The associations between smoking, physical inactivity, obesity, and asthma severity in the general US population
ABSTRACT The purpose of this study was to examine the associations between smoking, physical inactivity, obesity, and asthma severity among US adults. The magnitude of these associations was very strong. For example, those who visited an emergency room in the past year were 60% more likely than those who did not to smoke; those who used an inhaler > or =15 times in the past month (versus those who did not use an inhaler) were 90% more likely to be physically inactive; and those who had asthma symptoms all the time in the past 30 days (versus those with no symptoms) were 80% more likely to be obese.
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- "While the study by Gupta et al. may provide in vivo evidence that vitamin D levels are associated with ASM remodeling in children with severe asthma, the cross-sectional nature of the study prevents demonstration of a causal association between vitamin D and ASM (Gupta et al. 2011). Furthermore, vitamin D deficiency is associated with physical inactivity (Strine et al. 2007), which in turn is linked to the severity of asthma (Brock et al. 2010). As such, vitamin D may simply be acting as an indirect marker of physical activity levels. "
ABSTRACT: Vitamin D deficiency is associated with disease severity in asthma. We tested whether there is a causal association between vitamin D deficiency, airway smooth muscle (ASM) mass, and the development of airway hyperresponsiveness (AHR). A physiologically relevant mouse model of vitamin D deficiency was developed by raising BALB/c mice on vitamin D-deficient or -replete diets. AHR was assessed by measuring lung function responses to increasing doses of inhaled methacholine. Five-micron sections from formalin-fixed lungs were used for ASM measurement and assessment of lung structure using stereological methods. Transforming growth factor (TGF)-β levels were measured in bronchoalveolar lavage fluid (BALF). Lungs were dissected from embryonic day (E) 17.5 vitamin D-deficient and -replete fetal mice for quantification of ASM density and relative gene expression of TGF-β signaling pathway molecules. Eight-week-old adult vitamin D-deficient female mice had significantly increased airway resistance and ASM in the large airways compared with controls. Vitamin D-deficient female mice had a smaller lung volume, volume of parenchyma, and alveolar septa. Both vitamin D-deficient male and female mice had reduced TGF-β levels in BALF. Vitamin D deficiency did not have an effect on ASM density in E17.5 mice, however, expression of TGF-β1 and TGF-β receptor I was downregulated in vitamin D-deficient female fetal mice. Decreased expression of TGF-β1 and TGF-β receptor I during early lung development in vitamin D-deficient mice may contribute to airway remodeling and AHR in vitamin D-deficient adult female mice. This study provides a link between vitamin D deficiency and respiratory symptoms in chronic lung disease.03/2014; 2(3). DOI:10.1002/phy2.276
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ABSTRACT: In developed countries approximately one-quarter of adults with asthma are active cigarette smokers. These individuals have poorly controlled symptoms, impaired therapeutic responses to corticosteroids, and increased rates of health care utilization compared to nonsmokers with asthma. Persistent airflow obstruction can develop in asthma, particularly in smokers. Accelerated loss of lung function in adulthood as well as genetic, environmental risk factors (other than smoking), and submaximal lung growth in childhood may also contribute to the development of persistent airflow obstruction in smokers with asthma. The best strategy for managing symptoms due to persistent airflow obstruction in smokers with asthma is uncertain and, in particular, which recommendations from international guidelines for asthma or COPD are most appropriate for the management of this patient group.
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ABSTRACT: Over the past 30 years there has been an epidemic of both obesity and asthma in the western world. A large body of robust epidemiological data has linked obesity with the development and severity of asthma in both children and adults and weight reduction with improvements in asthma severity and symptoms. However, it remains unsettled whether this relationship is causal or confounded by some other factor(s) as mechanistic and physiological studies have produced heterogeneous and at times conflicting findings. This review examines the clinical and epidemiological relationship between obesity and asthma and the purported mechanisms that may link these two processes together.Thorax 12/2008; 63(11):1018-23. DOI:10.1136/thx.2007.086819 · 8.56 Impact Factor