Obesity, but not metabolic syndrome, as a risk factor for late-onset asthma in Japanese women

Evaluation of elevated plasma fatty acids as relevant factors for adult-onset asthma: The Nagahama Study

BACKGROUND

Obesity and increased body mass index (BMI) are the known risk factors for adult-onset asthma. Serum free fatty acid (FFA) and other blood lipid levels are generally elevated in patients with obesity and may be involved in the onset of asthma. However, it remains largely unknown. This study aimed to elucidate the relationship between plasma fatty acids and new-onset asthma.

METHODS

This community-based Nagahama Study in Japan enrolled 9804 residents. We conducted self-reporting questionnaires, lung function tests, and blood tests at baseline and 5 years later as follow-up. At the follow-up, plasma fatty acids were measured using gas chromatography-mass spectrometry. Body composition analysis was also measured at the follow-up. The associations between fatty acids and new-onset asthma were evaluated using a multifaceted approach, including targeted partial least squares discriminant analysis (PLS-DA).

RESULTS

In PLS-DA for new-onset asthma, palmitoleic acid was identified as the fatty acid most associated with asthma onset. In the multivariable analysis, higher levels of FFA, palmitoleic acid, or oleic acid were significantly associated with new-onset asthma, independent of other confounding factors. The high body fat percentage itself was not the relevant factor, but showed a positive interaction with plasma palmitoleic acid for new-onset asthma. When stratified by gender, the impacts of higher levels of FFA or palmitoleic acid on new-onset asthma remained significant in females, but not in males.

CONCLUSIONS

Elevated levels of plasma fatty acids, particularly palmitoleic acid, may be a relevant factor for new-onset asthma.

The association between body mass index, abdominal fatness, and weight change and the risk of adult asthma: a systematic review and meta-analysis of cohort studies

Obesity has been associated with increased risk of adult asthma, however, not all studies have found a clear association between overweight and the incidence of asthma, and data on other adiposity measures have been limited. Hence, we aimed to summarize evidence on association between adiposity and adult asthma. Relevant studies were retrieved through searches conducted in PubMed, and EMBASE up to March 2021. A total of sixteen studies (63,952 cases and 1,161,169 participants) were included in the quantitative synthesis. The summary RR was 1.32 (95% CI 1.21-1.44, I² = 94.6%, p_{heterogeneity}< 0.0001, n = 13) per 5 kg/m² increase in BMI, 1.26 (95% CI 1.09-1.46, I² = 88.6%, p_{heterogeneity} < 0.0001, n = 5) per 10 cm increase in waist circumference and 1.33 (95% CI 1.22-1.44, I² = 62.3%, p_{heterogeneity}= 0.05, n = 4) per 10 kg increase in weight gain. Although the test for nonlinearity was significant for BMI (p_nonlinearity < 0.00001), weight change (p_nonlinearity = 0.002), and waist circumference (p_nonlinearity = 0.02), there was a clear dose-response relationship between higher levels of adiposity and asthma risk. The magnitude of the associations and the consistency of the results across studies and adiposity measures provide strong evidence that overweight and obesity, waist circumference and weight gain increases asthma risk. These findings support policies to curb the global epidemic of overweight and obesity.

Female-biased association of NOS2-c.1823C>T (rs2297518) with co-susceptibility to metabolic syndrome and asthma

The nitric oxide (NO) pathway contributes to the pathogeneses of metabolic syndrome (MetS) and asthma. NOS2 encodes inducible-NO synthase, which is an important enzyme of the pathway, and its variations could affect the risk of asthma and MetS and thereby co-susceptibility to them. This study aims to estimate the association of NOS2-c.1823C>T with risk of asthma, MetS, and asthma with MetS condition (ASMetS), and with asthma stages: intermittent, mild, moderate, and severe asthma. The study included asthmatics (n = 555), MetS (n = 334), and ASMetS cases (n = 232) and 351 controls, which were genotyped by the PCR-RFLP method. The T allele was significantly associated with an increased risk of asthma and MetS in the sample population and females. CT genotype and CT+TT model were significantly associated with increased risk of ASMetS in females. A significant association between CT genotype and increased risk of ASMetS in the sample population and females was found in ASMetS versus MetS. In the sample population and among females, the T allele was significantly associated with severe asthma. The rs2297518 single nucleotide polymorphism of NOS2 contributes to the risk of MetS, asthma, and co-susceptibility to them, and this contribution may be stronger in females compared to males.

