Love Canal Follow-up Health Study - September 2002
Study Plan and Progress
Preliminary Results - Reproductive Health Study
Researchers presented preliminary findings about children born to Love Canal women at the May meeting of the Love Canal Expert Advisory Committee. Remember that the Love Canal Follow-up Health Study is really four separate but related studies — deaths, cancer, reproductive outcomes and blood sera. We are comparing births, deaths and cancer rates of Love Canal residents to upstate New York and Niagara County residents. We are measuring Love Canal Indicator Chemicals (LCICs) in blood sera taken from some former Love Canal residents. Preliminary results are presented to the Committee, and they advise us about future analyses and how best to notify study participants about the results.
The reproductive outcomes are preliminary results. The reproductive outcome data are less complete than our earlier preliminary results on cancer and mortality outcomes. Therefore, they could change significantly when more information is added. For example, births between 1960 and 1969 are not included in this data set, since the comparison data for these years were stored and recorded differently than the data collected after 1970. This represents a large portion of Love Canal births. In the future, we will report on Love Canal grandchildren and the other data that are still being compiled.
The May report covers some children born to Love Canal mothers. We selected four measures of reproductive effects and looked at that information in Love Canal births and in upstate New York and Niagara County births for comparison. We selected effects that have been shown to be associated with environmental exposure in other studies:
- birth weight;
- length of pregnancy;
- baby's sex; and
- presence or absence of a birth defect (also called congenital malformation).
Birth weights are reported in metric units (grams); infants weighing less than 2500 grams (about five pounds) are considered low birth weight babies, and those under 1500 grams are defined as being very low birth weight. Gestational age is the number of days of the pregnancy — too short a term results in a premature birth. Babies born before 37 weeks of pregnancy are considered premature. Congenital malformations are counted. Sex is male or female, and the sex ratio (number of girls divided by number of boys) for the Love Canal group is calculated.
The reproductive results presented in May are only a part of the entire data set, so that the findings might change when pending data are added. For this reason, it seems premature to report the data or attempt to interpret them. However, the results so far show a trend that Love Canal births might be different than upstate New York or Niagara County. In addition, we still want to look at reproductive outcomes in relation to likelihood of exposure. Remember, we will send you final results for this and other portions of the Love Canal Follow-up Health Study as they become available.
Based on the data compiled so far:
- The average birth weight of Canal babies was the same as upstate New York and Niagara County averages, but mothers living on the Canal during their pregnancy had more very low birth weight babies than mothers living outside of the study area;
- The rate of premature births for Love Canal women was the same as upstate New York and Niagara County women, but mothers living on the Canal had more premature births than mothers who had moved away;
- The rate of birth defects for Love Canal mothers was slightly higher than upstate New York and Niagara County (3% compared to 2%);
- More girls were born to Love Canal women (52%) than were born to upstate New York or Niagara County mothers (49%).
First, we identified women who moved to the Canal before or during part of their childbearing years, which included portions of the study years (between 1960 and 1996). They were not born at Love Canal, nor did their mothers live on the Canal before having them. We call these women "index mothers"; they make up 3136 of the 3219 female residents in the original Love Canal cohort. Out-of state births, grandchildren, and births to Canal fathers are not included in this report. Remember that the Love Canal cohort was defined for this study as people who participated in the Department of Health interview study between 1978 and 1982. Children who were under 18 at the time of the study were included if either of their parents participated.
We looked at our Vital Records Registry for the study years and obtained records about births to the index mothers. We call this process "matching". We also obtained birth records for 697 children who were not in the original cohort, but who we now know lived in the Love Canal area (perhaps they contacted us to be included, or we recently located them). Birth weight, gestational age, congenital malformations and sex were compared to upstate New York and Niagara County. The chart below shows more about the matching results. Also see the insert on data sources for the reproductive health study.
Because comparison data from the Vital Records Registry are only complete from 1970, only births from 1970 to 1996 are reported here. The 1960 — 1970 births are being summarized and will be reported in the future. Furthermore, the Congenital Malformations Registry was established in the early 1980's and its first year of complete reporting was 1983. This report considers birth defects from 1983 to 1996. We are looking at Niagara Falls area hospital records to learn more about birth defects prior to 1983.
When looking at any reproductive outcome study, the following background is useful.
