SECTION 7
This section provides a discussion of intrasubregistry file differences with regard to health outcomes and the possible relationships to types and levels of exposure. First, this section explores intrasubregistry differences for demographic and descriptive variables, as well as exposure variables. Table 7-1 provides a summary of descriptive information by site. Then, the relationship of rates of reported health outcomes to exposure levels and length of exposure are explored.
Statistical comparisons across sites were not performed. Site-specific information is noteworthy, however, because an assessment of the similarity of site subsamples with regard to age, sex, educational attainment, and smoking history might lead to the identification of unique or outstanding sites or groups of subregistry members with regard to some feature (for example, cumulative exposure, level of exposure, or demographic characteristic). Any anomalies of this type have the potential to skew the findings presented in Section 5 which pertain to subregistry and national comparisons of self-reported health conditions.
As can be seen in Table 7-1, the average age of all subregistry members was 34 years. The mean age varied from site to site, from a low of 31 years to a high of 37 years. The registrants associated with the Warner Electric Brake and Clutch Company site were younger, on the average, than registrants at the other sites. The Warner site also had the highest median cumulative exposure levels. Some variation in education attainment is shown in Table 7-1; the percentage of those with less than a high school diploma ranged from 8% to 39%. The percentage of persons who never smoked cigarettes varied from site to site, with a range of 45% to 63%.
Although there were some differences in demographic and descriptive characteristics from site to site, the magnitude of these differences was small. The summary information for the descriptive variables did not indicate that any one site was distinctly different from the others or would contribute disproportionately to any differences found in the comparisons made in this section or in the comparisons with the national norms made in Sections 5 and 6.
COMPARISON OF HEALTH OUTCOMES ACROSS EXPOSURE GROUPS
Creation of Exposure Subgroups
When exploring differences between exposure groups, there were several ways to group the TCE Subregistry members for purposes of comparison, including categorization according to (1) geographic location, (2) site area, (3) recorded environmental exposures levels, or (4) length of exposure. Given the geographic proximity of sites to each other within a state, three subgroupsIllinois, Indiana, and Michigancould be created based on state. Grouping according to these criteria was not pursued, however, because there was no substantive difference between the geographic locations. That is, Indiana subregistry members were not
Table 7-1.--Summary of age, sex, education attainment, and smoking history by site.
| Sites | Descriptive Variables |
||||||||
N |
Mean Age (sd) |
% Males |
Education Attainment (years) |
Smoking History | |||||
| <12
N (%)* |
12
N (%)* |
>13
N (%)* |
Current
N (%)* |
Ex-smoker N (%)* |
Never
N (%)* |
||||
| All TCE | |||||||||
| All | 3,915 | 34.0 (19.9) | 48 | 894 (30) | 1,305 (44) | 741 (25) | 1,241 (32) | 628 (16) | 2046 (52) |
| Males | 1,875 | 33.3 (19.4) | . | 440 (32) | 603 (43) | 344 (25) | 622 (33) | 339 (18) | 914 (49) |
| Females | 2,040 | 34.7 (20.2) | 454 (29) | 702 (45) | 397 (25) | 619 (30) | 289 (14) | 1132 (55) | |
| Verona Well Field and Dowagiac | |||||||||
| All | 203 | 35.6 (20.4) | 46 | 57 (38) | 57 (38) | 44 (23) | 74 (37) | 38 (19) | 91 (45) |
| Males | 93 | 35.9 (22.2) | 28 (43) | 23 (35) | 14 (21) | 33 (36) | 21 (23) | 39 (42) | |
| Females | 110 | 35.3 (18.8) | 29 (35) | 34 (41) | 20 (27) | 41 (37) | 17 (16) | 52 (47) | |
| McGraw-Edison Corporation | |||||||||
| All | 215 | 36.1 (19.8) | 42 | 52 (32) | 56 (34) | 55 (34) | 53 (25) | 31 (14) | 131 (61) |
| Males | 90 | 36.6 (20.3) | 25 (38) | 23 (34) | 19 (18) | 23 (26) | 16 (18) | 51 (57) | |
| Females | 125 | 35.7 (19.5) | 27 (28) | 33 (34) | 36 (37) | 30 (24) | 15 (12) | 80 (64) | |
| Superior Street | |||||||||
| All | 471 | 37.6 (20.3) | 50 | 46 (12) | 165 (44) | 165 (43) | 118 (25) | 86 (18) | 267 (57) |
| Males | 236 | 36.0 (20.2) | 26 (14) | 72 (39) | 84 (46) | 61 (26) | 48 (20) | 127 (54) | |
| Females | 235 | 39.2 (20.4) | 20 (10) | 93 (48) | 81 (42) | 57 (24) | 38 (16) | 140 (60) | |
| Central Area | |||||||||
| All | 76 | 33.7 (18.4) | 46 | 10 (16) | 32 (52) | 20 (32) | 18 (24) | 10 (13) | 48 (63) |
| Males | 35 | 33.5 (18.8) | 5 (17) | 15 (52) | 9 (13) | 8 (23) | 7 (20) | 20 (57) | |
| Females | 41 | 33.0 (18.3) | 5 (15) | 17 (51) | 11 (33) | 10 (24) | 3 (7) | 28 (68) | |
| Gemeinhardt Piccolo Company | |||||||||
| All | 480 | 34.0 (19.4) | 46 | 121 (33) | 178 (48) | 71 (19) | 164 (34) | 86 (18) | 230 (48) |
| Males | 223 | 32.3 (19.0) | 58 (35) | 77 (47) | 29 (17) | 80 (36) | 40 (18) | 103 (46) | |
| Females | 257 | 35.5 (19.8) | 63 (30) | 101 (49) | 42 (20) | 84 (33) | 46 (18) | 127 (49) | |
Table 7-1.--Continued.
| Sites | Descriptive Variables |
||||||||
N |
Mean Age (sd) |
% Males |
Education Attainment (years) |
Smoking History |
|||||
<12 N (%)* |
12 N (%)* |
>13 N (%)* |
Current N (%)* |
Ex-smoker N (%)* |
Never N (%)* |
||||
| Conrail Rail Yard | |||||||||
| All | 232 | 32.6 (18.9) | 54 | 37 (22) | 84 (50) | 48 (28) | 50 (22) | 36 (16) | 146 (63) |
| Males | 125 | 32.3 (18.6) | 21 (23) | 45 (49) | 25 (27) | 27 (22) | 25 (20) | 73 (58) | |
| Females | 107 | 32.9 (19.3) | 16 (20) | 39 (50) | 23 (29) | 23 (22) | 11 (10) | 73 (68) | |
| Southeast Rockford Groundwater Contamination | |||||||||
| All | 1718 | 33.2 (20.5) | 48 | 501 (39) | 578 (45) | 215 (16) | 624 (36) | 258 (15) | 836 (49) |
| Males | 820 | 32.4 (19.8) | 243 (40) | 265 (43) | 101 (17) | 310 (38) | 141 (17) | 369 (45) | |
| Females | 898 | 33.9 (21.0) | 258 (38) | 313 (46) | 114 (17) | 314 (35) | 117 (13) | 467 (52) | |
| Warner Electric Brake and Clutch Company | |||||||||
| All | 311 | 31.1 (15.6) | 49 | 18 (8) | 101 (46) | 102 (46) | 71 (23) | 48 (15) | 192 (62) |
| Males | 152 | 31.7 (14.9) | 9 (8) | 58 (51) | 47 (41) | 42 (28) | 24 (16) | 86 (57) | |
| Females | 159 | 30.6 (16.3) | 9 (8) | 43 (40) | 55 (51) | 29 (18) | 24 (15) | 106 (67) | |
| Other Illinois Sites | |||||||||
| All | 209 | 35.7 (20.2) | 50 | 52 (38) | 54 (39) | 31 (22) | 69 (33) | 35 (17) | 105 (50) |
| Males | 101 | 34.4 (18.6) | 25 (38) | 25 (38) | 16 (24) | 38 (38) | 17 (17) | 46 (46) | |
| Females | 108 | 36.8 (21.7) | 27 (38) | 29 (41) | 15 (21) | 31 (29) | 18 (17) | 59 (55) | |
*Percentage of total.
meaningfully different from Illinois subregistry members simply because of their current or former residence in their site state.
