Risk of high blood pressure in salt workers working near salt milling plants: a cross-sectional and interventional study.
BACKGROUND
Workers working close to salt milling plants may inhale salt particles floating in the air, leading to a rise in plasma sodium, which, in turn, may increase the blood pressure and the risk of hypertension.


METHODS
To test the above hypothesis, occupational health check-up camps were organized near salt manufacturing units and all workers were invited for a free health examination. The workers who worked with dry salt in the vicinity of salt milling plants were defined as "non-brine workers," while those working in brine pans located far away from milling plants were defined as "brine workers." Blood pressure (BP) was measured during each clinical examination. In all, 474 non-brine workers and 284 brine workers were studied.


RESULTS
Mean systolic blood pressure of non-brine workers (122.1 +/- 13.3 mm Hg) was significantly higher than that of brine workers (118.8 +/- 12.8 mm Hg, p < 0.01). Mean diastolic blood pressure of non-brine workers (71.5 +/- 10.4 mm Hg) was significantly higher than that of brine workers (69.7 +/- 9.4 mm Hg, p = 0.02). The prevalence of hypertension was significantly higher in non-brine workers (12.2%) than in brine workers (7.0%, p = 0.02). Nineteen salt workers were monitored while they used face masks and spectacles, for six days. Systolic, as well as diastolic, blood pressure of these workers began declining on the third day and continued to decline on the fourth day, but remained stationary up to the sixth day. The concentration of salt particles in the breathing zone of these workers was 376 mg/m3 air.


CONCLUSIONS
Inhalation of salt particles in non-brine workers may be an occupational cause of increased blood pressure.
Haldiya
Kripa Ram
KR
Desert Medicine Research Centre (ICMR), Jodhpur, 342005, India. haldiyakr@rediffmail.com
Mathur
Murli Lal
ML
Sachdev
Raman
R
Saiyed
Habibulla N
HN
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D007194:India / Q000453:epidemiology; D007221:Industry; D019570:Inhalation Exposure / Q000009:adverse effects* / Q000517:prevention & control; D008297:Male; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure / Q000009:adverse effects* / Q000517:prevention & control; D010808:Physical Examination; D018570:Risk Assessment; D012907:Smoking; D012965:Sodium Chloride / Q000097:blood / Q000633:toxicity*
D012965:Sodium Chloride