4.5 | Strength and limtations
Several limitations should be considered when interpreting the results
of this study. First, the definition of UL was not based on imaging, but
instead, on ICD-10 codes and outpatient clinic visits. Since UL is
mostly asymptomatic in early stages, women who have asymptomatic UL may
have been undiagnosed, which may cause the prevalence of UL to be
underestimated. Second, information about the size and number of ULs was
not available due to the database characteristics. Third, gynecologic
information, including parity, presence of polycystic ovarian syndrome,
or hormonal status, were also inaccessible; these factors can affect the
development of type 2 diabetes mellitus, and their absence lowers the
generalizability of our results. Finally, because this study was
conducted using the Korean nationwide database, the results might not be
generalizable to other ethnicities. However, this study is valuable
because, to our knowledge, it is the first large-scale, longitudinal
study to evaluate the association between presence of UL and development
of type 2 diabetes mellitus in young women.