Dear
Participant,
I am writing as a medical scientist from the USC School of Medicine to
ask for your help with an important project called the California Twin Program. Our
unit has conducted studies of the causes of chronic disease for nearly thirty years. Among those
is a study of 17,000 identical and fraternal twins from all over North America,
designed to help us understand why certain people get particular life-threatening
diseases, while others, similar in almost all respects, remain protected. This study led us
to conclude that we also should get information from all the twins, sick
or well, in a specific population. California, because of its size and diversity, is the best place
to do this. The state government has supported the program and has helped us locate
California-born twins. Your name was among the roughly 150,000 listed. So far, about 20,000 older
twins, the majority of those asked, have taken the trouble to participate. Much larger
numbers of participants of all ages, both sexes, and all races and ethnicities are needed
to ensure success. Assuming that you truly are a twin who was born in California, please
help us make this project successful. To express our appreciation in advance, we enclose a
sticker designed especially for California twins.
We will shortly send you a booklet
with a set of questions. We only ask that you help us by taking the time to mark the
answers. They ask about your individual experiences, about the choices you have made in
life, and about the differences between your experience and that of your twin. If you have
any questions about twins, or diseases in twins, we will try to answer them, and we do
plan to make available the results of the survey. Otherwise, participation in the project
will not benefit you personally (although most participants seem to enjoy searching their
memory to answer questions designed especially for twins). In addition, for those who are
interested, we hope that we soon can offer at cost a very inexpensive and very accurate
test of zygosity (i.e. a test to tell whether twins are truly identical or fraternal).
There is certainly no cost for
participation, except the time it takes to mark your responses, and you will not be asked
for money (your cooperation is more important than a charitable gift). All information
will be held in complete confidence, including the facts that you are a California native
and a twin. No outside persons will have access to your name, or to your answers, without
your permission. Results will only be released in statistical form, and no persons or twin
pairs will ever be identified. Please help; it will take only about a half-hour of your
time and you may withdraw at any time. If convenient, please encourage your twin to
participate also. The more twins who participate, especially as pairs, the bigger the
impact we can make against the many diseases and health-related problems that reduce the
quality of life.
You should receive the booklet in
a few weeks. Please fill it out and send it right back. If you are not a twin, still be
sure to open the envelope and send the booklet back to us with that message. Then we can
promptly cross you off our list so that you will not be disturbed again. If you have any
general or confidential questions, we will be happy to answer them by mail (address
below), phone (our toll-free number is 888-328-6478), or with our website,
(http://twins.usc.edu).
Thank you very, very much for your
cooperation.
Sincerely yours,
Thomas Mack M.D., M.P.H.
Professor
