Search Results (148)

Major mutations of SERPINA1, the gene encoding alpha1-antitrypsin (A1AT), are known to cause severe emphysema. Our study aimed to investigate the role of major mutations modulating A1AT levels in several lung pathologies and control groups. Blood samples were collected from healthy non-smokers (N⁰ = 85), healthy smokers (N⁰ = 291), healthy ex-smokers (N⁰ = 127), smokers with chronic obstructive lung disease (COPD, N⁰ = 187), ex-smokers with COPD (N⁰ = 64), and patients with asthma (N⁰ = 194), interstitial lung disease (ILD) (N⁰ = 93), sarcoidosis (N⁰ = 30) and cystic fibrosis (N⁰ = 26). Clinical and respiratory parameters, A1AT levels, the extent of emphysema and comorbidities on low-dose CT scans were evaluated, and patients answered a smoking history and comorbidity questionnaire. A1AT single-nucleotide polymorphisms were determined for the S, Z, M2/M4, 0 and eQTL locations by SNP probes using real-time PCR. A1AT levels showed significant differences between cigarette smoke-induced and other lung diseases. Compared to controls, A1AT levels were found to be lower in sarcoidosis and increasingly higher in smokers and patients with COPD, ILD and CF, respectively. The presence and pattern of emphysema were found to influence A1AT levels: lower values were observed in COPD patients without emphysema, while higher values were observed in patients with central and panlobular emphysema. Antitrypsin levels increased with COPD GOLD stages and asthma GINA stages. Variable A1AT levels were also found in ILD subgroups. The distribution of variants at the S, Z, M2/M4 and 0 polymorphic sites and the eQTL location showed no significant differences between patient groups with impaired lung function, except for Z heterozygotes, which were prevalent in patients with severe asthma. The eQTL TT genotypes had higher A1AT levels and the occurrence of emphysema and/or bronchitis was increased. A1AT levels correlated with several clinical and respiratory parameters in pulmonary patients, while FEV1/FVC inversely correlated with levels of A1AT. Molar antielastase activity was increased in smokers and patients with lung diseases; however, in COPD, antielastase activity decreased. The most reduced antielastase activity could be found in CF. Certain genotypes were characterized by increased cardiovascular comorbidity scores and antitrypsin levels. Our data suggest that in addition to emphysema, A1AT may play an important role in the development of a wide variety of lung diseases and cardiovascular comorbidities. Further research is needed to clarify the role of A1AT and its regulation in lung pathologies. Full article

Chronic obstructive pulmonary disease (COPD) is a chronic, debilitating condition that affects the lungs and airways. It is characterized by persistent bronchitis, a condition exemplified by the inflammation of the bronchial tubes, the hypersecretion of mucus, emphysema, and the destruction of the airway parenchyma. The combination of these conditions leads to persistent tissue damage, pulmonary fibrosis, and ongoing inflammation of the airways. The inflammatory response in COPD is a complex process that is orchestrated by a wide range of immune cells. These include lung epithelial cells, monocytes, macrophages, neutrophils, eosinophils, and T and B lymphocytes, among others. These cells work together to produce a wide range of inflammatory biomarkers that are involved in the pathogenesis of COPD. Some of the key inflammatory biomarkers that have been identified in COPD include a variety of cytokines, the C-reactive protein/serum albumin ratio, fibrinogen, soluble receptor for advanced glycation endproducts, club/clara cells in the lungs with a molecular weight of 16 kDa, surfactant protein D, adiponectin, reactive oxygen species, and proteases. This review aims to provide a comprehensive overview of the role of immune cells and key inflammatory biomarkers in the development and progression of COPD. It will delve into the intricacies of the inflammatory response in COPD, exploring the various cell types and biomarkers that are involved in this process. By understanding the underlying mechanisms that drive COPD, we can better develop targeted treatments that can help to alleviate the symptoms of COPD. Full article