Likewise, grouping according to site (for example, Gemeinhardt Piccolo Company or Acme Solvents Reclamation, Inc.) would be inappropriate for similar reasons. Each site has a different source of contamination and contaminants identified at each site and their reported levels varied greatly for the site addresses across sites. Also, there was great disparity within some sites in terms of the types, levels, and durations of exposures that were experienced by subregistry members. Further, several sites (for example, Frinks Industrial Wastes and Acme Solvents Reclamation, Inc.) had too few subregistry members to allow for meaningful comparisons to other, larger sites. Therefore, statistical comparisons between sites were not made.
A more appropriate mechanism for creating subgroups would take into consideration the types, lengths, and levels of environmental exposures of subregistry members. Using available environmental exposure information, the four sets of exposure groups created follow. A more detailed discussion of the categorization scheme used will be presented later. The categories created were:
(1) TCE level only--This scheme did not take into account the presence or levels of other chemicals. The maximum value recorded for each address was used. The subgroups were formed in two ways: using quartiles based on the number of samples (resulting in categories <2, 2 through 12, >12 through 60, and >60 through 12,800 parts per billion (ppb)) and using broader exposure limits (50, >50 through 500 and >500 ppb).
(2) Cumulative TCE level--This scheme utilized both the level of TCE and length of time at a residence (length of exposure), but did not consider the presence and levels of other chemicals. The subgroups formed were <50 ppb-years, 50 through 500 ppb-years, >500 through 5,000 ppb-years, and >5,000 ppb-years.
(3) Cumulative level using TCE and all structural and optical isomers of four chlorinated hydrocarbons--The four hydrocarbons included were dichloroethene (DCE), dichloroethane (DCA), trichloroethane (TCA) and perchloroethylene (PCE). The data used were restricted to those registrants having information for all four chemicals. The subgroups formed were <50 ppb-years, 50 through 500 ppb-years, >500 through 5,000 ppb-years, and >5,000 ppb-years.
(4) Length of exposure--The length of time the registrant used contaminated water (based on occupancy information) was considered the length of exposure. The subgroups formed were 2 years, >2 through 5 years, >5 through 10 years, and >10 years.
Using these four sets of subgroups, subregistry members were compared in terms of their responses to questions about physician-treated health conditions. These comparisons considered the possible confounding influences of demographic characteristics, occupational exposures and socioeconomic status. The comparisons made investigated the potential of a dose-response relationship.
Despite the merits of the subgrouping schemes, some caveats concerning the environ-mental data merit reiteration. As is discussed in Section 3, the environmental data for the subregistry were very limited and did not provide a complete record of the environmental exposures experienced by subregistry members. For most subregistry members, the environmental information included a one-time sample that merely verified exposure and level at one point in time. Within each site, the available samples that were taken at each site address were obtained at different times over an extended period. For this reason, it was unlikely that samples were taken at a consistent time during the period of contamination (for instance, while contamination was at the maximum levels ever experienced) and were representative of a given environmental exposure phase.
In some instances, the source of contamination of groundwater had been eliminated (for example, the company had been permanently closed for operation) at the time of sampling, although the groundwater continued to be contaminated with residual chemicals. Further, the environmental data were not complete for a sample; in some cases, the samples were not analyzed for the full spectrum of all possible volatile organic compounds (VOCs). In other cases, the samples were analyzed for all or most VOCs, but nondetectable results were not reported. Therefore, it would be inappropriate to conclude that lack of information on exposure to chemicals other than TCE (for example, exposure to trichloroethane or dichloroethane) was synonymous with nonexposure.
This section examines health outcome response rates across environmental groups. Three variables were used in creating the subgroups: level of exposure, length of exposure, and cumulative exposure. A discussion of each follows.
Level of Exposure
At the present time, there are 4,281 persons (4,042 living, 239 deceased) in the TCE Subregistry who have been exposed to TCE. For the purposes of this analysis, each individual has been assigned a level of exposure that represents the maximum level measured (in a small number of cases multiple readings for a well were available) for the site address associated with the individual. As mentioned previously, the maximum level assigned to each case might not be the true maximum level experienced.
Most TCE Subregistry members have been exposed to other chemicals. As expected at hazardous waste sites, mixtures of contaminants were present at each of the sites and each TCE-contaminated well was also contaminated with other chemicals. The typical sources of contamination for the sites were industrial processes that used a variety of other common industrial solvents in addition to TCE. These included chemicals such as tetrachloroethylene, benzene, carbon tetrachloride, freon, toluene, and xylene. Other reported secondary contaminants were chemical and biological degradation products of TCE and the other chlorinated hydrocarbons. The structural and optical isomers of the chemicals dichloroethene (DCE), dichloroethane (DCA), trichloroethane (TCA) and perchloroethylene (PCE) were most often reported and were included in the statistical analyses.
Table 7-2 presents a summary, by TCE levels, of the presence and levels of four other chemicals: DCE, DCA, TCA, and PCE. In some cases, the TCE levels were exceeded by the reported levels of the other chemicals. In particular, levels of DCE exceeded the levels of TCE (about 14% of the values) when TCE was less than 50 ppb. TCA exceeded 1% of the TCE levels when TCE was greater than 50 ppb. In a few instances, the levels of DCA or DCE exceeded the TCE levels (less than 5% exceeded the TCE levels below 500 ppb, less than 0.5% when TCE levels were greater than 500 ppb).
The registrants associated with the samples presented in Table 7-2 were exposed to TCE and at least one of the other four chemicals listed in the table. In the analyses presented in a later table, exposure information is presented for TCE and all of the four chemicals TCA, PCE, DCE, and DCA for 1,504 registrants. For the remaining registrants, information was missing
Table 7-2.Summary of levels of other chemicals by TCE level.
| Chemical Levels | Number of Positive Samples* | |||
| TCA† | PCE† | DCE† | DCA† | |
| TCE Levels 50 ppb | ||||
| All samples (N = 2,867) | 2,344
(82%)† |
1,891
(66%)† |
2,279
(79%)† |
1,731
(60%)† |
| 50 ppb | 1,672 | 1,880 | 2,071 | 1,687 |
| 51 - 500 ppb | 649 | 11 | 202 | 41 |
| 501 - 5,000 ppb | 23 | 0 | 6 | 3 |
| >5,000 ppb | 0 | 0 | 0 | 0 |
| TCE Levels 51-500 ppb | ||||
| All samples (N = 870) | 578
(66%) |
594
(68%) |
655
(75%) |
370
(42%) |
| 50 ppb | 267 | 550 | 453 | 215 |
| 51-500 ppb | 300 | 32 | 188 | 155 |
| 501-5,000 ppb | 11 | 5 | 14 | 0 |
| >5,000 ppb | 0 | 7 | 0 | 0 |
| TCE Levels 501-5,000 ppb | ||||
| All samples (N = 190) | 120
(63%) |
157
(83%) |
76
(41%) |
24
(13%) |
| 50 ppb | 87 | 153 | 28 | 12 |
| 51-500 ppb | 25 | 4 | 27 | 12 |
| 501-5,000 ppb | 2 | 0 | 21 | 0 |
| >5,000 ppb | 6 | 0 | 0 | 0 |
| TCE Levels >5,000 ppb | ||||
| All samples (N = 35) | 14
(40%) |
35
(100%) |
23
(66%) |
2
(6%) |
| 50 ppb | 10 | 35 | 2 | 2 |
| 51-500 ppb | 4 | 0 | 21 | 0 |
*Number of samples in that compound's range (percentage of total samples in TCE subgroup range).
