Relationship between heart rate variability and subclinical thyroid disorders of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)
Braz. j. med. biol. res
; 51(11): e7704, 2018. tab, graf
Article
in English
| LILACS
| ID: biblio-951722
Responsible library:
BR1.1
ABSTRACT
The association between subclinical thyroid dysfunctions and autonomic modulation changes has been described by many studies with conflicting results. We aimed to analyze the association between subclinical hyperthyroidism (SCHyper), subclinical hypothyroidism (SCHypo), and heart rate variability (HRV) using the baseline from ELSA-Brasil. SCHyper and SCHypo were classified by use of medication to treat thyroid disorders, thyrotropin levels respectively above and under the reference range, and normal free thyroxine levels. For HRV, the participants underwent 10 min in supine position and the R-R intervals of the final 5 min were selected for analysis. We first used linear regression models to report crude data and then, multivariate adjustment for sociodemographic (age, sex, and race) and cardiovascular risk factors (hypertension, dyslipidemia, diabetes, smoking, body mass index, use of alcohol, and leisure physical activity) using the euthyroid group as reference. From 9270 subjects (median age, 50; interquartile range 44-56), 8623 (93.0%) were classified as euthyroid, 136 (1.5%) as SCHyper, and 511 (5.5%) as SCHypo. Compared to euthyroid subjects, SCHyper participants presented significantly higher heart rate (68.8 vs 66.5 for euthyroidism, P=0.007) and shorter R-R intervals (871.4 vs 901.6, P=0.007). Although SCHyper was associated with lower standard deviation of NN interval (SDNN) (β -0.070; 95% confidence interval (95%CI) -0.014 to -0.009) and low-frequency (LF) (β -0.242, 95%CI -0.426 to -0.058) compared to the euthyroid group, these differences lost significance after multivariate adjustment for confounders. No significant differences were found for HRV in SCHypo. No association was found between HRV and SCHyper or SCHypo compared to euthyroid subjects in this sample of apparently healthy subjects.
Full text:
Available
Collection:
International databases
Database:
LILACS
Main subject:
Thyroid Diseases
/
Heart Rate
Type of study:
Etiology study
/
Observational study
/
Prognostic study
/
Risk factors
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
Country/Region as subject:
South America
/
Brazil
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
2018
Document type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Universidade Federal de Minas Gerais/BR
/
Universidade Federal do Espírito Santo/BR
/
Universidade Federal do Vale do São Francisco/BR
/
Universidade de São Paulo/BR