The synthetic cortisol analog budesonide (BUD) is an essential drug employed to manage chronic inflammatory diseases in humans, mainly those involving gastroenteric and airway mucosa, such as rhinitis, laryngitis, bronchitis, esophagitis, gastritis, and colitis, with high levels of success. As a glucocorticoid, BUD prevents the expression of pro-inflammatory cytokines/chemokines and the recruitment of immune cells into the inflamed mucosa. However, emerging evidence indicates that BUD, unlike classical glucocorticoids, is also a potent modulator of stem and cancer cell behavior/plasticity. Certainly, BUD stabilizes cell–cell adhesions, preventing embryonic stem cell differentiation and inhibiting the development of 3D gastruloids. In addition, BUD inhibits the motile/invasive propensity of different cancer cells, including breast, lung, and pancreatic cancer. Finally, it prevents the infection of positive single-stranded human-infecting RNA viruses such as SARS-CoV-2. At a molecular level, BUD induces epigenetic changes and modifies the transcriptome of epithelial, stem, and cancer cells, providing molecular support to the immune cell-independent activity of BUD. Here, we performed an in-depth review of these unexpected activities of BUD, identified by unbiased drug screening programs, and we emphasize the molecular mechanisms modulated by this efficacious drug that deserve further research. Full article

Chronic obstructive pulmonary disease (COPD) is a leading chronic disease worldwide, with significant healthcare utilization, morbidity, and mortality. Irreversible airflow obstruction identified on spirometry establishes the diagnosis of COPD, but the disease entity encompasses a heterogeneous collection of lung diseases, including chronic bronchitis and emphysema. Despite the enormous burden of COPD, there are no pharmacological therapies that slow its progression or reduce mortality, indicating the need for a deeper understanding. There are sex differences concerning COPD prevalence, pathology, and symptoms. Historically thought to primarily affect males, its effect on females has increased significantly over time due to a rising prevalence of smoking and exposure to harmful pollutants among females. Over the past decade, the age-adjusted prevalence of COPD has been consistently higher in females than in males. Despite this, the impacts of biological sex continue to be confusing and poorly defined. The primary goal of this review is to organize and collate sex-dependent factors that may contribute to disease differences in males and females, thereby identifying future research questions in this area. Full article

Background: Blood pressure elevation in children is an important health concern. The extent to which hypertension is diagnosed in German pediatric practices is not yet known. The aim of this study is, therefore, to examine the prevalence of hypertension diagnosis in children and adolescents treated in pediatric practices, as well as the factors associated with hypertension in this population. Methods: This retrospective case–control study used electronic medical records from 258 primary care pediatricians in Germany and included children and adolescents aged 0–17 years with an initial documented diagnosis of primary hypertension between January 2005 and December 2023. Hypertension patients were matched 1:5 with non-hypertension patients by age and sex. Conditional multivariable logistic regression models were used to estimate the association of chronic diseases and therapies with a risk of hypertension. Results: After 1:5 matching, the present study included 7482 children and adolescents with hypertension, and 37,410 controls without hypertension. The average prevalence of hypertension was 0.12% and the incidence was 1.24 cases per 1000 person-years, both increasing with age. In the multivariable regression analysis, a significant positive association was observed between hypertension and ten disorders including obesity (odds ratio, OR: 6.91; 95% confidence intervals, CI: 6.28–7.60), type 1 diabetes mellitus (OR: 2.85; 95% CI: 2.13–3.82), dyslipidemia (OR: 1.99; 95% CI: 1.46–2.72), chronic bronchitis (OR: 1.63; 95% CI: 1.39–1.90), hypothyroidism (OR: 1.62; 95% CI: 1.30–2.02), migraine (OR: 1.52; 95% CI: 1.17–1.98), ADHD (OR: 1.45; 95% CI: 1.28–1.65), scoliosis (OR: 1.40; 95% CI: 1.13–1.73), chronic rhinitis (OR: 1.31; 95% CI: 1.14–1.50), and reaction to severe stress and adjustment disorders (OR: 1.31; 95% CI: 1.04–1.65). Furthermore, paracetamol prescription was positively associated with hypertension risk (OR: 1.68; 95% CI: 1.41–2.00). Conclusions: The significant associations between hypertension and chronic disorders, particularly obesity, underscore the need for early prevention strategies. Prospective studies are needed to confirm these associations. Similarly, pathophysiological and mechanistic explanations for the associations identified need to be explored and verified in properly designed studies. Full article

