studies.

PRKCA: a positional candidate gene for body mass index and asthma

Asthma incidence and prevalence are higher in obese individuals. A potential mechanistic basis for this relationship is pleiotropy. We hypothesized that significant linkage and candidate-gene association would be found for body mass index (BMI) in a population ascertained on asthma affection status. Linkage analysis for BMI was performed on 657 subjects in eight Costa Rican families enrolled in a study of asthma. Family-based association studies were conducted for BMI with SNPs within a positional candidate gene, PRKCA. SNPs within PRKCA were also tested for association with asthma. Association studies were conducted in 415 Costa Rican parent-child trios and 493 trios participating in the Childhood Asthma Management Program (CAMP). Although only modest evidence of linkage for BMI was obtained for the whole cohort, significant linkage was noted for BMI in females on chromosome 17q (peak LOD = 3.39). Four SNPs in a candidate gene in this region (PRKCA) had unadjusted association p values < 0.05 for BMI in both cohorts, with the joint p value for two SNPs remaining significant after adjustment for multiple comparisons (rs228883 and rs1005651, joint p values = 9.5 x 10(-)(5) and 5.6 x 10(-)(5)). Similarly, eight SNPs had unadjusted association p values < 0.05 for asthma in both populations, with one SNP remaining significant after adjustment for multiple comparisons (rs11079657, joint p value = 2.6 x 10(-)(5)). PRKCA is a pleiotropic locus that is associated with both BMI and asthma and that has been identified via linkage analysis of BMI in a population ascertained on asthma.

Assessing physical activity in children with asthma: convergent validity between accelerometer and electronic diary data

Convergent validity of accelerometer and electronic diary physical activity data was assessed in children with asthma. Sixty-two participants, ages 9-18 years, wore an accelerometer and reported their physical activity level in quarter-hour segments every 2 hr using the Ambulatory Diary Assessment (ADA). Moderate validity was found between physical activity data from accelerometers and ADA (average individual participant Spearman r = .48, SD = 0.13). Within-participant accelerometer estimates for ADA sleep, rest, and light activity were different from each other and from higher activity (mixed model p < .0001), but moderate did not differ from strenuous activity (p = .70). Moderate validity between accelerometer and electronic diary data supports the use of ADA with short-term recall to capture gross changes in daily activity.

Body mass index in Belgian schoolchildren and its relationship with sensitization and allergic symptoms

Results of studies of the influence of body mass index (BMI) on the allergic status are controversial. As a part of the Aalst Allergy Study, we assessed the prevalence of the different BMI categories (underweight, normal weight, overweight, and obesity) and a possible association between BMI and atopy in 1576 unselected Belgian schoolchildren, aged from 3.4 to 14.8 yr. BMI was used to determine weight status. Skin prick testing with the most common aeroallergens was performed. A parental questionnaire documented data on respiratory and allergic disorders, demographic characteristics and other potential risk factors for sensitization. Among the total children, 4.1% of the children were underweight, 14.5% were overweight, and 7.4% were obese. More girls than boys were overweight (p = 0.015). In the group of children older than 12 yr, we found more overweight (p = 0.03) and obese (p = 0.004) girls, and more obese boys (p = 0.004) than in the younger age groups. In contrast with reports in the literature, an increased prevalence of allergic sensitization in underweight girls only [adjusted odd ratio (OR(adj)) = 2.9, 95% confidence interval (CI): 1.3-6.4] was documented. A strong association between obesity and exercise-induced respiratory symptoms was found in both boys (OR(adj) = 14.5, 95% CI: 2.9-73.3) and girls (OR(adj) = 4.9, 95% CI: 1.3-17.4). No correlations with allergic respiratory symptoms, eczema, or rhinoconjunctivitis could be documented.

Prospective study of physical activity and risk of asthma exacerbations in older women

RATIONALE

The potential role of physical activity in preventing asthma exacerbations is unknown.

OBJECTIVES

To investigate the longitudinal association between regular physical activity and asthma exacerbations.

METHODS

A total of 2,818 women with asthma from a large U.S. cohort (the Nurses' Health Study) were monitored from 1998 to 2000. Physical activity was self-reported at baseline, using a validated questionnaire, and categorized in quintiles. Exacerbations during follow-up were defined as a self-report of asthma-related hospitalization, emergency department visit, or urgent office visit. Baseline information about severity of asthma, treatment, previous exacerbations, sociodemographic factors, smoking, and other potential confounders was obtained.

