Association between serum transaminase levels and insulin resistance in euthyroid and non-diabetic adults

AIM

To evaluate the association between elevated serum transaminase levels and insulin resistance (IR) in a population of healthy individuals.

METHODS

We define IR with a cut-off point of homeostatic model assessment (HOMA-IR) ≥ 3.8. For aspartate aminotransferase (AST), we consider elevated values >30 U/L in women and values >36 U/L in men. For alanine aminotransferase (ALT), we consider elevated values >30 U/L in women and values >40 U/L in men. We performed a crude and adjusted generalized linear model from Poisson family with robust variance, in order to evaluate the association between elevated serum transaminase levels and IR. The associations were presented as prevalence ratio (PR) with their respective 95% confidence intervals (95% CI).

RESULTS

We included 261 participants in the study. The median age was 39 years (31-45) and 23.7% of the participants were men. The prevalence of elevated serum transaminase for AST and ALT were, 13.8% and 26.1%, respectively. The prevalence of IR was 34.1%. In the crude analysis we found statistical significance between elevated AST and ALT with IR (PR = 3.18; 95% CI: 2.33-4.34 and PR = 2.44; 95% CI: 1.88-3.30; respectively). However, in the multivariate analysis, the association only remained statistically significance with ALT, but lost its significance with AST, PR = 1.90; CI 95%: 1.31-2.77 and a PR = 1.23; CI 95%: 0.93-1.61; respectively.

CONCLUSION

Elevated serum levels of ALT were associated with insulin resistance. ALT could be used in clinical practice as an additional tool to assess IR in apparently healthy people.

Relationship between body fat percentage and insulin resistance in adults with Bmi values below 25 Kg/M2 in a private clinic

AIM

To evaluate the association between elevated body fat percent (BF%) and the prevalence of insulin resistance (IR) in the adult population with body mass index (BMI) in the normal values.

METHODS

We carry out an analytical cross-sectional study. The participants attended outpatient from 2012 to 2016 in a private clinic in Lima-Peru between 18 and 60 years with a BMI between 19 and 24.9/Kg/m2. We defined elevated BF% if the values were greater than 25% in men and 30% in women and IR with a cut-off point of HOMA-IR based in the 75th percentile. We performed a generalized linear model from family Poisson (crude and adjusted) with robust standard errors to evaluate the association between BF% and the IR. We reported as association measure the prevalence ratio (PR) with their respective 95% confidence intervals (CI).

RESULTS

We included 284 participants, the average age was 33.77 ± 10.86 (SD) years and the percentage of women was 88.1%. The prevalence of elevated BF% was 71.13% and the prevalence of IR was 25%. We found an association between the elevated BF% and IR, PR = 3.17; 95% CI: 1.46-6.91.

CONCLUSIONS

Body fat percentage seems to be a good indicator of IR in patients with normal BMI and without endocrine comorbidities. Longitudinal prospective studies are recommended to corroborate our findings.

Association between vitamin D deficiency and insulin resistance markers in euthyroid non-diabetic individuals

AIM

To evaluate the association between vitamin D deficiency and insulin resistance (IR) or hyperinsulinemia after oral glucose tolerance test (OGTT) in euthyroid non-diabetic individuals.

MATERIALS AND METHODS

We carried out an analytical cross-sectional study in euthyroid non-diabetic adults of both sexes, who attended the outpatient service of a private clinic in Lima-Peru during the 2012-2016 period. Participants were categorized in two groups according to their serum vitamin D levels: normal vitamin D levels (serum vitamin D values ≥ 20 ng/dL) and vitamin D deficiency (serum vitamin D values < 20 ng/dL). IR was defined as a Homeostasis Model Assessment (HOMA-IR) value ≥ 3.8 and hyperinsulinemia after OGTT was defined as a serum insulin value ≥ 80μU/mL after 120 min of 75-g glucose intake. We elaborated crude and adjusted Poisson regression models to assess the association between serum vitamin D levels and IR or hyperinsulinemia after OGTT. The reported association measure was the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI).

