Best Asbestos Mesothelioma Lawyers 2013 Learn About the Lawyers Find A Mesothelioma Lawyer Directory: Attorneys memphis tn Wallpaper Photos Pictures Pics Images 2013

Tuesday 16 July 2013

Attorneys memphis tn Wallpaper Photos Pictures Pics Images 2013

Attorneys memphis tn Biogarphy

Source(google.com.pk)

The white population of NYS excluding NYC was used as the reference population, or comparison population, for our study. This population was selected since it is a relatively large population with stable rates. The sociodemographic characteristics of the NYC population differ substantially from those of Upstate New York, justifying exclusion of NYC from the comparison group. Although all races were included in the study cohort, the reference population was restricted to whites because the study cohort was approximately 97% white, whereas the 1990 population of NYS excluding NYC was about 90% white.
To evaluate whether the Woodstock cohort differs from the reference population on risk factors for cancer, smoking and alcohol use reported by cohort members 18 years and older were compared to Behavioral Risk Factor Surveillance System (BRFSS) estimates for white residents of NYS excluding NYC. For the years 1986-1988, the BRFSS survey included approximately 700 residents of NYS excluding NYC each year (2037 total). We compared aggregated BRFSS data for the years 1986-1988 to data on Woodstock residents registered between 1986 and 1988. The BRFSS question, "Have you smoked at least 100 cigarettes in your life?" was closest in content to our category of "ever smokers," obtained by aggregating current smokers and past smokers. We categorized average number of drinks per day as "greater than two" and "less than two" in order to match the BRFSS category of two or more drinks per day, categorized as "chronic drinking."
Health outcomes
The health outcome of the study is a first diagnosis of a primary cancer, with a focus on gastrointestinal, respiratory, and total cancers. The NYS Cancer Registry (NYSCR) was used to confirm cancer diagnoses and to identify unreported cancers among WAER participants. NYSCR data were also used to calculate cancer rates for the reference population. Since the entire town water supply may have contained some level of asbestos starting around 1960, the follow-up period for observation of outcomes was defined as January 1980 through December 1998. Starting follow-up in 1980 allowed 20 years of latency, which is consistent with the expected latency of 20-30 years or more for asbestos-related cancers (Mossman and Gee, 1989). Although the NYSCR has been in existence since 1940, a start date of 1980 also was of practical significance since NYSCR data were complete on a statewide basis and accessible beginning in 1980.
International Classification of Diseases 9th revision (ICD-9) codes 150-159 were used to define gastrointestinal cancers and include cancers of the esophagus, stomach, small intestine, colon, rectum, liver, gall bladder, pancreas, and peritoneum. Respiratory cancers were defined as ICD-9 codes 161-163 and 164.2-165.9, which encompass cancers of the larynx, trachea, bronchus, lung, pleura, and mediastinum. Mesotheliomas were identified as malignant tumors reported to the NYSCR with a morphology code (based on ICD-02) between 9050 and 9055. ICD-9 codes 140-208 were included in the total cancers category.
Participants who moved out of NYS
It was not feasible for us to obtain comparable ascertainment of incident cancers for WAER participants living out of state. For this reason, the primary data analysis focuses on the subgroup of the cohort consisting of individuals who were NYS residents (referred to as "NYS residents") at the last date of follow-up and include only cancers confirmed by the NYSCR. In addition, all analyses were repeated for the entire study cohort ("whole cohort"). For analysis of the whole cohort, outcomes consisted of self-reported cancer diagnoses among residents who moved out of state and confirmed cancer diagnoses among NYS residents.
Exposure assessment
Timing and duration of residence in a home serviced by the Woodstock water supply were used as indirect measures of asbestos exposure. Duration and latency analyses were limited to gastrointestinal and respiratory cancer categories due to small numbers within duration and latency strata for individual cancer subsites.
Duration of residence
Duration of residence on the water supply was used as a proxy measure of cumulative exposure. Stratified analyses were performed based on duration of residence on the water supply from 1960 through 1985. Duration of residence was categorized as less than five years, five to 15 years, and greater than 15 years.