Petroleum refining and petrochemical complexes are significant sources of air pollution, emitting a variety of harmful pollutants with substantial health risks for nearby populations. While much of the information regarding this issue and the potential health impacts of this pollution has been documented, it remains fragmented across studies focusing on specific regions or health outcomes. These studies are often clustered into meta-analyses or reviews or exist as undeclared knowledge held by experts in the field, making it difficult to fully grasp the scope of the issue. To address this gap, our review consolidates the existing knowledge on the sources of air pollution from petroleum refining and petrochemical industries, the main pollutants involved, and their associated health outcomes. Additionally, we conducted an umbrella review of systematic reviews and meta-analysis and also included critical reviews. With this approach, we identified 12 reviews that comprehensively evaluate the health impacts in populations living near petroleum refining and/or petrochemical complexes. These reviews included studies spanning several decades (from 1980 to 2020) and encompassing regions across North America, Europe, Asia, South America, and Africa, reflecting diverse industrial practices and regulatory frameworks. From these studies, our umbrella review demonstrates that residents living near these facilities face elevated risks related to leukemia, lung and pancreatic cancer, nonmalignant respiratory conditions (such as asthma, cough, wheezing, bronchitis, and rhinitis), chronic kidney disease, and adverse reproductive outcomes. Furthermore, we discuss the key challenges in mitigating these health impacts and outline future directions, including the integration of cleaner technologies, which can significantly reduce harmful emissions; strengthening policy frameworks, emphasizing stringent emission limits, continuous monitoring, and regulatory enforcement; and advancing research on underexplored health outcomes. This review emphasizes the need for coordinated global efforts to align the industry’s evolution with sustainable development goals and climate action strategies to protect the health of vulnerable communities. Full article

Chronic coughing is a common complaint in small animal medicine and it has an extensive differential diagnosis with very different treatment and prognosis. Coughing is considered chronic when it lasts at least 8 weeks. This retrospective study aimed to describe the most common causes of chronic coughing in a population of dogs that presented to a referral hospital in England between January 2012 and December 2021. In addition, we aimed to evaluate if an association with signalment, weight, coughing characteristics, and/or concomitant clinical signs could be identified. A total of 329 dogs met the inclusion criteria. The most frequent diagnoses were airway collapse (102/329, 30.7%), chronic bronchitis (80/329, 24.3%), neoplasia (62/329, 18.8%), and infectious bronchopneumonia (54/329, 16.4%). Other diagnoses were also identified in a lower number of cases. Pomeranian, Chihuahua, and Yorkshire Terrier were over-represented breeds for airway collapse. No predictive factors were identified for chronic bronchitis. Lower body weight (odds ratio [OR] 0.92, 95% confidence interval [CI]: 0.90–0.95), non-productive (OR 14.3 CI 3.44–50) paroxysmal coughing (OR 4.9, 95%, CI: 2.2–11.0), and exercise intolerance (OR 3.3, 95%, CI: 1.7–6.3) increased the odds of airway collapse. Older dogs (OR 1.025, 95%, CI: 1.014–1.036), higher body weight (OR 1.048, 95%, CI: 1.018–1.080), lethargy (OR 5.1, 95%, CI: 1.5–17.7), haemoptysis (OR 8.6, 95%, CI: 1.9–38.4), weight loss (OR 4.0, 95%, CI: 1.1–15.3), and inappetence (OR 6.5, 95%, CI: 1.9–22.1) increased the odds of neoplasia. Productive coughing (OR 3.0, 95%, CI: 1.5–6) and nasal discharge (OR 4.1, 95%, CI: 1.4–11.9) were predictive factors of infectious bronchopneumonia. Younger age (OR 0.96, 95%, CI: 1.061–1.150), higher body weight (OR 1.097, 95%, CI: 1.037–1.161), and haemoptysis (OR 11.8, 95%, CI: 1.8–78.5), increased the odds of airway foreign body. Higher body weight (OR 1.105, 95%, CI: 1.061–1.150), older age (OR 1.041, 95%, CI: 1.022–1.061), and regurgitation were predictive factors of laryngeal paralysis. Epiglottic retroversion was associated with younger age (OR 0.969, 95%, CI: 0.943–0.994), dysphagia (OR 42.5, 95%, CI: 4.7–382.7), and regurgitation (OR 11.6, 95%, CI: 1.2–113.1). All the aforementioned findings are valuable for prioritising differential diagnoses and consequently increasing the efficacy of the diagnostic plan and prioritising tests, which becomes even more important in cases where financial constraints are present. Finally, an appropriate selection of diagnostics tools helps optimise veterinary resources. Full article

