THYROID DYSFUNCTION AND SERUM LIPIDS: A COMMUNITY BASED STUDY

Abstract

Background

In community clinics across India, it is common to meet adults who come with vague tiredness, weight changes, or concerns about rising cholesterol, only to discover during routine testing that thyroid function has shifted subtly. These hormonal fluctuations often remain unnoticed for months, and by the time individuals seek evaluation, both thyroid indices and lipid markers may already be moving in parallel. Because fasting lipid profile and basic thyroid assays are inexpensive and widely available in district-level laboratories, understanding how thyroid dysfunction shapes lipid patterns may help clinicians intervene earlier.

Aim

To examine how different categories of thyroid dysfunction relate to fasting serum lipid levels among adults living in the community.

Methods

A cross-sectional study was carried out among 200 adults from urban and peri-urban localities. All participants underwent thyroid function testing and fasting lipid analysis. Individuals were classified into euthyroid, subclinical hypothyroid, overt hypothyroid, subclinical hyperthyroid, and overt hyperthyroid groups. Lipid parameters were compared across categories, and the predictive behaviour of TSH and FT4 for dyslipidemia was explored using ROC analysis.

Results

Shifts in thyroid status were accompanied by clear changes in lipid parameters. Mean total cholesterol and LDL-C rose steadily from the euthyroid group (TC 172 ± 28 mg/dL; LDL-C 108 ± 24 mg/dL) to overt hypothyroidism (TC 228 ± 35 mg/dL; LDL-C 148 ± 31 mg/dL). Triglycerides showed a similar pattern, climbing from 136 ± 41 mg/dL to 192 ± 56 mg/dL. HDL-C decreased modestly across hypothyroid categories but remained higher among hyperthyroid adults. Differences across groups were statistically significant for all major lipid markers (ANOVA, p < 0.0001). Subclinical hypothyroidism already showed a dyslipidemic pattern, though less pronounced than overt disease. ROC analysis demonstrated that TSH had good discriminatory performance for predicting elevated LDL-C (AUC ≈ 0.85), while FT4 showed moderate predictive utility.

Conclusion

Even mild thyroid dysfunction was associated with meaningful shifts in lipid levels, and the gradient became more prominent in overt hypothyroidism. Because both tests are routine in general practice, these findings highlight the usefulness of integrating thyroid evaluation into lipid screening pathways to detect cardiometabolic risk at an earlier stage.