Allergy and infection have being exerted seriously adverse effect on children’s health. On the one hand, asthma and allergy have become the most common chronic diseases in childhood and the leading cause of pediatric hospitalization worldwide. The prevalence of childhood asthma has considerably increased since the 1950s, with some suggestion of plateauing in developed regions but rapidly increasing in low- and middle-income countries over recent years. On the other hand, pneumonia as the most prevalent infectious disease is the leading cause of mortality in children under 5 years old globally. Approximately 99% of the pneumonia death occurs in developing countries. During recent decade, China has witnessed a rapid increase in the prevalence of childhood asthma and allergies and the morbidity of childhood infectious diseases such as pneumonia tend to be very high. Environmental exposure is thought to be the most important factor which is responsible for this rising trend and serious burden of childhood allergic and infectious diseases. Ambient air pollution has been widely suggested to be associated with the incidence and prevalence of allergies and infections, and a distinct need is then to find out the key component of air pollution and the critical exposure window so as to develop more effective measures of prevention and intervention. A large body of evidence mainly from developed countries suggested that traffic-related air pollution (TRAP) plays a key role in the exacerbation and development of allergies and infections. However, differences in the chemical and physical composition of air pollution, both in level and source, between China and developed countries prompts the need for further investigation into the role of outdoor air pollution in the development of childhood allergic and infectious diseases. On the other hand, due to the rapid urbanization progress in China, a huge number of people, especially the new couples and expected parents, migrated into new buildings in urban areas during the past decade. New building materials, decoration materials, and new furniture caused high indoor level chemicals, such as volatile and semi volatile organ compounds (VOCs and SVOCs). Due to lack of central air conditioning and heating systems, mold and dampness in dwellings is very serious in the southern China with subtropical climate. Thus, indoor environmental risk factors are also serious in China, which play important role in the rapid increase in the allergic diseases and high prevalence of infectious diseases in childhood. Although the impact of environmental pollution on children’s health has attracted wide attention and extensive research, some key scientific issues such as “main environmental pollutants, critical exposure windows, and whether the exposure cause diseases” still remain unclear. This paper summarizes the effects of prenatal (one year before pregnancy, entire pregnancy and three trimesters of pregnancy) and postnatal (first year, past year, and entire postnatal period) exposure to both indoor and outdoor environmental pollution on childhood allergic and infectious diseases, and also analyzed the relative importance of the critical exposure time windows for different diseases. We concluded that most studies mainly from developed countries found a positive association between traffic related air pollution and childhood allergic diseases. However, in China, early life exposure to classical air pollution (such as industrial air pollution) also exerts an adverse effect on childhood asthma and allergies. The recent studies identified relative importance of traffic-related air pollution exposure in different critical time windows (such as different trimester of pregnancy) in the development of different allergic diseases. This paper also concluded that early-life exposure to indoor mould/dampness and renovation significantly increased risk of childhood allergic and infectious diseases. According to the analysis of available literatures, this study proved the hypothesis of “fetal origins of disease” in children, and revealed that exposure to indoor and outdoor environmental pollution during pregnancy and early postnatal period played an important role in the onset and development of childhood allergic and infectious diseases, which provides a scientific basis for effective prevention and intervention strategies to reduce childhood allergies and infections. Finally, this study summarized the different influences, and expected the problems and challenges of effective prevention and reduction of childhood allergies and infections.
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Jan 23, 2019
Wenke Fan + 2
Open Access
