Nobuhiro Yamada

Fruit intake and incident diabetic retinopathy with type 2 diabetes.

Background: Antioxidants and dietary fiber are postulated to have preventive effects on diabetic retinopathy, but evidence is lacking. We investigated this association in a cohort with type 2 diabetes 40–70 years of age with hemoglobin (Hb)A1C ≥6.5%, originally part of the Japan Diabetes Complications Study. Methods: After excluding people who did not respond to a dietary survey and patients with diabetic retinopathy or a major ocular disease at baseline, we analyzed 978 patients. Baseline dietary intake was assessed by a food frequency questionnaire based on food groups and 24-hour dietary records. Primary outcome was incident diabetic retinopathy determined using international severity scales. Results: Mean fruit intake in quartiles ranged from 23 to 253 g/day, with increasing trends across quartiles of fruit intake for vitamin C, vitamin E, carotene, retinol equivalent, dietary fiber, potassium, and sodium. Mean energy intake ranged from 1644 to 1863 kcal/day, and fat intake was approximately 25%. HbA1C, body mass index, triglycerides, and systolic blood pressure were well controlled. During the 8-year follow-up, the numbers of incident cases of diabetic retinopathy from the first through the fourth quartiles of fruit intake were 83, 74, 69, and 59. Multivariate-adjusted hazard ratios for the second, third, and fourth quartiles of fruit intake compared with the first quartile were 0.66 (95% confidence interval = 0.46–0.92), 0.59 (0.41–0.85), and 0.48 (0.32–0.71) (test for trend, P < 0.01). There was no substantial effect modification by age, sex, HbA1C, diabetes duration, overweight, smoking, and hypertension. Risk for diabetic retinopathy declined with increased intake of fruits and vegetables, vitamin C, and carotene. Conclusion: Increased fruit intake in ranges commonly consumed was associated with reduced incident diabetic retinopathy among patients adhering to a low-fat energy-restricted diet.

Cohort Profile: The Japan Diabetes Complications Study: a long-term follow-up of a randomised lifestyle intervention study of type 2 diabetes

The Japan Diabetes Complications Study, a randomised lifestyle intervention study of type 2 diabetes conducted at 59 institutes throughout Japan that enrolled 2033 eligible patients from January 1995 to March 1996, was directed at: (i) determining the incidence and progression rates of complications of diabetes; (ii) exploring clinical risk factors for complications of diabetes; and (iii) determining the association between lifestyle factors, including diet and physical activity, and complications of diabetes, in addition to comparing, in a randomised manner, the effects on type 2 diabetes of an extensive lifestyle intervention and conventional treatment. The protocol for the study originally specified four study populations according to primary outcomes, consisting of: (1) a macroangiopathy group (N = 1771); (ii) a nephropathy group (N = 1607); (iii) a retinopathy-incident group (N = 1221); and (iv) a retinopathy-progression group (N = 410). The primary outcomes were: (i) development of retinopathy; (ii) progression of retinopathy; (iii) development of overt nephropathy; and (iv) occurrence of macroangiopathic events including proven coronary heart disease and stroke. The study was originally planned to follow patients for 8 years, and an extended follow-up is ongoing. Information about primary outcomes, laboratory tests, and other clinical variables for each patient was collected at a central data centre through an annual report from each investigator. Additionally, extensive lifestyle surveys were conducted at baseline and 5 years after the beginning of the study intervention in both the intervention and conventional treatment groups. A description of the occurrence of complications of diabetes and of all-cause mortality, provided in this paper, demonstrated a clear gender-based difference in cardiovascular disease and all-cause mortality.