Latency
A time interval, or latency, of 20 to 30 years or more has been observed between first exposure to asbestos and diagnosis of asbestos-related cancers (Mossman and Gee, 1989). Latency was taken into account in the analysis by performing lagged analyses in which person-time at risk began after an interval following first exposure. The analysis was repeated for three "lag" periods: five, 10, and 20 years following first exposure. For the five-year lag, people who moved into a Woodstock residence during or before 1975 entered follow-up in 1980. People who moved onto the water district in subsequent years (i.e. 1976 through 1985) had a lag period of five years between first residence on the water supply and start of follow-up. The 10-year and 20-year lagged analyses were handled similarly, providing minimum intervals of 10 years and 20 years before start of person-time accrual.
Start of exposure
The earliest evidence of asbestos in the Woodstock drinking water dated to 1976. We have no measurements of drinking water asbestos levels during the first 15 years that the AC piping was in place. For this reason, in addition to analyses based on the assumption that exposure began in 1960 soon after the AC piping was first installed, we also repeated all analyses using a more conservative assignment of exposure with 1976 as the start date.
Water use patterns
We collected information by questionnaire on consumption of tap or bottled water, clothes dryer use and venting, and humidifier use. Response frequencies are reported as descriptive information. These data were not part of a detailed quantitative assessment because the small numbers of observations would not support comparisons based on these characteristics.
Statistical Analysis
Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated for individual cancer sites and the cancer groupings of interest: total, gastrointestinal, and respiratory cancers. An SIR is the observed number of cancers in the study population divided by the expected number of cases (Kelsey et al., 1996). The expected number of cases were calculated as the product of person-years of observation and cancer incidence rates from the reference population for each stratum of age (0-44, 45-49,..., 80-84, >85 years), sex, and calendar year (1980-1984, 1985-1989, 1990-1994, 1995-1998). Ages <45 years were grouped since gastrointestinal and respiratory cancers are rare in younger age groups. Confidence intervals for the SIR were calculated based on the Poisson distribution.
Results
The 625 service connections on the Woodstock water supply included approximately 67 nonresidential connections, 14 additional connections to parcels with multiple family dwellings, five residences recently connected to the water supply in 1985, and three vacant dwellings. Although it was difficult to distinguish solely commercial properties and commercial properties with residential units, approximately 536 properties with residential units were serviced by the Woodstock water supply in 1985 (including about 48 parcels with multiple family dwellings). Of approximately 488 single-family dwellings, 394 households (80.7%) serviced by the public water supply in 1985 were represented in the WAER. We were unable to accurately estimate response rates for multiple family units. In all, 2,936 current or former Woodstock residents participated in the WAER.
A total of 247 WAER participants died or were diagnosed with cancer prior to 1980 and were therefore not included in the study cohort. An additional 66 registrants were excluded from analysis because of missing date of birth (52) or missing duration of residence on the water supply (14). The study cohort consisted of the remaining 2,623 WAER participants. Table 2 shows the exclusions and follow-up status for the WAER. Fifty-nine individuals in the study cohort were lost to follow-up prior to 1998, 712 moved out of state, and 1,852 remained in NYS.
Table 3 summarizes the gender, age, and race distribution of the cohort along with data on smoking and alcohol use among cohort members 18 years and older at registration. Race was not included on the questionnaire at the start of enrollment, resulting in a high number of missing observations for that variable. The person who completed the questionnaire will be referred to as the primary respondent. Unknown values for smoking and alcohol use most often occurred for individuals who were not primary respondents. Unknown responses were recorded more than five times more frequently for individuals for whom information was provided by a family member or friend, compared to primary respondents. Among those for whom relationship to the respondent was known, information was provided by the participant himself or herself for 36.3% of cohort members, by an immediate family member for 54.7%, by an extended family member for 4.2%, and by an unrelated source for the remaining 4.8%.