- Different birth defects have different "causes" or risk factors. Some are genetic, some we just don't know much about, and others may have environmental causes. Examples of environmentally caused birth defects are: Fetal Alcohol Syndrome, caused by mother's alcohol consumption during pregnancy; limb reduction defects, caused by the prescription drug Thalidomide; and low birth weight, caused by tobacco exposure.
- It is not appropriate to compare different types of birth defects to each other.
- Some hospitals do a much better job of reporting congenital malformations than others. For example, we have learned from routine audits done by the Congenital Malformations Registry that Child's Hospital in Niagara Falls and Long Island Jewish Hospital have excellent reporting rates. This means that an apparently high rate of birth defects in populations served by these hospitals needs to be further considered to determine whether it is a true higher rate, or if it could be the result of more complete reports from the hospital, or a combination of the two.
There are additional considerations specific to the Love Canal study:
- Relationships between birth outcomes and likelihood of exposure still need to be examined.
- One of the big problems that we face is that the Congenital Malformations Registry was not formed until the early 1980's, so we do not have these same data for birth defects prior to 1983. We are gathering what information we can about birth defects by reviewing certain hospital records and mother's reports from the 1978 health study. However, in the original study only hospital records of mothers who reported birth defects were collected. Ideally, all reports would be verified by hospital records. Other limitations include data gaps, the fact that most birth defects are not noticeable at birth, and identifying an appropriate comparison population.
If you would like a set of the data tables, we will provide them to you. You can call, fax, write or E-mail for the data. Include your name and address when you contact us.
Highlights of May Committee Meeting
In addition to presenting the Love Canal birth data, Health Department researchers discussed other study topics with the Committee. As always, the Committee made many helpful suggestions to improve the quality and focus of our work. This time they advised us about statistical modeling, the study timeline, serum analysis, using data from other states and community involvement.
One of the study statisticians presented simulations done using a statistical model that has been tested and refined over the past year. The model is used to describe each individual's likelihood of exposure to Canal chemicals. The Committee agreed that the model would be useful for comparing health outcomes to likelihood of exposure. One of the problems encountered in developing the model was our desire to look at the length of people's residence in each Canal area and under different Canal conditions (open, closed, late periods). Many Canal residents lived in the same home for several years, overlapping open, closed and late periods. This makes it hard to separate the Canal conditions to learn more about their relationship to health effects. Suppose a resident from Tier 3 lived in their home from birth till the age of 20, then married and moved into a home in Tier 4, where the resident had three children, and then was diagnosed with cancer at the age of 55. The resident died 12 years later of heart failure. The statistical model would be unable to assign each of the health effects (birth, death, cancer) to a single possible exposure, since the resident falls into Tier 3, open and closed periods; and Tier 4, closed and late periods. It was agreed that our model could combine some of the exposure information in such a way that we could still detect associations of residential location and time periods.
The study was originally scheduled to last five years, but has gone past that and is now in the sixth year. This occurred partly because our original study design was expanded to include additional projects, such as laboratory analysis of stored blood sera and locating 99 th Street School students; however, we need to bring the study to an end. While funding could be extended for a short time after the close of the funding contract, we need to move into the data analysis and interpretation phases. The Committee agreed with our concerns and suggested that we stop all data collection by November of 2002, and not start collecting any new data unless it can be completed by then. This means that we are unlikely to have enough information about children of Love Canal fathers to report on them. However, we will keep all the study information, including information not used in the final reports, so it will be available for future studies. The information we obtain may be as important to future researchers as the stored serum samples and 99th Street School lists are to us.
Laboratory analysis of stored blood serum for LCICs has been ongoing. The Laboratory's response to the independent reviewers' suggestions about possible problems associated with the unexpected potential for thawing of samples during storage and a few other issues was discussed with the Committee. The reviewers and the Committee generally agree that serum analysis, an objective and measurable indicator of exposure, is a real strength in this study.
Laboratory scientists are nearly done analyzing the serum from people who gave permission for analysis. Because a large number of people did not respond to our request for permission to analyze their serum, we presented options for pooling serum from people who did not respond, which is permitted under state law. Our letter requesting permission to test participants' serum informed them of the possibility of pooling their sample with others. While our recommended method was generally acceptable to the Committee, they noted that the benefits of pooling were relatively low and suggested that we make another effort to get permission from those who did not respond to our first request. Two of our community consultants offered to co-sign the letter requesting participation. We have already sent a letter to each person for whom we have a serum sample if they did not respond to the first mailing. We are very grateful for the support of our community consultants.
