Childhood Environmental Exposures and Adult Disease.

The association of early life adverse events with worse adult outcomes was first proposed by David Barker, the Developmental Origins of Health and Disease (DOHaD). Subsequently we have learned that adverse exposures are not merely important during pregnancy, but also exert transgenerational effects. Most of our knowledge derives from studies of nicotine and tobacco exposure. Adverse intrauterine exposures lead to low birth weight and premature delivery; altered airway and parenchymal structure; altered immune function; sensitization to later adverse exposures; and premature aging manifest by premature telomere shortening. Impaired spirometry for most tracks from birth to late middle age, and especially a low forced vital capacity, is associated with premature respiratory and all cause morbidity and mortality. Childhood exposure to passive smoking exacerbates antenatal effects on lung function, as does pollution. Pollution also increases the risk of early life respiratory infection which are a cause of impaired lung function in at least some studies, and also are associated with premature mortality. Diseases traditionally thought of as arising in adult life, including late-onset and occupational asthma, chronic obstructive pulmonary disease, lung cancer and idiopathic pulmonary fibrosis all have their roots in early life adverse exposures, especially childhood onset smoking. Smoking provides proof of concept that prevention of adult disease must start earlier than adult life if it is to be effective. It is also likely that other early adverse exposures contribute to adult disease. Political action is needed to counteract the view that children "just grow out of it". They do not.