1.
Protective Effect of Breastfeeding on the Adverse Health Effects Induced by Air Pollution: Current Evidence and Possible Mechanisms.
Zielinska, MA, Hamulka, J
International journal of environmental research and public health. 2019;(21)
Abstract
Air pollution is a major social, economic, and health problem around the world. Children are particularly susceptible to the negative effects of air pollution due to their immaturity and excessive growth and development. The aims of this narrative review were to: (1) summarize evidence about the protective effects of breastfeeding on the adverse health effects of air pollution exposure, (2) define and describe the potential mechanisms underlying the protective effects of breastfeeding, and (3) examine the potential effects of air pollution on breastmilk composition and lactation. A literature search was conducted using electronic databases. Existing evidence suggests that breastfeeding has a protective effect on adverse outcomes of indoor and outdoor air pollution exposure in respiratory (infections, lung function, asthma symptoms) and immune (allergic, nervous and cardiovascular) systems, as well as under-five mortality in both developing and developed countries. However, some studies reported no protective effect of breastfeeding or even negative effects of breastfeeding for under-five mortality. Several possible mechanisms of the breastfeeding protective effect were proposed, including the beneficial influence of breastfeeding on immune, respiratory, and nervous systems, which are related to the immunomodulatory, anti-inflammatory, anti-oxidant, and neuroprotective properties of breastmilk. Breastmilk components responsible for its protective effect against air pollutants exposure may be long chain polyunsaturated fatty acids (LC PUFA), antioxidant vitamins, carotenoids, flavonoids, immunoglobins, and cytokines, some of which have concentrations that are diet-dependent. However, maternal exposure to air pollution is related to increased breastmilk concentrations of pollutants (e.g., Polycyclic aromatic hydrocarbons (PAHs) or heavy metals in particulate matter (PM)). Nonetheless, environmental studies have confirmed that breastmilk's protective effects outweigh its potential health risk to the infant. Mothers should be encouraged and supported to breastfeed their infants due to its unique health benefits, as well as its limited ecological footprint, which is associated with decreased waste production and the emission of pollutants.
2.
[Air pollution and atopic eczema : Systematic review of findings from environmental epidemiological studies].
Krämer, U, Behrendt, H
Der Hautarzt; Zeitschrift fur Dermatologie, Venerologie, und verwandte Gebiete. 2019;(3):169-184
Abstract
BACKGROUND Among the many risk factors for the development of atopic eczema (AE), the influence of air pollution has recently been discussed more often. A systematic review about this topic however is lacking. AIMS Which effects of outdoor air pollution (particles, nitric oxides, sulfur dioxide, ozone or general traffic exhaust emissions) on AE can be demonstrated in a systematic analysis of available environmental epidemiologic studies? METHODS All environmental epidemiologic studies on AE and air pollution found in the literature database PubMed were identified. The most important key figures of these studies were tabulated, the quality of evidence was graded and the studies described. RESULTS A total of 57 studies were identified. Only one of the 15 cross-sectional studies with a large-scale exposure assessment found a significant association between AE and air pollution. In contrast 23 of 30 studies with small-scale exposure assessment found a significant association between AE and traffic related emissions-especially from trucks. Of the 30 studies, 14 were cohort studies (1 adult, 13 birth cohorts). The sole adult cohort found an association with intrinsic AE. In the East Asian cohorts (all published since 2015), an association between maternal exposure to traffic-related pollution and incidence of AE in the offspring was found. This was less clear in cohorts from Europe/US or simply not investigated. In 5/5 panel studies (all from South Korea), symptom severity of AE was found to be significantly and positively related to outdoor air pollution. CONCLUSIONS In a systematic analysis of environmental epidemiologic studies about air pollution and AE rather good evidence was found that, based on small-scale exposure measurements, especially truck traffic emissions increased AE prevalence, while large-scale exposure to larger particles (PM10) or SO2 was without effect. Considering pathophysiologic aspects traffic exhaust emissions seem to affect both skin barrier function and activation of immune responses.
3.
A systematic literature review and critical appraisal of epidemiological studies on outdoor air pollution and tuberculosis outcomes.
Popovic, I, Soares Magalhaes, RJ, Ge, E, Marks, GB, Dong, GH, Wei, X, Knibbs, LD
Environmental research. 2019;:33-45
Abstract
Ambient air pollution is the leading environmental risk factor for disease globally. Air pollutants can increase the risk of some respiratory infections, but their effects on tuberculosis (TB) are unclear. In this systematic literature review, we aimed to assess epidemiological studies on the association between outdoor air pollutants and TB incidence, hospital admissions and death (collectively referred to here as 'TB outcomes'). We sought to consolidate available evidence on this topic and propose recommendations for future studies. Following PRISMA guidelines, we searched PubMed, Web of Science, Google Scholar, and Scopus with no restrictions imposed on year of publication. A total of 11 epidemiological studies, performed in Asia, Europe and North America, met our inclusion criteria (combined sample size: 215,337 people). We extracted key study characteristics from each eligible publication, including design, exposure assessment, analytical approaches and effect estimates. The studies were assessed for overall quality and risk of bias using standard criteria. The pollutant most frequently associated with statistically significant effects on TB outcomes was fine particulate matter ( < 2.5 µm; PM2.5); 6/11 studies assessed PM2.5, of which 4/6 demonstrated a significant association). There was some evidence of significant associations between PM10 ( < 10 µm), nitrogen dioxide (NO2) and sulfur dioxide (SO2) and TB outcomes, but these associations were inconsistent. The existing epidemiological evidence is limited and shows mixed results. However, it is plausible that exposure to air pollutants, particularly PM2.5, may suppress important immune defence mechanisms, increasing an individual's susceptibility to development of active TB and TB-related mortality. Considering the small number of studies relative to the demonstrably large global health burdens of air pollution and TB, further research is required to corroborate the findings in the current literature. Based on a critical assessment of existing evidence, we conclude with methodological suggestions for future studies.