RESULTS

We analyzed 204 participants, the average age was 38.5 ± 10.6 (SD) years, 40 (19.6%) were males and the vitamin D median was 25.0 (IQR: 19.0-33.3) ng/dL. The prevalence of vitamin D deficiency, IR and hyperinsulinemia after OGTT was 29.4% (n = 60), 29.9% (n = 61) and 25.0% (n = 51). In the adjusted Poisson regression models, the prevalence of hyperinsulinemia after OGTT was higher among the vitamin D deficient group (aPR=1.75; 95%CI: 1.06-2.90); however, we did not find statistically significant association between vitamin D deficiency and IR (aPR=0.99; 95%CI: 0.61-1.63).

CONCLUSIONS

We found an association between vitamin D deficiency and hyperinsulinemia after OGTT in euthyroid people with no T2DM.Our findings are consistent with previous reports; providing evidence that serum vitamin D deficiency could be an IR marker.

Triglycerides and glucose index as an insulin resistance marker in a sample of healthy adults

AIM

To assess the association between elevated triglycerides/glucose index (TGI) and insulin resistance (IR) or hyperinsulinemia after oral glucose tolerance test (OGTT) in a sample of healthy adults.

METHODS

We conducted an analytical cross-sectional study in euthyroid non-diabetic adults, who attended the outpatient service of a private clinic in Lima-Peru during the 2012-2016 period. Participants were categorized in two groups according to the presence or absence of elevated TGI, IR or hyperinsulinemia after OGTT. A TGI value ≥ 8.65 was considered as elevated. We defined IR as a Homeostasis Model Assessment (HOMA-IR) value ≥ 2.28 and hyperinsulinemia after OGTT as a serum insulin value ≥ 80μU/mL after 120 min of 75-g glucose intake. We elaborated crude and adjusted Poisson regression models to assess the association between elevated TGI and IR or hyperinsulinemia after OGTT. The reported association measure was the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI).

RESULTS

We analyzed 118 individuals, the average age was 37.5 ± 11.3 years, 21 (17.8%) were males and the median BMI was 22.7 ± 1.6 kg/m². The prevalence of elevated TGI was 25.4% (n=30) while the prevalence of IR and hyperinsulinemia after OGTT was 24.6% (n=29) and 17.0% (n=20) respectively. In the adjusted model, elevated TGI was associated with both IR (aPR=6.36; 95%CI: 3.41-11.86) and hyperinsulinemia after OGTT (aPR=4.19; 95%CI: 1.81-9.70).

CONCLUSIONS

We found that elevated TGI was associated with both IR markers in a sample of euthyroid adults without T2DM and with a normal BMI. The simplicity of the TGI calculation makes it the first-choice alternative when the hyperinsulinemic-euglycemic clamp or HOMA-IR are not available.

High waist-to-hip ratio levels are associated with insulin resistance markers in normal-weight women

AIM

To assess the association between high waist-to-hip ratio (WHR) levels and insulin resistance (IR) or hyperinsulinemia after oral glucose tolerance test (OGTT) in a sample of normal-weight women.

METHODS

We conducted an analytical cross-sectional study in euthyroid non-diabetic women, who attended the outpatient service of a private clinic in Lima-Peru from 2012 to 2016. Participants were divided in two groups according to the presence or absence of high WHR levels, IR or hyperinsulinemia after OGTT. We considered WHR values > 0.85 as high levels. IR was defined as a Homeostasis Model Assessment (HOMA-IR) value > 2.39 and hyperinsulinemia after OGTT as a serum insulin value ≥ 80μU/mL after 120 min of 75-g glucose intake. We elaborated crude and adjusted Poisson generalized linear models to evaluate the association between high WHR levels and IR or hyperinsulinemia after OGTT and reported the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI).