MEASUREMENTS AND MAIN RESULTS

Participants had a mean age of 63 years, and 71% had mild-to-moderate persistent asthma. About half of the women were ever-smokers (48% former, 6% current), and median physical activity was 10 MET x hours/week (equivalent to walking at a brisk pace for 20 minutes three times per week). Risk of exacerbations during follow-up decreased with increasing level of physical activity. In a multivariate logistic regression model, the higher level of physical activity, the lower risk of admission (odds ratio 0.85, 0.81, 0.78, and 0.76, for the 2nd, 3rd, 4th, and 5th quintiles compared with the 1st quintile, P for trend = 0.05). There were no relevant differences on stratifying by age group, smoking status, body mass index, baseline use of inhaled corticosteroids, or previous exacerbations.

CONCLUSIONS

Regular physical activity was associated with reduced risk of exacerbations in women with asthma in this longitudinal study.

The association of BMI and sedentary time with respiratory symptoms and asthma in 5th grade schoolchildren in Kaohsiung, Taiwan

This study aimed to evaluate the association of body fatness and sedentary status with asthma and respiratory symptoms in schoolchildren in Kaohsiung, Taiwan. A questionnaire study elicited episodes of respiratory symptoms and data on lifestyle and anthropometric parameters in 1329 5th grade schoolchildren. Results showed that 12.4% of boys and 9.5% of girls had physician-diagnosed asthma, whereas 15.1% of boys and 12.4% of girls had suspected asthma. Significantly greater proportions of boys had non-exercise-induced respiratory symptoms than girls (p < 0.05). The number of respiratory symptoms was positively correlated with TV-watching time per day and self-reported sedentary time per weekend-day in girls (p < 0.05). Underweight was positively associated with one of the seven respiratory symptoms in girls (p < 0.05). At risk of overweight was positively associated with two of the seven respiratory symptoms in boys and one of the seven respiratory symptoms in girls (all p < 0.05). The risk of having physician-diagnosed asthma and suspected asthma increased 93% and 72%, respectively, in schoolchildren at risk of overweight (p < 0.05). Overweight was associated with a 78% increase in physician-diagnosed asthma (adjusted odd ratio (aOR) = 1.78, 95% CI = 1.08-2.91, p < 0.05). Higher sedentary time was significantly associated with more occurrences of one of the seven respiratory symptoms in girls (aOR = 1.05, 95% CI = 1.00-1.11, p < 0.05). Higher body mass index (BMI) was significantly correlated with longer TV-watching time per day in girls and longer self-reported sedentary time per weekday in boys (p < 0.05). In summary, schoolchildren who are at risk of overweight or overweight and/or have more sedentary time have increased risk of respiratory symptoms and asthma. Weight and sedentary statuses of schoolchildren can affect their respiratory health.

Wheeze and asthma in children: associations with body mass index, sports, television viewing, and diet

BACKGROUND

Obesity, physical activity, and dietary habits are distinct but strongly interrelated lifestyle factors that may be relevant to the prevalence of wheeze and asthma in children. Our goal was to analyze the relationship of body mass index (BMI), regular sports participation, TV viewing, and diet with current wheezing and asthma.

METHODS

We investigated 20,016 children, aged 6-7 years, who were enrolled in a population-based study. Parents completed standardized questionnaires. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), while adjusting for several confounders and simultaneously considering BMI, regular sports activity, TV viewing and selected dietary items.

RESULTS

A total of 1575 children (7.9%) reported current wheezing and 1343 (6.7%) reported current asthma. In a multivariate model, an elevated BMI was associated with wheeze and current asthma: children from the highest quintile (compared with the lowest quintile) had an increased risk of wheeze (OR = 1.47; CI = 1.20-1.82) or current asthma (1.61; 1.28-2.01). Wheeze or asthma was not associated with regular sports activity. Subjects who spent 5 or more hours per day watching television were more likely to experience wheeze (1.53; 1.08-2.17) or current asthma (1.51; 1.04-2.2) compared with those who viewed TV less than 1 hour a day. Adding salt to food was strongly and independently associated with current wheeze (2.58; 1.41-4.71) and current asthma (2.68; 1.41-5.09).

CONCLUSIONS

Our data support the hypothesis that high body weight, spending a lot of time watching television, and a salty diet each independently increase the risk of asthma symptoms in children.

Factors associated with asthma symptoms in schoolchildren from Greece: the Physical Activity, Nutrition and Allergies in Children Examined in Athens (PANACEA) study

To evaluate whether dietary habits and anthropometric and lifestyle characteristics are associated with the prevalence of asthma symptoms, a sample of 700 Greek schoolchildren were evaluated through a standardized questionnaire. Body height and weight were measured, and body mass index was calculated. Multiple logistic regression and multivariate techniques (principal components analysis) were performed. Overall lifetime prevalence for asthma symptoms was found to be 23.7%. Increased body weight, sedentary lifestyle, and consumption of sulphur-dioxide-enriched foods and beverages seem to promote asthma symptoms, while avoidance of this chemical preservative and physical activity was associated with reduced odds of reporting asthma symptoms.

