Lack of Association between Poor Glycemic Control in T2DM and Subclinical Hypothyroidism

The impact of diabetes and subclinical hypothyroidism association with coronary artery calcium: results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Objective

We aimed to analyze the association of diabetes and subclinical hypothyroidism with subclinical atherosclerosis measured by coronary artery calcium (CAC) in the baseline of the ELSA-Brasil study.

Materials and methods

CAC was measured using a 64-detector computed tomographic scanner. The association of CAC > 0 was presented as an odds ratio (OR) and 95% confidence intervals (95%CI) in logistic models and as β (95%CI) in linear models after multivariable adjustment for confounders.

Results

We analyzed 3,809 participants (mean-age (SD) 50.5 (8.8); 51.7% women). In the main analysis, we did not find an association of diabetes and subclinical hypothyroidism with CAC. However, in stratified analysis according to age strata, we found no significative interaction terms, an important heterogeneity between the groups, with the younger age strata showing an association of the group with both diseases and CAC > 0 (OR 7.16; 95%CI, 1.14; 44.89) with a wide but significative 95%CI, suggesting that the smaller number of participants in the younger group may influence the results. Our findings also showed an association of CAC > 0 and log (CAC+1) with diabetes in logistic (OR, 1.31; 95%CI, 1.05-1.63) and linear models (β, 0.24, 0.16, 0.40), respectively. Diabetes was independently associated with CAC > 0 in linear models.

Discussion

In conclusion, our results showed a great heterogeneity in stratified analysis based on age in the younger age strata. Although we found no significant interaction factors, the smaller sample size for the analysis may influence the negative findings.

The association of diabetes, subclinical hypothyroidism and carotid intima-media thickness: results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brazil)

INTRODUCTION

The association of diabetes with subclinical thyroid diseases may increase the risk of cardiovascular diseases. We analyzed the association of subclinical hypothyroidism, diabetes, and both diseases with carotid Intima-Media Thickness (cIMT) as a surrogate maker for early cardiovascular disease in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

METHODS

Cross-sectional analysis with data from the 3^rd visit (2017‒2019). Linear regression models were used to evaluate the association of subclinical hypothyroidism, diabetes and of both diseases with a cIMT presented as Beta (95% Confidence Interval ‒ 95% CI) without adjustment, with adjustment for sociodemographic variables (Model 1) and multivariable adjustment (Model 1 more cardiovascular risk factors). We also used logistic regression models to analyze the Odds Ratio (OR) and 95% CI for the association of both diseases using cIMT > P75%.

RESULTS

After the exclusion of patients with previous cardiovascular disease, 5,077 participants with no diseases, 1578 with diabetes, 662 with subclinical hypothyroidism, and 234 with both diseases were included in the analysis. Linear regression models showed an association of cIMT with only diabetes (β = 0.019; 95% CI 0.012 to 0.027; p < 0.0001) and subclinical hypothyroidism more diabetes (β = 0.03; 95% CI 0.010‒0.047, p < 0.0001). The logistic regression model reported an association between diabetes and CIMT higher than P75% (OR = 1.49, 95% CI 1.30‒1.71). No interaction between diabetes and subclinical hypothyroidism was detected using cIMT respectively as a continuous (p = 0.29) or as a categorical variable (p = 0.92).

DISCUSSION

Diabetes was associated with higher cIMT values. However, no additive effect of subclinical hypothyroidism associated with diabetes over cIMT was detected.

Relation between Uric Acid Levels and Subclinical Hypothyroidism in Diabetic Patients

BACKGROUND AND AIM

Subclinical hypothyroidism (SCH) is frequently seen in diabetic patients. Elevated levels of uric acid (UA) were also reported in diabetic patients. No study assessed the relation between SCH and UA levels in diabetic patients. We aimed to evaluate this relation and the association of both conditions with other clinical and laboratory parameters in diabetic patients.

SUBJECTS AND METHODS

This cross-sectional study included 100 T2DM patients in addition to 50 age and sex matched healthy controls. Diabetic patients comprised 50 patients with SCH and 50 euthyroid patients. All participants were subjected to careful history taking, thorough clinical examination and standard laboratory work up. The performed investigations included fasting and postprandial blood sugar, fasting insulin levels, HbA1c levels, thyroid hormones (FT3, FT4 and TSH), renal profile and serum UA.

RESULTS

Comparison between the studied groups regarding serum UA levels revealed significantly higher levels in the diabetic group (5.4 ± 1.9 versus 4.2 ± 1.0 mg/dl, p<0.001). SCH + DM patients had significantly higher UA levels in comparison to DM group (6.1 ± 1.8 versus 4.8 ± 1.7 mg/dl, p<0.001) and control group (6.1 ± 1.8 versus 4.2 ± 1.0 mg/dl, p<0.001). SCH + DM patients had significantly higher HbA1c levels (8.9 ± 1.1 versus 7.6 ± 1.3 %, p<0.001), HOMA-IR (3.9 ± 0.8 versus 2.8 ± 1.0, p<0.001) and UA levels (6.1 ± 1.8 versus 4.8 ± 1.7, p<0.001). Correlation analysis identified a significant direct correlation between serum UA and HOMA-IR in DM + SCH patients (r=0.4,p=0.004). In univariate analysis, presence of SCH [OR (95% CI): 2.57 (1.07-6.15), p=0.034] and nephropathy [OR (95% CI): 4.57 (1.77-11.8), p=0.002] were significant predictors of higher (upper tertile) UA in the studied patients. However, in multivariate analysis, only nephropathy [OR (95% CI): 4.25 (1.62-11.17), p=0.003] continued to be significant while SCH showed a marginal trend [OR (95% CI): 0.43 (0.17-1.08), p=0.073].

CONCLUSIONS

The present study suggests an association between SCH and increased UA levels in diabetic patients.