For five consecutive years since 2001, World Diabetes Day on November 14 has focused on the prevention and control of diabetes complications. 2001 was on diabetes and cardiovascular disease, 2002 on diabetes and eye disease, 2003 on diabetes and kidney disease, 2004 on diabetes and obesity, and 2005 on diabetes and foot care. Why has the World Diabetes Day theme focused on the complications of diabetes in recent years and how can diabetes complications be prevented and controlled? The main danger of diabetes comes from complications The high incidence of complications in diabetes leads to high rates of death and disability. Studies have shown that 30% to 40% of patients develop at least one complication 10 years after the onset of diabetes. The prevalence of neuropathy can reach 30%-40%, 60%-70% and 90% after 5, 10 and 20 years of diabetes, respectively. Retinopathy complicates the disease in 40% to 50% and 70% to 80% of patients after 10 and 15 years of disease. About 10% of patients will develop severe visual impairment after 15 years of disease onset, while 2% will be completely blind. Microalbuminuria is a precursor to diabetic nephropathy. The incidence of microalbuminuria can reach 10%-30% and 40% after 10 and 20 years of disease, and 5%-10% of patients deteriorate to end-stage renal disease after 20 years. Forty percent of diabetic patients with youth onset develop severe nephropathy by age 50, requiring hemodialysis and kidney transplantation, or face death. In addition, the risk of cardiovascular disease in diabetic patients is two to four times higher than in the general population, and the age of onset is earlier. Due to vascular and neurological lesions in diabetic patients, foot ulcers and consequent amputations often result. In terms of cause of death, the main causes of death in diabetic patients are various complications. Among them, ischemic heart disease is the most important cause of death in diabetic patients, accounting for 60% to 80% of deaths in diabetic patients. Cerebrovascular disease causes about 10% of deaths, and its mortality rate is twice that of non-diabetic patients. Diabetic nephropathy generally accounts for 10-30% of all deaths, and the younger the age of onset, the higher the percentage of deaths due to diabetic nephropathy. Important means to prevent and control diabetic complications Diabetes is a chronic disease with many risk factors, complex pathogenesis and a lifelong course. Hyperglycemia in patients is often accompanied by hypertension, hyperlipidemia and insulin resistance, i.e. metabolic syndrome. To curb the epidemic of this complex disease and reduce the harm it causes to individuals, families and society, China must introduce advanced theories and practical experience in the prevention and treatment of chronic diseases. Over the past decade, several landmark studies have provided irrefutable evidence that interventions and intensive treatment can successfully reduce diabetes and its complications. A 6-year prospective study in Daqing, China, reduced the incidence of hypoglycemic tolerance progressing to diabetes by 46% over 6 years through health education and implementation of interventions to increase physical activity and attention to dietary balance. This result proves that primary prevention can prevent people at high risk for diabetes from developing diabetes. There are numerous studies demonstrating that secondary prevention (that is, keeping blood glucose within normal limits whenever possible) is successful in reducing diabetes and its complications. Several clinical studies have confirmed that secondary prevention of diabetes, whether type 1 or type 2 diabetes, involves strict control of associated risk factors such as blood pressure, lipids, and weight in addition to strict control of blood glucose during intensive treatment, which can reduce the incidence of many microvascular and macrovascular complications of diabetes, such as stroke, heart failure, and fundopathy, by 30% to 60% and significantly reduce diabetes-related deaths. The prevention and control of diabetes and its complications in China should follow the chronic disease prevention and control strategy advocated by the World Health Organization, and vigorously carry out population-based tertiary prevention and integrated prevention of diabetes. Through health education and health promotion means, we will raise the awareness of the whole society about the hazards of diabetes, emphasize that diabetes can be prevented, increase the knowledge of the general public and medical personnel about diabetes prevention and control, improve the skills of professionals, and create a social environment that supports health. For high-risk groups, such as those aged 40 years or older with a positive family history of diabetes, overweight and obese people, people with a predominantly sedentary lifestyle, people with hypertension, people with dyslipidemia and women who have given birth to a huge fetus (over 4,000g), regular checkups or screenings should be enhanced to achieve early detection, diagnosis and treatment of diabetes.