TPO and hypothyroidism: In group A1, we assessed three categories and compared them to each other: subjects who had either anti-TPO or anti-Tg prior to the onset of subclinical/overt hypothyroidism, subjects who had anti-TPO prior to the onset of subclinical/overt hypothyroidism, and subjects who had anti-Tg prior to the onset of subclinical/overt hypothyroidism.