Identification of asthma cases in Japan using health insurance claims data: Positive and negative predictive values of proposed discrimination criteria: A single-center study

BACKGROUND

Asthma cases have been increasingly investigated using claims data. However, the validity of defining asthma cases using health insurance claims in Japan is unclear. This study aims to assess the positive and negative predictive values of our proposed discrimination criteria for asthma.

METHODS

We developed discrimination criteria for asthma based on both the International Statistical Classification of Diseases and Related Health Problems (ICD)-10 disease codes for asthma and health insurance claims data for prescriptions and the treatment of asthma. Inclusion criteria were patients aged ≥16 years with at least one health insurance claim from April 2018 to March 2019 in all departments of our hospital. Physician-diagnosed asthma documented in the charts was used as the reference standard. Positive and negative predictive values of the discrimination criteria for physician-diagnosed asthma were estimated and compared with those estimated from discrimination criteria based solely on ICD-10 codes.

RESULTS

The new discrimination criteria had a high positive predictive value (PPV) of 86.0%, which was significantly higher than the PPV for the criteria defined solely by the ICD-10 codes (61.5%) (P < 0.01). The negative predictive values for both criteria were 100%. Allergic rhinitis and chronic cough were frequently misclassified as asthma using the discrimination criteria based solely on ICD-10 codes but were more likely to be appropriately classified using our proposed criteria.

CONCLUSIONS

Our proposed criteria adequately identified asthma subjects using health insurance claims data in Japan with a high PPV. Further studies are needed for external validation of these criteria.

Longitudinal changes in the prevalence of adult asthma: An epidemiological survey among Japanese salaried employees and their dependents using healthcare insurance claim from 1999 to 2019

BACKGROUND

Information on changes in asthma prevalence and the treatment status for asthma is used as basic information for taking medical and administrative measures against asthma. However, this information among adults is relatively limited.

METHODS

To elucidate changes in the prevalence of asthma and treatment status over time among Japanese adults, health insurance claim data from some health insurance societies covering salaried employees and their dependents were studied longitudinally. Claim data from FY1999 to 2007 were obtained from two health insurance societies, and data from FY 2011 to 2019 were obtained from three different health insurance societies, and changes in standardized asthma prevalence among subjects aged 20-59 years, proportion of asthma patients prescribed ICS, leukotriene receptor antagonist (LTRA), and LABA, and the mean number of acute asthma exacerbations per year were analyzed.

RESULTS

The prevalence of asthma increased from 1.6% in 1999 to 3.0% in 2007 and 2.9% in 2011 to 4.6% in 2019. Increased trends in asthma prevalence from 2011 to 2019 were more noticeable in subjects in their 50s than those in their 20s for both sexes. The number of emergency visits related to asthma was 1.5 per year in 1999, which decreased to 0.8 per year in 2019. The proportion of people prescribed all anti-asthma medications (ICS, LTRA, and LABA) increased over time.

CONCLUSIONS

The prevalence of adult asthma among Japanese salaried employees and their dependents has increased over the last 20 years, suggesting more attention should be paid to the prevention of this disease in adults.

Obesity affects pulmonary function in Japanese adult patients with asthma, but not those without asthma

Obesity is associated with the severity of asthma, which is characterized by airway obstruction. Pulmonary function testing is one of the important examinations for evaluating airway obstruction. However, the impact of obesity on pulmonary function in patients with asthma is not fully understood. A total of 193 patients with asthma and 2159 patients without asthma who visited Saga University Hospital were investigated retrospectively. Obesity was defined as a body mass index (BMI) greater than 25 kg/m². Pulmonary functions including forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) were compared between patients with and without asthma, focusing especially on obesity. FVC percent predicted and FEV₁ percent predicted were significantly lower in patients with asthma than in those without asthma (p = 0.03, < 0.01 respectively). In patients with asthma, FVC percent predicted and FEV₁ percent predicted were significantly lower in patients with obesity than in those without obesity (all p < 0.01). In addition, BMI was negatively correlated with FEV₁ (r =- 0.21, p = 0.003) and FVC (r = - 0.15, p = 0.04), along with the percent predicted. On multivariate analysis in patients with asthma, FVC (β [95% confidence interval] 0.12 [0.02-0.22], p = 0.02) and FEV₁ (0.13 [0.05-0.22], p < 0.01) were still significantly different between patients with and without obesity. However, these obesity-associated differences were not observed in patients without asthma. Obesity reduces pulmonary function, including FVC and FEV₁, in patients with asthma, but not in those without asthma.