Smoking and alcohol use reported by cohort members 18 years and older is compared to Behavioral Risk Factor Surveillance System (BRFSS) estimates for white residents of NYS excluding NYC in Table 4. Exclusions based on age, interview date, and missing values reduced the Woodstock population to 1,586 and 1,408 for the smoking and alcohol use comparisons, respectively. Although the stratified estimates are based on small numbers for both the WAER and BRFSS populations and are therefore fairly unstable, the proportion of ever smokers and chronic drinkers was not consistently higher or lower among men and women in the Woodstock cohort compared to the BRFSS estimate. The differences in reported ever smoking and chronic drinking among males 18-24 years of age might be explained by proxy reporting since a parent provided information for 75% of Woodstock participants in this age group.
Water use patterns
Routine use of tap water for drinking and cooking was reported for 97.5% of the WAER study cohort. A clothes dryer vented indoors was reported for 6.9% of the study cohort and use of a humidifier in the home for 16.2%. Small numbers prohibited comparison of cancer incidence by water use patterns.
NYS residents, 1960-1985
Table 5 presents observed numbers of cancers and SIRs for the unlagged analysis based on residency on the water supply between 1960 and 1985 among NYS residents. The SIRs for total, gastrointestinal, and respiratory cancer groupings are all approximately 1.00 or slightly below 1.00 and all confidence intervals (CIs) include unity. For the gastrointestinal subsites, the SIR for pancreatic cancer was marginally statistically significant at 2.19 (95% CI=1.00-4.16). The excess in pancreatic cancer occurred primarily among men (SIR=3.08; 95% CI=1.13-6.70) and was only slightly elevated among women (SIR=1.39; 95% CI=0.29-4.06). The SIR for esophageal cancer was also elevated among men. However, the increase was not statistically significant and was based on a small number of cases. With one exception, all respiratory cancers were cancers of the lung and bronchus. Therefore respiratory cancers are not listed by subsite. No cases of mesothelioma were observed among WAER participants.
Duration of residence on the Woodstock water supply is examined in Table 6. No discernable patterns are observed in the incidence of gastrointestinal cancers across the three categories of length of residency. While SIRs for respiratory cancer increased with duration among males, the SIR remained less than 1.00 even in the longest duration category. Confidence intervals for all duration categories overlapped and none excluded unity.
The results of the lagged analyses are shown in Table 7. Increasing lag periods resulted in small decreases in the SIRs for gastrointestinal cancer among both men and women and small increases in the SIRs for respiratory cancer among women. The confidence intervals for the different lag periods overlapped and none excluded unity with the exception of a reduced risk of gastrointestinal cancer among women associated with a minimum of 10 years following first exposure. The numbers of observations were too small to analyze individual gastrointestinal sites by latency.
Although the number of individual gastrointestinal subsite cases was too small to permit formal analysis of latency and duration, duration and latency were examined for pancreatic cases to see if the length and timing of residence on the water supply were consistent with an influence of asbestos exposure on cancer risk. Duration of residence on the Woodstock water supply was less than ten years for five pancreatic cancer cases, 10 to <20 years for two cases, and 20 years or more for two cases. Latency between start of residence on the Woodstock water supply and cancer diagnosis was less than 10 years for three pancreatic cancer cases, 10-<20 years for two cases, and 20 years or more for four cases.
NYS residents, 1976-1985
The analyses reported above were repeated using 1976 as the date of first exposure. The results for total, gastrointestinal, and respiratory cancer incidence (Table 8) are generally similar to those assuming exposure started in 1960 (Table 5). Duration and latency analyses were also performed using the 1976 exposure start date. Again, the results were similar to those presented in Tables 6 and 7 which assumed exposure started in 1960 (data not shown).
Whole cohort, 1960-1985
Analysis of cancer incidence for the whole cohort (including residents who moved out of state), based on exposure from 1960 through 1985, is summarized in Table 9. The incidence of gastrointestinal cancer, respiratory cancer, and all cancers combined was very similar to that observed for the NYS residents cohort (Table 5).
Discussion
This prospective cohort study, with a retrospective component for the years 1980-1985, did not demonstrate an increased incidence of total gastrointestinal cancer, total respiratory cancer, or all cancers combined among individuals living on a water supply contaminated with asbestos. When individual gastrointestinal cancers were examined, only pancreatic cancer was significantly elevated and the excess occurred primarily among males.