†TCA = trichloroethane, PCE = perchloroethylene, DCA = dichloroethane, DCE = dichloroethene.
for one or more of the additional chemicals; this might indicate that the water was not tested for these chemicals, or that it was tested and none of the additional chemicals were found. There was no way to confirm either of the two possibilities.
Table 7-3 presents the reported levels of other chemicals, including methylene chloride, chloroform, carbon tetrachloride, benzene, butylbenzyl phthalate, vinyl chloride, trichlorofluoromethane, toluene, ethyl benzene, and magnesium. In most cases the levels of these contaminants were low, and occurred only at high levels of TCE contamination at a few site addresses within some sites (for example, the occurrence of magnesium). At the Conrail site, the carbon tetrachloride exposure levels exceeded the TCE levels in 14 of the 249 samples (the 14 exceeded the 500 ppb TCE level). Vinyl chloride and trichlorofluoromethane were present at low levels (<50 ppb) at a few households at the Superior site.
Table 7-3.Summary of other chemicals present.
| Chemical | N* | M† | Level of Chemical (ppb) | |||
| 50 | 51-500 | 501-5,000 | >5,000 | |||
| Methylene chloride | 230 | 3,812 (94%) | 221 (6%)§ | 0 (0%) | 0 (0%) | 9 (1%) |
| Chloroform | 603 | 3,439 (85%) | 595 (15%) | 8 (<1%) | 0 (0%) | 0 (0%) |
| Carbon tetrachloride | 441 | 3,601 (89%) | 317 (8%) | 106 (3%) | 15(<1%) | 3 (1%) |
| Benzene | 46 | 3,996 (99%) | 46 (1%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Butylbenzyl phthalate | 51 | 3,991 (99%) | 51 (1%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Chloromethane | 44 | 3,998 (99%) | 36 (1%) | 8 (<1%) | 0 (0%) | 0 (0%) |
| Vinyl chloride | 24 | 4,018 (99%) | 22 (1%) | 2 (1%) | 0 (0%) | 0 (0%) |
| Trichlorofluoromethane | 59 | 3,983 (98%) | 47 (1%) | 12 (1%) | 0 (0%) | 0 (0%) |
| Toluene | 18 | 4,024 (99%) | 18 (1%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Xylene | 12 | 4,030 (99%) | 12 (1%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Ethylbenzene | 13 | 4,030 (99%) | 13 (0%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Magnesium | 22 | 4,020 (99%) | 0 (0%) | 0 (0%) | 0 (0%) | 22 (1%) |
| Butyl (ethylhexyl)
phthalate |
51 | 3,991 (99%) | 0 (0%) | 51 (1%) | 0 (0%) | 0 (0%) |
*Total number of samples reporting that chemical.
†Number of samples for which there was no information on that chemical (percentage of total samples).
§Percentage (rounded to the nearest whole number) of total number of samples for which chemical was in the
indicated range.
Length of Exposure
As is indicated by Figure 7-1, the estimated maximum length of exposure at a site, and consequently for individuals, varied from 6.5 years (Warner Electric Brake and Clutch Company) to 18 years (Conrail). The length of time since exposure ceased at a site varied from 9 years (McGraw Edison) to those where exposure had continued until time of data collection. The time elapsed since the beginning of exposure varied from 7 years (Beloit) to 18 years (Conrail). As was discussed previously, the start dates for exposure at each site were the Agency for Toxic Substances and Disease Registry (ATSDR) estimates that were based on available information for each site. In each case, the exposure period was an estimate of the true exposure period (see Section 3).
The length of exposure for each individual was calculated using one of two pieces of information: (1) the start date of exposure at the site or (2) the move-in date for that person if the move-in date occurred after the beginning of the exposure period. The end of exposure for each person was either (1) the move-out date for that person or (2) the date the exposure period ended, whichever occurred first. This information is summarized in Table 7-4.
Cumulative Exposure
Cumulative exposure values were calculated for each individual using the following information: (1) TCE exposure levels only and (2) TCE, TCA, PCE, DCE, and DCA exposure levels (for the subset having information for all of these chemicals). Cumulative exposure for TCE was calculated as the product of maximum level (in cases in which multiple samples had been taken) and length of exposure (as defined previously). When additional chemicals were included, the total cumulative exposurethe sum of the individual products (maximum level multiplied by length of exposure)was used. A summary of cumulative exposures by site is shown in Table 7-4.
For the cumulative TCE exposure subgroups and for the cumulative total exposure (TCE, TCA, PCE, DCE, and DCA) subgroups the following categories were created: (1) <50 ppb-years; (2) 50 through 500 ppb-years; (3) >500 through 5,000 ppb-years; and (4) >5,000 ppb-years. The parameters of these categories were intended to be broad enough to differentiate between exposure outcomes and yet create subgroups that were large enough for valid statistical analysis.
Variables Used in Analyses
The statistical analyses performed compared the reporting rate for health outcomes across the four exposure subgroups. The rate of positive responses for each of the health outcomes considered in Section 5 (most were consistent with the NHIS data file) was analyzed. These outcomes were: in the "Have you ever had" category--conditions: hypertension, stroke, and heart problems; "Do you now have" category--conditions: speech or hearing impairment and mental retardation; and "In the last 12-months have you had" category--conditions: rash, anemia, kidney problems, urinary tract problems, ulcer or other stomach problems, liver problems, asthma, respiratory allergies or other respiratory problems, arthritis, diabetes, or Figure 7-1.--Summary of site exposure periods.
Figure 7.1
cancer. Several variables were considered to be possibly confounding and were examined in the statistical analyses. A discussion of these variables follows.
Table 7-4.Summary of length of exposure and cumulative exposure by site.
|
Site |
Exposure Variable |
|||||||||||
Length of Exposure (number of years) |
Cumulative Exposure (ppb x years) |
|||||||||||
N |
Mean |
sd |
Med* |
Low |
High |
N |
Mean |
sd |
Med* |
Low |
High |
|
| All Sites | ||||||||||||
| All | 3,678 | 5.6 | 4.4 | 4.5 | <1 | 18.0 | 3,614 | 970 | 5,206 | 38 | 1 | 140,800 |
| Males | 1,752 | 5.5 | 4.4 | 4.5 | <1 | 18.0 | 1,720 | 955 | 4,593 | 37 | 1 | 82,401 |
| Females | 1,926 | 5.7 | 4.4 | 4.7 | <1 | 18.0 | 1,895 | 564 | 1,798 | 35 | 1 | 10,614 |
| Verona Well Field and Dowagiac | ||||||||||||
| All | 192 | 6.0 | 3.1 | 6.2 | <1 | 10.0 | 154 | 450 | 2,112 | 9 | 1 | 15,000 |
| Males | 86 | 5.8 | 3.0 | 5.8 | <1 | 10.0 | 64 | 565 | 2,618 | 6 | 1 | 15,000 |
| Females | 106 | 6.2 | 3.1 | 6.8 | <1 | 10.0 | 90 | 369 | 1,673 | 17 | 1 | 15,000 |
| McGraw-Edison Corporation | ||||||||||||
| All | 178 | 4.0 | 2.7 | 4.4 | <1 | 7.0 | 156 | 226 | 687 | 7 | 1 | 4,881 |
| Males | 68 | 3.9 | 2.7 | 4.0 | <1 | 7.0 | 60 | 181 | 538 | 7 | 1 | 3,255 |
| Females | 110 | 4.1 | 2.7 | 4.4 | <1 | 7.0 | 96 | 255 | 767 | 7 | 1 | 4,882 |
| Warner Electric Brake and Clutch Company | ||||||||||||
| All | 309 | 4.5 | 2.0 | 5.4 | <1 | 6.6 | 309 | 3,302 | 6,069 | 829 | 1 | 33,360 |
| Males | 151 | 4.5 | 2.0 | 5.1 | <1 | 6.6 | 151 | 3,377 | 6,189 | 892 | 1.5 | 32,904 |
| Females | 158 | 4.5 | 2.1 | 5.0 | <1 | 6.6 | 158 | 3,230 | 5,973 | 762 | 1 | 33,360 |
| Southeast Rockford Groundwater Contamination | ||||||||||||
| All | 1,701 | 5.4 | 4.6 | 3.8 | <1 | 12.6 | 1,753 | 113 | 190 | 26 | 1 | 1,525 |
| Males | 809 | 5.2 | 4.6 | 3.3 | <1 | 12.6 | 838 | 104 | 182 | 25 | 1 | 1,162 |
| Females | 892 | 5.6 | 4.6 | 4.1 | <1 | 12.6 | 915 | 122 | 197 | 31 | 1 | 1,525 |
Table 7-4.--Continued.
