Peak flow variability in childhood and body mass index in adult life

Long-term effect of asthma on the development of obesity among adults: an international cohort study, ECRHS

INTRODUCTION

Obesity is a known risk factor for asthma. Although some evidence showed asthma causing obesity in children, the link between asthma and obesity has not been investigated in adults.

METHODS

We used data from the European Community Respiratory Health Survey (ECRHS), a cohort study in 11 European countries and Australia in 3 waves between 1990 and 2014, at intervals of approximately 10 years. We considered two study periods: from ECRHS I (t) to ECRHS II (t+1), and from ECRHS II (t) to ECRHS III (t+1). We excluded obese (body mass index≥30 kg/m²) individuals at visit t. The relative risk (RR) of obesity at t+1 associated with asthma at t was estimated by multivariable modified Poisson regression (lag) with repeated measurements. Additionally, we examined the association of atopy and asthma medication on the development of obesity.

RESULTS

We included 7576 participants in the period ECRHS I-II (51.5% female, mean (SD) age of 34 (7) years) and 4976 in ECRHS II-III (51.3% female, 42 (8) years). 9% of participants became obese in ECRHS I-II and 15% in ECRHS II-III. The risk of developing obesity was higher among asthmatics than non-asthmatics (RR 1.22, 95% CI 1.07 to 1.38), and particularly higher among non-atopic than atopic (1.47; 1.17 to 1.86 vs 1.04; 0.86 to 1.27), those with longer disease duration (1.32; 1.10 to 1.59 in >20 years vs 1.12; 0.87 to 1.43 in ≤20 years) and those on oral corticosteroids (1.99; 1.26 to 3.15 vs 1.15; 1.03 to 1.28). Physical activity was not a mediator of this association.

CONCLUSION

This is the first study showing that adult asthmatics have a higher risk of developing obesity than non-asthmatics, particularly those non-atopic, of longer disease duration or on oral corticosteroids.

High Insulin in Early Childhood Is Associated with Subsequent Asthma Risk Independent of Body Mass Index

BACKGROUND

Asthma and obesity are major, interconnected public health challenges that usually have their origins in childhood, and for which the relationship is strengthened among those with insulin resistance.

OBJECTIVE

To determine whether high insulin in early life confers increased longitudinal risk for asthma independent of body mass index.

METHODS

The study used data from the Tucson Children's Respiratory Study (TCRS) and the Avon Longitudinal Study of Parents and Children (ALSPAC). Nonfasting insulin was measured in TCRS participants at age 6 years and fasting insulin in ALSPAC participants at age 8 years. Physician-diagnosed active asthma was determined at baseline and at subsequent assessments up to age 36 years in TCRS and 17 years in ALSPAC.

RESULTS

In TCRS, high insulin (upper quartile) at age 6 years was associated with increased odds of having active asthma from ages 8 to 36 years compared with low insulin (odds ratio,1.98; 95% CI, 1.28-3.05; P = .002). Similarly, in ALSPAC, high insulin was associated with a significantly higher risk of active asthma from ages 11 to 17 years compared with low insulin (odds ratio, 1.59; 95% CI, 1.12-2.27; P = .009). These findings were independent of baseline body mass index in both cohorts, and were not related to other demographic and asthma risk factors nor other tested markers of systemic inflammation and metabolic syndrome.

CONCLUSIONS

In 2 separate birth cohorts, higher blood insulin level in early childhood was associated with increased risk of active asthma through adolescence and adulthood, independent of body mass index. High insulin indicates a novel mechanism for asthma development, which may be a target for intervention.

Individual and Environmental Factors Associated with Participation in Physical Activity as Adolescents Transition to Secondary School: A Qualitative Inquiry

The transition from elementary to secondary school is an emotionally and socially complex time when adverse behaviors appear, such as decreased levels of physical activity (PA). Behavioral and environmental factors that influence PA during this time are poorly understood. Therefore, we aimed to identify factors that influence PA as adolescents transition to secondary school. Qualitative interviews were conducted with a sample of 27 ethnically diverse child–parent dyads within the public-school system in British Columbia, Canada (50% boys, 68% mothers, 25% White). The interviews probed for environmental and behavioral factors in school, family, and social contexts that potentially initiated changes in PA, specifically related to the adolescents’ transitions. Interviews were recorded and transcribed verbatim. Thematic analyses identified factors at the individual, social, familial, and school levels that may trigger adolescents to change their participation in PA as they transition from elementary to secondary school. Twenty-two factors emerged from the qualitative analysis including school factors (8), household factors (3), social factors (4), and intrapersonal factors (7). These findings contribute to a better understanding of adolescents’ PA behaviors and highlight the influence of changing environments as they transition from elementary school to secondary school.

Sex Differences in the Prevalence and Severity of Exercise-Induced Bronchoconstriction in Kindergarteners in Japan

BACKGROUND

Exercise-induced bronchoconstriction (EIB), a strong positive predictor of asthma, becomes progressively less frequent with age. Although asthma tends to become less common only in boys during adolescence, sex differences in EIB, especially in preschoolers, remain unclear. To find EIB for early diagnosis and intervention asthma, mass-screening tests considering sex differences in preschoolers are needed. In this study, we investigated whether sex differences influence the prevalence and severity of EIB in prepubertal children aged 5-6 years.

METHODS

Fifty-one children aged 5-6 years who were attending a kindergarten in Matsuyama City, Ehime, Japan, were enrolled in this cross-sectional study. The children underwent a 6-minute free-running test in 2015. The peak expiratory flow rate (PEFR) was measured before exercise and 0, 3, 10, and 20 minutes after exercise. The severity of EIB was classified according to the reduction in PEFR, measured as the difference between the postexercise PEFR and the highest pre-exercise PEFR.

RESULTS

Of the 51 children (23 boys and 28 girls) enrolled, the prevalence of EIB defined as three criteria: a ≥15%, ≥20%, or ≥25% decrease was 54.9% (28/51), 41.2% (21/51), and 25.5% (13/51), respectively. The prevalence of EIB defined as ≥25% decrease was significantly higher in girls than in boys (39.3% vs 8.7%, P = .013). In girls, the mean percentage change in PEFR was significantly higher 20 minutes than 10 minutes postexercise (P = .043).

CONCLUSIONS

Sex difference in the prevalence and severity of EIB should be considered when evaluating EIB, even in young, prepubertal children.