Associations Between Asthma and Polycystic Ovary Syndrome: Current Perspectives

A potential correlation between polycystic ovary syndrome (PCOS) and asthma, used to be identified as diseases originating from two independent systems, has been supported by increasing evidence. From an epidemiological perspective, mounting studies have confirmed that women suffering from PCOS exhibit increased susceptibility to asthma. Meanwhile, PCOS and asthma seem to share several mutual pathological conditions, such as metabolic disorders, hormonal fluctuation, proinflammatory state, etc. Here, we further elucidate the correlation between asthma and PCOS by focusing on the internal common pathophysiology and adverse influences on women's health. Understanding the internal connection between PCOS and asthma may shed light on developing new prevention and control strategies to fight against these conditions.

Uncontrolled Asthma Determinants In Overweight And Obese Adults

Relevance of the research — epidemiological and clinical studies in recent years confirmed the existence of a bronchial asthma (BA) phenotype associated with obesity. In the current literature, obesity is considered a possible risk factor for the development of BA. Nonetheless, the factors contributing to the uncontrolled course of BA among overweight patients need to be elucidated. The need for a personalized approach to patient management is reflected in the latest edition of the international consensus document on the asthma treatment – GINA (Global Initiative for Asthma: Global Strategy for Asthma Management and Prevention). Despite substantial number of epidemiological studies on the prevalence of BA in obese patients, the threshold values of major risk factors for the development of uncontrolled BA (vitamin D, IL-17, IL-10, BMI; intake of total fat, carbohydrates and cholesterol) remain unclear. Objective: to identify the risk of developing an uncontrolled course of BA depending on the levels of IL-17, IL-10 and vitamin D; dietary characteristics (intake of total fat, cholesterol and carbohydrates); and body mass index (BMI). Material and methods — The study involved 79 patients with an established diagnosis of BA, 18-69 years old. Patients were split among three groups according to their BMI values. Group I included 27 patients with normal body weight (BMI: 18.5-24.9 kg/m2), 56 (42-61) years of age. Group II comprised 28 overweight patients (BMI: 25-30 kg/m2), 57 (50.5-63.5) years of age; Group III encompassed 24 obese patients (BMI≥30 kg/m2), 58 (54-65) years of age. Results — the risk of developing uncontrolled BA increased by 1.8 times with increase of a total fat intake (95% CI: 1.28-2.72; p=0.001); by 5.7 times with BMI>26.7 kg/m2 (95% CI:2.05-15.92; p<0.001); by 5.2 times with IL-17 level >83.5 pg/mL (95% CI:1.71-15.8; p=0.003); by 8.32 times with vitamin D content <24.5 ng/mL (95% CI: 2.9-23.72; p<0.001). Conclusion — patients with BMI>26.7 kg/m2, vitamin D deficiency (i.e., vitamin D content <24.5 ng/mL), IL-17 content >83.5 pg/mL, as well as excessive consumption of total fat, carbohydrates and cholesterol, could be attributed to the risk group for developing an uncontrolled BA.

Obesity, Inflammation, and Severe Asthma: an Update

Purpose of Review

Obesity-associated difficult asthma continues to be a substantial problem and, despite a move to address treatable traits affecting asthma morbidity and mortality, it remains poorly understood with limited phenotype-specific treatments. The complex association between asthma, obesity, and inflammation is highlighted and recent advances in treatment options explored.

Recent Findings

Obesity negatively impacts asthma outcomes and has a causal link in the pathogenesis of adult-onset asthma. Imbalance in the adipose organ found in obesity favours a pro-inflammatory state both systemically and in airways. Obesity may impact currently available asthma biomarkers, and obesity-associated asthma specific biomarkers are needed. Whilst surgical weight loss interventions are associated with improvements in asthma control and quality of life, evidence for pragmatic conservative options are sparse. Innovative approaches tackling obesity-mediated airway inflammation may provide novel therapies.

Summary

The immunopathological mechanisms underlying obesity-associated asthma require further research that may lead to novel therapeutic options for this disease. However, weight loss appears to be effective in improving asthma in this cohort and focus is also needed on non-surgical treatments applicable in the real-world setting.

Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective

An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia.

Methods

We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development.

