HEART RATE VARIABILITY OF HYPERTENSIVE FORMER WORKERS EXPOSED TO ASBESTOS IN BRAZIL

K. Pithon¹, T. Brito¹, L.G. Brito¹, C. Jesus¹, J.C. Milan-Mattos², A.C. Farche², A.C. Takahashi², A.M. Catai²

¹State University of Southwest Bahia, Health Department, Jequié, Brazil, ²Federal University of São Carlos, Physiotherapy, São Carlos, Brazil

Background: Asbestos has become one of the leading causes of death among occupational workers in the world. The pulmonary diseases associated with asbestos contamination are well known and have shown a latency time that ranges between ten to sixty years. However, the association between asbestos exposition and cardiovascular disease is less reported.

Purpose: The aim of this study was to analyze the heart rate variability (HRV) of former mine workers exposed to asbestos.

Methods: From 1930 until 1967, asbestos mining was done in the city of Bom Jesus da Serra, in the state of Bahia, Brazil. 28 participants were divided into group one (G1) with 14 ex-workers (12 men and two woman) of a mine, exposed to asbestos and with controlled arterial hypertension and group two (G2) with 14 healthy participants, without hypertension, who had similar sex and age profiles to the G1. The heart rate variability was collected with a heart rate monitor (Polar H10) during 10 minutes in supine position. The data was collected in a noise-free and temperature-controlled environment from 9 to 12 A.M. All participants were guided to refrain from drinking alcohol and coffee for one day before and in the day of the HRV test. Tobacco smoking was also prohibited 30 min before the test. Series of 256 points was analyzed in time and frequency domains. The time domain was composed of mean and variance of R-R intervals in milliseconds. The frequency domain, by spectral analysis, was composed by indexes of low frequency power (LF) and high-frequency power (HF) in both absolute and normalized units (nu), that representing cardiac sympathetic and parasympathetic modulation, respectively. The data is expressed in median and interquartile interval (Q3 minus Q1). The data had a non-normality distribution (Shapiro Wilk test). For group analysis, the Mann Whitney test was used. Pvalues <0.05 were considered to be significant.

Results: The median (interquartile interval) age of G1 was 77.5 (11.25) years and G2 was 68.5(11) years (p>0.05); body mass index was 23.69 (4.92) kg.m^-2to G1 and G2: 24.21(3.93) kg.m^-2. LF nu was G1: 33.48(45.05); G2: 72.40(26.76) and HF absolute was G1: 50.11(78.24) and G2: 66.68(60.24). A statistical difference was observed between frequency domain bands: LF absolute (p=0.001), LF nu (p=0.006) and HF nu (p=0.006)) when G1 and G2 were compared.

Conclusions: The asbestos mine former workers with associated hypertension showed adaptative modifications in heart rate variability with higher parasympathetic and smaller sympathetic cardiac modulation when compared to the healthy group.

Implications: The heart rate variability is a simple and easy way to assess the cardiac autonomic control. It could be used as an assessment method to verify the protocols efficiency. On the other hand, asbestos is a rare disease about which there isn’t much information regarding cardiac adaptations to the patient health condition.

Funding acknowledgements: This research was supported by State University of Southwest Bahia, Brazil.

Keywords:
heart rate variability
asbestos
hypertension

Topics:
Cardiorespiratory
Older people

Did this work require ethics approval? Yes

Institution: State University of Southwest Bahia (UESB)

Committee: CEP/UESB

Ethics number: 4046232