The effect of early-life exposure to water-borne diseases on old-age mortality in the United States

The aim of the proposed study is to investigate whether exposure in early life to water-born infectious diseases leads to permanent scarring and increase in old-age mortality. Given exposure to infectious diseases
during childhood and in-utero increases the risk of developing chronic conditions at the old age, then cohorts born in large cities before the water filtration system was widely implemented would also have higher mortality than cohorts born afterwards, or those born in rural areas. This applies in particular to black population as compared to the white one. Based on the data from Social Security Medicare Part B merged at Duke University with the Numerical Identification Files from the Social Security Administration, the proposed study would use the individual level information on exact place of birth. The method applied is premiminary a visual assesment of mortality surfaces presenting data where random noise was eliminated with two-dimentional P-spline smoothing methods and estimation of a series of Cox proportional hazard models. Result of a preliminary study demonstrate that cohorts born in Washigton DC, Atlanta GA, Baltimore MA after the water purification was started on large scale had significantly lower mortality than cohorts born before this date, as compared to the total population of the country.