Mucins 5AC (MUC5AC) and 5B (MUC5B) are the major mucins providing the organizing framework for the airway’s mucus gel. We retrieved bronchial mucosal biopsies and bronchial wash (BW) samples through bronchoscopy from patients with chronic obstructive pulmonary disease (n = 38), healthy never-smokers (n = 40), and smokers with normal lung function (n = 40). The expression of MUC5AC and MUC5B was assessed immunohistochemically. The mucin concentrations in BW were determined using the slot-blot technique. The immunohistochemical expression of MUC5AC and MUC5B was localized to goblet cells and submucosal glands. Smokers had higher MUC5AC and lower MUC5B goblet cell expression and higher concentrations of soluble MUC5AC in BW than never-smokers. The MUC5B expression in goblet cells correlated positively with expiratory air flows, diffusing capacity, and the dyspnoea score. Chronic bronchitis, emphysema, and the progression of chronic airflow limitation during a median follow-up time of 8.4 years were associated with higher MUC5AC and lower MUC5B expression in goblet cells. Sustainers, slow progressors, and rapid progressors of airflow obstruction differed in their MUC5B expression at baseline. Emphysema and bronchial wall thickening on CT at a follow-up visit were associated with lower MUC5B expression at baseline. Our findings strengthen the hypothesis that MUC5AC and MUC5B are yet another contributing factor to smoking-associated lung disease progression. Full article

Human immunodeficiency virus type-1 (HIV-1) associated comorbidities account for the majority of poor health outcomes in people living with HIV (PLWH) in the era of antiretroviral therapy. Lung-related comorbidities such as chronic obstructive pulmonary disease (COPD) and bacterial pneumonia are primarily responsible for increased morbidity and mortality in PLWH, even when compensated for smoking. Smokers and COPD patients demonstrate cilia shortening, attenuated ciliary beat frequency (CBF), dysfunctional ciliated cells along with goblet cell hyperplasia, and mucus hypersecretion. This is exacerbated by the fact that almost 60% of PLWH smoke tobacco, which can exacerbate inflammation and mucociliary clearance (MCC) dysfunction. This study shows that HIV Tat alters the microRNAome in airway epithelial cells and upregulates miR-34a-5p with consequent suppression of its target, Sirtuin 1 (SIRT1). SIRT1 is known to suppress Metalloproteinase 17 (ADAM17), a protease activating Notch signaling. HIV and cigarette smoke (CS) upregulate ADAM17. ADAM17 upregulation followed by SIRT1 suppression can lead to decreased ciliation, mucus hypersecretion, and attenuated MCC, a hallmark of chronic bronchitis in smokers and COPD. It is, therefore, essential to understand the pathophysiological mechanism resulting in acquired Notch dysregulation and its downstream impact on HIV-infected smokers. Full article

Air pollutants have both acute and chronic impacts on human health, affecting multiple systems and organs. While PM2.5 exposure is commonly assumed to be strongly associated with all respiratory diseases, this relationship has not been systematically analyzed. This study employed a two-sample Mendelian randomization approach to investigate the effects of PM2.5 on eight common lung diseases, using data from GWAS. Additionally, multivariable Mendelian randomization was applied to assess the direct effects of various air pollutants and the mediating roles of common factors such as BMI and smoking. At a significance threshold of 5×10⁻⁸, PM2.5 showed a significant causal relationship with both asthma and COPD. When the screening threshold was relaxed to 5× 10⁻⁶, this exposure continued to demonstrate significant associations not only with asthma and COPD, but also with other respiratory diseases, including pneumonia, emphysema/chronic bronchitis, and lung cancer. In the multivariable Mendelian randomization analysis, which controlled for smoking and bacterial infections, the association with pneumonia became non-significant, while the relationships with the other four diseases persisted. This study provides a systematic exploration of the relationship between PM2.5 and eight pulmonary diseases from a new perspective, deepening our understanding of the impact of air pollution on health and laying the foundation for future efforts to mitigate these effects. Full article

Background: Antibiotics are inappropriately prescribed for respiratory tract infections for various reasons. The differences of the effects of education based on these reasons has not been fully elucidated. This study assessed the impact of an educational film on antibiotic prescription patterns according to physicians’ prescribing justifications. Methods: This was a secondary analysis of a nationwide web-based survey involving 1100 physicians. The physicians were required to view a short educational film and determine the need for prescribing antibiotics in simulated scenarios of different acute respiratory tract infectious diseases. The associations between the reasons for antibiotic prescription to patients not requiring antibiotics before viewing the educational film and the positive effects of the intervention were analyzed. Results: The educational intervention positively affected prescribing trends among physicians who prescribed antibiotics for “fever” in mild acute rhinosinusitis (prescription rates from 100% to 25.9%), “pus in the laryngopharynx” in mild acute pharyngitis (prescription rates from 100% to 29.6%), and “purulent sputum” in acute bronchitis without chronic lung disease (prescription rates from 100% to 29.9%) before viewing the film. In contrast, no benefits were observed when the justification was “patient’s desire for antibiotics” in mild acute pharyngitis (prescription rates from 100% to 48.5%) and acute bronchitis without chronic lung disease (prescription rates from 100% to 44.0%) or “parents’ desire for antibiotics” in narrowly defined common cold in children (prescription rates from 100% to 45.7%). Conclusions: although educational interventions might reduce inappropriate antibiotic prescription by providing accurate knowledge about respiratory tract infections, they appear ineffective for physicians who prescribe antibiotics based on patients’ or parents’ desires for antibiotic treatment. Full article

