Dynamics of a glucose-insulin model.

Diabetes mellitus is a noncommunicable disease, which is a serious threat to human health around the world. In this paper, we propose a simple glucose-insulin model with Michaelis-Menten function as insulin degradation rate to mimic the pathogenic mechanism of diabetes. By theoretical analysis, a unique positive equilibrium of model exists and it is globally asymptotically stable. The four strategies are designed for diabetes patients based on the sensitivity of parameters, including insulin injection and medicine treatments. Numerical simulations are given to support the theoretical results.

The analysis of a drug transmission model with family education and public health education.

In this paper, we formulate a six dimensional drug transmission model to study the effect of family education and public health education. The dynamical behaviors of the model are discussed in terms of the basic reproduction number R 0 . By constructing Lyapunov functions, we obtain the drug-free equilibrium is globally asymptotically stable if R 0 ≤ 1 and the drug addiction equilibrium is globally asymptotically stable if R 0 > 1 . Sensitivity analyses are performed to seek for effective control measures for drug spread. The analysis show that both the family and public health education can influence the spread of drug transmission. However, the combination of family and public health education is more effective to reduce the prevalence of drugs. Some numerical simulations are given to confirm the obtained theoretical results.

Prevalence of dyslipidemia and associated factors in the Yi farmers and migrants of Southwestern China.

There are scant data on serum lipid profile in the Yi people in China. The Yi farmers and migrants provide an unusual opportunity to estimate effects of environmental factors on serum lipid levels. We conducted a cross-sectional study in the Yi people to estimate prevalence of dyslipidemia and associated factors. It was found that prevalence of high total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), abnormal ratio of TC/HDL-C and low high-density lipoprotein-cholesterol (HDL-C) were 1.82%, 5.07%, 1.56%, 9.30% and 39.47%, respectively in the Yi farmers. And those in the Yi migrants were 4.81%, 22.21%, 3.24%, 26.56% and 40.53%. Prevalence of dyslipidemia increased with time period in the Yi farmers after their emigrating to urban areas for less than 25 years, except high TC. It was also found that prevalence of dyslipidemia of the Yi migrants increased with time period before their emigration, including hypertriglyceridemia, low HDL-C and high ratio of TC/HDL-C. Their body mass index (BMI), history of type 2 diabetes mellitus (T2DM), gender, ever alcohol drinking and physical activity all were associated with dyslipidemia, but no factors associated with high LDL-C was found. In conclusion, all these results suggest that the Yi migrants have a higher prevalence of dyslipidemia than the Yi farmers do, which possibly can attribute to their urbanized lifestyles.

Association between insulin receptor gene polymorphism and the metabolic syndrome in Han and Yi Chinese.

Insulin resistance has been a possible underlying pathophysiologic defect inducing the metabolic syndrome (MS). However association studies regarding Insulin receptor gene in different ethnic groups are scarce in literature. Here we conduct an association study between MS and genetic polymorphism of the INSR gene in Yi and Han Chinese. In a cross-sectional study, 3,436 Yi and Han people were investigated. Ethnicity-specific case-control studies were designed, with MS patients diagnosed as cases and non-MS people as controls matched on gender and age. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the genotypes of the exon 8 of the INSR gene. Data were analyzed using one-way analysis of variance, chi-square test, and logistic regression where appropriate. Systolic blood pressure (SBP) was significantly higher in MS patients with the N1N2/N2N2 genotypes than that in those with the N1N1 genotype of both ethnic population (p<0.05). Frequency of the N2 allele was significantly higher in MS patients than that in controls of ethnic Han (p=0.020). Multivariable logistic regression analysis showed that the NsiI polymorphism of the exon 8 of the INSR was an independent predictor for MS in Han people adjusted for total cholesterol, sex, physical activity, educational level, family income, alcohol intake and smoking (OR=2.55, 95% CI: 1.31-4.94, p=0.006). The results indicated that NsiI polymorphism of the INSR gene is associated with SBP in these two different ethnic groups, and significantly associate with MS in Han Chinese. These findings contribute to our better understanding on the genetic basis of MS.

Association of the adiponectin gene (ADIPOQ) +45 T > G polymorphism with the metabolic syndrome among Han Chinese in Sichuan province of China.

The metabolic syndrome is a cluster of abnormalities characterized by obesity, impaired glucose metabolism, hypertension or elevated blood pressure, and dyslipidemia. The aim of this study was to investigate the association of the adiponectin gene (ADIPOQ) +45 T > G polymorphism with the metabolic syndrome among Han Chinese in Sichuan province of China. A case-control design was used including 116 patients with the metabolic syndrome and 108 unrelated controls, matched on age and gender. The ADIPOQ +45G allele (TG+GG) had a significant association with risk of the metabolic syndrome (odds ratio=1.88, 95% confidence interval: 1.03-3.44, p=0.039) adjusted for education, physical activity, family history of related diseases, smoking and drinking, compared with subjects with TT genotype. The association between the ADIPOQ +45 T>G polymorphism and the metabolic syndrome was independent of multiple confounders.

