Is obesity a major risk factor for diabetes? Can scientific weight loss reduce the incidence rate?

Obesity and Non-Insulin-Dependent Diabetes

Epidemiological Studies of Diabetes
The 14th International Diabetes Federation announced that there are 100 million people with diabetes worldwide. The prevalence rate among white Americans is as high as 6%–8%. A 1994 epidemiological survey of 250,000 people of various ethnic groups aged 25 and above in 19 provinces and cities in my country (including urban and rural areas) showed that the prevalence of diabetes had increased from 0.67% in 1980 to 2.5%, with some cities even exceeding 4%. The increased diabetes is mainly non-insulin-dependent diabetes. Currently, there are approximately 20 million people with diabetes in China.

Obesity has a significant impact on diabetes. Recent studies have found that early malnutrition easily leads to metabolic abnormalities in later life, and high birth weight infants are more likely to develop type 2 diabetes in adulthood. Individuals with a BMI > 25 kg/m² have an 8 times higher risk of developing non-insulin-dependent diabetes than those with a BMI < 22 kg/m², and the risk is even higher for those with a BMI > 30 kg/m². The Department of Endocrinology at Tianjin Medical College conducted an oral glucose tolerance test (OGTT) on 63 patients with a BMI > 30 kg/m², analyzing their insulin release, blood lipids, and apolipoprotein E phenotype. The results showed no significant difference in OGTT glucose tolerance curves between the obese and control groups, but the concentrations of insulin at each time point were significantly higher in the obese group than in the control group.

Blood lipid (TC/TG/LDL) concentrations were significantly elevated. There were no significant differences in apo-E phenotype distribution and apo-E allele frequency distribution between the obese and control groups. This experiment indicates that obese patients with a BMI > 30 kg/m² have hyperinsulinemia and elevated blood lipids. A study at Boston University in the United States estimated that preventing weight gain in adults could reduce the incidence of diabetes by more than half. Even within the normal BMI range of 23–25 kg/m², weight loss can reduce the incidence of diabetes.

A US study followed 51,529 men aged 45–75 for 5 years and found a significant correlation between BMI and diabetes. After adjusting for age, family history, and smoking, men with a BMI between 25 and 26.9 kg/m² (mildly obese) had a 2.2 times higher risk of developing diabetes than those with a BMI < 23 kg/m² (normal weight). The higher the BMI, the greater the risk. Follow-up results for women were very similar to those for men.

A 6-year follow-up study of 600 non-diabetic individuals in Daqing, my country, showed that among non-diabetic individuals with fasting blood glucose below 5.88 mmol/L, the incidence of diabetes in those with a BMI > 25 kg/m² and BMI > 27 kg/m² was 3-4 times higher than in those with a BMI < 24 kg/m², indicating that obesity is a significant risk factor for non-insulin-dependent diabetes mellitus in my country.

Further research shows that the longer the duration of obesity, the greater the risk of developing non-insulin-dependent diabetes mellitus. Individuals with a BMI > 30 kg/m² for more than 10 years have twice the risk of developing non-insulin-dependent diabetes mellitus compared to those who have been obese for less than 5 years.

Centralized obesity carries a greater risk of developing diabetes compared to those with uniform obesity.