|
Site |
Exposure Variable |
|||||||||||
Length of Exposure (number of years) |
Cumulative Exposure (ppb x years) |
|||||||||||
N |
Mean | sd | Med* | Low | High |
N |
Mean |
sd |
Med* |
Low | High |
|
| Central Area | ||||||||||||
| All | 69 | 4.2 | 2.6 | 5.2 | <1 | 7.0 | 69 | 27 | 70 | 2 | 1 | 388 |
| Males | 31 | 3.8 | 2.7 | 2.6 | <1 | 7.0 | 31 | 28 | 66 | 1 | 1 | 261 |
| Females | 38 | 4.5 | 2.6 | 6.2 | <1 | 7.0 | 38 | 27 | 74 | 2 | 1 | 388 |
| Superior Street | ||||||||||||
| All | 409 | 6.4 | 3.9 | 6.9 | <1 | 11.0 | 409 | 4,183 | 13,482 | 225 | 1 | 140,800 |
| Males | 207 | 6.3 | 3.8 | 6.3 | <1 | 11.0 | 207 | 3,531 | 10,927 | 216 | 1 | 82,402 |
| Females | 202 | 6.6 | 4.0 | 7.5 | <1 | 11.0 | 202 | 4,852 | 15,676 | 266 | 1 | 140,800 |
| Conrail Rail Yard | ||||||||||||
| All | 205 | 6.1 | 5.6 | 3.6 | <1 | 18.0 | 205 | 1,085 | 2,669 | 280 | 13 | 17,766 |
| Males | 106 | 6.2 | 5.8 | 3.4 | <1 | 18.0 | 106 | 1,121 | 2,710 | 248 | 1 | 17,766 |
| Females | 99 | 5.9 | 5.5 | 3.8 | <1 | 18.0 | 99 | 1,046 | 2,638 | 300 | 1 | 17,766 |
| Gemeinhardt Piccolo Company | ||||||||||||
| All | 408 | 6.7 | 5.8 | 4.5 | <1 | 17.0 | 408 | 473 | 2,490 | 16 | 1 | 27,200 |
| Males | 194 | 6.8 | 5.8 | 4.6 | <1 | 17.0 | 194 | 630 | 2,944 | 19 | 1 | 27,200 |
| Females | 214 | 6.5 | 5.8 | 4.4 | <1 | 17.0 | 214 | 332 | 1,990 | 14 | 1 | 27,200 |
*Median value
Occupational Exposure
At the time of data collection, an attempt was made to distinguish between those people with and those without occupational exposures that might have significantly added to or confounded the environmental exposures.
People who replied positively to being currently employed were asked for the following: (1) their job title; (2) what kind of work they did or what their duties on the job were; (3) what type of business or industry they were employed in, what product was made, or what service was given by their place of employment; and (4) whether the industry was mainly manufacturing, wholesale, retail, or something else (the answers "don't know" and "refused" were allowed). The responses were coded using the 1980 Census Listing for Occupational and Industrial Classifications (29) system; answers to (1) and (2) were used to determine the occupational portion and answers to (3) and (4) determined the industry portion of the code. In addition, people who were employed were asked if they were employed in what they considered to be their primary occupation. If the answer was "yes," no further information was sought; if the answer was "no," respondents were then asked what their primary occupation was. This information on primary occupation was coded using the same Census classification system (29) and became part of the occupational history code.
Registrants who responded that they were not currently employed but had been in the past were asked to provide what they considered their "primary occupation." This information was then coded for the file using the 1980 Census Listing for Occupational and Industrial Classifications (29) system.
Based on this occupational and industry information, subregistry members were classified as either occupationally exposed or not occupationally exposed. Persons in jobs that appeared to have the potential for pertinent, chemical occupational exposures (persons with codes 634 through 645, 703 through 725, 755 through 757, 766, and 768) were classified as having a possible occupational exposure; otherwise, subregistry members were assumed not to have confounding occupational exposures. This classification is a subjective evaluation. More definitive information would be collected if an epidemiologic study were undertaken.
When classified, 246 (8%) of the TCE registrants (19 years of age or older) were identified as potentially occupationally exposed. When looking at sites, the range was from 2% (1% females, 3% males) in Superior (Elkhart) to 13% (7% females, 19% males) in Southeast Rockford. This dichotomous occupational exposure variable was included in the statistical analyses as a possible confounding variable.
Cigarette Smoking History
TCE Subregistry members' cigarette smoking history was used as a possible confounding variable. The categories of smokers that were examined were current smoker, ex-smoker, and never smoked.
Statistical Methods
Differences between environmental exposure groups were explored using regression analysis and, as the dependent variable, the rate of reporting for each health outcome (grouped according to the NHIS time frames discussed in Section 5). Age, sex, occupational exposure, smoking history, and education level were considered potentially confounding factors and were included in the statistical analyses involving health outcomes and environmental exposure subgroups. When using the total sample, age and sex variables were included; the analyses were restricted to persons 19 years of age and older when the variables occupational history, smoking history, and education level were included. Consistent with Section 5, the analyses in this section were restricted to people reporting their race to be white.
Logistic regression was the statistical method used for these comparisons. The inclusion and exclusion of potential variables in the model was determined by published methods (30). Estimated prevalence ratios for the health outcomes, adjusted for the potential confounders, were calculated by exponentiating the ß-coefficients from the exposure variables in the regression equation. The health outcome variables were modeled as dichotomous, binary dependent variables in the regression models. Nominal, independent variables were modeled using dummy variables. The main effectsthe independent variables of interestused were: (1) age categories, (2) occupational categories, (3) education level, and (4) environmental exposure categories (for example, TCE exposure, other chemicals using levels and length of exposure).
RESULTS OF EXPOSURE SUBGROUP COMPARISONS
Summaries of the variables age, sex, and education are shown by environmental exposure groups in Table 7-5. A summary of the responses for each of the health outcomes (using the time frames discussed in Section 5 that were consistent with the National Health Interview Survey (NHIS) database) by exposure subgroup was shown in Appendix E. The percentage of registrants classified as occupationally exposed ranged from 9% (0 to 50 ppb category) to 2% (>500 ppb category) for maximum TCE exposure groups; from 10% (51 to 500 ppb-years category) to 2% (>5,000 ppb-years category) for cumulative TCE exposure groups; and from 13% (51 to 500 ppb-years category) to 8% (>5,000 ppb-years category) for cumulative total chemical (TCE, PCE, TCA, DCE, and DCA) exposure groups. In all cases, the lowest percentage of occupationally exposed people was associated with the highest environmental exposure level group.