Background: The goal of this study was to evaluate whether the medical recommendation of Angocin^®Anti-Infekt N (heretofore referenced as Angocin^®) on the day of diagnosis of acute bronchitis is negatively associated with the recurrence of acute bronchitis diagnosis, antibiotic prescriptions, incidence of chronic bronchitis, and duration of sick leave. Methods: This study included patients in general practices in Germany with a first documented diagnosis of acute bronchitis between 2005 and 2022 (index date) and a prescription of Angocin^®, thyme products, essential oils, mucolytics or antibiotics on the index date. The association between Angocin^® prescription and the risks of a relapse of acute bronchitis, development of chronic bronchitis, or subsequent antibiotic prescription were evaluated using Cox regression models. Univariable conditional logistic regression models were used to investigate the association between Angocin^® prescription and duration of sick leave. Results: After a 1:5 propensity score matching, 598 Angocin^® patients and 2990 patients in each of the four comparison cohorts were available for analysis. Angocin^® prescription was associated with significantly lower incidence of a renewed confirmed diagnosis of acute bronchitis as compared to essential oils (Hazard ratio (HR): 0.61; 95% Confidence Interval (CI): 0.46–0.80), thyme products (HR: 0.70; 95% CI: 0.53–0.91), mucolytics (HR: 0.65; 95% CI: 0.49–0.85) or antibiotics (HR: 0.64; 95% CI: 0.49–0.84). Also, there were significantly lower incidences of subsequent re-prescriptions of antibiotics when compared to mucolytics (HR: 0.73; 95% CI: 0.53–0.99) or antibiotics (HR: 0.53; 95% CI: 0.39–0.72) and a significantly lower risk of chronic bronchitis as compared to essential oils (HR: 0.60; 95% CI: 0.46–0.78), thyme products (HR: 0.53; 95% CI: 0.41–0.69), mucolytics (HR: 0.49; 95% CI: 0.38–0.63) or antibiotics (HR: 0.59; 95% CI: 0.45–0.76). Conclusions: Considering the limitations of the study, the results shed light on the sustaining effectiveness of Angocin^® prescription in the management of acute bronchitis and the associated outcomes when compared to several other treatments commonly used for this condition. Full article

Moraxella catarrhalis has been recognized as an important cause of upper respiratory tract and middle ear infections in children, as well as chronic obstructive pulmonary disease and chronic bronchitis in adults. We aim to study the clonal structure, antimicrobial resistance, and serotypes of M. catarrhalis strains recovered from patients of different ages. Nasopharyngeal swabs, middle ear fluid, and sputum samples were collected. In vitro susceptibility testing was performed according to EUCAST criteria. The monoclonal Ab hybridoma technique was used for serotyping. All strains were subjected to MLST. The studied population demonstrated susceptibility to all tested antimicrobials M. catarrhalis strains, with the majority being serotype A (90.4%), followed by B (6.8%), and C (2.7%). We observed a predominant clonal complex CC224 (21.9%) along with other clusters including CC141 (8.2%), CC184 (8.2%), CC449 (6.8%), CC390 (5.5%), and CC67 (2.7%). Two primary founders, namely, ST224 and ST141, were identified. The analyzed genetic lineages displayed diversity but revealed the predominance of two main clusters, CC224 and CC141, encompassing multidrug-resistant sequence types distributed in other regions. These data underscore the need for ongoing epidemiological monitoring of successfully circulating clones and the implementation of adequate antibiotic policies to limit or delay the spread of multidrug-resistant strains in our region. Full article

