Westernization of Lifestyle and Atherosclerosis in the Japanese: Lessons from the Hawaii - Los Angeles - Hiroshima Study.

Japanese Americans include Japanese individuals migrating from Japan to the United States (first-generation Japanese Americans [JA-1]) and their offspring (second- or later-generation Japanese Americans [JA-2]). Although Japanese Americans share their genetic predisposition with the Japanese, their lifestyles have been westernized rapidly and extensively. We conducted a medical survey for atherosclerosis among Japanese Americans living in Hawaii and Los Angeles and native Japanese living in Hiroshima for 50 years since 1970 (the Hawaii-Los Angeles-Hiroshima Study) and obtained the following results:(1) In the 1990s, a westernized lifestyle induced hyperlipidemia among Japanese Americans, and based on the evaluation of the carotid artery intima-media wall thickness (IMT), atherosclerosis was apparently more advanced in Japanese Americans than in native Japanese. In addition, the advancement of atherosclerosis corresponded to the degree of westernization of lifestyles in JA-1 and JA-2.(2) In the 2010s, the serum total cholesterol and low-density lipoprotein cholesterol levels in native Japanese were significantly higher than those in Japanese Americans, and the difference in the progression of carotid artery IMT was smaller between native Japanese and Japanese Americans.(3) Maintaining a healthy Japanese lifestyle since childhood may suppress future worsening of risk factors for atherosclerosis (such as obesity and diabetes mellitus) and contribute to atherosclerosis prevention in the Japanese.

Progression of Carotid Atherosclerosis in Two Japanese Populations with Different Lifestyles.

AIM: We have conducted medical surveys on two Japanese populations (Japanese Americans living in the US and native Japanese living in Japan) to investigate the impact of westernization of lifestyles on diseases in Japanese people. A 1998 survey revealed that the progression of carotid intima-media wall thickness (IMT) was faster by approximately 20 years in Japanese Americans than in native Japanese. In this study, we compared the progression of atherosclerosis in native Japanese versus that in Japanese Americans using carotid IMT data from medical examinations conducted in the 2010s. METHODS: This study included 115 native Japanese living in Hiroshima who underwent a medical examination in 2014 and 112 Japanese Americans living in Hawaii who underwent a medical examination in 2012, excluding those receiving medication for diabetes mellitus (DM) or dyslipidemia. Carotid IMT was compared between the two Japanese populations. RESULTS: Serum total and low-density lipoprotein cholesterol levels were significantly higher in native Japanese than in Japanese Americans. The median carotid IMT was significantly greater in Japanese Americans than in native Japanese [median (25th-75th percentile): 1.27 (0.86-2.02) mm vs. 1.00 (0.80-1.30) mm, P =0.001]. Regression curves showed that the age at which IMT exceeded 1.1 mm was estimated at ＞50 years in Japanese Americans and at approximately 60 years in native Japanese. CONCLUSIONS: According to surveys conducted in 2012 and 2014, carotid IMT was still greater in Japanese Americans than in native Japanese. However, a comparison with data from the 1998 survey showed that current native Japanese had higher serum lipid levels and more advanced atherosclerosis.

Efficacy and safety of insulin degludec in Japanese patients with type 1 and type 2 diabetes: 24-week results from the observational study in routine clinical practice.

This is first observational prospective study of insulin degludec in routine clinical practice that we evaluated the effect on glycemic control and risk of hypoglycemia in basal-bolus insulin therapy. We found that insulin degludec can maintain glycemic control at a lower insulin dose and frequency of hypoglycemia in type 1 diabetes, while it can improve glycemic control at equally insulin dose in type 2 diabetes. These results mean that insulin degludec is of use in routine clinical practice.