The summary of the results, using each of the four environmental groupings, is presented in Tables 7-6 through 7-15. The results of all analyses are summarized in Table 7-16. The tables show the estimated, adjusted prevalence odds ratios and the 95% confidence intervals for the odds ratios. The lowest exposure level subgroups were considered the comparison groups (assigned a value of 1) and the other ratios represent the comparison to the lowest groups or to the number one. There were some analyses (indicated in the tables) for which there were insufficient data to execute the model designated; this was particularly true for the expanded models.
The results of the analyses (age and sex in model) using maximum TCE exposure cutoff points for the exposure categories, show that the disease categories respiratory problems and speech problems had elevated odds ratios (not statistically significant) across exposure categories (Table 7-6). It is important to note, however, the small number of observations in the exposure category >500 ppb, as well as the wide confidence interval for the estimate of speech problems. The results of logistic regression analyses did not indicate any consistently statistically significant (age and sex in the model) increases of reported health outcomes with increased environmental exposure levels for the subgroups in which cumulative TCE exposure was used (Table 7-7). When cumulative exposure for all chemicals (age and sex in the model) was used in the cutoff points of the subgrouping, elevated odds ratios were seen for asthma, rashes, respiratory problems (statistically significant), and urinary diseases across the exposure categories (Table 7-8).
When the adjustments for cigarette smoking, occupational exposure, and education level were included and the population limited to those over 19 years of age, the effects seen were very similar but the number of elevated disease conditions was reduced. The elevated odds ratios for respiratory problems (maximum TCE exposure categories, Table 7-9) were not evident, which could indicate that this was an effect associated with the group less than 19 years of age. No consistent elevations were found for cumulative TCE exposure categories (Table 7-10).
Table 7-5.Summary of descriptive variables by exposure groups.
Exposure Category |
N | Age (years) | Education | Cigarette Smoking History | ||||
| Mean | sd | <12 years | 12 years | Current | Ex | Never | ||
| Maximum TCE | ||||||||
| 50 ppb | ||||||||
| All | 2,761 | 34.1 | 20.3 | 1,347 (49)* | 1,410 (51)† | 908 (32)§ | 436 (16)¶ | 1,417 (51)** |
| Females | 1,452 | 34.8 | 20.6 | 675 (46) | 775 (54) | 450 (31) | 202 (14) | 800 (55) |
| Males | 1,309 | 33.3 | 19.9 | 672 (51) | 635 (49) | 458 (35) | 234 (18) | 617 (47) |
| 51-500 ppb | ||||||||
| All | 854 | 33.9 | 19.2 | 378 (44) | 474 (56) | 261 (31) | 139 (16) | 454 (53) |
| Females | 436 | 34.8 | 19.7 | 189 (43) | 245 (56) | 135 (31) | 62 (14) | 239 (55) |
| Males | 418 | 32.9 | 18.6 | 189 (45) | 229 (55) | 126 (30) | 77 (18) | 215 (51) |
| >500 ppb | ||||||||
| All | 222 | 33.8 | 17.4 | 69 (31) | 153 (69) | 48 (22) | 38 (17) | 136 (61) |
| Females | 115 | 33.2 | 17.8 | 30 (31) | 67 (69) | 22 (19) | 20 (17) | 73 (63) |
| Males | 107 | 34.6 | 16.5 | 32 (30) | 75 (70) | 26 (24) | 18 (17) | 63 (59) |
| Cumulative Total Exposure | ||||||||
| 50 ppb-years | ||||||||
| All | 378 | 28.6 | 19.3 | 222 (59) | 156 (41) | 133 (35) | 48 (13) | 197 (52) |
| Females | 195 | 29.0 | 18.8 | 110 (56) | 85 (44) | 68 (35) | 22 (11) | 105 (54) |
| Males | 183 | 28.2 | 19.9 | 112 (61) | 71 (39) | 65 (36) | 26 (14) | 92 (50) |
| 51-500 ppb-years | ||||||||
| All | 462 | 33.4 | 20.3 | 233 (50) | 228 (50) | 159 (34) | 80 (17) | 223 (48) |
| Females | 245 | 34.9 | 21.4 | 123 (50) | 121 (50) | 79 (32) | 38 (16) | 128 (52) |
| Males | 217 | 31.8 | 19.0 | 110 (51) | 107 (49) | 80 (37) | 42 (19) | 95 (44) |
| 501-5,000 ppb-years | ||||||||
| All | 419 | 35.9 | 19.16 | 210 (56) | 209 (50) | 147 (35) | 75 (18) | 197 (47) |
| Females | 241 | 35.8 | 20.0 | 116 (48) | 125 (52) | 79 (33) | 42 (17) | 120 (50) |
| Males | 178 | 36.0 | 19.0 | 94 (53) | 84 (47) | 68 (38) | 33 (19) | 77 (43) |
| >5,000 ppb-years | ||||||||
| All | 77 | 43.5 | 21.5 | 39 (51) | 38 (49) | 25 (32) | 21 (27) | 31 (40) |
| Females | 40 | 47.6 | 20.6 | 16 (40) | 24 (60) | 15 (38) | 11 (28) | 14 (35) |
| Males | 37 | 39.0 | 21.8 | 23 (62) | 14 (38) | 10 (27) | 10 (27) | 17 (46) |
Table 7-5.--Continued.
| Exposure
Category |
N | Age (years) | Education | Cigarette Smoking History | ||||
| Mean | sd | <12 years | 12 years | Current | Ex | Never | ||
| Cumulative TCE Exposure | ||||||||
| 50 ppb | ||||||||
| All | 1,940 | 31.7 | 19.6 | 960 (49) | 978 (50) | 624 (32) | 287 (15) | 1,029 (53) |
| Females | 1,004 | 32.8 | 19.9 | 465 (46) | 538 (54) | 311 (31) | 131 (13) | 562 (56) |
| Males | 936 | 30.5 | 19.3 | 495 (53) | 440 (47) | 313 (33) | 156 (17) | 467 (50) |
| 51-500 ppb | ||||||||
| All | 1,048 | 35.3 | 19.6 | 479 (46) | 566 (54) | 347 (33) | 173 (16) | 528 (50) |
| Females | 567 | 35.3 | 20.0 | 259 (46) | 305 (54) | 182 (32) | 82 (14) | 303 (53) |
| Males | 481 | 35.4 | 19.0 | 220 (46) | 261 (54) | 165 (34) | 91 (19) | 225 (47) |
| 501-5,000 ppb | ||||||||
| All | 483 | 38.6 | 19.5 | 186 (38) | 297 (62) | 133 (28) | 93 (19) | 257 (53) |
| Females | 255 | 40.0 | 20.0 | 95 (37) | 160 (63) | 63 (25) | 47 (18) | 145 (57) |
| Males | 228 | 37.1 | 18.9 | 91 (40) | 137 (60) | 70 (31) | 46 (21) | 112 (49) |
| >5,000 | ||||||||
| All | 143 | 36.3 | 18.4 | 50 (35) | 93 (65) | 30 (21) | 24 (17) | 89 (62) |
| Females | 68 | 36.6 | 18.5 | 22 (32) | 46 (68) | 13 (19) | 10 (15) | 45 (66) |
| Males | 75 | 36.2 | 18.4 | 28 (37) | 47 (63) | 17 (23) | 14 (19) | 44 (59) |
| Length of Exposure (years) | ||||||||
| <2 | ||||||||
| All | 684 | 35.1 | 12.5. | 202 (29) | 482 (70) | 355 (52) | 114 (17) | 215 (31) |
| Females | 368 | 35.0 | 13.3 | 104 (28) | 264 (72) | 186 (50) | 61 (17) | 121 (33) |
| Males | 316 | 35.2 | 11.6 | 98 (31) | 218 (69) | 169 (53) | 53 (17) | 94 (30) |
| 2-5 | ||||||||
| All | 619 | 37.2 | 12.9 | 166 (27) | 452 (73) | 258 (42) | 120 (19) | 241 (39) |
| Females | 321 | 37.5 | 13.3 | 87 (27) | 234 (73) | 121 (38) | 52 (16) | 148 (46) |
| Males | 298 | 36.9 | 12.4 | 79 (29) | 218 (73) | 137 (46) | 68 (23) | 93 (31) |
| >5-10 | ||||||||
| All | 778 | 41.7 | 15.8 | 189 (24) | 589 (76) | 273 (35) | 164 (21) | 341 (44) |
| Females | 423 | 42.2 | 16.2 | 98 (23) | 325 (77) | 142 (35) | 77 (19) | 182 (45) |
| Males | 355 | 41.2 | 15.4 | 91 (26) | 264 (74) | 131 (370) | 87 (24) | 137 (39) |
| Table 7-5.--Continued. |
||||||||
| Exposure Category | N | Age (years) | Education | Cigarette Smoking History | ||||
| Mean | sd | <12 years | 12 years | Current | Ex | Never | ||
| >10 | ||||||||
| All | 684 | 51.7 | 18.2 | 265 (39) | 418 (61) | 218 (32) | 182 (27) | 284 (42) |
| Females | 362 | 52.7 | 18.1 | 134 (37) | 227 (63) | 103 (28) | 77 (21) | 182 (50) |
| Males | 322 | 50.7 | 18.3 | 131 (41) | 191 (59) | 115 (36) | 105 (33) | 102 (32) |
*Number in category (percentage of subgroup).