There is limited literature regarding seasonal influenza vaccination (SIV) among those with a history of chronic obstructive pulmonary disease (HCOPD) prior to the COVID-19 pandemic, and no information on the topic assessing the years following the pandemic. This cross-sectional study used the Behavioral Risk Factor Surveillance Survey (BRFSS) data from the years 2017 to 2022 (n = 822,783 adults ages 50–79 years; 50.64% males). The exposure was a HCOPD, and the outcome was SIV within the past year. Weighted and adjusted logistic regression models were conducted overall and by the significant effect modifiers: smoking status, sex, and year. Having an HCOPD significantly increases the weighted adjusted odds (WAO) of SIV when compared to not having an HCOPD overall and by smoking status, sex, and year. For 2017 through 2022, among all current, former, and never smokers with an HCOPD, the WAO of SIV were: 1.36 (1.28, 1.45), 1.35 (1.27, 1.43), and 1.18 (1.09, 1.27), respectively. Among males with an HCOPD who were current, former, and never smokers, the WAO of SIV were: 1.35 (1.23, 1.48), 1.45 (1.33, 1.58), and 1.23 (1.05, 1.44), respectively. Among females with an HCOPD who were current, former, and never smokers, the WAO of SIV were: 1.31 (1.20, 1.43), 1.24 (1.15, 1.35), and 1.13 (1.04, 1.23), respectively. Study findings suggest males had significantly greater WAO ratios of receiving SIV than females in 2020 and 2022, during and after the COVID-19 pandemic. More specifically, males with an HCOPD who were former smokers had significantly greater WAOR of receiving SIV than females in 2020 and 2022. Understanding the potential barriers to SIV receipt by smoking status and sex, especially during a pandemic, and especially for individuals impacted by an HCOPD, is essential for better health interventions in times of a national crisis such as a pandemic. Additionally, SIV receipt is low among those with an HCOPD, and efforts should be made to improve this. Full article

Background: Some epidemiological studies suggest that early exposure to animal allergens during infancy reduces the risk of bronchial asthma in school-age children. However, the observed associations in some cases may be an effect of the study used (epidemiological observational studies, especially a cross-sectional study) and indicate reverse causality. Aim: This study aimed to determine the association between exposure to animal allergens and the prevalence of respiratory diseases, including bronchial asthma, considering the potential impact of reverse causality on the observed relationships. Material and methods: An analysis of data from a cross-sectional epidemiological study conducted in 2020 involving 3237 primary school students aged 7–15 years in the Silesian Province (Southern Poland) was carried out. The parents of students completed a questionnaire based on The International Study on Asthma and Allergies in Childhood (ISAAC). The relationship between the occurrence of chronic cough, wheezing, and dyspnea in the last 12 months, night waking due to dyspnea, and asthma in the presence of pets was assessed. Exposure to animal allergens was determined by answering the question, “Are there any furry or feathered animals in the home?” with three response options: “yes; they have been in the past; no” (Scenario 1). For the analyses and to reveal a potential reverse causality effect, the last two response categories regarding pet ownership were combined to form a “no” category in Scenario 2, and the first two answers were combined into a “yes” category in Scenario 3. A chi-square test was used to assess the relationship between variables, and a statistical significance level of p < 0.05 was adopted. Results: Chronic cough affected 9.5% of children, wheezing in the last 12 months—9.2%, night waking due to dyspnea—5.8%, dyspnea in the last 12 months—4.8%, bronchial asthma—9.2%. Analysis considering the category of having or not having pets (yes vs. no) showed that bronchial asthma was statistically significantly more common in children who did not have pets at home (10.9% vs. 7.9%, p = 0.002). A similar situation was observed for wheezing in the past 12 months (10.7% vs. 8.1%; p = 0.01) and nocturnal awakening due to dyspnea (6.8% vs. 5.1%, p = 0.03). No statistically significant differences were observed for the other symptoms. Analysis by time of pet ownership (a. present; b. present but in the past; c. not present) highlighted similar relationships. Asthma (a. 7.7% vs. b. 13.4% vs. c. 7.7%; p = 0.004), wheezing in the past 12 months (a. 8.1% vs. b. 8.9% vs. c. 10.9%, p = 0.03) and night waking (a. 5.0% vs. b. 4.5% vs. c. 7.1%; p = 0.04) were more common in children without pets and those who had owned pets in the past. The highest proportion of children with asthma was in homes where pets were present in the past. Conclusions: Analyses indicating a relationship between a higher prevalence of asthma and some respiratory symptoms, and the absence of pets cannot be considered as a casual association. The analysis conducted did not reveal a reverse causality effect. The results of observational epidemiological studies, especially a cross-sectional study, should always be interpreted with caution, considering possible distortions and conclusions drawn. Full article