Associations of genetic determinants of serum vitamin B12 and folate concentrations with hay fever and asthma: a Mendelian randomization meta-analysis

Association of food folate with asthma in US children and adolescents: a cross-sectional study

BACKGROUND

Asthma is a chronic inflammatory disease. Currently, contradictory findings exist regarding the association between food folate and asthma. Therefore, we hypothesize a positive correlation between food folate and asthma.

PURPOSE

To investigate the possible relationship between food folate intake and the development of asthma in children and adolescents in the United States.

METHODS

Data from the U.S. National Health and Nutrition Examination Survey (NHANES) from 2009 to 2018 were analyzed cross-sectionally by covariate adjustment using multivariate logistic regression, restricted triple spline curves, threshold effects, and stratified analyses.

RESULTS

There were 8,821 participants, of whom 1,697 (19.2%) self-reported having received a diagnosis of asthma from a physician or other health professional. After accounting for potential confounders, the adjusted odds ratios (ORs) for asthma in the second (T2, 111-178 µg/day) and third (T3, >178 µg/day) groups were 1.15 (1-1.33) and 1.23 (1.04-1.46), respectively, compared with the group with the lowest food folate intake (T1, <111 µg/day). In addition, the association between food folate intake and asthma showed an inverse L-shaped curve (non-linear relationship, p = 0.003), and stratified analysis further validated the robustness of the results. The OR of asthma in subjects with food folate intake less than 263.9 µg/day was 1.002 (1.001-1.004).

CONCLUSION

In children and adolescents in the United States, there is a non-linear association (inverted "L" shape) between food folate intake and asthma, with an inflection point at 263.9 micrograms per day.

Dietary patterns and micronutrients in respiratory infections including COVID-19: a narrative review

BACKGROUND

COVID-19 is a pandemic caused by nCoV-2019, a new beta-coronavirus from Wuhan, China, that mainly affects the respiratory system and can be modulated by nutrition.

METHODS

This review aims to summarize the current literature on the association between dietary intake and serum levels of micronutrients, malnutrition, and dietary patterns and respiratory infections, including flu, pneumonia, and acute respiratory syndrome, with a focus on COVID-19. We searched for relevant articles in various databases and selected those that met our inclusion criteria.

RESULTS

Some studies suggest that dietary patterns, malnutrition, and certain nutrients such as vitamins D, E, A, iron, zinc, selenium, magnesium, omega-3 fatty acids, and fiber may have a significant role in preventing respiratory diseases, alleviating symptoms, and lowering mortality rates. However, the evidence is not consistent and conclusive, and more research is needed to clarify the mechanisms and the optimal doses of these dietary components. The impact of omega-3 and fiber on respiratory diseases has been mainly studied in children and adults, respectively, and few studies have examined the effect of dietary components on COVID-19 prevention, with a greater focus on vitamin D.

CONCLUSION

This review highlights the potential of nutrition as a modifiable factor in the prevention and management of respiratory infections and suggests some directions for future research. However, it also acknowledges the limitations of the existing literature, such as the heterogeneity of the study designs, populations, interventions, and outcomes, and the difficulty of isolating the effects of single nutrients from the complex interactions of the whole diet.

TCN1 Expression Is Increased in Asthma

INTRODUCTION

Asthma is a chronic disease that affects populations worldwide. The purpose of this study was to investigate the expression of TCN1 in sputum and its correlation with inflammation and lung function in asthma.

METHODS

We recruited 141 subjects, detected TCN1 mRNA level by quantitative reverse transcription polymerase chain reaction, detected TCN1 protein expression by Western blot, detected TCN1 protein level by enzyme-linked immunosorbent assay, and analyzed the correlation between TCN1 and fraction of exhaled nitric oxide (FeNO), IgE, EOS%, lung functions, and some Th2 cytokines. The diagnostic value of TCN1 was evaluated by receiver operating characteristics curve. The expression of TCN1 was further confirmed by human bronchial epithelial cell in vitro.

RESULTS

Compared with the health group, the expression of TCN1 in induced sputum cells increased in asthma group and was correlated with FeNO, IgE, and EOS%. TCN1 level was also elevated in the induced sputum supernatant of asthma patients. The protein level of TCN1 in induced sputum supernatant was correlated with FeNO, IgE and PC-20, forced expiratory volume in the first second (FEV1)%pred, FEV1/FVC, and some cytokines (IL-4, IL-5, IL-10, IL-13, MUC5AC). TCN1 was also differentially expressed in patients with different severity of asthma. Four weeks after ICS treatment, the expression of TCN1 in induced sputum supernatant increased. In vitro, the protein level of TCN1 in human bronchial epithelial cells' supernatant increased after stimulated with IL-4 and IL-13.

CONCLUSION

The expression of TCN1 was increased in asthma patients' sputum, and was positively correlated with some inflammatory markers, negatively correlated with lung function. TCN1 may be used as a potential biomarker for the diagnosis and treatment of asthma.

