| Abstract|| |
Contexts: Association of lipid markers and occurrence of impaired fasting glucose (IFG) have a different pattern in different populations. Aims: The present study aimed to investigate the associations of some lipid markers with impaired fasting glucose in Kermanshah city, 2013. Settings and Designs: By a case-control study, 120 IFG subjects and 240 controls were recruited. Materials and Methods: Each subject was interviewed using a sociodemographic questionnaire and lipid markers including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), and fasting plasma glucose (FPG) were checked. Statistical Analysis Used: Chi-square test (χ 2 ), independent samples t-test, Pearson correlation coefficient, and a multiple logistic regression were used for statistical analyses. Results: IFG subjects had significantly higher TC, TG, and LDL-c than controls (P < 0.05) but both groups had comparable body mass index (BMI) and HDL-c, (P > 0.05). FPG was positively and significantly correlated with TG and TC ranges but not with BMI, LDL-c, and HDL-c. The highest correlation coefficients (r) with FPG was for TG rather than TC (r = 0.14, P < 0.01). In multivariable regression, the odds ratios (ORs) estimated for lipid markers were not associated with IFG but ORs in those females reported to have a history of oral contraceptive pill (OCP) usage was 2.4-fold compared to the controls [OR = 2.4, confidence interval (CI): 1.16-4.95]. Conclusions: TC, LDL-c, and TG had significantly higher values in IFG subjects and should be taken into consideration for the prevention of IFG.
Keywords: Cholesterol, high-density lipoprotein cholesterol (HDL-c), impaired fasting glucose (IFG), Iran, low-density lipoprotein cholesterol (LDL-c), triglyceride (TG)
|How to cite this article:|
Babanejad M, Asadollahi K, Najafi F, Hashemian AH, Delpisheh A, Parizad EG. Association of lipid markers and impaired fasting glucose: A case-control study. Ann Trop Med Public Health 2015;8:182-5
|How to cite this URL:|
Babanejad M, Asadollahi K, Najafi F, Hashemian AH, Delpisheh A, Parizad EG. Association of lipid markers and impaired fasting glucose: A case-control study. Ann Trop Med Public Health [serial online] 2015 [cited 2019 Apr 23];8:182-5. Available from: http://www.atmph.org/text.asp?2015/8/5/182/162674
| Introduction|| |
Lipid markers including cholesterol, triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) are associated with the occurrence of diabetes and its complications such as impaired fasting glucose (IFG). ,,, These factors might work together and reinforce the development of IFG. 
Since only a limited number of studies have investigated the association of IFG and obesity and lipid markers in the Iranian population, it is essential to know this association in our population. In addition, since IFG is the early phase of diabetes and cardiovascular diseases, identifying preventable risk factors associated with IFG at this stage is necessary for the prevention and management of these diseases. Therefore, the present study aimed to investigate the associations of some lipid markers with IFG.
| Materials and Methods|| |
This case-control study was conducted in Kermanshah city in the west of Iran with a total population of 851,405 in 2011.  A total of 360 subjects (120 cases and 240 controls) aged 20 years, refereed to two governmental and central laboratories of Kermanshah city were interviewed. For the purpose of this study, we used convenient sampling. All the subjects were recruited for more than 2 months (January 28, 2013 until April 20, 2013). Cases of IFG were selected from all subjects whose fasting plasma glucose (FPG) was between 100 mg/dL and 125 mg/dL after fasting for more than 8 h and those who did not have previous history of hyperglycemia; therefore, they were incident cases.  Two healthy controls who had FPG < 100 mg/dL were considered for each case.
Our inclusion criteria for cases were: Age ≥20 years old and having FPG between 100 mg/dL and 125 mg/dL. Those who had FPG >125 mg/dL, history of heart disease, myocardial infarction or heart failure,  migraine,  and previous history of hyperglycemia (type 1, 2, and gestational diabetes) were excluded.
Blood samples, including FPG, serum cholesterol [total cholesterol (TC), LDL-c, and HDL-c], and TG concentrations, were measured by commercially accessible enzymatic reagents (Pars Azmon, Iran) using the Selectra auto analyzer (Pars Azmon, Iran). The protocol was approved by Kermanshah University of Medical Sciences Ethics Committee. Each subject gave informed oral consent before participating in the study. All participants were interviewed using a questionnaire to obtain information on demographic data including age, gender, job, marital status, residential area, hypertension history, family history of diabetes in first-degree relatives (parents, siblings, and children), history of oral contraceptive pill (OCP) usage, and information about whether the participant had birth weight of more than 4 kg.
Height and weight were measured to calculate the body mass index (BMI) (kg/m 2 ) as an indicator of obesity. Data analysis was performed using SPSS statistical software version 16 for Windows (SPSS Inc., Chicago). Chi-square test (χ2 ), independent samples t-test, Pearson correlation coefficient, and a multiple logistic regression analysis were performed and the last was used to control confounding. For the purpose of multiple logistic regressions, we excluded LDL as it has colinearity with TC. In addition, odds ratio (OR) with 95% confidence interval (CI) was estimated for comparing IFG cases and normal individuals. The presented P values are two-sided and considered significant when <0.05.
| Results|| |
The total number of subjects included in this analysis was 360, of whom 120 were cases of IFG and 240 were controls. Out of the total, 185 subjects (51.4%) were female and 175 subjects (48.6%) were male. Their ages ranged from 20 years to 83 years with a mean and standard deviation (SD) of 50.98 ± 12.37 years for IFG cases and 44.4 ± 13.97 years for controls, respectively, (P < 0.0001).