Associations of BMI, TV-watching time, and physical activity on respiratory symptoms and asthma in 5th grade schoolchildren in Taipei, Taiwan

The study evaluated the associations of body fatness, TV-watching time, and physical activity with the occurrences of asthma and respiratory symptoms in schoolchildren in Taipei, Taiwan. A questionnaire survey was conducted to elicit episodes of respiratory symptoms and data on lifestyle and anthropometric factors in 2290 5th-grade schoolchildren. Results show that overweight was positively associated with 5 of the 7 respiratory symptoms. The risk of having respiratory symptoms increased 47%-94% in overweight schoolchildren. Watching TV > or = 3 hrs/day was associated with more occurrences of respiratory symptoms (aOR = 1.42-1.90). Physical activity > or =3 times/week was associated with fewer occurrences of respiratory symptoms (aOR = 0.66-0.73). Overweight was positively associated with an increased risk of suspected asthma in boys (aOR = 1.56, 95% CI = 1.07-2.29), but not in girls. In summary, overweight and greater TV-watching time increase the risk of respiratory symptoms, while habitual physical activity decreases the risk of respiratory symptoms. Weight status, sedentary life, and frequency of physical exercise are the factors that can impact on the respiratory health of schoolchildren.

Measurement of television viewing in children and adolescents: a systematic review

The relationship between television (TV) viewing and overweight in children is likely to be influenced by the quality of measures used. We systematically reviewed studies related to overweight in children that had included a measure of TV exposure. Literature searches were conducted in MedLINE, PsychInfo, SportDiscus and ISIWeb of Science. Methods of assessing TV viewing were evaluated, including the type of measure, the administration procedure and reported psychometric properties. The majority of studies assessed TV viewing using self-report surveys and very few studies used direct observation. The validity or reliability of measures was often not examined. The majority of tools that were evaluated were compared with another self-report measure or an objective measure of physical activity. TV viewing measures should be selected that are specific to the research question, the study design, as well as methodological feasibility. However, it is recommended that measures of TV viewing be used only if they have psychometric data to support their validity and reliability. Selecting measures that are valid and reliable enables us to examine with greater accuracy the influence of TV viewing on childhood overweight, as well as the efficacy of interventions designed to reduce TV viewing in children.

Demographic and clinical characteristics of children and adolescents with severe or difficult-to-treat asthma

BACKGROUND

Young patients with severe or difficult-to-treat asthma are an understudied population.

OBJECTIVE

To assess age-associated and gender-associated differences in children and adolescents in the observational study, The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens.

METHODS

Cross-sectional baseline data for patients greater than or equal to 6 years and less than or equal to 17 years (n = 1261) were stratified by age group (6-8, 9-11, 12-14, and 15-17 years). The chi(2) test for categorical variables and analysis of variance for continuous variables were used to identify differences among age groups, stratified by gender.

RESULTS

Most patients had moderate (55%) or severe (41%) asthma by physician assessment. Of those using greater than or equal to 3 long-term controllers (62%), 53% of children (6-11 years) and 44% of adolescents (12-17 years) reported an oral corticosteroid burst and 25% and 19%, respectively, had an emergency department visit in the previous 3 months; 10% and 15%, respectively, reported past intubation. In females, weight for age ranged between the 67th and 70th percentiles; height for age was between the 42nd and 54th percentiles (P < .01 among age groups). Lung function was lower in adolescents than children: prebronchodilator percent predicted forced expiratory volume in 1 second (FEV(1))/forced vital capacity was 0.92 (6-8 years) and 0.83 (15-17 years), P less than .05, in males; and 0.94 (6-8 years) and 0.87 (15-17 years), P less than .05, in females.

CONCLUSIONS

Children and adolescents demonstrated high rates of health care use and loss of lung function, despite using multiple long-term controllers.

CLINICAL IMPLICATIONS

Asthma treatments that prevent loss of lung function and reduce health care resource use are needed in young patients with severe or difficult-to-treat asthma.

Pattern of growth and adiposity from infancy to adulthood in atopic dermatitis

BACKGROUND

Impaired linear growth has been reported in children with atopic dermatitis (AD) but the pattern of growth in height and weight through childhood and adolescence has not been described.

OBJECTIVES

To define the pattern of linear growth and adiposity in AD from early childhood through to adult life.

PATIENTS AND METHODS

Growth measurements of 70 male and 40 female patients with AD followed through childhood and adolescence were studied retrospectively and compared with the 1990 U.K. normal values. Height, weight and body mass index (BMI) were converted to standard deviation scores (SDS). Regression analysis examined whether the mean trend was different from zero.

