Lack of Association Between Subclinical Hypothyroidism and Carotid-Femoral Pulse Wave Velocity in a Cross-Sectional Analysis of the ELSA-Brasil

Background: There is little available data on carotid-femoral pulse wave velocity (cf-PWV) in subjects with subclinical hypothyroidism (SCH). We aimed to analyze the association between SCH and cf-PWV using baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Methods: We included subjects with normal thyroid function (thyrotropin (TSH): 0.4-4.0 mIU/l, and normal free thyroxine (FT4: 0.8-1.9ng/dl) and SCH (TSH > 4.0 mIU/l and normal FT4) evaluated for cf-PWV in a cross-sectional analysis. We excluded individuals using medications that interfere in thyroid function, antihypertensives, or diuretics, and subjects with chronic kidney disease or previous cardiovascular disease. Generalized linear and logistic regression models evaluated cf-PWV as a dependent variable and SCH as an independent variable, adjusted for cardiovascular risk factors.

Results: Of 8,341 subjects (52.3% women), 7,878 (94.4%) were euthyroid and 463 (5.6%) showed SCH. The median age was 50 years (interquartile range: 44-56). The groups differed by age, sex, body mass index, glomerular filtration rate, and C-reactive protein. SCH was not associated with cf-PWV in the full-adjusted linear model (β = -0.039; P = 0.562) and with cf-PWV >75^th percentile in the full-adjusted logistic model (odds ratio = 0.94; 95% confidence interval = 0.72-1.22).

Conclusion: In a large sample, SCH was not associated with increased cf-PWV.