In previous epidemiologic studies, an association has been observed between asbestos fibers in drinking water and incidence of stomach cancer and other gastrointestinal or respiratory cancers (Meigs et al., 1980), (Conforti et al., 1981), (Toft et al., 1981), (Sigurdson, 1983), (Polissar et al., 1984), (Andersen et al., 1993), while others do not support an association (Millette et al., 1983), (Howe et al., 1989). Our study does not confirm the increased risk of stomach cancer noted in some prior studies. The observation of an excess stomach cancer risk in these other studies was limited to men, suggesting that occupation or lifestyle characteristics that differ by gender may play a role in the findings. Sigurdson (1983) noted that stomach cancer mortality had been elevated in the Duluth population prior to the start of asbestos exposure, possibly due to ethnic dietary practices. In the Duluth population, stomach cancer mortality was also elevated among females but the difference was not statistically significant. Norwegian lighthouse keepers exposed to asbestos-contaminated drinking water also experienced higher than expected rates of stomach cancer. Andersen et al. (1993) speculated that lack of refrigeration equipment prior to the late 1960s and a diet high in dried, salted, and smoked foods, may have accounted for the elevated incidence of stomach cancer among lighthouse keepers.
Although we observed a statistically significant excess of pancreatic cancer among males, the incidence of other individual gastrointestinal cancer sites, respiratory cancer, and all cancers combined, was not elevated and most SIRs were less than 1.00. Of the studies summarized in Table 1, a significant association between asbestos exposure and pancreatic cancer was observed in studies by Meigs et al. (1980) and Conforti et al. (1981). Meigs et al. (1980) presented site- and sex-specific results for two study periods: 1955-1964 and 1965-1974. The regression coefficient for the estimated concentration of asbestos fibers in the water supply was statistically significant for pancreatic cancer among males for the 1955-1964 study period only. Since little AC pipe was reported to have been in place in Connecticut water supplies prior to 1950, a stronger association would instead have been expected for the 1965-1974 interval if pancreatic cancer was causally related to asbestos exposure (Meigs et al., 1980). In the study by Conforti et al. (1981), a positive association between asbestos and pancreatic cancer among females was based on significant correlation and regression coefficients. The authors noted that the fit of the regression model was poor and suggested that the "regression data must be viewed with caution." A test for trend to determine the presence of a dose-response relationship between asbestos exposure and pancreatic cancer was not significant. Also a nonsignificant excess of pancreatic cancers among females and a nonsignificant deficit of pancreatic cancers among males were observed in the case-control study by Polissar et al. (1984). Although a positive association between exposure to asbestos in drinking water and pancreatic cancer was noted in an early investigation of some of the other study populations cited in Table 1 (Masson et al., 1974), (Levy et al., 1976), (Wigle, 1977), the association did not persist in follow-up investigations of the same populations with an extended observation period and longer latency.
Several explanations other than a causal relation might account for the observed excess of pancreatic cancer among males in our study. Cigarette smoking is the risk factor most consistently associated with pancreatic cancer. In our study, a history of cigarette smoking was available for eight of nine pancreatic cancer cases. Seven of the eight cases were current or former smokers. Secondly, the observation of an increase in pancreatic cancer primarily among men, but not women, suggests the influence of occupational or lifestyle risk factors. If environmental exposure to asbestos via drinking water was responsible, elevations in pancreatic cancer among both males and females might be expected. Also, due to the anatomic location of the pancreas and the usually poor prognosis at the time of diagnosis, the proportion of pancreatic cancers confirmed histologically is less than that for any other major cancer (Anderson et al., 1996). Problems with ascertainment and misclassification are therefore a concern in epidemiologic studies of pancreatic cancer. Lastly, a chance positive finding is possible, particularly when examining 14 sex-specific estimates.
Duration of residence on the water supply was used as a surrogate for cumulative exposure to asbestos in the current study in an effort to assess dose-response. Cancer incidence did not significantly increase with longer duration of residence. Uncertainty about timing of first exposure as well as small numbers of observations by category of duration limited our ability to more accurately and precisely examine the influence of duration of residence on the water supply.
