Low fitness and increased sedentary time are associated with worse asthma-The National Youth Fitness Survey

Abstract

Background: Asthma is the most common chronic illness in children and is independently impacted by obesity and by fitness. The National Youth Fitness Survey collected data on aerobic fitness, body composition, and health outcomes in children 6 to 11 years old. The goal of this study is to test hypotheses regarding relationships between asthma, aerobic fitness, and sedentary time in this uniquely studied cohort of young children.

Methods: A total of 665 children (6-11 years old; 49% male) were included in analyses. We explored relationships between asthma outcomes and aerobic fitness (measured by endurance time), self-reported sedentary time, and body mass index categories. Fitness was categorized as unfit (lowest 25% of endurance times) or fit. Multivariate logistic regression models were created for asthma outcomes and adjusted for race, age, sex, poverty status, and overweight/obesity.

Results: Among the participants, 17.9% had a previous history of asthma and 11.4% had current asthma. Additionally, 37.3% of participants were overweight or obese. Low fitness was significantly associated with increased odds of past asthma, current asthma, asthma attacks, wheeze with exercise, and wheeze with activity limitations in multivariate models. Increased sedentary time was significantly associated with increased odds of previous asthma, current asthma, asthma attacks, and wheeze with activity limitations.

Conclusion: Decreased aerobic fitness and increased sedentary time were associated with worse asthma outcomes in this group of children (6-11 years old). This data suggest that fitness and sedentary time, both modifiable factors, each have an independent effect on asthma and should be included in assessments and management of asthma health.

Keywords: asthma and early wheeze; epidemiology; pulmonology (general).

Figure 1.

Mean endurance times are significantly lower in children with previous history of asthma, current asthma, and those with asthma attacks (gray bars) compared to controls (black bars). *Asterisks indicate p value < 0.05.

Figure 2.

Mean endurance times (95% CI) by healthy controls vs asthma and normal weight vs overweight/obese. Ow/Ob children with asthma have the shortest endurance times compared to normal weight controls for all of the asthma outcomes. For asthma attacks, controls include those with current asthma but no asthma attacks as well as healthy controls. *Asterisks indicates significant difference between Ow/Ob children with asthma outcome and normal weight controls (p value < 0.05).