†Number in category (percentage of subgroup).
§Number in category (percentage of subgroup).
¶Number in category (percentage of subgroup).
**Number in category (percentage of subgroup).
Table 7-6.--Logistic regression analysis (categorical maximum TCE exposure, adjusted for age and sex).
Outcome |
Categories of Maximum TCE Exposure | ||
| 50 ppb | >50-500 ppb | >500 ppb | |
| Anemia and other
blood disorders |
1.0* | 1.03 (.66, 1.61)* | .44 (.14, 1.40)* |
| Arthritis | 1.0 | 1.05 (.77, 1.43) | .83 (.46, 1.52) |
| Asthma, emphysema | 1.0 | .87 (.62, 1.22) | .75 (.39, 1.44) |
| All cancers | 1.0 | 1.20 (.63, 2.28) | .70 (.17, 2.95) |
| Diabetes | 1.0 | .81 (.50, 1.32) | .42 (.13, 1.34) |
| Hearing impairment | 1.0 | .75 (.43, 1.30) | .71 (.26, 1.98) |
| Heart conditions | 1.0 | 1.03 (.80, 1.33) | .57 (.33, 1.01) |
| Hypertension | 1.0 | 1.01 (.80, 1.33) | .57 (.33, 1.01) |
| Kidney disease | 1.0 | .74 (.36, 1.53) | .94 (.29, 3.09) |
| Liver problems | 1.0 | .28 (.04, 2.12) | † |
| Mental retardation | 1.0 | .59 (.13, 2.66) | 1.30 (.17, 10.19) |
| Skin rashes | 1.0 | 1.00 (.76, 1.33) | .99 (.60, 1.63) |
| Respiratory allergies | 1.0 | 1.33 (.98, 1.82) | 1.27 (.73, 2.21) |
| Speech impairment | 1.0 | 1.67 (.80, 3.48) | 1.41 (.32, 6.09) |
| Stroke | 1.0 | .94 (.50, 1.75) | .56 (.13, 1.17) |
| Stomach problems | 1.0 | .89 (.66, 1.21) | .62 (.33, 1.17) |
| Urinary tract
disorders |
1.0 | 1.12 (.76, 1.66) | .59 (.24, 1.48) |
| Total§ | 2,761 | 854 | 222 |
*Odds ratio (95% confidence intervals) using lowest exposure category as the standard.
†Too few responses for analysis.
§Number of registrants included in analyses.
Table 7-7.--Logistic regression analysis (categorical cumulative TCE exposure, adjusted for age and sex).
Outcome |
Cumulative TCE Exposure Categories | |||
| <50 ppb | 50-500 ppb | >500-5,000 ppb | >5,000 ppb | |
| Anemia and other
blood disorders |
1.0* | .86 (.56, 1.33)* | .78 (.43, 1.41)* | .20 (.03, 1.44)* |
| Arthritis | 1.0 | .92 (.68, 1.26) | 1.06 (.73, 1.54) | .78 (.38, 1.62) |
| Asthma,
emphysema |
1.0 | 1.00 (.72, 1.38) | .97 (.63, 1.50) | .58 (.23, 1.46) |
| All cancers | 1.0 | 1.05 (.55, 2.0) | 1.13 (.51, 2.48) | .96 (.22, 4.14) |
| Diabetes | 1.0 | .99 (.64, 1.55) | 1.08 (.63, 1.86) | .40 (.09, 1.66) |
| Hearing impairment | 1.0 | 1.25 (.77, 2.04) | .73 (.34, 1.57) | .30 (.04, 2.21) |
| Heart conditions | 1.0 | 1.00 (.77, 1.29) | 1.05 (.76, 1.45) | .52 (.26, 1.06) |
| Hypertension | 1.0 | .95 (.75, 1.20) | 1.04 (.78, 1.39) | .66 (.38, 1.15) |
| Kidney disease | 1.0 | 1.05 (.55, 1.98) | .79 (.32, 1.96) | 1.01 (.24, 4.35) |
| Liver problems | 1.0 | .57 (.15, 2.16) | .73 (.15, 3.50) | † |
| Mental retardation | 1.0 | .25 (.03, 2.03) | 1.26 (.26, 6.02) | † |
| Skin rashes | 1.0 | .94 (.71, 1.24) | 1.23 (.87, 1.73) | .74 (.37, 1.48) |
| Respiratory
allergies |
1.0 | 1.04 (.75, 1.43) | 1.25 (.84, 1.87) | .99 (.47, 2.08) |
| Speech impairment | 1.0 | 1.37 (.64, 2.92) | 1.30 (.43, 3.93) | 1.03 (.14, 7.90) |
| Stroke | 1.0 | 1.55 (.86, 2.78) | 1.19 (.55, 2.55) | .46 (.06, 3.50) |
| Stomach problems | 1.0 | .88 (.65, 1.18) | .92 (.63, 1.34) | .49 (.21, 1.14) |
| Urinary tract
disorders |
1.0 | .75 (.50, 1.14) | 1.13 (.70, 1.83) | .34 (.08, 1.40) |
*Odds ratio (95% confidence intervals) using lowest exposure category as standard.
†Too few responses to perform analysis.
Table 7-8.--Logistic regression analysis (cumulative chemical exposure, adjusted for age and sex).