There were no statistically significant differences in gender, job, marital status, residential area, and family history of diabetes between IFG subjects and controls [Table 1]. Nevertheless, the risk of IFG for those females reported to have a history of OCP usage was 2.52-fold (OR = 2. 52, 95% CI: 1.32-4.82) and for those who had a history of more than 4 kg birth weight was 2.45-fold (OR = 2. 45, 95% CI: 1.12-5.37), compared to the control group. In addition, a patient with history of hypertension was more likely to develop IFG (OR = 1.53, 95% CI: 0.93-2.51) [Table 1]. IFG subjects had significantly higher TC (P = 0.002), TG (P = 0.018), and LDL-c (P = 0.018) than the controls but the distribution of BMI (P = 0.11) and HDL-c (P = 0.98) was almost the same in the two groups, [Table 2].
|Table 2: Comparison of the levels of BMI and lipids between IFG subjects and controls|
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FPG was positively and significantly correlated with TG and TC and although it was positively correlated with BMI, LDL-c, and HDL-c, its correlation was not statistically significant. The highest correlation coefficients (r) was related to TG so that for the four lipid markers, TG was more correlated with FPG (r = 0.14, P < 0.01), [Table 3].
|Table 3: Pearson correlation analysis of selected variables in both IFG subjects and controls|
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After adjusting for desired variables, overall, those with history of OCP usage had a higher risk of IFG (OR = 2. 4, CI: 1.16-4.95) but the ORs estimated for lipid markers had almost no remarkable effect on IFG [Table 4].
| Discussion|| |
In this community-based, case-control study of IFG in the Iranian population, we found that IFG subjects had higher TC, TG, and LDL-c. Association of insulin resistance and dysregulation of lipoprotein metabolism is well documented. Abnormal lipids in the increased FPG state may be a demonstration of primary insulin resistance, which is a characteristic of type 2 diabetes and abdominal obesity. Insulin resistance develops hyperinsulinemia, increased hepatic gluconeogenesis, and glucose output. In addition, it decreases the suppression of lipolysis that results in elevated free acid flux and it raises the very low density lipoprotein secretion in the liver leading to hypertriglyceridemia and reduced levels of HDL-c.  Qian et al. declared that the distribution of lipid markers, including cholesterol and triglyceride, has been strongly associated with IFG; hence, IFG subjects had a higher cholesterol and triglyceride compared to the controls but the HDL-c was introduced as a significant lipid marker such that its level in IFG subjects was lower than in the controls.  Wael found that the elevation in TG had a strong impact on increasing the levels of glucose and it can be said that this had a strong effect on diabetes. In addition, the association of cholesterol and increased glucose has not been significant.  Overall, major studies showed a clear and significant association between TG and TC (LDL-c and HDL-c) and glucose levels, and the glucose level has been much higher in those with increased glucose. ,
The present study showed that HDL-c and BMI were not significantly associated with IFG and IFG subjects have a higher BMI than the controls. More studies indicated that HDL-c is inversely associated with IFG or hyperglycemia and IFG subjects have lower HDL-c.  One study indicated that subjects with impaired glucose tolerance (IGT) that is defined as having 2 h postprandial glucose of 140-199 mg/dL  had lower HDL-c as compared to IFG subjects.  It seems that HDL-c in the FPG level of our IFG subjects had not decreased and it may require a higher FPG level to show the changes. In addition, glycemia and its process in some cases has not been associated with HDL-c and this can be investigated further. , In addition, the BMI has been introduced as a predictive factor for IFG and totally for hyperglycemia that can result in higher insulin concentration, secretion, and resistance. ,,,, Nevertheless, some studies revealed that BMI and insulin resistance are not associated. 
The present study results also suggest that TG can be more strongly correlated with IFG than TC. In a similar result, Qian et al. found that increased fasting TGs were more correlated with TC.  Moreover, Love-Osborne and colleagues reported that increased fasting TGs could predict the risk of hyperglycemia.  Therefore, TG as a lipid marker can be considered as one of the most important predictors of IFG.
The values of TC, TG, and LDL-c in IFG subjects were significantly more than in the controls but the distribution of BMI and HDL-c was almost the same in the two groups. FPG was positively and significantly correlated with TG and TC but not significantly with LDL-c, HDL-c, and BMI. After adjusting for desired variables, overall the ORs estimated for lipid markers had almost no remarkable effect on IFG. The significant and high value factors should be taken into consideration simultaneously for prevention of IFG.
| Acknowledgments|| |
We are grateful to the subjects for participating in this study. The medical outpatient clinic staff of Kermanshah and the laboratory staff of Markazi (reference) and Mahdiyeh are deeply appreciated for their assistance regarding data collection and laboratory investigations, respectively.
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Kermanshah Health Research Center (KHRC), Kermanshah University of Medical Sciences, Kermanshah
Source of Support: Ilam University of Medical Sciences,, Conflict of Interest: None
[Table 1], [Table 2], [Table 3], [Table 4]