| BackgroundDiabetes mellitus (DM) is a complex of metabolic disorder characterized with chronic hyperglycemia. Type 2 diabetes (T2DM), which accounts for 90-95% of DM, results from both genetic and environmental risk factors such as physical inactivity, unhealthy dietary habits, and obesity. In recent years, T2DM has reached an epidemic level globally. Following tumor and cardiovascular diseases, T2DM has become the third chronic disease which is most seriously harmful to human health in the world.In the past few decades, the prevalence of T2DM in China increased rapidly. With the rapid raising in prevalence of T2DM, the hazard by T2DM and its complications became more and more seriously. T2DM associated long-term damage, dysfunction, and failure of various organs, and clustering of metabolic disorders are common phenomenons in individuals with T2DM. T2DM not only affects health, but also causes the greatly economic burden for family and society. At the same time, contrast to the fast raising of the prevalence for T2DM, the rates of awareness, treatment, and control of T2DM are relatively low. T2DM had become a serious public health problem in China.The present study was designed to provide current and reliable data on the prevalence, awareness, treatment, control, and risk factors of T2DM in the Chinese adults. It also wants to analyze the relationship between the clustering of metabolic disorders and T2DM, to compare central and overall obesity measurements as correlates of T2DM and impaired fasting glucose (IFG) and furtherly to determine which single measurement is more powerful for predicting T2DM and IFG.Study design and methodsInternational Collaborative Study of Cardiovascular Disease in ASIA (Inter ASIA), a cross-sectional study, was conducted in 2000～2001. A 4-stage stratified sampling strategy was used to select a nationally representative sample of the Chinese general population aged 35-74 years. 31 provinces (and municipalities) were stratified into northern and southern China, as divided by the Chang Jiang River. Five provinces or municipalities from northern China and five from southern China were selected to be representative of the geographic and economic developing status in their regions. A total of 15 838 persons (7684 men and 8154 women) were selected and completed the study. The present analysis was restricted to the 15 236 adults aged 35 to 74 years who had fasting glucose measured. Data was collected by questionnaire interview (demographic characteristics, T2DM familly history, the awareness and treatment information, behavior risk factors, and diet information), anthropometric measurements (height, weight, waist and hip circumferences, and blood pressure), and laboratory measurements [fasting plasma glucose, total cholesterol (TC), triglyeride (TG), and high density lipoprotein cholesterol (HDL-C)]. Cross-sectional and case-control study designs were used to analyze the prevalence, awareness, treatment, control, risk factors, and the relationship between the clustering of metabolic disorders and T2DM. Receiver operating characteristric (ROC) curve was used to compare central and overall obesity measurements as correlates for predicting T2DM and IFG.Results1. Prevalence of IFG and T2DM: The prevalence rates of IFG and DM for the Chinese adults aged 35 to 74 years were 7.33% and 5.49%, respectively, and the age-standardized prevalence of IFG and DM were 7.33% and 5.49% (2000 national population census dada were used as standard population ), respectively. There were no significant differences between males and females for the prevalence rates of T2DM (7.66% for males vs. 5.24% for females) and IFG (6.98% for males vs. 5.77% for females) (all P>0.05). The prevalence rates of IFG and T2DM all increased significantly with age (all P<0.0001). The prevalence rate of T2DM in urban areas (7.64%) was statistically significantly higher than that in rural ones (4.95%) (P<0.0001), however, there was no significant difference for the prevalence rate of IFG between urban and rural areas (7.69% vs. 7.24%) (P>0.05). The prevalence rates of IFG and T2DM in north were significantly higher than those in south (8.01% vs. 6.83% for IFG and 6.41% vs. 4.83% for