Therefore, although some potential risk factors for macular degeneration, including daily antioxidants intake, body mass index, myopia degrees, and thyroid hormone levels, are unavailable in the NHIRD, we believe that we have considered the effects of these unknown variables by considering diabetes, hypertension, hyperlipidemia, CAD, myopia, hyperthyroidism, and hypothyroidism. This evidence concerns the gene TG and hypothyroidism.