Results

Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73–5.82) for the family history of asthma, 3.50 (95% CI: 2.62–4.67) for the family history of atopy, 3.57 (95% CI: 3.03–4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47–2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12–6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23–1.38), cigarette smoke exposure (1.44, 95% CI: 1.30–1.60), cigarette smoking (1.66, 95% CI: 1.44–1.90), body mass index (BMI)–related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO₂, PM10, and O₃; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32).

Conclusions

The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00273-x.

A Potential Link Between Polycystic Ovary Syndrome and Asthma: a Meta-Analysis

While there exists some evidence indicating a higher prevalence of asthma in polycystic ovary syndrome (PCOS) patients, whether PCOS is an independent risk factor for asthma remains debatable. In this report, a systematic review and meta-analysis were performed to assess the association between PCOS and asthma. Using of the terms "PCOS," "polycystic ovary syndrome," "polycystic ovarian syndrome," "Stein Leventhal Syndrome," "asthma," and "wheezing," PubMed, Embase, Web of Science, Scopus, Cochrane Trial Register, China National Knowledge Infrastructure (CNKI), and Wanfang databases were searched for studies published from their inceptions to February 2021. The data were extracted and a meta-analysis was conducted under the guidance of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A random-effects model was used to calculate the odds ratios (OR) and 95% confidence intervals (95% CI). A total of 6 articles involving 26,876 PCOS women and 156,143 healthy controls were included in this survey. Our results indicate that PCOS patients showed an increased risk of asthma (OR = 1.75, 95% CI = 1.40-2.19, I² = 91.2%, P = 0.000, random-effects model). No statistically significant differences were obtained when these data were stratified by region, diagnostic criteria for asthma, and study design. PCOS is associated with a higher risk of asthma, a relationship which is independent of region, diagnostic criteria for bronchitis, and study design.

Additive Effect of Obesity and Dyslipidemia on Wheezing in Korean Adults: A Nationwide Representative Survey Study

Besides obesity, there are limited studies regarding the relationship between the individual components of metabolic syndrome and wheezing. It is largely unknown whether the co-existence of other metabolic syndrome components has additive effects on wheezing in the adult population. The association between the individual components of metabolic syndrome and current wheezing was evaluated in adults using data from the Korea National Health and Nutrition Examination Survey from 2008 to 2012. Subjects with metabolic syndrome more frequently had wheezing during the past 12 months (current wheezing) (adjusted odds ratio [aOR] = 1.56; 95% confidence interval [CI] = 1.37–1.77) and wheezing during exercise in the past 12 months (aOR = 1.59; 95% CI = 1.37–1.84). Of the individual metabolic syndrome components, central obesity (aOR = 1.48; 95% CI = 1.31–1.66) and low high-density lipoprotein (HDL) cholesterol (aOR = 1.18; 95% CI = 1.05–1.34) were significantly associated with current wheezing. There were no significant associations between the other components of metabolic syndrome (high triglyceride level, blood pressure, and fasting plasma glucose level) and the presence of current wheezing. In addition, the association was much higher when both central obesity and low HDL cholesterol were present together compared to when either of the conditions was present alone (aOR = 1.67; 95% CI = 1.44–1.94). There is a significant association between metabolic syndrome and current wheezing in Korean adults. Of the components of metabolic syndrome, low HDL cholesterol and central obesity are independently and additively associated with the increased rate of current wheezing.

Clinical Differences between Early- and Late-Onset Asthma: A Population-Based Cross-Sectional Study

Background

Limited information exists about the nature of late-onset asthma (LOA) without medication intervention when compared to early-onset asthma (EOA). Our goal was to understand how EOA and LOA affect clinical and pathophysiological features.

Methods

A population-based cross-sectional study was carried out in Zhongshan Hospital (Shanghai, China). EOA and LOA were based on age of diagnosis (before and after age 40 years, respectively). Clinical variables were collected with an emphasis on allergic features, analyzed, related, and compared using one-way ANOVA or Kruskal-Wallis test. Correlations between blood basophils and clinical data were evaluated by Spearman's rank test. Statistical analyses were conducted with SPSS v24.0.

