High atherogenic index of plasma in subclinical hypothyroidism: Implications in assessment of cardiovascular disease risk

THE RELATIONSHIP BETWEEN TSH LEVELS, THYROID AUTOANTIBODIES AND ATHEROGENIC INDEX OF PLASMA, AST TO PLATELET RATIO INDEX SCORE, AND FIBROSIS 4 INDEX IN PATIENTS WITH HYPOTHYROIDISM

Context

Thyroid hormones have metabolic effects such as relationship between hypothyroidism and atherosclerosis.

Objective

Evaluate the effects of hypothyroidism on Non-Alcoholic Fatty Liver Disease and atherosclerosis by using AIP, APRI score, FIB-4 indices.

Material and Methods

1370 patients with hypothyroidism who applied to the Endocrinology and Metabolism outpatient clinic between 01.01.2017-30.12.2021 were included the study. Pregnants, patients with a history of thyroid carcinoma, cardiovascular and liver diseases were excluded. TSH, fT4, Anti TPO, Anti TG, thrombocyte, ALT, AST, HDL, Triglyceride values of the cases were analyzed and atherogenic index of plasma (AIP), AST to Platelet Ratio Index (APRI) and Fibrosis-4 (FIB-4) indices were calculated.

Results

1170 (85.4%) of the cases were female.The age of those who had high risk of AIP was found to be higher than those with low and moderate risk (p=0.001; p=0.003; p<0.01). The ages of those who had low-risk FIB-4 Index were found to be lower than those with moderate risk and high risk (p=0.001; p=0.001; p<0.01). A positive relationship was detected between APRI and FIB-4 (r=0.681; p=0.001; p<0.01).AIP increased as TSH increased in hypothyroid patients. No significant correlations were detected between TSH, APRI, and the FIB-4 Index. No significant differences were detected between AIP, APRI, FIB-4, and thyroid autoantibodies.

Conclusion

In hypothyroid patients, the AIP index increased with age and the increase in TSH. A strong relationship was detected between AIP and TSH . For this reason, we think that keeping TSH within the normal range with regular follow-ups and treatment in patients with hypothyroidism will reduce the risk of atherosclerosis.

Atherogenic index of plasma and coronary artery disease: A systematic review

Various studies suggest that the atherogenic index of plasma (AIP) is associated with the risk of coronary artery disease (CAD) in different clinical scenarios. This review aimed to synthesize evidence of the association between AIP values and CAD. A literature search was carried out on four databases, namely, PubMed, Scopus, Web of Science, and Ovid-Medline. A handsearch was performed on preprint repositories (MedRxiv and Research Square). The effect measurements were expressed as odds ratios (OR) with their corresponding 95% confidence intervals (CI). For the quantitative synthesis, we employed a random-effects model. We analyzed 14 articles (with 40,902 participants) from seven different countries. The quantitative analysis revealed that an increase in one unit of AIP was associated with higher odds of developing CAD (OR 2.11; 95% CI 1.65-2.69; P < 0.001; I ² = 98%). We conducted subgroup analyses of Chinese (OR 1.89; 95% CI 1.40-2.56; P < 0.001) and non-Chinese studies (OR 2.51; 95% CI 1.42-4.42; P < 0.001). The sensitivity analysis by risk of bias continued to demonstrate an association, and the heterogeneity remained unchanged (OR 1.75; 95% CI 1.33-2.31; P < 0.001; I ² = 98%). Higher AIP values were associated with higher odds of developing CAD.

Prospective Analysis of Lipid Variations in Hyperthyroid Subjects from Lahore, Pakistan

Perturbations in the actions of T3 and T4 influence the normal metabolic pathways. Responsiveness of lipid biomarkers like LDL-C, HDL-C, TC, TG, Apo-A, and Apo-B after rehabilitation of thyroid profile attaining euthyroid state was determined. A total of 179 age-matched subjects of both genders were recruited for this research. Sixty healthy controls, thirty-four subclinical, fifty overt hyperthyroid, and thirty-five follow-up subjects having 3 months of Carbimazole therapy were enrolled. Biochemical analysis was performed by chemistry analyzer, RIA, and ELISA. One-way ANOVA was applied for the statistical analysis, while significance (P < 0.05) of means was compared by the Student-Newman-Keuls (SNK) test. Pronounced reduction (P < 0.001) of cholesterol in overt as compared to control and subclinical was noticed, whereas marked improvement (P < 0.001) was evidenced in follow-up. Prominent elevation (P < 0.05) of TG in follow-up was evidenced as compared to control. Overt presented marked reduction of HDL-C as compared to subclinical and control (P < 0.01 and P < 0.001), respectively. Pronounced elevation (P < 0.001) of HDL-C was evidenced after treatment. Overt presented reduction of LDL-C as compared to subclinical and control (P < 0.01 and P < 0.05, respectively). The follow-up group demonstrated considerable (P < 0.001) improvement of LDL-C after treatment and elevation (P < 0.05) as compared to control. Overt presented reduction of Apo-B as compared to subclinical and control (P < 0.05 and P < 0.001, respectively). Improvement (P < 0.05) of Apo-B was evidenced in follow-up. Reduction (P < 0.05) of Apo-A in overt as compared to control and elevation (P < 0.05) in follow-up as compared to overt was evidenced. Conclusively, improvement after treatment was evidenced in lipid profile.

CORRELATION BETWEEN SUBCLINICAL HYPOTHYROIDISM AND DYSLIPIDEMIA IN WOMEN IN NORTHEAST CHINA

CONTEXT

It is well known that thyroid hormones are important, being involved in affects the metabolism of carbohydrate, protein, lipids. The relationship between thyroid hormones and lipid metabolism is the focus of recent research.

OBJECTIVE

To investigate the relationship between subclinical hypothyroidism and lipid metabolism in women.

