ABSTRACT
St. Louis City and St. Louis County, Missouri share the same public drinking water source, namely the Missouri River. The 'all cancer' and most organ specific cancer mortality rates have been consistently and considerably higher for St. Louis City than for St. Louis County for the period 1960 through 1972. A change in the St. Louis County water treatment process, which included increasing the chlorine dosage and delaying the addition of ammonia to form chloramines until just prior to distribution, was instituted in 1955. St. Louis City has, by contrast, continued the lower chlorine level and early ammoniation. Trend analysis using the period 1960-67 and 1972-76 showed higher percentage as well as net cancer mortality rate per million increases for large bowel, liver and bladder cancers for St. Louis County. An apparent association between a probable increase in trihalomethane production in the St. Louis County water since 1955 and an increase in these specific cancer rates which exceed the increases in the St. Louis City rates appears to have been shown. This does not imply causality but is in general agreement with other studies which have examined water chlorination and cancer mortality.
Subject(s)
Chlorine , Water Supply , Adult , Aged , Ammonia , Chloramines , Chlorofluorocarbons, Methane , Epidemiologic Methods , Female , Humans , Male , Middle Aged , Missouri , Neoplasms/etiology , Neoplasms/mortalityABSTRACT
Mortality rates for specific cancer types and age-sex groups computed for large numbers of cities typically show extreme fluctuation. This is primarily due to the rare occurrence of specific cancer deaths in most of the small and moderate size cities during a fixed time period. Assuming a Poisson death process, we use an empirical Bayes method to obtain adjusted rates that are more stable for comparison of cities and prediction of future mortality. We have chosen stomach and bladder cancers in Missouri cities to illustrate the problems, techniques and results.
PIP: An empirical Bayes method is used to obtain adjusted rates of cancer mortality that are more stable for use in comparisons among cities and to predict future mortality trends. The method is illustrated using data on stomach and bladder cancers in Missouri cities.
Subject(s)
Bayes Theorem , Epidemiologic Methods , Neoplasms/mortality , Probability , Aged , Female , Humans , Male , Middle Aged , Missouri , Stomach Neoplasms/mortality , Urinary Bladder Neoplasms/mortality , Water SupplySubject(s)
Pulmonary Emphysema/etiology , Air Pollution , Female , Humans , Male , Pulmonary Emphysema/epidemiology , Smoking/complicationsSubject(s)
Neoplasms/mortality , Adult , Aged , Female , Humans , Male , Middle Aged , Missouri , Respiratory Tract Neoplasms/epidemiology , United StatesSubject(s)
Carcinogens , Lung Neoplasms , Smoking , Benzopyrenes/analysis , Carbon/analysis , Carcinogens/analysis , Chromium/analysis , Humans , Lead/analysis , Plants, Toxic , Nicotiana/analysis , VolatilizationABSTRACT
A study was designed to evaluate the representativeness and accuracy of data collected on swine birth defects by mailed questionnaire. The study was conducted in the three contiguous counties of Johnson, Lafayette and Pettis in west central Missouri. A personal interview survey and an examination of malformed pigs were used to validate mailed questionnaire data which estimated the frequency and distribution of malformations observed in pigs over a six month period. This period between April and September 1970 was defined as the study period. The results were compared to a previous six month period (April-September 1969), or baseline period, when only the mailed questionnaire was used. The frequency and distribution of the reported malformations by type did not differ significantly (at the p=0.05 level) between the study period (70.4% response) and the baseline period (31.3% response). Evaluation of this and additional data collected during the study suggested that the mailed questionnaire can be used effectively to estimate the frequency and distribution of swine malformations within a defined geographic area.
