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

The relationship of polyunsaturated and monounsaturated fatty acids intake and serum concentrations on inhalant allergen sensitization and allergic rhinitis development

BACKGROUND

The increasing prevalence of allergic rhinitis may be attributed to lifestyle changes such as dietary habits. Regarding dietary factors, n-3 and n-6 polyunsaturated fatty acids (PUFAs) are considered to be involved in the pathogenesis. Therefore, we examined whether the intake and serum concentrations of fatty acids affect inhaled allergen sensitization and the development of allergic rhinitis.

METHODS

In total, 571 participants (20-69 years) from the Iwaki Health Promotion Project, a community-based project in 2022, were surveyed. Based on the results of PUFA intake and serum fatty acid concentrations obtained using a self-administered diet-history questionnaire, we examined whether n-3 or n-6 PUFAs were involved in reducing or increasing the risk of sensitization, respectively, and developing the disease. We also analyzed whether monounsaturated fatty acids-palmitoleic acid and oleic acid-were risk factors for sensitization and development. Univariate dietary intake, serum concentration, and logistic regression analyses were performed to identify the risk factors.

RESULTS

Our study revealed that higher serum concentrations of n-3 PUFAs were associated with a decreased risk of developing rhinitis, but had no effect on allergen sensitization in younger age group <50 years. Furthermore, palmitoleic acid had increased sensitization, and oleic acid may also increase the risk of the allergen sensitization.

CONCLUSIONS

n-3 PUFAs may reduce the risk of developing allergic rhinitis. Notably, palmitoleic acid may be a new risk factor that increases the risk of inhalant allergen sensitization and allergic rhinitis. These findings are significant in understanding the role of dietary factors in allergic rhinitis.

Serum bile acid and unsaturated fatty acid profiles of non-alcoholic fatty liver disease in type 2 diabetic patients

BACKGROUND

The understanding of bile acid (BA) and unsaturated fatty acid (UFA) profiles, as well as their dysregulation, remains elusive in individuals with type 2 diabetes mellitus (T2DM) coexisting with non-alcoholic fatty liver disease (NAFLD). Investigating these metabolites could offer valuable insights into the pathophy-siology of NAFLD in T2DM.

AIM

To identify potential metabolite biomarkers capable of distinguishing between NAFLD and T2DM.

METHODS

A training model was developed involving 399 participants, comprising 113 healthy controls (HCs), 134 individuals with T2DM without NAFLD, and 152 individuals with T2DM and NAFLD. External validation encompassed 172 participants. NAFLD patients were divided based on liver fibrosis scores. The analytical approach employed univariate testing, orthogonal partial least squares-discriminant analysis, logistic regression, receiver operating characteristic curve analysis, and decision curve analysis to pinpoint and assess the diagnostic value of serum biomarkers.

RESULTS

Compared to HCs, both T2DM and NAFLD groups exhibited diminished levels of specific BAs. In UFAs, particular acids exhibited a positive correlation with NAFLD risk in T2DM, while the ω-6:ω-3 UFA ratio demonstrated a negative correlation. Levels of α-linolenic acid and γ-linolenic acid were linked to significant liver fibrosis in NAFLD. The validation cohort substantiated the predictive efficacy of these biomarkers for assessing NAFLD risk in T2DM patients.

CONCLUSION

This study underscores the connection between altered BA and UFA profiles and the presence of NAFLD in individuals with T2DM, proposing their potential as biomarkers in the pathogenesis of NAFLD.

Increased blood eosinophils and airflow obstruction as new-onset asthma predictors in the elderly: The Nagahama study

BACKGROUND

Asthma in the elderly needs more attention in an aging society. However, it is likely to remain underdiagnosed and undertreated. This study aimed to clarify clinical characteristics of new-onset asthma in the elderly, describing the prevalence, predictive factors, and comorbidities after asthma diagnosis of new-onset asthma in the elderly in the general population.

METHODS

This community-based prospective cohort study enrolled 9804 generally healthy participants (30-74 years old) in Nagahama City, and conducted a follow-up assessment after 5 years. Elderly participants were those aged ≥65 years at baseline. Patients with new-onset asthma were defined as participants without asthma at baseline assessment and with asthma at the follow-up assessment.

RESULTS

Among the 7948 participants analyzed in this study, 28 (1.4%) elderly and 130 (2.2%) non-elderly had new-onset asthma. Multiple logistic regression analysis revealed low forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) and high blood eosinophil counts at baseline as predicting factors for new-onset asthma in the elderly. Additionally, subsequent incidence of new-onset asthma was higher in elderly participants with both predictors (high blood eosinophil counts and low FEV1/FVC at baseline) than those with none or one of the predictors before asthma diagnosis. Lastly, elderly patients with new-onset asthma had more frequent comorbidity of moderate to severe sleep disordered breathing than those non-elderly.

CONCLUSIONS

Eosinophilic inflammation and airflow obstruction may predict subsequent new-onset asthma after the age of 65 years. Revealing the characteristics of new-onset asthma in the elderly can aid in the prevention of underdiagnosed asthma.