Background: Graves' disease, painless thyroiditis and subacute thyroiditis are important in the differential diagnosis for hyperthyroidism in Japan. Methods: We retrospectively picked up patients who had been diagnosed as having hyperthyroidism, at National Center for Global Health and Medicine Kohnodai Hospital, between January 2010 and October 2018. According to the guideline for diagnosis of Graves' disease, painless thyroiditis and subacute thyroiditis presented by the Japan Thyroid Association, we diagnosed patients as having such diseases. We obtained clinical and laboratory data by using electronic medical records and database after showing the opt-out. Results: Among 91 patients who showed hyperthyroidism, we found 74 patients with Graves' disease including thyroid storm (n = 5), and seven with painless thyroiditis and 10 with subacute thyroiditis. Graves' disease patients included a significantly higher percentage of female patients than painless thyroiditis and subacute thyroiditis patients. Serum free triiodothyronine (FT3) level in Graves' disease patients was significantly higher than that in painless thyroiditis and subacute thyroiditis patients. Serum free thyroxine (FT4) level and the ratio of FT3 to FT4 were significantly higher in Graves' disease than in painless thyroiditis. The levels of thyroid autoantibodies were significantly higher in Graves' disease than in other two diseases. Our study showed an increase of white blood cells (WBCs) and percentage of neutrophil in WBC together with a decrease of percentages of lymphocyte and eosinophil in subacute thyroiditis as compared with Graves' disease and painless thyroiditis. Serum albumin level was significantly lower in subacute thyroiditis patients than in Graves' disease patients. Serum C-reactive protein (CRP) level was significantly higher in subacute thyroiditis patients than in Graves' disease patients. Conclusions: Present study elucidated characteristic clinical and laboratory findings for patients with Graves' disease, painless thyroiditis and subacute thyroiditis who showed hyperthyroidism.

Since HDL is an anti-atherogenic lipoprotein which plays a role in reversing cholesterol transport from the peripheral tissues to the liver, low HDL-cholesterol (HDL-C) levels are associated with the development of cardiovascular diseases. We previously studied effects of intake of various dietary fat on serum HDL-C levels to make "Dietary Reference Intakes for Japanese 2015", and found that the substitution of fatty acids (FAs) for carbohydrates is beneficially associated with HDL-C, monounsaturated FA (MUFA) intake may not affect HDL-C and trans FA (TFA) is significantly associated with reduction of HDL-C. Consumption of n-3 poly-unsaturated FA (PUFA) was favorably associated with HDL-C. Here we review meta-analyses on the effects of various FA consumption on serum HDL-C levels, to make "Dietary Reference Intakes for Japanese 2020". Consumption of ruminant-TFA may not affect HDL; however, increased industrially produced TFA intake was associated with a significant decrease in HDL and a significant increase in LDL. An intake of n-3 PUFA and MUFA was associated with an increase of HDL. An intake of saturated FA (SFA) was associated with an increase of HDL; however, SFA was also associated with an increase of LDL.

We previously studied effects of glycemic index (GI) and intake of dietary fiber on serum high-density lipoprotein (HDL)-C levels to make "Dietary Reference Intakes for Japanese 2015", by using data obtained by clinical trials which evaluated effects of GI and intake of dietary fiber on HDL-C in Asian populations. We found that low GI and an increased intake of dietary fiber may be beneficially associated with HDL metabolism. Here we review meta-analyses on the effects of GI and intake of dietary fiber on serum HDL-C levels, to make "Dietary Reference Intake for Japanese 2020". A search was conducted by using PubMed, Embase and Google Scholar, and the search period was comprised up to May 2018. In spite of significant associations of low GI and dietary fiber intake with reduction of low-density lipoprotein (LDL)-C, we could not observe any significant influences of low GI and dietary fiber intake on HDL metabolism.