Since the latency period for asbestos-related cancers can be 20-30 years or more (Mossman and Gee, 1989), cancers observed in the early years following exposure to asbestos in drinking water might not be attributable to this exposure. A lagged analysis was conducted, in which individuals were not considered at risk and were not counted in the follow-up for an interval following first exposure. When a causal relationship exists and an appropriate lag period is used, a higher cancer incidence rate would be expected in lagged analyses since the estimated rates would not be diluted by observation time for individuals not yet at risk of exposure-related cancer. After allowing for latency, significantly higher cancer rates were not observed in the current study for gastrointestinal cancers, respiratory cancers, or all cancer sites combined. Uncertainty about timing of first exposure restricts our interpretation of lagged analyses. The longest interval between first exposure and the end of follow-up in 1998 was 39 years based on exposure starting in 1960 but would be only 23 years if exposure started in 1976. In addition, the small number of WAER participants with long latency limited statistical power of estimates stratified by latency.
Although the number of individual gastrointestinal subsite cases was too small to permit formal analysis of duration and latency, pancreatic cases were examined in more detail to see if duration and latency were consistent with exposure to asbestos in the water supply. Among the nine pancreatic cancer cases in our cohort, duration of residence on the Woodstock water supply was less than ten years for five pancreatic cancer cases, 10 to <20 years for two cases, and 20 years or more for two cases. Latency between start of residence on the Woodstock water supply and cancer diagnosis was less than 10 years for three pancreatic cancer cases, 10-<20 years for two cases, and 20 years or more for four cases. It is unlikely that cancers diagnosed within ten years of first exposure would be related to asbestos exposure.
An important limitation of this study is the lack of historical exposure data needed to establish when leaching of asbestos into the water supply first produced measurable exposure. The AC pipes were installed in the mid- to late-1950s, but asbestos contamination was first detected in 1985. A 10-year-old water sample that was tested in 1986 contained higher-than-normal levels of asbestos. This indicates that leaching had begun by 1976. The use of 1976 as the starting time of exposure produced similar results to the analysis based on a 1960 start date.
Other than the one water sample believed to have been collected in 1976, we have no evidence regarding the extent of the asbestos contamination in the Woodstock water supply prior to 1985, nor can we estimate changes in exposure over time or by location on the water supply. The water sampling that was performed in November 1985 occurred after the water mains were flushed (an attempt to remedy the water pressure problem). Deterioration of the pipe was probably aggravated by the forceful flow of water, both from turning the water on after it was turned off for repairs and from flushing the water mains. The asbestos levels measured may not have represented usual concentrations. Gradual leaching of asbestos may have resulted in generally low concentrations of asbestos. Due to limited information on the actual levels of exposure, this study's findings regarding risk associated with asbestos exposure cannot be generalized to other exposure experiences. The exposures experienced by the WAER cohort do not appear to have led to a detectable increased risk of cancer.
We could not directly control for potential confounding due to risk factors such as smoking, alcohol use, and socioeconomic status in our SIR estimates. However, we examined registry, survey, and census data to determine whether the WAER cohort was comparable to the population of NYS excluding NYC with respect to these risk factors. The frequency of cigarette smoking and alcohol use among the WAER participants did not differ substantially from survey estimates for the population of NYS excluding NYC. Education and income information were not available through the registry so census data were used to assess socioeconomic status. Based on 1990 U.S. Bureau of Census data, the Town of Woodstock population had a higher level of education than the population of NYS excluding NYC. Thirty-nine percent of Town of Woodstock residents had a bachelor's degree or higher, compared to 23% of the population of Upstate NY excluding NYC. Stomach and lung cancer are associated with low socioeconomic status and colorectal cancer is associated with high socioeconomic status (Nomura, 1996), (Blot and Fraumeni, 1996), (Schottenfeld and Winawer, 1996). The greater proportion of residents with advanced education, indicative of higher socioeconomic status, could explain the somewhat lower than expected incidence of respiratory cancer among males in the study cohort. We did not have information on other risk factors for stomach and colon cancers such as diet, physical activity, and body mass (Nomura, 1996); (Tomeo et al., 1999).

Attorneys memphis tn Wallpaper Photos Pictures Pics Images 2013