Table 1.

Characteristics of studies selected for estimation of prevalence of GO

Study	Study population	Country	Years studied	Type of study
Abraham-Nordling et al. [18]	3.5 million general population	Sweden	2003–2005	Prospective, population registry-based, reporting on incidence of Graves’ hyperthyroidism and all grades of severity of GO
Zaletel et al. [19]	1.0 million general population	Slovenia	1999–2009	Single institution, prospective cohort study of patients with thyroid disease, including Graves’ hyperthyroidism as a subgroup
Laurberg et al. [20]	0.5 million general population	Denmark	1992–2011	Single institution, prospective cohort study, reporting on incidence of moderate-to- severe GO