The Role of Vitamins in the Pathogenesis of Asthma

Vitamins play a crucial role in the proper functioning of organisms. Disturbances of their levels, seen as deficiency or excess, enhance the development of various diseases, including those of the cardiovascular, immune, or respiratory systems. The present paper aims to summarize the role of vitamins in one of the most common diseases of the respiratory system, asthma. This narrative review describes the influence of vitamins on asthma and its main symptoms such as bronchial hyperreactivity, airway inflammation, oxidative stress, and airway remodeling, as well as the correlation between vitamin intake and levels and the risk of asthma in both pre- and postnatal life.

Low Vitamin B12 Levels and Its Association With Insulin Resistance: A Potent Cardiovascular Risk Indicator in Childhood Asthma

Introduction As insulin resistance metabolically affects the body mass index (BMI), obese asthma children have more severe diseases than children with normal body mass index. A low level of vitamin B12 (Vit B12) is a known atherogenic factor by increasing the homocysteine level and therefore promotes cardiovascular morbidity and mortality. Limited studies have evaluated the role of serum B12 and insulin resistance among poorly controlled asthma in children. The purpose of the study was to compare the cardio-metabolic risk factor such as BMI, waist-hip ratio (WHR), insulin resistance, and vitamin B12 in well-controlled and poorly-controlled asthma patients and to determine the relationship between these parameters with the severity of asthma as assessed by Pulmonary Function Test. Methodology Based on the asthma control questionnaire and Global Initiative for Asthma (GINA) criteria, chronic asthma patients (n=60) of age 10-15 years were divided into two groups, namely well-controlled and poorly-controlled (30 each). Anthropometry was assessed by BMI and waist-hip ratio, and fasting blood samples were collected for the estimation of blood glucose, insulin, and serum vitamin B12 levels. Insulin resistance (HOMA-IR) was calculated using the formula- fasting glucose (mg/dL) x fasting insulin (µIU/mL)]/405. Forced expiratory volume (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio were measured to assess the pulmonary function test. Results There were significant differences in the values of the BMI, insulin resistance, vitamin B12, and pulmonary function tests between poorly controlled and well-controlled asthma (p<0.01). The FEV1: FVC% was negatively correlated with BMI (r=0.53), WHR (r=0.50), glucose (r=0.68), insulin (r=0.68), Insulin resistance (r=0.80), and positive correlation with Vit B12 (0.73). In addition, Vit B12 and HOMA-IR correlate negatively (r=0.76). Conclusion This study concludes that the level of Vit B12 is decreased and insulin resistance is increased in poorly controlled asthmatic children in comparison to well-controlled asthma. These factors along with the increased BMI in poorly controlled asthma can predispose to cardiometabolic risk which needs attention.

Causal risk factors for asthma in Mendelian randomization studies: A systematic review and meta-analysis

BACKGROUND

Several risk factors for asthma have been proposed; however, the causality of these associations is sometimes unclear. Mendelian randomization is a powerful epidemiological approach that can help elucidate the causality of risk factors. The aim of the present study was to identify causal risk factors for asthma through Mendelian Randomization studies.

METHODS

A systematic search of PubMed and EMBASE was conducted, to identify studies investigating risk factors for asthma or respiratory allergies through Mendelian Randomization. When two or more studies investigated the same risk factor a meta-analysis was conducted. Of 239 studies initially identified, 41 were included.

RESULTS

A causal association between adiposity and adult asthma risk was found in 10 out of 12 studies with a summary risk ratio of 1.05 per kg/m2 increase in BMI (95% CI: 1.03-1.07). Puberty timing (n = 3), alcohol (n = 2), and linoleic acid (n = 1) had causal effects on asthma risk, while vitamins/minerals (n = 6) showed no consistent effect on asthma. The effect of smoking on adult asthma conflicted between studies. Several of the significant associations of asthma with immune related proteins (n = 5) and depression (n = 2) investigated through multiple traits analyses could generally benefit from replications in independent datasets.

CONCLUSION

This systematic review and meta-analysis found evidence for causal effects of adiposity, puberty timing, linoleic acid, alcohol, immune related proteins, and depression on risk of asthma.

Smoking behavior might affect allergic rhinitis and vasomotor rhinitis differently: A mendelian randomization appraisal

BACKGROUND

Allergic rhinitis and vasomotor rhinitis are harassing numerous patients and their risk factors have not been well investigated. Here, we try to identify their risk factors and distinguish these 2 diseases.

METHODS

A two-sample Mendelian randomization (MR) study was implemented to discover the risk factors of allergic and vasomotor rhinitis. Based on previous studies, we selected 15 potential risk factors and the genome-wide summary statistics were extracted from the non-FinnGen consortium. The genome-wide summary statistics of rhinitis were obtained from the FinnGen consortium. Both univariable MR and multivariable MR analyses were performed to identify the causal risk factors. The Cochrane's Q value was calculated to appraise the heterogeneity. MR-Egger intercept and MR-RPESSO were utilized to appraise the pleiotropy.