Results

Of a total of 12,760 adults with cough, sputum, or chest tightness, 90 subjects with EOA (mean age ± standard deviation (SD):28.73 ± 5.89), 111 with LOA (mean age ± SD: 60.25 ± 9.85), and 106 with chronic obstructive pulmonary disease (COPD) (mean age ± SD: 61.58 ± 10.95) were selected. FEV₁/FVC (%), FEV₁% predicted, and FVC% predicted were all significantly lower in LOA compared to EOA (p < 0.01). The values of post-bronchodilator FEV₁ in bronchodilator reversibility testing were higher in the LOA and EOA groups compared to subjects with COPD (p < 0.01). Among allergic features, mite sensitization was most common in EOA patients, followed by LOA and COPD, whereas mold sensitization was more prevalent in LOA than EOA. Moreover, blood eosinophils were a typical feature of asthma in both EOA and LOA compared to COPD and controls (p < 0.01), and there were no differences in blood neutrophils in LOA compared to controls. Interestingly, blood basophils were increased in both EOA (p < 0.01) and LOA (p < 0.05) compared to COPD and controls. This variable correlated with eosinophils in EOA (r = 0.549, p=0.002) but not in LOA.

Conclusion

LOA is a distinct clinical entity from EOA. In LOA, atopy was less frequent and spirometry values were lower when compared to EOA. In EOA, blood basophils and eosinophils were significantly correlated owing to pathophysiological differences between the two forms of the disease.

Metabolic Syndrome and Incident Asthma in Chinese Adults: An Open Cohort Study

BACKGROUND

Although metabolic syndrome is awell-known risk factor for many non-communicable diseases, its contribution to asthma remains controversial.

OBJECTIVE

The aim of this study was to explore the associations of metabolic syndrome and its components with incident asthma in Chinese adults.

METHODS

We conducted an open cohort study of participants who were asthma-free at baseline (n=42,304) in the Shandong multi-center health check-up longitudinal study from 2004 to 2015. Participants aged ≥20 years and had regular physical examination (once ayear) more than three times during follow-up.

RESULTS

Ninety subjects (38 women and 52 men) developed incident asthma over 12 years of follow-up. Our study suggested that metabolic syndrome itself was not significantly associated with incident asthma in either women or men (P>0.050). Interestingly, we found that overweight and/or obesity was arisk factor for incident asthma among women but not men in the Cox proportional hazards model after adjusting covariates (adjusted incidence rate ratio (IRR)= 2.940, 95% confidence interval (CI): 1.467-5.894, P=0.002). The result was consistent with the Poisson regression model (hazard ratio (HR)= 2.241, 95% CI: 1.135-4.988, P=0.026). After stratifying according to overweight and/or obesity, we found that female subjects with overweight and obesity were associated with the occurrence of incident asthma (P<0.050). However, we did not find this result among men.

CONCLUSION

Metabolic syndrome was not significantly associated with incident asthma in both women and men; however, overweight and/or obesity was shown to be asignificant risk factor for incident asthma but only in women, not in men.

Crosstalk Among Circadian Rhythm, Obesity and Allergy

The circadian clock system works not only as a cellular time-keeper but also as a coordinator for almost all physiological functions essential to maintaining human health. Therefore, disruptions or malfunctions of this system can cause many diseases and pre-symptomatic conditions. Indeed, previous studies have indicated that disrupted clock gene expression rhythm is closely related to obesity, and that allergic diseases can be regulated by controlling peripheral clocks in organs and tissues. Moreover, recent studies have found that obesity can lead to immune disorders. Accordingly, in this review, we assess the connection between obesity and allergy from the point of view of the circadian clock system anew and summarize the relationships among the circadian clock system, obesity, and allergy.

Severe asthma in Japan

The characteristic phenotype of severe asthma in Japan seems to be distilled into the following two features: low incidence of obesity and high prevalence of patients with type 2 inflammation. Only 5-7% of Japanese severe asthma patients had a body mass index (BMI) ≥30 kg/m², and more than 80% of patients with severe asthma exhibited type 2 inflammation. Although the relationship between obesity and non-type 2 inflammation is complex, the low incidence of obesity might explain the prevalence of type 2 inflammation. Some asthma cohorts in Japan have investigated the roles of type 2 biomarkers extensively, including periostin, to identify a severe phenotype, suggesting the utility of combining biomarkers to identify an exacerbation-prone subgroup. Although the prevalence of severe asthma is comparable to Western countries, the rate of asthma death and disease burden seems to be lower in Japan. These trends might be due to the system of public health insurance for the whole nation, leading to good access to hospital and asthma specialists due to the geographically narrow country. In this review article, we will discuss the definition, epidemiology, comorbidities, biomarkers, specific phenotype, and current treatment for severe asthma in Japan.