Lung health and heart rate variability changes in salt workers

India is the third largest salt producing country in the World, with a global annual production of 230 million tonnes. Large number of salt workers get employed in these salt milling plants risking their life from the effects of salt. Recent foreign evidences reported that these salt workers are exposed to aerosol salt particles that disturb their lung and cardiovascular autonomic control.

To compare the status of lung health, cardiovascular autonomic control and biochemical changes in a group of salt industry workers with that of the age-matched normal subjects.

Volunteers of both sexes (25-35 years) were divided into Group I (n=10) controls and Group II (n=10) non-brine salt workers in salt milling plants. From fasting blood sample, complete blood count, plasma electrolyte and lipid profile estimation were done. After resting for 15min, blood pressure and lead II ECG were recorded. Spirometry was done using RMS Helios spirometer. Data collected were later analysed using GraphPad Prism 5.0 with statistical significance set at p<0.05.

Blood pressure recorded showed a slight elevation in the subjects than that in the controls. Significant rise of plasma sodium (141.9±0.4, 138.7±1.0, p<0.008) and chloride (113.9±1.3, 107.7±1.4, p<0.005). Spirometric tests showed mild obstructive airway disease in the subjects with FEV1 and FEV1/FVC significantly lower than the controls (81.11±3.8, 92.0±3.3, p<0.049), (37.4±4.0, 112.8±1.7, p<0.0001), FEF25-75% (123.3±5.6, 101.0±5.6, p<0.01). Heart rate variability parameters also showed statistically significant variation.

Exposure to salt aerosols by the workers in the salt industry has shown a little or no impact on the respiratory system, however there are changes in the blood and cardiovascular system, which need to be further studied to understand the long-term influences of salt in this population.