THYROID DISORDERS IN PATIENTS WITH MELASMA

Background and objectives: Melasma, a common pigmentary disorder is major cosmetic concernamong patients. The aim of our study was to determine the frequency of thyroid disorders in melasma cases. Methodology: Thisobservational study was conducted at RIHS DermatologyDepartment Islamabad from 20thFeb–20thMay 2021. Diagnosed cases of melasma (>18 years) were selected via consecutive sampling technique.Themedically/surgically treated cases of thyroid, melasma secondary to other dermatosis, organ failure, Addisons disease, pregnancy and subclinical thyroid disorders were excluded. After detailed clinical evaluation, thyroid status documented on the basis of thyroid function tests. Data analysed by SPSS with significant p-value<0.05. Results: Amongst 150 melasma cases 117(78%) females and 33(22%) males, mean age was 35.45+9.68 years. 36(24%) were euthyroid, 109(72.7%) hypothyroid and 5(3.3%) hyperthyroid. Mean TSH was 1.82+18.64 mIU/L. 75(50%) had epidermal, 38(25.3%) dermal and 37(24.7%) mixed melasma, hypothyroidism frequent in all three types. Dermal melasma frequent in 41-50 years, epidermal in 20-30 years and mixed in 31-40 years. Thyroid status had significant association with age group, hypothyroidism more common in 41-50 years and Euthyroid in <30 years. Obesity observed in 55(36.7%) having significant association with hypothyroidism. Mandibular melasma observed in 88%, malar 77.3%, centro-facial18.7% and neck melasma 9.3%. Conclusion: Thyroid disorders, particularly hypothyroidism is frequent among melasma cases.Authors recommend to screen all melasma cases regardless of age or gender for thyroid disorders, in particular obese cases. The diagnosis and management of thyroid disease in melasma cases may improve quality of life, prevent thyroid related complications and improve outcome of melasma treatment.

Abstract P490: Subclinical Thyroid Disorders and Triglyceride-rich Lipoprotein Particles Concentration. ELSA-Brasil Cohort

Background: Subclinical thyroid disorders have been associated with atherosclerosis and increased cardiovascular risk. Subclinical hypothyroidism is associated with higher levels of total cholesterol and Low-density lipoprotein cholesterol as well as high levels of triglycerides and low levels of high-density lipoprotein cholesterol. Triglyceride-rich Lipoprotein Particles concentration (TRLP) have recently emerged as a causal factor for atherogenesis. Aim: To evaluate the relationship between Subclinical Hypothyroidism and Subclinical Hyperthyroidism and Triglyceride-rich Lipoprotein Particles. Methods: Participants from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) were classified according to the baseline thyroid function as Subclinical Hypothyroidism, Euthyroidism, and Subclinical Hyperthyroidism. Conventional lipid concentrations (total, HDL cholesterol, and triglycerides were determined by a nonprecipitated colorimetric method. The TRLP subfractions were analyzed through Nuclear Magnetic Resonance spectroscopy. To examine the association between TRLP subfractions and thyroid function, we conducted a multivariate linear regression model adjusted for demographic characteristics (race, gender, and educational level), body-mass index, diabetes, smoking status, and alcoholic beverages intake. Results: Of 3,550 individuals free of cardiovascular or thyroid diseases (54%, women; median age 51 years; 51% White, and 53% with at least college education) 92%of them were euthyroid, 6.8% had subclinical hypothyroidism, and 1.2% had subclinical hyperthyroidism. No differences were observed concern the levels of total, HDL, and LDL-cholesterol, but triglycerides were higher for people with Subclinical Hypothyroidism. After adjustment by the covariates described above and using subjects with normal thyroid function as the reference group, for people with Subclinical hypothyroidism a difference of means ( and 95% Confidence Interval) for Total TRLP levels (in ng/L) obtained was 0.06 (-0.00 to 0.13), and for the TRLP subfractions elevated for Very-Small [0.16 (0.02 to 0.28)] and Very-Large [0.21 (0.05 to 0.36)], and similar values for Small [-0.01 (-0.13 to 0.12)]; Medium [0.05 (-0.08 to 0.17)] and Large [0.16 (-0.06 to 0.38)] subfractions. In Subclinical Hyperthyroidism, there was a reduction in Total TRLP (-0.24 (-0.40 - -0.08)), seemingly driven by reduced Very Small-TRLP (0.23 (-0.11 - 0.57). Conclusion: This study suggests that subclinical hypothyroidism is associated with high levels of Very-Small and Very-Large TRLP, which are related to an unfavorable atherogenic profile. Subclinical Hyperthyroidism is associated with low concentrations of Very-Small TRLP.