RESULTS

While dermatitis was the predominant atopic problem in all 110 patients, 92 had a history of asthma which was mild in 85 of 92. Regression analyses showed that the trends in height, weight and BMI SDS for AD patients were significantly different from zero and also different between males and females. Both sexes were short and relatively overweight from early childhood, a trend that was more pronounced in males than females. At 5 years (school entry), the 50th centile BMI of male (but not female) patients was 0.44 kg m(-2) higher than the reference population but height and weight were lower. The age at adiposity rebound in AD males and females was 0.8 year and 0.7 year later than the U.K. population (6.2 years vs. 5.4 years and 6.2 years vs. 5.3 years, respectively). AD patients attained peak height velocity later than the 1990 U.K. population (males 16.0 years vs. 13.5 years, P = 0.0002; females 13.4 years vs. 11.0 years, P = 0.008). In addition, males had greater mean gain in height during late adolescence (12.2 vs. 8.8 cm, P = 0.03) and were shorter as young adults (170.9 vs. 177.6 cm, P = 0.0005).

CONCLUSIONS

Our patients with AD were relatively overweight very early but had a later adiposity rebound, were short in childhood and had a delayed adolescent growth spurt. Serial growth measurements should be done on all children with troublesome AD and can be helpful in counselling about the growth prognosis.

High body mass index and dietary pattern are associated with childhood asthma

The increasing prevalence of asthma has coincided with an increase of body mass index (BMI) in both children and adults. We investigated the relationship between BMI and the symptom prevalence of asthma and the possible influences of dietary pattern. This was a community-based, cross-sectional study of 24,260 school children aged 6-12 years. Prevalences of asthma and potential confounding factors were assessed using a Korean version of the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire which was completed by parents. We analyzed the relationship between BMI and symptoms of asthma and the possible influences of dietary pattern. A significant positive association between high BMI and previous 12-month prevalence of wheeze remained in boys (adjusted odds ratio, 1.610; 95% confidence interval, 1.274-2.033) but not in girls. In addition, there were significant associations between high BMI and lifetime prevalence of wheeze, previous 12-month wheeze, exercise-induced wheeze, diagnosis, and treatment of asthma. There were significant associations between high BMI and previous 12-month wheeze regardless of breast-milk feeding or whole-milk feeding. Frequent intake of fresh seafood, fresh fruits, and vegetables was associated with reduced prevalence of current asthma symptoms and was also associated with decreased BMI. These results indicate that BMI may be an independent risk factor for the development of asthma symptoms in boys. Intake of fresh seafood, fresh fruit, and vegetables, which may be associated with decreased BMI, may contribute to protect against the development of asthma symptoms in Korean elementary schoolchildren.

Paediatric asthma and obesity

None of the explanations proposed for the increase in paediatric asthma have been adequate. It is becoming apparent that the cause of the increase in asthma must be multi-factorial. Increasing attention has been focused on the role of lifestyle in the development of asthma. Lifestyle changes that have occurred in children are those in diet and decreased physical activity, with obesity being the product of these changes. The increase in asthma, obesity and a sedentary lifestyle have occurred together. However, a temporal relationship between asthma, obesity and decreased physical activity has not been determined in the paediatric literature. Limited data suggest that decreased physical activity could be playing a role in the aetiology of asthma independent of obesity. Furthermore, there has been substantial research on the benefits of exercise programmes for paediatric patients with asthma. Longitudinal trials monitoring physical activity, obesity and the development of asthma are needed.

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.

Are overweight asthmatics more difficult to control?

The relationship between asthma and obesity appears to be quite complex. The aim of this study was to assess the effect of excess weight on asthma control evolution in a cohort of asthmatics. A prospective database was set up, which enrolled adult asthmatics with persistent (mild, moderate or severe) asthma. The control of asthma was defined as a binary variable, acceptable or unacceptable. In order to evaluate the effect of body mass index (BMI; <25 or > or =25), data were analysed using a continuous time homogeneous Markov model in which the forces ruling the transition between the two health states were estimated. The following confounding covariates were also evaluated in the model: severity of asthma, current treatment with oral corticosteroids (OCS) and history of OCS over the year preceding inclusion. About 406 asthmatics were included who made a total of 1639 consultations; the median length of follow up was 182 days. Using a univariate model, overweight patients had a lower risk of transiting from the unacceptable to the acceptable health state (RR = 0.45; P < 0.01). The effect of weight remained significant (RR = 0.53; P < 0.01) in the multivariate model including the other covariates. Moreover, transition probabilities stabilized more rapidly for patients with BMI < 25 (200 vs 300 days). In this study, we thus demonstrated that there is an association between excess weight and transition from unacceptable to acceptable control. Because control of asthma clearly drives asthma management, this finding has consequences for defining original new strategies for managing asthma in overweight patients.