RESULTS

We analyzed the data of 248 euthyroid, non-diabetic and normal-weight women. The prevalence of high WHR levels was 68.9% (n = 171) while the prevalence of IR and hyperinsulinemia after OGTT was 25% (n = 62) and 15.3% (n = 38), respectively. WHR values were positively correlated with HOMA-IR (r = 0.307; p < 0.001) and serum insulin after OGTT (r = 0.260; p < 0.001). In the adjusted model, high WHR levels were associated with both IR (aPR = 2.63; 95%CI: 1.39-5.01) and hyperinsulinemia after OGTT (aPR = 2.35; 95%CI: 1.03-5.38).

CONCLUSION

High WHR levels were associated with both IR markers used in our study, appearing to be a useful anthropometric indicator to assess IR in euthyroid normal-weight women without type 2 diabetes mellitus.

High triglycerides to HDL-cholesterol ratio is associated with insulin resistance in normal-weight healthy adults

AIM

To evaluate the association between high triglyceride/HDL-cholesterol (TG/HDL-C) ratio and insulin resistance (IR) or hyperinsulinemia after oral glucose tolerance test (OGTT) in normal-weight healthy adults.

METHODS

We carried out an analytical cross-sectional study in euthyroid non-diabetic adults, who attended the outpatient service of a private clinic in Lima-Peru from 2012 to 2016. Participants were divided in two groups according to the presence or absence of high TG/HDL-C ratio, IR or hyperinsulinemia after OGTT. TG/HDL-C ratio values ≥ 3 were considered as high. IR was defined as a Homeostasis Model Assessment (HOMA-IR) value ≥ 2.28 and hyperinsulinemia after OGTT as a serum insulin value ≥ 80μU/mL after 120 min of 75-g glucose intake. We elaborated crude and adjusted Poisson generalized linear models to evaluate the association between high TG/HDL-C ratio and IR or hyperinsulinemia after OGTT and reported the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI).

RESULTS

We analyzed the data of 118 individuals. Prevalence of high TG/HDL-C ratio was 17.8% (n = 21) while the prevalence of IR and hyperinsulinemia after OGTT was 24.6% (n = 29) and 17.0% (n = 20), respectively. TG/HDL-C-ratio values were positively correlated with HOMA-IR (r = 0.498; p < 0.01) and serum insulin after OGTT (r = 0.326; p < 0.001). In the adjusted model, high TG/HDL-C ratio was associated with both IR (aPR = 3.16; 95%CI: 1.80-5.77) and hyperinsulinemia after OGTT (aPR = 2.36; 95%CI: 1.20-4.63).

CONCLUSIONS

High TG/HDL-C ratio was associated with both IR markers used in our study, appearing to be a clinically useful tool to assess IR in euthyroid normal-weight adults without type 2 diabetes mellitus.

Association between serum vitamin B12 levels and metabolic syndrome in a euthyroid population

AIMS

To determine the association between serum levels of vitamin B12 and metabolic syndrome (MetS) in a population of euthyroid adults.

MATERIALS AND METHODS

We carried out an analytical cross-sectional study in euthyroid adults of both sexes, who attended the outpatient service of a private clinic in Lima-Peru during the 2012-2016 period. Participants were divided into tertiles (low, intermediate and high) according to their serum vitamin B12 values. MetS was defined when three or more metabolic criteria were met by the participants. We elaborated crude and adjusted Poisson regression models to evaluate the association between the serum vitamin B12 tertiles and the presence of MetS. The reported association measure was the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI).

RESULTS

We analyzed 346 participants, the average age was 38.3 ± 10.8 (SD) years, 117 (33.8%) were males, the serum vitamin B12 median was 364.1 (IQR: 274.2-473.4) pmol/L and the prevalence of MetS was 30.1% (n = 104). In the crude Poisson regression model, we found an association between the serum vitamin B12 tertiles and the presence of MetS, with marginal significance. The association gained statistical significance in the adjusted model by potential confounders; and compared with the low serum vitamin B12 tertile, the prevalence of MetS was 36% lower (aPR = 0.64; 95%CI: 0.43-0.96) among the high tertile group.

