As one of the most common chronic respiratory diseases; asthma affects about 358 million people worldwide. It is projected that by 2025, this number will increase to 400 million. As a major cause of disability, absenteeism, and huge medical expenses, asthma places a substantial burden on the whole society. The total annual cost of asthma; including the direct medical cost of asthma (such as hospitalization and pharmacological treatment); the indirect nonmedical cost of asthma (such as missed workdays and school days); is estimated to be EUR 19.3 billion in Europe and $81.9 billion in the United States.
Obesity, as is known to all, is also a worldwide public health problem. In 2015, approximately 107.7 million children and 603.7 million adults worldwide were obese; accounting for about 30% of the world’s population. A recent study that analyzed data from 195 countries around the world found that the prevalence of obesity has doubled in more than 70 countries over the past 25 years.
Databases including PubMed, Web of Science, China National Knowledge Infrastructure, China Biology Medicine disc, Chinese Scientific and Technological Journal Database and Wanfang Data searched up to February 2018 to collect all relevant studies. Reference lists of related articles also checked. After study selection and data extraction, a meta-analysis to calculate the pooled odds ratio (OR) and corresponding 95% confidence interval (CI).
Subgroup analyses by study design and age groups of participants further performed. Publication bias via Begg’s rank correlation and Egger’s linear regression methods. A total of 13 studies included in the final meta-analysis, including 2 case-control studies, 6 cohort studies, and 5 cross-sectional studies. Our meta-analysis observed a positive association between abdominal obesity and asthma (OR = 1.47, 95% CI 1.35-1.59).
No evidence of heterogeneity (I2 = 10.7%) or publication bias (Begg’s test P = 0.200, Egger’s test P = 0.146). Subgroup analyses by study design and age groups of participants obtained consistently positive results across subgroups. Moreover, our meta-analysis observed similar results when considering this association separately in males and females (Males: OR = 1.37, 95% CI 1.18-1.58; Females: OR = 1.39, 95% CI 1.22-1.58).
Abdominal overweight and asthma
In addition, the association between abdominal overweight and asthma was further explored in this meta-analysis and the pooled OR and 95% CI was 1.13 (1.03, 1.24), indicating that there is a dose-response relationship between abdominal weight status and asthma.
The meta-analysis shows a positive association between abdominal obesity and asthma. Moreover, this association is similar in males and females. In addition, our meta-analysis indicates that there is a dose-response relationship between abdominal weight status and asthma. Therefore, addressing abdominal obesity issue is of great importance. More studies are the future to clarify the association between abdominal obesity and asthma.