Trends of overweight and obesity in Yi people between 1996 and 2007: an Yi migrant study.

OBJECTIVE: To evaluate trends of overweight and obesity prevalence between 1996 and 2007 in Yi farmers and Yi migrants. METHODS: An Yi migrant study was conducted in Liangshan Yi Autonomous Prefecture, Sichuan Province, China from 1996 to 2007. Data were collected with identical methods, including standardized questionnaire and body measurements. RESULTS: Age- and sex-specific body mass index (BMI) significantly increased from 20.02 in 1996 to 22.36 in 2007, among Yi farmers, which was significantly different from those among Yi migrants (23.67 in 2007 and 20.90 in 1996) (P<0.05). Prevalence of obesity rose from 1.21 % in 1996 to 4.55 % in 2007 (OR=1.15, P<0.001) in Yi migrants, while that in Yi farmers from none in 1996 to 0.12 % in 2007 (P>0.05). Prevalence of overweight rose significantly to 26.24 % in 2007 from 17.24 % in 1996 (OR=1.06, P<0.001) in Yi migrants, while that in Yi farmers from 1.29 % in 1996 to 4.45 % in 2007 (OR=1.14, P>0.001). Yi migrants appeared to have a 5.52-fold higher risk on developing overweight and obesity than Yi farmers have. CONCLUSION: The Yi migrants had a steeper increase of overweight with year and consequently caused more obesity. Change in lifestyle may contribute most likely to higher prevalence of overweight and obesity in Yi migrants.

An association study of SNP + 45 T > G of the AdipoQ gene with type 2 diabetes in Yi and Han people in China.

BACKGROUND: The Yi people are considered the most primitive society in China, and live in the remote mountainous areas of Southwestern China. There have been no previous publications on genetic research concerning type 2 diabetes (T2D) in the Yi people. This is the first report that presents the association between SNP + 45 T > G (rs2241766) of the AdipoQ gene and T2D in Yi people. Our previous study showed that the prevalence of T2D in Yi people was lower than the national level in 2008. Genetic differences between Yi and Han people might be one possible explanation for this observation. Studies on the single nucleotide polymorphism SNP + 45 T > G (rs2241766) of the AdipoQ gene in Chinese Han people showed inconsistent results. This study was designed to identify genetic variants of the AdipoQ gene that contribute to the development of T2D in Yi and Han people. METHODS: A case-control study on the association between SNP + 45 T > G (rs2241766) of the AdipoQ gene and T2D was carried out based on a cross-sectional study in the Liangshan area, Sichuan province in Southwestern China. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to test for the presence of SNP + 45 T > G (rs2241766) in the AdipoQ gene. RESULTS: Distributions of genotypes variants (TT/GG/TG) were not significantly different between T2D cases and controls both in Yi and Han people in China (p > 0.05). The allele frequencies (T/G) demonstrated a non-significant association with T2D, displaying OR of 1.1 (95 % CI: 0.8, 1.6) in Yi people and OR of 1.0 (95 % CI: 0.7, 1.4) in Han people. CONCLUSIONS: The SNP + 45 (rs2241766) of the AdipoQ gene is not associated with T2D neither in Yi nor in Han people in southwestern China.

[Drug resistance and associated factors on HIV in Liangshan prefecture, Sichuan province].

OBJECTIVE: To investigate the HIV drug resistance among HIV/AIDS patients who had received highly active antiretroviral treatment (HAATR) in Liangshan prefecture and related factors. METHODS: This investigation was conducted from August to October 2010. Data on epidemiology, treatment, CD4(+) T cell, viral load and drug resistance tests were collected. RESULTS: 233 (73.50%) had a viral load of < 1000 copy/ml, with the median CD4(+) T cell count as 329 cell/µl. 26 samples appeared to be drug resistant, with the rate as 8.20%. Among 84 patients with antiviral therapy failure, the overall drug resistance rate was 30.95% (26/84). While 24 (28.57%) were resistant to non-nucleoside reverse transcriptase inhibitor (NNRTI) drugs. Among nucleoside reverse transcriptase inhibitors (NRTI), 7 (8.33%) were resistant. 1 (1.19%) had protease inhibitor (PI) resistance mutations identified. Factors that significantly associated with drug resistance would include: being injecting drug users (AOR = 3.37, 95%CI: 1.06 - 10.66, P = 0.0390), having had chronic diarrhea > 1 month (AOR = 8.38, 95%CI: 1.87 - 37.69, P = 0.0055), having had CD4(+) T cell < 200 (AOR = 3.48, 95%CI: 1.29 - 9.39, P = 0.0139), being residents from Butuo area (AOR = 17.68, 95%CI: 4.97 - 62.86, P < 0.0001). When comparing with other areas, data from Butuo showed that people who carried Yi ethnicity (AOR = 17.35, 95%CI: 2.01 - 149.73, P = 0.0095) and were literate (having had primary or higher levels of education) (AOR = 0.18, 95%CI: 0.08 - 0.42, P < 0.0001), being married or having cohabited relations (AOR = 8.17, 95%CI: 2.35 - 28.39, P = 0.001) were found to be less adherent (AOR = 0.05, 95%CI: 0.02 - 0.13, P < 0.0001) to the treatment. CONCLUSION: Successful antiviral outcomes were seen among those AIDS patients under treatment, in Liangshan prefecture. Resistance rates were significantly different in regions. For IDUs, enforcement on subjects including prevention on drug resistance, adherence to HAART and treatment for drug addiction should be strengthened and programs being integrated.

