This reversible dimension has been postulated to be negatively correlated to the duration of the symptoms, which would mean that the longer the OSA is left untreated, the less reversible are the consequences. Somatic and metabolic consequences
Similarly to adults, OSA in children is linked to a higher risk for cardiovascular morbidities, due to increased sympathetic activity and impaired cardiac autonomic control. Amongst the cardiovascular dysfunctions resulting from OSA, we can find systemic hypertension and blood pressure dysregulation (elevated blood pressure, or variability of the blood pressure for example). The variability of the blood pressure has been shown to be correlated with the severity of the symptoms such as the frequency of the apnea and hypopnea. Pulmonary hypertension is also common amongst the cardiovascular problems resulting from OSA. Children with obstructive sleep-disordered breathing also show a faster heart rate during wakefulness and during sleep.In adult patients, OSA has been shown to be associated with insulin resistance. In children, metabolic consequences of OSA are complicated to assess as they can also be associated to puberty and obesity (if present). However, when OSA is associated with obesity, the interaction of the two conditions can lead to metabolic disturbances such as insulin resistance and altered lipidemia, liver disease, abdominal adiposity and metabolic syndrome. Obesity interact with those effects.
In 1893 attempts were made to chlorinate the water supply in Hamburg, Germany and in 1897 Maidstone, England, was the first town to have its entire water supply chlorinated. In 1905, following an outbreak of typhoid fever, the City of Lincoln, England, instituted permanent water chlorination. The first permanent disinfection of drinking water in the US was made in 1908 to the Jersey City, New Jersey, water supply. Credit for the decision to build the chlorination system has been given to John L. Leal. The chlorination facility was designed by George W. Fuller.Outbreaks in traveling military groups led to the creation of the Lyster bag in 1915; a bag with a faucet which can be hung from a tree or pole, filled with water, and comes with a chlorination tablet to drop into the water. The Lyster bag was essential for the survival of American soldiers in the Vietnam War. Direct transmission and carriers
There were several occurrences of milk delivery men spreading typhoid fever throughout the communities they served. Although typhoid is not spread through milk itself, there were several examples of milk distributors in many locations watering their milk down with contaminated water, or cleaning the glass bottles the milk was placed in with contaminated water. Boston had two such cases around the turn of the 20th century. In 1899 there were 24 cases of typhoid traced to a single milkman, whose wife had died of typhoid fever a week before the outbreak.