Principal Findings
This 13-year retrospective cohort study revealed an increased incidence
of Graves’ diseases in PCOS patients with an aHR of 1.34 (95%C.I.
1.00-1.81) after adjusting for age and confounders listed in table 1. In
stratification analysis, the independent association of PCOS with
Graves’ disease was especially significant in group aged 31 to 40
(aHR=2.31, 95%C.I. 1.48-3.61). The cluster of PCOS and Graves’ disease
at this age may due to the nature of PCOS, a common endocrinopathy of
reproductive age-group women. Several comorbidities were found
influential in our Cox regression model, such as CAD (aHR=2.66, 95%C.I.
1.08-6.56) and DM (aHR=2.17, 95%C.I. 1.06-4.44). In our stratification
study investigating into the association of PCOS and Graves’ diseases in
different subgroups, we found that in patients with hypertension, the
independent association of PCOS with Graves’ disease became
insignificant, which may be explainable due to probable effect of other
coexisting comorbidities and relatively small numbers of events.
However, in patients with hyperlipidemia, PCOS increases the risk of
Graves’ diseases by 10 folds, higher than PCOS acting alone. In general,
after adjusting for confounders in our study, the overall independent
association of PCOS with Graves’ disease remains strong, which may
supports the hypothesis of PCOS as a possible risk factor to the
development of Graves’ diseases.