Outcome |
Cumulative Exposure (Total Chemical) Categories | |||
| <50 ppb | 50-500 ppb |
>500-5,000 ppb |
>5,000 ppb |
|
| Anemia and other
blood disorders |
1.0* |
1.74 (.81, 3.74)* | .92 (.39, 2.18)* | .46 (.06, 3.73)* |
| Arthritis | 1.0 | 1.11 (.60, 2.05) | 1.62 (.90, 1.90) | .91 (.33, 2.47) |
| Asthma, emphysema | 1.0 | 1.83 (1.00, 3.38) | 1.83 (.98, 3.43) | 1.48 (.47, 4.63) |
| All cancers | 1.0 | .61 (.20, 1.88) | .52 (.16, 1.69) | .38 (.04, 3.30) |
| Diabetes | 1.0 | .49 (.18, 1.28) | .79 (.32, 1.91) | .71 (.18, 2.83) |
| Hearing impairment | 1.0 | † |
† |
† |
| Heart conditions | 1.0 | .77 (.47, 1.26) | 1.28 (.81, 2.02) | .62 (.24, 1.57) |
| Hypertension | 1.0 | .94 (.59, 1.49) | 1.22 (.78, 1.92) | .97 (.47, 2.04) |
| Kidney disease | 1.0 | .80 (.28, 2.27) | .30 (.08, 1.20) | .60 (.07, 5.22) |
| Liver problems | 1.0 | † |
† |
† |
| Mental retardation | 1.0 | † |
† |
† |
| Skin rashes | 1.0 | 1.02 (.61, 1.70) | 1.29 (.78, 2.13) | 1.20 (.47, 3.05) |
| Respiratory allergies | 1.0 | 1.87 (.98, 3.58) | 2.19 (1.14, 4.22) | 1.30 (.36, 4.72) |
| Speech impairment | 1.0 | 1.97 (.48, 8.06) | .46 (.05, 4.51) | 3.06 (.30, 31.51) |
| Stroke | 1.0 | 1.08 (.36, 3.26) | 1.09 (.36, 3.30) | 2.02 (.50, 8.12) |
| Stomach problems | 1.0 | .86 (.50, 1.48) | .75 (.43, 1.32) | .13 (.02, .96) |
| Urinary tract disorders | 1.0 | 1.72 (.79, 3.73) | 1.56 (.70, 3.47) | 2.47 (.72, 8.45) |
*Odds ratio (95% confidence intervals) using lowest exposure category as standard.
†Too few responses to perform analysis.
Table 7-9.--Logistic regression analysis (categorical TCE exposure, adjusted for age, sex,
smoking, occupational exposure, and education).
Outcome |
TCE Categories | ||
| 50 ppb | >50-500 ppb |
>500 ppb |
|
| Anemia and other blood
disorders |
1.0* |
1.03 (.64, 1.67)* | .55 (.17, 1.77)* |
| Arthritis | 1.0 | 1.05 (.76, 1.44) | .97 (.53, 1.78) |
| Asthma, emphysema | 1.0 | .89 (.60, 1.33) | .65 (.28, 1.52) |
| All cancers | 1.0 | 1.17 (.61, 2.23) | .31 (.04, 2.29) |
| Diabetes | 1.0 | .84 (.52, 1.37) | .50 (.15, 1.61) |
| Hearing impairment | 1.0 | 1.01 (.54, 1.91) | 1.41 (.49, 4.09) |
| Heart conditions | 1.0 | 1.09 (.82, 1.44) | .63 (.34, 1.18) |
| Hypertension | 1.0 | .99 (.78, 1.26) | .75 (.47, 1.20) |
| Kidney disease | 1.0 | .82 (.39, 1.73) | 1.16 (.35, 3.88) |
| Liver problems | 1.0 | .31 (.04, 2.38) | † |
| Mental retardation | 1.0 | † | † |
| Skin rashes | 1.0 | 1.06 (.77, 1.46) | .89 (.48, 1.65) |
| Respiratory allergies | 1.0 | 1.18 (.83, 1.69) | .84 (.41, 1.69) |
| Speech impairment | 1.0 | 1.62 (.40, 6.51) | 2.69 (.31, 23.60) |
| Stroke | 1.0 | 1.00 (.53, 1.90) | 1.01 (.53, 1.90) |
| Stomach problems | 1.0 | .93 (.68, 1.28) | .69 (.35, 1.34) |
| Urinary tract disorders | 1.0 | 1.11 (.72, 1.70) | .68 (.26, 1.71) |
*Odds ratio (95% confidence intervals) using lowest exposure category as standard.
†Too few responses to perform analysis.
Table 7-10.--Logistic regression analysis (categorical cumulative TCE exposure, adjusted for age, sex, smoking, occupational exposure, and education).
| Outcome | Cumulative TCE categories | |||
| <50 ppb | 50 ppb-500 | >500-5,000 ppb | >5,000 ppb | |
| Anemia and other
blood disorders |
1.0* |
.90 (.57, 1.43)* | .81 (.44, 1.52)* | .24 (.03, 1.79)* |
| Arthritis | 1.0 | .91 (.66, 1.24) | 1.07 (.73, 1.57) | .86 (.41, 1.78) |
| Asthma, emphysema | 1.0 | 1.07 (.74, 1.55) | .97 (.59, 1.58) | .67 (.24, 1.87) |
| All cancers | 1.0 | 1.03 (.54, 1.97) | 1.09 (.49, 2.39) | .43 (.06, 3.24) |
| Diabetes | 1.0 | 1.01 (.64, 1.58) | 1.13 (.66, 1.58) | .45 (.11, 1.91) |
| Hearing impairment | 1.0 | 1.20 (.67, 2.16) | .66 (.27, 1.63) | .43 (.06, 3.21) |
| Heart conditions | 1.0 | .98 (.75, 1.30) | 1.11 (.78, 1.56) | .56 (.26, 1.20) |
| Hypertension | 1.0 | .94 (.74, 1.19) | 1.09 (.81, 1.46) | .72 (.41, 1.25) |
| Kidney disease | 1.0 | 1.23 (.63, 2.38) | .94 (.37, 2.38) | 1.32 (.30, 5.79) |
| Liver problems | 1.0 | .57 (.15, 2.26) | .75 (.15, 3.65) | † |
| Mental retardation | 1.0 | † | † | † |
| Skin rashes | 1.0 | .96 (.69, 1.31) | 1.12 (.75, 1.65) | .64 (.27, 1.50) |
| Respiratory allergies | 1.0 | .85 (.57, 1.22) | 1.12 (.72, 1.75) | .65 (.26, 1.66) |
| Speech impairment | 1.0 | † | † | † |
| Stroke | 1.0 | 1.43 (.79, 1.60) | 1.19 (.55, 2.56) | .49 (.06, 3.76) |
| Stomach problems | 1.0 | .88 (.65, 1.20) | .99 (.67, 1.47) | .48 (.19, 1.22) |
| Urinary tract disorders | 1.0 | .85 (.55, 1.33) | 1.21 (.72, 2.03) | .41 (.10, 1.72) |
* Odds ratio (95% confidence intervals) using lowest exposure category as standard.
† Too few responses to perform analysis.