T2DM) (both P<0.05). There were no statistically significant differences for the prevalence rates of IFG and T2DM among different education levels, and marital status. There was statistical difference for the prevalence rate of IFG among individuals with different occupations (P<0.01), but there was no difference for the prevalence rate of T2DM. The T2DM rates but not IFG increased across average yearly individual income levels.2. Awareness, treatment, and control of T2DM: Among 986 T2DM participants, 23.66% were aware of their DM diagnosis, 20.33% were taking prescription medication or nonpharmacological interventions, and 8.28% were having their fasting glucose level under 126mg/dl. Among diabetics who reported a prior diagnosis of DM, 85.22% were taking prescription medication or nonpharmacological interventions, 35% had fasting plasma glucose < 126 mg/dl. Among diabetics who reported a prior DM diagnosis using different treatment methods, the rates of control in diabetics for using insulin (17.65%) or oral hypoglycemic medication (31.3%) were significantly lower than that in diabetics for using nonpharmacological treatment (50.38%) (P<0.05).3. Risk factors of T2DM: After adjusted for age, education level, occupation, marital status, average yearly individual income, and geographic region (urban or rural, north or south), logistic regression analysis shows that family history of diabetes (OR=5.734, 95%CI: 3.915-8.398), TC level (OR=1.467, 95%CI: 1.049-2.052), and TG level (OR=1.002, 95%CI: 1.001-1.004) were significantly positively associated with T2DM, whereas, smoking (OR=0.685, 95%CI: 0.489-0.960) and the frequency of fruit intake (OR=O.915, 95%CI: 0.876-0.956) were nagatively associated with the development of T2DM in males. For females, the family history of diabetes (OR=4.992, 95%CI: 3.453-7.217), waist-to-hip ratio (WHR) (OR=1.713, 95%CI: 1.260-2.330), systolic blood pressure level (OR=1.018, 95%CI: 1.260-2.330), TG level (OR=1.004, 95%CI: 1.009-1.027), HDL-C (OR=1.011, 95%CI: 1.004-1.018), and the frequency of intake of beans (OR=1.077, 95%CI: 1.041-1.114) were significantly positively related to the development of T2DM.4. The relationship between the cluster of metabolic disorder indexes and T2DM: Central obesity, high blood pressure, low HDL-C, and high TG were all significantly associated with T2DM when only one index was compared. The ORs (95%CI) were 2.573 (2.160-3.066), 2.338 (1.955-2.796), 6.782 (4.124-11.125), and 2.855 (2.392-3.408) for central obesity, high blood pressure, low HDL-C level, and high TG level, respectively. The risk to have T2DM was enhanced with the increase of metabolic disorder indexes and the hazard to have T2DM is biggist (OR=1 0.939, 95%CI=4.575-26.157) when four indexes clusterd.5. The identijyting abilities of different obesity measurements for T2DM and IFG: ROC analysis reveals significant differences between areas under ROC curve (AUCs) for WHR (0.666, 95%CI: 0.647-0.685) and body mass index (BMI) (0.622, 95%CI: 0.601-0.642) and waist circumference (WC) (0.661, 95%CI: 0.643-0.682) and BMI for identifying T2DM (all P<0.0001). The analysis also demonstrates the significant differences between AUCs for WHR (0.638, 95%CI: 0.619-0.655) and BMI (0.607, 95%CI: 0.589-0.627) and WC (0.637, 95%CI: 0.615-0.654) and BMI for identifying IFG(all P<0.001).Conclusions1. The prevalence rate of T2DM for the Chinese adults is comparatively high, and shows a trend to keep increasing; at the same time, the on-set age for having T2DM is decreasing. The effective intervention strategies and measures for T2DM based on population (community) are urgently needed in China.2. There is stringent need for the diabetes screening program in high risk population to increase the awareness rate. It is also need to strengthen the management of the diabetics so that to improve the treatment and control status.3. Central rather than overall obesity is related more closely to T2DM and IFG in the Chinese adult population and both WHR and WC are equally able to identify T2DM and IFG. Central obesity should be emphasiszed in the population especially for those individuals with BMI within the normal range. |
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