Noise induced hypertension and prehypertension in Pakistan
The present study investigates the relationship of different sound levels with hypertension and prehypertension in Pakistani population. A cross sectional study was conducted to determine the prevalence of hypertension and prehypertension due to exposure of sound level <80 dBA (A weighted sound pressure level), 81-94 dBA and >95 dBA in November 11, 2005 to January 30, 2007. Sites were selected with stable sound ranges according to the above mentioned criteria. After selecting sampling sites, workers living in that area for at least 8 hours per day were categorized on the basis of blood pressure in groups called as normotensive, prehypertensive and hypertensive. Persons with diabetes, chronic bacterial or viral infections, alcohol addiction, kidney problems were excluded from the study. For getting homogenous groups, age range of 30-50 years was selected. Out of 566 samples, 90 excluded samples were consisted of 8% diabetic patients, 5% hepatitis C patients, 3% hepatitis B patients and 0% AIDS patients. Out of 476 participants, 389 samples were found with age 40±10 years. High noise increased the risks of hypertension (Odds ratio: 4.41; Confidence interval: 2.123-9,196) and prehypertension (Odds ratio: 3,809; Confidence Interval: 1,804-8,042) as compared to the normal sound level. However increased chances of hypertension (Odds ratio: 2,271; Confidence interval: 1,043-4,946) and prehypertension (Odds ratio: 3,028; Confidence Interval: 1,440-6,367) were observed on median noise exposure also. These findings suggest that sound level more than 81 dBA increases the chances for development of hypertension and prehypertension in Pakistani population.