ABSTRACT
Background: We tested the hypothesis that multiple
obesity-related risk factors (obesity, physical activity,
cardiopulmonary physical fitness, sleep-disorder breathing (SDB), and
sleep quality) are associated with childhood asthma using a Mendelian
randomization (MR) design. Furthermore, we aim to investigate whether
these risk factors were associated with incident asthma prospectively.
Methods: In total, 7069 children aged 12 from the Taiwan
Children Health Study were enrolled in the current study.
Cross-sectional logistic regression, one-sample MR, summary-level MR
sensitivity analyses, and prospective survival analyses were used to
investigate each causal pathway.
Results: In MR analysis, three of the five risk factors
(obesity, SDB, and sleep quality) were associated with asthma, with the
highest effect sizes per interquartile range (IQR) increase observed for
sleep quality (odds ratio [OR] =1.42; 95% confidence interval
[CI]: 1.06 to 1.92) and the lowest for obesity (OR = 1.08; 95% CI:
1.00–1.16). In the prospective survival analysis, obesity showed the
highest risk of incident asthma per IQR increase (hazard ratio [HR]
= 1.28; 95% CI: 1.05 to 1.56), followed by SDB (HR = 1.18; 95% CI:
1.08 to 1.29) and sleep quality (HR = 1.10; 95% CI: 1.03 to 1.17).
Conclusion: The most plausible risk factors for asthma were
obesity, SDB, and poor sleep quality. For the prevention of childhood
asthma, relevant stakeholders should prioritize improving children’s
sleep quality and preventing obesity comorbidities such as SDB.
Keywords: Obesity; Asthma; Mendelian randomization study;
Prospective study; Pulmonary function