RESULTS

In the univariable model, the number of cigarettes per day can decrease the risk of allergic rhinitis (IVW OR = 0.29[0.18, 0.47], p-value = 2.70 × 10-7) while increasing the risk of vasomotor rhinitis (IVW OR = 1.30[1.04, 1.62], p-value = 0.022). Besides, no other risk factors could affect the risk of either allergic or vasomotor rhinitis. After adjusting for age of smoking initiation and alcohol intake, the cigarettes per day could still decrease the risk of allergic rhinitis (IVW OR = 4.66 × 10-3 [1.99 × 10-4, 0.11], p-value = 0.003) while not affecting the risk of vasomotor rhinitis (IVW OR = 0.92[0.44, 1.96], p-value = 0.834).

CONCLUSION

Smoking can affect the risk of allergic and vasomotor rhinitis differently where it decreases the risk of allergic rhinitis and increases the risk of vasomotor rhinitis.

Dietary Intake and Asthma in Preschoolers: A Logistic Lasso Regression Analysis

BACKGROUND

Asthma is a common chronic disease among children, especially preschoolers. Some evidence suggests that diet may play a role in asthma, but the current findings are contradictory. The objective of our study was to determine the association between dietary intake and asthma in preschool children aged 2-5 years.

METHODS

We selected preschool children aged 2-5 years with complete data on asthma diagnosis, diet, and body mass index (BMI) from the national health and nutrition examination survey (NHANES) database. In a selected population, children with self-reported asthma were included in the final sample. In children without self-reported asthma, we further used propensity score matching (PSM) to match age and sex for sampling, maintaining a ratio of 1:4 for cases. Lasso regression was used to identify dietary factors affecting asthma in preschoolers.

RESULTS

A total of 269 children with self-reported asthma and 1,076 children without self-reported asthma were included in our study. Univariate analysis showed that there were significant differences in ethnicity and dietary zinc intake between asthmatic children and children without asthma. After adjusting for all dietary and demographic variables, the results of logistic Lasso regression analysis showed that non-Hispanic black (β = 0.65), vitamin B12 (β = 0.14), and sodium (β = 0.05) were positively associated with childhood asthma, while Vitamin K (β = -0.04) was negatively associated with childhood asthma.

CONCLUSION

In conclusion, our study confirms that non-Hispanic black and dietary sodium intake are associated with a higher risk of asthma in preschoolers. In addition, our study found that dietary vitamin B12 was positively associated with childhood asthma, while vitamin K was negatively associated with childhood asthma.

Mineral Micronutrients in Asthma

Asthma represents one of the most common medical issues in the modern world. It is a chronic inflammatory disease characterized by persistent inflammation of the airways and disturbances in redox status, leading to hyperresponsiveness of bronchi and airway obstruction. Apart from classical risk factors such as air pollution, family history, allergies, or obesity, disturbances of the levels of micronutrients lead to impairments in the defense mechanisms of the affected organism against oxidative stress and proinflammatory stimuli. In the present review, the impact of micronutrients on the prevalence, severity, and possible risk factors of asthma is discussed. Although the influence of classical micronutrients such as selenium, copper, or zinc are well known, the effects of those such as iodine or manganese are only rarely mentioned. As a consequence, the aim of this paper is to demonstrate how disturbances in the levels of micronutrients and their supplementation might affect the course of asthma.

Immunologic Strategies for Prevention of Asthma

A new understanding of factors leading to the development of asthma has pointed to potential primary, secondary, and tertiary prevention strategies. Some, such as genetic makeup, are not yet modifiable. Interventions targeting other factors such as maternal intake of vitamin D or environmental control can be used to decrease the risk of asthma development (primary prevention). The benefits of a diversified microbiome could be considered when recommending allergen avoidance and pet ownership. In addition to reducing symptoms, allergen immunotherapy is also worth considering for prevention of new sensitivities (secondary prevention) in addition to the development of asthma. Ongoing studies involving the use of bacterial vaccines and biologics may provide additional strategies for primary prevention of asthma and for reducing symptoms once it has developed (tertiary prevention). As the relative benefits of these strategies are defined, they should have an increasingly important place in the prevention and management of asthma.

AllergoOncology: Microbiota in allergy and cancer-A European Academy for Allergy and Clinical Immunology position paper

The microbiota can play important roles in the development of human immunity and the establishment of immune homeostasis. Lifestyle factors including diet, hygiene, and exposure to viruses or bacteria, and medical interventions with antibiotics or anti-ulcer medications, regulate phylogenetic variability and the quality of cross talk between innate and adaptive immune cells via mucosal and skin epithelia. More recently, microbiota and their composition have been linked to protective effects for health. Imbalance, however, has been linked to immune-related diseases such as allergy and cancer, characterized by impaired, or exaggerated immune tolerance, respectively. In this AllergoOncology position paper, we focus on the increasing evidence defining the microbiota composition as a key determinant of immunity and immune tolerance, linked to the risk for the development of allergic and malignant diseases. We discuss novel insights into the role of microbiota in disease and patient responses to treatments in cancer and in allergy. These may highlight opportunities to improve patient outcomes with medical interventions supported through a restored microbiome.