CONCLUSION

Euthyroid participants with elevated levels of serum vitamin B12 showed a lower prevalence of MetS compared to those who had low levels of this marker.

Association between free thyroid hormones values and the lipid profile in middle-aged women with chronic symptoms

AIMS

To determine the association between the thyroid hormones(FT3, FT4 and TSH) and the lipid profile markers(HDL-c, LDL-c and triglycerides) values in middle-aged women with no metabolic disorders and recurrent chronic symptomatology.

MATERIALS AND METHODS

We carried out an analytical cross-sectional study in euthyroid women with recurrent chronic symptoms of at least six months with no apparent diagnosis who attended the endocrinological gynaecology outpatient service of a private clinic in Lima-Peru during 2012-2014. Participants who met the eligibility criteria were evaluated according to their thyroid hormones(FT3, FT4 and TSH) and lipid profile markers(HDL-c, LDL-c and triglycerides) values. We elaborated univariate/multivariate linear regression models to evaluate the association between the thyroid markers and the lipid profile levels. The reported association measure was the beta coefficient(β) with its respective p-value.

RESULTS

We analyzed 211 participants, the average age was 44.9 ± 14.0(SD) years, the FT3 and FT4 mean levels were 3.2 ± 0.4 pg/mL and 1.2 ± 0.2 ng/dL respectively, while the TSH median was 2.8(IQR:1.9-4.0) μU/mL. The mean or median levels of LDL-c, HDL-c and triglycerides were of 137.5 ± 37.9 mg/dL, 54.0 ± 15.0 mg/dL and 118.5(IQR:79.5-169.5) mg/dL respectively. In the multivariate linear regression model between the FT3 and LDL-c levels, we found that for each increase in a FT3 unit, the LDL-c values decreased on average 30.85 mg/dL(p < 0.01). We found no statistically significant associations in the other multivariate models of linear regression, among the other thyroid hormones and lipid markers.

CONCLUSION

We found an inverse association between the FT3 and LDL-c values in women with chronic gynaecological symptoms.

High free triiodothyronine and free-triiodothyronine-to-free-thyroxine ratio levels are associated with metabolic syndrome in a euthyroid population

AIMS

To determine the association between free triiodothyronine (FT3), free thyroxine (FT4) and free-triiodothyronine-to-free-thyroxine ratio (FT3/FT4) levels and Metabolic Syndrome (MetS).

MATERIALS AND METHODS

We carried out an analytical cross-sectional study in euthyroid adults of both sexes, who attended the outpatient service of a private clinic in Lima-Peru during the 2014-2016 period. Participants were divided into tertiles (low, intermediate and high) according to their FT3, FT4, and FT3/FT4 ratio values. MetS was defined when three or more metabolic criteria were met by the participants. ROC curves were constructed, and Youden's Index were used to identify the optimal cut-points of each thyroid marker. We elaborated crude/adjusted Poisson regression models to evaluate the association between the thyroid markers and the presence of MetS. The reported association measure was the prevalence ratio (PR) with their respective 95% confidence intervals (95% CI).

RESULTS

We analyzed 245 participants, the average age was 38.5 ± 10.3 years, 29.8% were males, and the prevalence of MetS was 31%. In the adjusted Poisson regression models, the prevalence of MetS was higher among the high FT3 tertile compared to the low tertile (aPR = 2.01; 95% CI: 1.22-3.34). The prevalence of MetS was higher among the intermediate FT3/FT4 ratio tertile and the high FT3/FT4 ratio tertile compared to the low tertile, (aPR = 1.78; 95% CI: 1.02-3.10) and (aPR = 2.80; 95% CI: 1.67-4.72); respectively. The highest areas under the curve (AUC) were found for FT3 and FT3/FT4 ratio with areas of 0.654 (95% CI: 0.58-0.73) and 0.649 (95% CI: 0.57-0.72); respectively.

CONCLUSION

Elevated levels of FT3 and FT3/FT4 ratio were associated with MetS in a euthyroid population.