Issue link: https://hi.iaq.net/i/670243
Every breath we take: the lifelong impact of air pollution 3.5 Conclusions There is no doubt that air pollution can affect the fetus, either indirectly through the health of the mother, or directly by affecting developing fetal organs and systems. These effects can have a permanent influence on growth and health throughout life. Exposure of the young child to air pollution can produce definite harm and even increase the risk of death from lung infections. There is evidence that it may produce deleterious effects on growth, intelligence and neurological development. Increasingly, it is being discovered that certain genetic polymorphisms make some individuals more susceptible than others to the effects of particular pollutants. In studies that have examined 'dose' effects of air pollution, harmful effects have been detected at current regulatory levels and there appears to be no lower limit below which harmful effects do not occur. The evidence of harm due to air pollution to the fetus and the young child is not as strong as it is for adults, because the topic is relatively new and has not been so heavily researched. In addition, the effects on the baby and child may be more subtle and take many decades to appear, so that a causal relationship 46 © Royal College of Physicians 2016 Environment alters the epigenome Interaction effect Mechanism for the effect of the environment Epigenome In utero environment Low lung function after birth T T C C A A G G Me Me Fig 10. Harmful environmental exposures during intrauterine development can modify DNA through epigenetic effects, resulting in long-lasting alterations to gene regulation ('Me' indicates methylation). This could not only alter development of organs (such as the lungs), leading to physiological differences at birth, but may also lead to altered responses to further exposure later in life. Thus, epigenetic programming provides a pathway through which early life environmental exposures can influence health through the lifecourse. Figure modified with permission from: Lockett GA, Huoman J, Holloway JW. Does allergy begin in utero? Pediatr Allergy Immunol 2015;26:394–402.