DESIGN

We conducted an epidemiological survey of thyroid diseases among women in Northeast China from September 2014 to December 2014.

SUBJECTS AND METHODS

A total of 1397 women underwent physical examinations and laboratory tests for thyroid function and lipid metabolism.

RESULTS

We found that the detection rate of subclinical hypothyroidism was 13.03%. Patients with subclinical hypothyroidism showed significantly higher levels of triglyceride (1.69±1.9 vs. 1.45±1.4) and the risk of hyper triglyceridemia in women with thyroid stimulating hormone (TSH) levels ≥10mIU/L was 4.96-fold higher compared with that in the normal population (P<0.01).

CONCLUSION

Disorders of lipid metabolism in women with subclinical hypothyroidism show a direct correlation with the level of TSH, and the risk of hyper triglyceridemia is significantly increased when the level of TSH ≥10mIU/L.

ATHEROGENIC INDICES IN THE ASSESSMENT OF CARDIOVASCULAR DISEASE RISK IN CHILDREN WITH OBESITY AND SUBCLINICAL HYPOTHYROIDISM

Background

The frequency of subclinical hypothyroidism (SH) in patients with obesity is increased compared with the normal population. However, data on the risk of cardiovascular disease (CVD) in patients with SH are still scarce. Lipid parameters are strong predictors of early CVD. We aimed to investigate the role of lipid indices in predicting CVD risk compared to conventional lipid components.

Methods

A total of 220 euthyroid obese children (EU) and 90 obese children with SH were included in the study. All data were collected from hospital files. Lipid indices were evaluated. Atherogenic index of plasma (AIP), cardiac risk ratio (CRR) and atherogenic coefficient (AC) were calculated. AIP>0.24, CRR>5 ve AC>3 were considered as cardiovascular risk criteria.

Results

The presence of SH increased the risk of higher AIP and the risk of CRR, compared to euthyroid obese children.

Conclusion

Subclinical hypothyroidism in obese children may cause dislipidemia carrying a high cardiovascular disease risk.

Subclinical Hypothyroidism (SH) and Atherogenic Index of Plasma (AIP) in Women: A Case-Control Study From a Tertiary Care Hospital in South India

Introduction

Subclinical hypothyroidism (SH) is defined as an increase in serum-thyroid stimulating hormone (S-TSH) above the normal level with free triiodothyronine (T4) and free thyroxine (T3) within the normal range. It is more common in females. The association between SH and dyslipidemia is unclear. There are many controversial studies regarding the same. This is the single largest study of Atherogenic index of plasma (AIP) in SH among women from our country. Our aim is to study the lipid profile and AIP in SH patients. We will also study the correlation between AIP and S-TSH levels in SH patients.

Materials and methods

It was a retrospective study conducted in a tertiary care center. A total of 97 females with SH were taken as cases and 86 normal females were taken as euthyroid (ET) controls. They were matched for demographic characteristics. T3, T4, S-TSH, total cholesterol, S-triglycerides (S-TG), high-density lipoprotein - cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and AIP were compared between the two groups. Spearman’s correlation between TSH and AIP was studied in the SH group. Mann-Whitney U test was performed.

Results

The TG, HDL, AIP levels were significantly different between both groups. TG, AIP was higher in the SH group compared to the ET group (p value of TG= 0.01, p value of AIP <0.0001). HDL was lower in the ET group compared to the SH group (p value <0.0001). AIP showed a significant positive correlation with S-TSH levels in the SH group. (r value=0.72, p value=<0.001).

Conclusion

It is important to regularly monitor SH patients for dyslipidemia, in order to start early therapy with levothyroxine/statins. Emphasis should be laid on lifestyle changes such as diet and exercise from the time of diagnosis. Community level education and awareness should be encouraged. Also, AIP is a better parameter to assess cardiovascular risk in SH patients than a conventional lipid profile.

Associations between the levels of thyroid hormones and lipid/lipoprotein levels: Data from National Health and Nutrition Examination Survey 2007-2012

Data from National Health and Nutrition Examination Survey for the years 2007-2012 were used to investigate associations between thyroid hormones and lipid/lipoprotein levels for a representative sample of general US population aged ≥20 years. There were no statistically significant differences for adjusted high density lipoprotein levels among thyroid function groups, namely, subclinical hyperthyroid (SCHPR), clinical hyperthyroid (CHPR), euthyroid (EU), clinical hypothyroid (CHYP), and subclinical hypothyroid (SCHYP). For the general US population, positive associations for thyroid stimulating hormones (TSH) and negative associations for free thyroxine (FT4) levels were observed with total cholesterol (TC, p<0.01), apolipoprotein B (APOB, p<0.01), and triglycerides (TG, p<0.01). A 10% increase in TC levels was associated with a 2% increase in TSH levels and 0.8% decrease in FT4 levels. Among EU subjects, TG levels were positively correlated with TSH (p<0.01) and negatively correlated with FT4 (p<0.01). For CHYP subjects, TG levels were negatively correlated with TSH (p<0.01). For iodine deficient participants, low density lipoprotein levels (LDL) were lower for SCHPR when compared with EU or CHYP (p<0.01). TC levels were usually lower for SCHPR than for EU, CHYP, and SCHYP but the differences were not necessarily statistically significant. For all participants and for iodine replete participants, TG levels for SCHPR were lower than for CHYP (p<0.01). CHYP and SCHYP had higher levels of TG than other three thyroid function groups. APOB levels were lower for SCHPR than for EU and CHYP for all participants and for iodine replete participants (p<0.01). There was a positive association between the four quartiles of thyroid stimulating hormones and TC, TG, and APOB. There was also an inverse association between the quartiles of free thyroxine levels and LDL, TC, TG, and APOB.