Association of Tumor Necrosis Factor Alpha, Interleukin 6, and C-Reactive Protein with the Risk of Developing Type 2 Diabetes: A Retrospective Cohort Study of Rural Thais

The linkage of obesity, inflammation, and type 2 diabetes mellitus (T2DM) has been extensively investigated for over a decade. However, the association between inflammatory biomarkers, including C-reactive protein (CRP), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α), and T2DM is still inconsistent and limited. Thus, this study is aimed at elucidating the association between inflammatory marker levels and the risk of developing T2DM in many aspects. Among 296 subjects enrolled in 2013, 248 non-T2DM subjects who were completely reinvestigated in 2014 and 2015 were included in a 2-year retrospective analysis. Multivariate logistic regression was performed to evaluate the association of baseline inflammatory marker levels and variation with incidence of T2DM. After the 2-year follow-up, 18.6% of total subjects had developed T2DM. The risk of developing T2DM was significantly increased in subjects with a high level of baseline CRP (OR = 4.02, 95% CI: 1.77-9.12, P = 0.001), and a stronger impact was found with the combination of high CRP and IL-6 levels (OR = 5.11, 95% CI: 1.27-20.49, P = 0.021). One-year inflammatory marker variation analysis also revealed the significant association of elevated TNF-α and risk of developing T2DM (OR = 4.88, 95% CI: 1.01-23.49, P = 0.048). In conclusion, besides consideration of CRP levels alone, our findings suggested that IL-6 outstandingly plays a contributing role in T2DM progression and elevated TNF-α levels over time could be a potential predictor of T2DM.

Association of retinol binding protein 4 and transthyretin with triglyceride levels and insulin resistance in rural thais with high type 2 diabetes risk

BACKGROUND

Retinol binding protein 4 (RBP4), a protein secreted by adipocytes and bound in plasma to transthyretin (TTR), has been associated with obesity, the early phase of insulin resistance, metabolic syndrome, and type 2 diabetes mellitus. The objective of this study was to elucidate the relationship between RBP4, TTR, triglyceride (TG) and type 2 diabetes risk in rural Thailand.

METHODS

We measured the serum RBP4, TTR, glucose, triglyceride and insulin levels, and glucose tolerance of 167 volunteers from Sung Noen District, Nakhon Ratchasima Province, Thailand. Student's t-test, Pearson's correlation and logistic regression analysis were used to evaluate the relationships between RBP4, TTR and type 2 diabetes markers.

RESULTS

RBP4 and TTR levels, as well as homeostatic model assessment of insulin resistance (HOMA-IR) values, were significantly elevated among subjects with high triglyceride levels (p < 0.01, p < 0.05, p < 0.05, respectively). Triglyceride levels correlated with RBP4 (r = 0.34, p < 0.001) and TTR (r = 0.26, p < 0.01) levels, as well as HOMA-IR values (r = 0.16, p < 0.05). After adjustment for age and gender, the risk of hypertriglyceridemia was 3.7 times greater (95% CI =1.42-9.73, p = 0.008) in the highest RBP4 tertile as compared to the lowest tertile. Similarly, the highest TTR and HOMA-IR tertiles had greater risk of hypertriglyceridemia at 3.5 (95% CI = 1.30-9.20, p = 0.01) and 3.6 (95% CI = 1.33-9.58, p = 0.01) times higher than the respective lowest tertiles. The correlation between TTR and blood glucose was statistically significant (r = 0.18, p < 0.05), but not found this relationship in RBP4.

CONCLUSIONS

The associations of RBP4 and TTR with hypertriglyceridemia and insulin resistance may have important implications for the risk of heart disease and stroke.

Elevated C-reactive protein, interleukin 6, tumor necrosis factor alpha and glycemic load associated with type 2 diabetes mellitus in rural Thais: a cross-sectional study

BACKGROUND

The elevated levels of inflammatory markers, including C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL6) are supposed to be associated with type 2 diabetes mellitus (T2DM). Frequent high glycemic load (GL) consumption, central obesity, and a lack of physical activity are considered to be T2DM risk factors. This study aimed to determine the difference of these inflammatory markers as well as GL in individuals with versus those without T2DM in rural Thais.

METHODS

A total of 296 participants aged 35-66 living in Sung Noen District, Nakhon Ratchasima Province, Thailand, were recruited. Blood was collected to evaluate blood glucose levels, lipid profiles, and inflammatory markers. A Semi-food frequency questionnaire was utilized to assess GL followed by socioeconomic and anthropometric assessment. Statistical analysis was subsequently performed.

RESULTS

Elevated CRP and IL6 levels were associated with increased risk of developing T2DM [OR (95% CI): 7.51 (2.11, 26.74) and 4.95 (1.28, 19.11)], respectively. There was a trend towards increased risk of T2DM with elevated TNF-α levels [OR (95% CI): 1.56 (0.39, 6.14)]. GL correlated significantly with fasting blood glucose (r = 0.289, P = 0.016), suggesting that it is involved in T2DM in this study group.

CONCLUSION

In this study, CRP, IL6, and TNF-α associated with T2DM. Our findings suggested that these inflammatory markers, especially CRP, may initiate T2DM.

Seasonal levels of the major American cockroach allergen per a 9 (arginine kinase) in Bangkok and their relevance for disease severity

Monitoring the levels of cockroach (CR) allergen in the environment has medical relevance as a clear dose response relationship between CR allergen exposure, sensitization and hospitalization has been reported. In this study, a cross-sectional survey of the levels of a major American cockroach (Periplaneta americana) allergen, i.e. Per a 9 (arginine kinase) in dust samples collected in various seasons throughout the year 2007 from 76 houses of CR allergic Thai patients in the Bangkok metropolitan area were determined. A monoclonal antibody-polyclonal antibody (MAb-PAb) based-sandwich ELISA was used. The MAb was specific to Per a 9 and the PAb was raised in a rabbit against the crude extract of P. americana. The detection limit of the assay was 122 pg of the allergen or 0.024 microg per gram of fine dust powder. The concentrations of Per a 9 were found to be highest during the winter months and lowest in summer. The levels of this CR allergen had a direct correlation with disease exacerbation; i.e. the majority of the CR allergic patients had their most severe clinical manifestations during winter. Moreover, the CR allergen levels were found to be higher in wood based-houses than in concrete houses.

C-reactive protein, interleukin-6, and tumor necrosis factor-alpha levels in overweight and healthy adults

This study aimed to 1) compare levels of high sensitivity c-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) between overweight Thais and apparently healthy controls, and 2) investigate the association between serum hs-CRP, IL-6, and TNF-alpha levels and other biochemical parameters. A total of 180 health-conscious adults aged 25-60 years, who resided in Bangkok, participated in this study. No significant difference was found in age and sex between the overweight subjects and controls. Serum levels of hs-CRP, IL-6, TNF-alpha, glucose, lipid profile, body mass index (BMI), waist circumference (WC), hip circumference (HC) and waist hip ratio (WHR) were determined in these volunteers. The mean levels of white blood cells (WBC), uric acid, total cholesterol (TC), triglyceride (TG), and hs-CRP were significantly higher in the overweight subjects than those in the controls, whereas high density lipoprotein-cholesterol (HDL-C) values were significantly higher in the controls than the overweight subjects (p < 0.05). Hs-CRP levels were significantly positively correlated with levels of TG, BMI, WC, HC and WHR. HDL-C levels were significantly negative correlated with hs-CRP levels. In conclusion, the prevalence of elevated serum hs-CRP levels was higher in overweight subjects than controls. However, more data in larger and other population groups are needed to confirm this study.