[A research on prevalence and risk factors of type 2 diabetes mellitus in the farmers and immigrants of Yi people in Liangshan, Sichuan province, China].

OBJECTIVE: To explore the difference on the prevalence and the risk factors of type 2 diabetes(T2DM) between Yi farmer and immigrants in Liangshan, Sichuan province. METHODS: A representative sample of 2878 Yi people (including 1549 farmers and 1329 immigrants) aged from 16 to 76 was selected by the method of multistage and cluster sampling in Liangshan, Sichuan province, China, during 2007 - 2008. The samples were divided into 5 groups by the factor of age (16-, 25-, 35-, 45- and 55-76). The standardized prevalence of T2DM was calculated by the national census data in 2000. Logistic regression analysis was used to study the related risk factors of T2DM. RESULTS: The prevalence of Yi farmer was 4.33% (67/1549) (male: 6.15% (42/683), female: 2.89% (25/866)), and that of Yi migrants was 9.03% (120/1329) (male: 11.31% (88/778), female: 5.81% (32/551)). The standardized prevalence (SP) was calculated by the data of national census 2000. The SP of Yi farmer was 5.97%in male, and that of the female was 2.40%. The SP of Yi migrant was 10.25% in male, and that of the female was 6.29%. For Yi people, sex (male versus female, OR = 1.69, 95%CI: 1.02 - 2.81), age (versus the group aged 16- and 25-, group aged 35 to 54: OR = 5.04, 95%CI: 2.93 - 8.69; group aged above 54: OR = 6.19, 95%CI: 3.23 - 11.86), hypertension (versus normal group, borderline hypertension value: OR = 1.61, 95%CI: 1.08 - 2.38; hypertension group: OR = 2.40, 95%CI: 1.37 - 4.22), smoking (OR = 1.55, 95%CI: 1.01 - 2.37), triglyceride (TG) level (OR = 1.65, 95%CI: 1.10 - 2.46) and high-density lipoprotein cholesterol (HDL-C) level (OR = 1.64, 95%CI: 1.13 - 2.37) were the positive factors correlated with T2DM, and drinking (the alcohol volume from 22.67 to 52.50 g/d ) was negative factor (OR = 0.53, 95%CI: 0.30 - 0.95) correlated with T2DM. CONCLUSION: The prevalence of T2DM in Yi immigrants was higher than that in Yi farmers;sex, age, blood pressure, smoking, TG, HDL-C, drinking were influencing factors of T2DM.

Effect of lifestyle on the prevalence of the metabolic syndrome among farmers, migrants with Yi ethnicity and Han population in Sichuan province of China.

Yi people are the most primitive society in China. Little information on the metabolic syndrome (MS) is available in Yi people. We explored whether differing lifestyle affected the prevalence of MS among farmers and migrants of Yi ethnicity and Han population in one of the Southwestern parts of China. The prevalence of MS among the three populations was described under the same International Diabetes Federation (IDF) criteria. The study populations comprised of 1,535 Yi farmers, 1,306 Yi migrants and 2,130 Han people. The effects of physical activity, obesity and other risk factor on MS were evaluated. Results showed that the age- and sex-adjusted prevalence of MS was 9.9 times higher in Yi migrants (23.8%) and 6.3 times higher in Han people (15.2%) than in Yi farmers (2.4%). In addition, the prevalence of MS increased significantly with age in both sexes, except for a slight increase in Yi farmers. The prevalence of overweight and obesity was much lower in Yi farmers (9.3% in men and 16.5% in women) than that in Yi migrants (46.2% in men and 34.8% in women) and Han people (40.6% in men and 31.9% in women). Levels of physical activity were much greater in Yi farmers than in Yi migrants and Han people. These results indicated that lifestyle had strongly influenced the development of MS in Han and Yi Chinese and our study provided one more piece of evidence imputing that high prevalence of MS might be related to a change in lifestyle associated with urbanization.