Keywords
cohort
database
data linkage
lactation.
How to Cite
Abstract
Breast cancer is the most common malignancy among
women. Despite the relatively high radiosensitivity of breast tissue,
epidemiological evidence on the effects of radioactive fallout following
nuclear accidents on breast cancer risk remains limited and
inconclusive. This underscores the need to establish large, well-characterized
cohorts with the capacity for individual dose assessment
and consideration of modifying factors. The development of a dedicated
database represents a critical step toward conducting such
studies. Objective. To evaluate the process of cohort formation and
the development of a registry of women exposed during lactation
as a result of the Chornobyl Nuclear Power Plant accident, as well
as the effectiveness of approaches to data collection, verification,
and linkage for subsequent epidemiological research. Material and
мethods. The cohort of the Ukrainian-American program «Health
Effects in the Ukrainian Cohort of Women Exposed During Lactation
to Chornobyl Fallout» was established from women who, at the time
of the accident, resided in the most radioactively contaminated areas
of Kyiv, Zhytomyr, and Chernihiv regions and could have been
breastfeeding during that period. The registry was developed using
data from maternity hospital records, databases of Ukrainian-American
studies, and additional information sources. The study included
several stages: development of a registry of potential participants;
preliminary questionnaire screening to verify eligibility and obtain
informed consent; and updating of demographic and contact information.
Identification of oncological outcomes was performed
through data linkage with the National Cancer Registry of Ukraine.
Results. A total of 11,533 live-birth records were obtained from
maternity facility registers. Through integration of multiple data
sources, a registry comprising 14,894 potential participants was established.
During the preliminary survey, 4,449 questionnaires were
collected for 4,318 women: 59 by mail, 1,791 via telephone contact,
and 2,599 with the involvement of local personnel. Based on
questionnaire data, 4,041 participants were confirmed to meet the
inclusion criteria. Several rounds of data linkage with the National
Cancer Registry of Ukraine were conducted, enabling the identification
of cancer cases within the cohort. Conclusions. A registry
and database of women exposed during lactation as a result of the
Chornobyl accident and residing in radiation-contaminated areas
have been established. The applied approaches to data collection,
verification, and linkage demonstrated practical effectiveness and
may be useful for the development of similar cohorts in radiation
epidemiology. Perspectives. The established database provides a
foundation for future epidemiological studies, including those in-
corporating individual dose reconstruction and risk factor analysis.
It also offers opportunities for cohort expansion and regular linkage
with national registries.
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