Table 7-11.--Logistic regression analysis (categorical cumulative chemical exposure adjusted for age, sex, smoking, occupational exposure, and education).
| Outcome | Cumulative Chemical Exposure Categories | |||
| <50 ppb | 50-500 ppb | >500-5,000 ppb | >5,000 ppb | |
| Anemia and other blood
disorders |
1.0* |
1.54 (.68, 3.52)* | .98 (.40, 2.41)* | .48 (.06, 3.98)* |
| Arthritis | 1.0 | 1.19 (.64, 2.24) | 1.58 (.86, 2.90) | .95 (.34, 2.64) |
| Asthma, emphysema | 1.0 | 1.38 (.63, 3.01) | 1.58 (.73, 3.41) | 1.06 (.28, 4.06) |
| All cancers | 1.0 | .60 (.19, 1.89) | .53 (.16, 1.72) | .33 (.04, 2.93) |
| Diabetes | 1.0 | .53 (.20, 1.39) | .82 (.34, 2.00) | .72 (1.80, 2.94) |
| Hearing impairment | 1.0 | 3.44 (.74, 16.08) | 1.63 (.31, 8.63) | † |
| Heart conditions | 1.0 | .86 (.50, 1.48) | 1.27 (.75, 2.14) | 1.01 (.48, 2.14) |
| Hypertension | 1.0 | .92 (.57, 1.47) | 1.22 (.77, 1.93) | 1.01 (.48, 2.14) |
| Kidney disease | 1.0 | .96 (.29, 3.11) | .40 (.09, 1.75) | .73 (.08, 6.69) |
| Liver problems | 1.0 | † | † | † |
| Mental retardation | 1.0 | † | † | † |
| Skin rashes | 1.0 | 1.12 (.61, 2.08) | 1.13 (.60, 2.10) | 1.11 (.39, 3.20) |
| Respiratory allergies | 1.0 | 1.76 (.79, 3.92) | 1.91 (.86, 4.23) | .95 (.20, 4.58) |
| Speech impairment | 1.0 | † | † | † |
| Stroke | 1.0 | 1.06 (.35, 3.21) | .93 (.30, 2.88) | 1.80 (.44, 7.32) |
| Stomach problems | 1.0 | .88 (.49, 1.55) | .76 (.42, 1.37) | .13 (.02, 1.0) |
| Urinary tract disorders | 1.0 | 1.77 (.71, 4.42) | 1.82 (.73, 4.54) | 2.94 (.80, 10.81) |
*Odds ratio (95% confidence intervals) using lowest exposure category as standard.
†Too few responses to perform analysis.
Table 7-12.--Logistic regression analysis (maximum TCE exposure adjusted for age, sex, smoking, occupational exposure, and education).
| Outcome | Maximum TCE Level Categories (Quartiles) | |||
| 1st
<2 ppb |
2nd
2-12 ppb |
3rd
>12-60 ppb |
4th
>60-12,800 ppb |
|
| Anemia and other
blood disorders |
1.0* |
1.60 (.92, 2.79)* | .76 (.39, 1.48)* | 1.24 (.68, 2.25)* |
| Arthritis | 1.0 | 1.07 (.73, 1.55) | 1.18 (.80, 1.73) | 1.16 (.79, 1.70) |
| Asthma, emphysema | 1.0 | 1.17 (.75, 1.83) | 1.24 (.78, 1.97) | .83 (.51, 1.36) |
| All cancers | 1.0 | .52 (.23, 1.15) | .67 (.31, 1.46) | .79 (.38, 1.64) |
| Diabetes | 1.0 | 1.42 (.83, 2.44) | 1.32 (.75, 2.33) | .94 (.51, 1.73) |
| Hearing impairment | 1.0 | 2.03 (.92, 4.49) | 1.68 (.72, 3.90) | 1.51 (.64, 3.55) |
| Heart conditions | 1.0 | .78 (.56, 1.08) | .75 (.53, 1.06) | .83 (.59, 1.15) |
| Hypertension | 1.0 | .96 (.73, 1.27) | .98 (.73, 1.30) | .96 (.72, 1.27) |
| Kidney disease | 1.0 | .95 (.44, 2.09) | .98 (.43, 2.21) | .78 (.33, 1.83) |
| Liver problems | 1.0 | 1.11 (.25, 5.04) | 1.38 (.30, 6.26) | .31 (.03, 3.02) |
| Mental retardation | † | † | † | † |
| Skin rashes | 1.0 | 1.01 (.69, 1.48) | 1.09 (.74, 1.60) | .95 (.64, 1.41) |
| Respiratory allergies | 1.0 | 1.19 (.77, 1.85) | .95 (.59, 1.52) | 1.08 (.69, 1.68) |
| Speech impairment | † | † | † | † |
| Stroke | 1.0 | 4.14 (1.54, 11.09) | 3.88 (1.40, 10.74) | 3.20 (1.14, 8.99) |
| Stomach problems | 1.0 | .94 (.66, 1.34) | .92 (.64, 1.34) | .82 (.56, 1.20) |
| Urinary tract disorders | 1.0 | 1.08 (.64, 1.81) | 1.01 (.59, 1.75) | 1.05 (.62, 1.77) |
*Odds ratio (95% confidence intervals) using lowest exposure category as standard.
†Too few responses to perform analysis.
Note: Limited to observations of age 19 years.
Table 7-13.--Logistic regression analysis (cumulative chemical exposure adjusted for age, sex, smoking, occupational exposure, location, and education).
| Outcome | Cumulative Chemical Exposure Categories (Quartiles) | |||
| 1st
<37 ppb-yrs |
2nd
37-238 ppb-yrs |
3rd
>238-1,190 ppb-yrs |
4th
>1,190 ppb-yrs |
|
| Anemia and other
blood disorders |
1.0* |
1.69 (.69, 4.13)* | .86 (.31, 2.37)* | 1.03(.39, 2.72)* |
| Arthritis | 1.0 | 1.88 (.92, 3.87) | 1.41 (.67, 2.95) | 1.85 (.91, 3.74) |
| Asthma, emphysema | 1.0 | 1.55 (.64, 3.75) | 2.04 (.88, 4.75) | 1.15 (.46, 2.88) |
| All cancers | 1.0 | .52 (.14, 2.03) | .68 (.20, 2.34) | .46 (.13, 1.70) |
| Diabetes | 1.0 | .89 (.29, 2.67) | .73 (.24, 2.28) | 1.24 (.45, 3.43) |
| Hearing impairment | 1.0 | 2.02 (.38, 10.73) | 3.20 (.65, 15.62) | .65 (.09, 4.85) |
| Heart conditions | 1.0 | .84 (.46, 1.55) | .90 (.50, 1.63) | 1.13 (.64, 2.00) |
| Hypertension | 1.0 | 1.18 (.70, 1.98) | .79 (.47, 1.36) | 1.27 (.76, 2.11) |
| Kidney disease | 1.0 | .80 (.19, 3.29) | 1.02 (.27, 3.93) | .52 (.11, 2.46) |
| Liver problems | 1.0 | † | † | † |
| Mental retardation | 1.0 | † | † | † |
| Skin rashes | 1.0 | .95 (.46, 1.97) | 1.46 (.75, 2.85) | 1.15 (.57, 2.31) |
| Respiratory allergies | 1.0 | 1.30 (.54, 3.16) | 2.10 (.93, 4.75) | 1.16 (.47, 2.87) |
| Speech impairment | 1.0 | † | † | † |
| Stroke | 1.0 | .90 (.27, 2.97) | .95 (.30, 3.03) | .79 (.24, 2.55) |
| Stomach problems | 1.0 | .97 (.53, 1.76) | .45 (.23, .90) | .49 (.25, .96) |
| Urinary tract disorders | 1.0 | 1.61 (.57, 4.57) | 1.73 (.62, 4.82) | 2.63 (.98, 7.02) |
*Odds ratio (95% confidence intervals) using lowest exposure category as standard.
†Too few responses to perform analysis.
Note: Limited to observations of persons aged 19 years - refers to entire table.
Table 7-14.--Logistic regression analysis (length of exposure categories, adjusted for age and sex).
| Outcome | Length of Exposure Categories (years) | |||
| 2 | >2-5 | >5 -10 | >10 | |
| Anemia and other
blood disorders |
1.0* |
.78 (.43, 1.39)* | .94 (.55, 1.61)* | 1.13 ( .65, 1.97)* |
| Arthritis | 1.0 | 1.02 (.66, 1.57) | .98 (.66, 1.47) | 1.03 ( .69, 1.55) |
| Asthma, emphysema | 1.0 | .84 (.56, 1.26) | .81 (.53, 1.21) | 1.41 ( .95, 2.11) |
| All cancers | ||||