Inter-relationships between DNA damage, ascorbic acid and glycaemic control in Type 2 diabetes mellitus.

AIMS: The onset of complications in Type 2 diabetes mellitus (DM) patients cannot be predicted in individuals. Evidence suggests a link between complications and hyperglycaemia, oxidative stress and antioxidants, but causality is unclear. This study investigated baseline (entry) fasting plasma ascorbic acid, lymphocytic DNA damage and glycaemic control in Type 2 DM as part of a long-term study, the aim of which is to explore a biomarker profiling approach to identify and improve outcome in high-risk subjects. METHODS: A cross-sectional study, in which DNA damage, glycated haemoglobin (HbA(1c)), fasting plasma glucose (FPG) and ascorbic acid (AA) were measured on fasting blood samples collected from 427 Type 2 DM subjects. RESULTS: DNA damage was significantly (P < 0.0001) and directly correlated to both FPG (r = 0.540) and HbA(1c) (r = 0.282), and was significantly (P < 0.0001), independently and inversely correlated to plasma AA (r = -0.449). In those subjects with both poor glycaemic control and low AA (< 48 microm, the overall mean value for the study group), DNA damage was significantly (P < 0.005) higher compared with those subjects with a similar degree of hyperglycaemia but with AA above the mean. CONCLUSIONS: The novel finding of a significant inverse relationship between plasma AA and DNA damage in Type 2 DM indicates that poorly controlled diabetic subjects might benefit from increased dietary vitamin C. The data also have important implications for biomarker profiling to identify those subjects who might benefit most from intensive therapy. Longer-term follow-up is underway.

The epidemiology of myopia in Hong Kong.

INTRODUCTION: The prevalence of myopia amongst the Chinese has escalated in recent decades. While this refractive error was previously a little more than an inconvenience and a source of unwanted expense to the affected individuals, it is now sufficiently prevalent to warrant national concern. Myopia is also a major cause of low vision. This review aims to provide information on the prevalence of myopia in the Chinese community in Hong Kong. MATERIALS AND METHODS: Based on a number of studies carried out mainly at the Centre for Myopia Research in The Hong Kong Polytechnic University, myopia in the Chinese community in Hong Kong is described. RESULTS: Infants in Hong Kong appear to have refractive errors similar to infants of European descent; however, by the age of 7 years myopia is already prevalent. The annual incidence of myopia thereafter averages 11% to 12%; by the age of 17 years more than 70% are myopic, and this prevalence is greater than in people of European descent. In Hong Kong, myopia is much less prevalent in the older generation. CONCLUSION: The increase in prevalence of myopia over a short period of time is postulated to be due to environmental factors. Children of Chinese descent have a susceptibility to environmental factors which cause myopia.