TPO and hypothyroidism: Furthermore, people who were born in 1952 or 1953 and exposed to radionuclides (mostly 131I) released from the Mayak nuclear weapons facility site from 1948 to 1960 also did not show any increase in the prevalence of autoimmune thyroid disease (diagnosed by the presence of hypothyroidism, positive anti-TPO antibodies, or findings of ultrasound examination or palpitation) (6.4%, 37/581 for exposed vs 8.0%, 25/313 for non-exposed) when evaluated ~50 years later [43].