If we still need to obtain permission from certain residents to learn more about the serum levels in people living at certain areas of the Canal, or of certain age groups, etc., we will phone or otherwise reach those individuals. Whether we do this will depend on whether we get enough response to our letter requests. We will update the Committee in the fall about your responses and how many permission slips we have received. The Committee will help us decide whether we need to pool any samples, and if so, which ones.
Please respond if you received a letter about testing your serum for Love Canal Indicator Chemicals. If you prefer that your serum not be analyzed, you can indicate that on the form and we will NOT analyze it or mix it with other sera to form a pooled sample. If we do not know your wishes, it is possible that we would at some point consider pooling your serum sample with other serum samples.
Data from other States
While there wasn't time for the data tables to be reviewed for presentation at the May Committee meeting, we had the out-of-state cancer reports back from eight states with both cancer registries and large numbers of former Love Canal residents: Texas, Florida, Arizona, Pennsylvania, Ohio, California, Virginia and North Carolina. We noticed that the cancer incidence of residents who moved to these states was lower than that of residents who stayed in New York State. It was lower before they left New York, too. The Committee suggested that we report the out-of-state information separately and look at the questionnaire information to see if there is an explanation for the difference. We also wanted to ask the Committee about this observation because if they thought we should not combine the out-of state groups, it could affect whether we should gather information on births from mothers who moved out of state. The Committee suggested that we not pursue the out-of-state birth information in any case, because this effort can't be completed within six months.
Releasing Study Results
The Committee offered advice about releasing study results, and suggested the newsletter as a way to prepare study participants for the final results. Within the next year or so, reports about cancer, birth outcomes, deaths and blood serum levels will be prepared. You may remember that there are requirements about how the data get released, including a peer review process before release. The agency funding the health study, U.S. Agency for Toxic Substances and Disease Registry (ATSDR) has been expediting the review of preliminary data for the Committee meetings. However, they cannot eliminate the need for peer review before final reports are released. Peer review ensures scientific integrity by generating discussion and critical thinking about the meaning of any findings. In the process, peer reviewers consider the method's strengths and limitations and also whether our interpretations are justified by the data. We encourage you to share any questions and concerns with us now, so we can report what you want to know, or explain items that are unclear ahead of time in the newsletters.
Love Canal Follow-up Health Study
Documents Available by Mail
- Exposure Assessment - May 2001 Draft
- Expert Advisory Committee Meeting Minutes
- June 1998
- November 1998
- April 1999
- October 1999
- May 2000
- September 2000
- May 2001
- May 2002
- Preliminary Mortality Results - Data Tables
- Preliminary Cancer Results - Data Tables
- Preliminary Reproductive Results - Data Tables
Documents Available on-line
Newsletters and Reports are posted on the Internet at http://www.health.state.ny.us/environmental/investigations/love_canal/
Fall 2002 Meeting — Will You Be There?
We could also use Committee meetings to help explain study findings. Committee members thought that if we tell you about the agenda items in the newsletter, you'd know what to expect. We talked about modifying the meeting structure — for example, having a "not so technical" presentation on the study and encouraging you to send in questions ahead of time so we can be sure to answer them to the best of our ability. We really would like to hear from you, and encourage you to ask questions and tell us how we can do a better job informing you about the study. Please use the enclosed sheet to share your thoughts with us. Thanks for your participation.
We hope to present the following items to the Committee at the fall 2002 meeting:
- Cancer results, an update on any differences between characteristics of residents who moved to the eight states with cancer registries, and possibly results of grouping together cancer sites that may be associated with chemical exposure;
- Mortality results for Love Canal residents;
- Update on reproductive outcome data;
- Results of efforts to obtain permission to analyze stored blood serum;
- Laboratory update on serum analysis efforts to date, and discuss sample letter to participants explaining their individual results; and
- Community involvement update.
What questions or concerns could we address for you? We would like to hear from you! Please complete the enclosed comment sheet and send it to us by fax, e-mail or regular mail. Your thoughts will be used to help prepare for releasing study results and to plan the fall meeting format.
How to Reach Us
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