A body of evidence suggests that major changes involving the atmosphere and the climate, including global warming induced by anthropogenic factors, have impact on the biosphere and human environment. Studies on the effects of climate change on respiratory allergy are still lacking and current knowledge is provided by epidemiological and experimental studies on the relationship between allergic respiratory diseases, asthma and environmental factors, such as meteorological variables, airborne allergens, and air pollution. Urbanization with its high levels of vehicle emissions, and a westernized lifestyle are linked to the rising frequency of respiratory allergic diseases and bronchial asthma observed over recent decades in most industrialized countries. However, it is not easy to evaluate the impact of climate changes and air pollution on the prevalence of asthma in the general population and on the timing of asthma exacerbations, although the global rise in asthma prevalence and severity could also be an effect of air pollution and climate change. Since airborne allergens and air pollutants are frequently increased contemporaneously in the atmosphere, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of respiratory allergy and asthma in atopic subjects in the last 5 decades. Pollen allergy is frequently used to study the relationship between air pollution and respiratory allergic diseases, such as rhinitis and bronchial asthma. Epidemiologic studies have demonstrated that urbanization, high levels of vehicle emissions, and westernized lifestyle are correlated with an increased frequency of respiratory allergy prevalently in people who live in urban areas in comparison with people living in rural areas. Climatic factors (temperature, wind speed, humidity, thunderstorms, etc.) can affect both components (biological and chemical) of this interaction.
Air Pollutants ; Air Pollution* ; Allergens ; Asthma ; Atmosphere ; Climate Change* ; Climate* ; Developed Countries ; Epidemiologic Studies ; Global Warming ; Humans ; Humidity ; Hypersensitivity* ; Inflammation ; Life Style ; Prevalence ; Rhinitis ; Rhinitis, Allergic, Seasonal ; Urbanization ; Vehicle Emissions ; Weather ; Wind

Background/Aims: The global proportion of hepatocellular carcinoma (HCC) attributable to metabolic dysfunction-associated fatty liver disease (MAFLD) is unclear. The MAFLD diagnostic criteria allows objective diagnosis in the presence of steatosis plus defined markers of metabolic dysfunction, irrespective of concurrent liver disease. We aimed to determine the total global prevalence of MAFLD in HCC cohorts (total-MAFLD), including the proportion with MAFLD as their sole liver disease (single-MAFLD), and the proportion of those with concurrent liver disease where MAFLD was a contributary factor (mixed-MAFLD). Methods: This systematic review and meta-analysis included studies systematically ascertaining MAFLD in HCC cohorts, defined using international expert panel criteria including ethnicity-specific BMI cut-offs. A comparison of clinical and tumour characteristics was performed between single-MAFLD, mixed-MAFLD, and non-MAFLD HCC. Results: 22 studies (56,565 individuals with HCC) were included. Total and single-MAFLD HCC prevalence was 48.7% (95% confidence interval [CI] 34.5–63.0%) and 12.4% (95% CI 8.3–17.3%), respectively. In HCC due to chronic hepatitis B, C, and alcohol-related liver disease, mixed-MAFLD prevalence was 40.0% (95% CI 30.2–50.3%), 54.1% (95% CI 40.4–67.6%) and 64.3% (95% CI 52.7–75.0%), respectively. Mixed-MAFLD HCC had significantly higher likelihood of cirrhosis and lower likelihood of metastatic spread compared to single-MAFLD HCC, and a higher platelet count and lower likelihood of macrovascular invasion compared to non-MAFLD HCC. Conclusions MAFLD is common as a sole aetiology, but more so as a co-factor in mixed-aetiology HCC, supporting the use of positive diagnostic criteria.