Influence of motorization and supermarket-proliferation on the prevalence of type 2 diabetes in the inhabitants of a small town on Okinawa, Japan.

BACKGROUND: Motorization and supermarket-proliferation affect lifestyles. About 15 years ago, Okinawans went to several shops on foot, but now they go to supermarkets by car. The influences of these changes on the prevalence of diabetes are uncertain. OBJECTIVE AND MEASUREMENTS: The influence of motorization and supermarket-proliferation on the prevalence of diabetes was studied in the inhabitants of a town on Okinawa, Japan. Measurements were composed of anthropometry and blood chemistry. Participants were asked where they buy food and daily necessities (several shops or a supermarket) and how they get there (by car or on foot). DESIGN: Serial cross-sectional. PARTICIPANTS: Inhabitants of the island of Okinawa were studied. RESULTS: In 1991, 24% went to several shops and 20% to a supermarket. However, in 2004, only 3.1% went to several shops and 83% to a supermarket. In 1991, 55% went to shopping places on foot and 38% by car. However, in 2004, only 14% went on foot and 76% by car. The prevalence of diabetes in Okinawa increased from 4.7% in 1991 to 8.4% in 2004. The prevalence of diabetes correlated positively with the percent of inhabitants going to supermarkets, and those going there by car. In 1991, the prevalence of type 2 diabetes was 4.7% in men and 4.6% in women; no difference was noted between men and women. In 2004, the prevalence of type 2 diabetes increased to 9.2% in men and to 7.5% in women. The increase in the prevalence of type 2 diabetes from 1991 to 2004 was higher in men than in women. CONCLUSIONS: About 15 years ago, Okinawans went to shops on foot, but now they go to supermarkets by car. The prevalence of diabetes is increasing. Motorization and supermarket-proliferation are associated with the increases of the prevalence of diabetes. The increase in diabetes prevalence was higher in men than in women.

The suppressive effects of dietary protein restriction on the progression of renal impairment in OLETF rats.

BACKGROUND: The suppressive effect of dietary protein restriction on the progression of diabetic nephropathy remains controversial. We investigated the effects of protein and energy restrictions on both albuminuria and morphology using diabetic-prone Otsuka Long-Evans Tokushima fatty (OLETF) rats. METHODS: In this study, male OLETF rats were divided into two groups according to their energy intake. They were then further divided into three subgroups based on their amount of dietary protein, which ranged between 10% and 30% of their total intake. Urinary albumin excretion (UAE) was used as a marker of renal impairment, and body weight fasting (F) and postchallenge (P), blood glucose (BG) levels, and systolic blood pressure (SBP) were all measured during various experimental periods up to 28 weeks of age. RESULTS: The OLETF rats fed with the high-calorie diet started to gain weight at 12 weeks, and their FBG and PBG were elevated at 22 weeks, while SBP did not differ between the two groups. In addition, UAE increased significantly in the rats fed with the high-calorie diet. However, the increasing rates of UAE with age were higher in the rats with a higher protein diet within the same energy groups. UAE correlated well with the amounts of dietary energy and protein at 16 and 28 weeks of age, while it correlated with both the FBG and PBG at only 28 weeks of age. A linear regression analysis, using the data obtained at 28 weeks, showed that the amount of protein intake and FBG explained 63.4% and 23.9% of the variation in UAE, respectively. Histological studies revealed that protein and energy restriction markedly reduced the sclerotic changes of the glomeruli. CONCLUSION: Dietary protein restriction starting very early in the life of OLETF rats, in combination with energy restriction, clearly suppressed UAE and the typical morphological changes that otherwise occurred at around 16 weeks of age. This method also seemed to be more effective than energy restriction alone in slowing down any increase in UAE. The influence of BG levels on UAE was lower at an early age, while it became an increasingly important factor at later ages in the experimental rat model.