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.

PAX4 mutation (R121W) as a prodiabetic variant in Okinawans.

We previously reported that a missense mutation at codon 121 (CGG(Arg) to TGG(Trp), R121W) of PAX4 may be associated with the onset of type 2 diabetes in Japanese. In this study, we determined the frequency of the R121W mutation of PAX4 and characterized the prodiabetic phenotype in a population-based study. Healthy 372 residents participated in annual health check-ups in Nishihara (Okinawa, Japan) and unrelated 193 type 2 diabetic patients from the outpatient clinic of Ryukyu University Hospital were enrolled. Diagnosis of diabetes was based on the 1997 American Diabetes Association criteria. The R121W mutation in PAX4 was genotyped by PCR-RFLP analysis. In healthy residents, R121W mutation was detected in 12 of 372 residents (3.1%). The prevalence of newly diagnosed type 3 diabetes (25% vs. 5%, p=0.004) and HbA(1c) (5.6+/-1.9 vs. 5.1+/-0.7, p=0.026) was higher in the variants than in the wild-types. The odds ratio of diabetes in the R121W variants was 5.98 with 95% confidence interval from 1.50 to 23.9. The R121W mutation was observed in 12 of the 193 type 2 diabetic patients (6.2%). Onset-ages of diabetes were earlier (37+/-10 vs. 47+/-13 years, p=0.010) and the rate of insulin user was two times higher (83% vs. 41%, p=0.005) in the variants. The R121W mutation in PAX4 is a predisposing factor for the development of type 2 diabetes in Okinawans.

Cytotoxic T-lymphocyte antigen-4 gene polymorphisms and human T-cell lymphotrophic virus-1 infection: their associations with Hashimoto's thyroiditis in Japanese patients.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) decreases the immune response of T cells by inactivating the signal that occurs with interaction between CD28 on T cells and B7 on antigen-presenting cells. Gene polymorphisms involving CTLA-4 promoter (-318 C/T), exon 1 (49 A/G), and exon 4 (microsatellite (AT)n) have been linked to Hashimoto's thyroiditis (HT) and other autoimmune diseases. HT also has a reported association with human T-cell lymphotrophic virus-1 (HTLV-1) infection. We investigated the occurrence of CTLA-4 polymorphisms in Japanese patients with HT with and without anti-HTLV-1 antibodies (HTLV-1 Ab). DNA samples from 143 patients with HT and 199 controls were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis using the restriction enzymes, Bbv 1, Tse 1, and Mse 1. In the HTLV-1 Ab-positive group the exon 1 G allele was more frequent in patients with HT than in controls (67% vs. 53%, p = 0.0377), and in HTLV-1 Ab-negative group it was also frequent in patients with HT than in controls (68% vs. 53%, p = 0.0041). Frequency of the G allele in HT with HTLV-1 Ab was comparable to those without HTLV-1 Ab. Frequency of polymorphism in the promoter did not differ between patients with HT and controls, nor between controls with and without HTLV-1 Ab. HTLV-1 infection is not associated with CTLA-4 polymorphisms in either HT or controls. HTLV-1 infection is not regulated by genetic factor such as CTLA-4, and may affect occurrence of HT as an independent purely environmental factor.