Editorial

1270 www.thelancet.com Vol 383 April 12, 2014

For more on tinnitus see Seminar Lancet 2013;

382: 160007

Although the deleterious health e ects of air pollution have received welcome attention over the past few years, noise pollution has been neglected by comparison. Part of the problem has been lack of knowledge. However, understanding of the molecular mechanisms behind the loss of auditory sensory cells and of the non-auditory public health e ects of noise has been increasing. In a Review in todays Lancet, Mathias Basner and colleagues describe what is known.

Many people adapt to noise, which can occur in the workplace (eg, industrial settings), in social situations (eg, bars), or in the wider environment (eg, road, rail, and air transport). But the extent that people habituate to noise pollution di ers and is rarely complete. Chronic and high-level exposure can lead to negative health outcomes.

Noise-induced hearing loss can be caused by a one-time exposure (eg, gun re) or by long-term exposure to sound pressure levels higher than 7585 dB(A) (A-weighting accounts for the relative loudness perceived by the human ear). WHO estimates that 10% of the worlds population are exposed to sound pressure levels than could potentially

cause noise-induced hearing loss. Such loss is the most common occupational disability in the USA. Implementation of occupational hearing safety legislation is varied worldwide and better adherence will help prevent hearing loss as well as other auditory problems such as tinnitus.

The non-auditory health e ects of noise include annoyance and sleep disturbance. Several studies have also shown that noise pollution can increase the prevalence of cardiovascular disease and mortality in highly noise-exposed groups. Environmental noise exposure can also negatively a ect childrens learning outcomes and cognitive performance. WHO estimates that this type of noise pollution causes the loss of 45 000 disability-adjusted life-years every year for children aged 719 years in high-income western European countries.

Although drugs to protect against noise-induced hearing loss are being pursu ed, they are at least a decade away from becoming a reality. Prevention is therefore the option. Hearing protection and noise control are important areas of public health that deserve far greater recognition. The Lancet

Sound advice for public health

A new direction for hepatitis CIn a week in which London hosts the International Liver Congress (April 913), publication of the rst WHO Guidelines for the Screening, Care and Treatment of Persons with Hepatitis C Infection brings hepatitis C virus (HCV) into the limelight. It is estimated that 185 million people globally are infected with HCV causing 499 000 deaths annually. More than 90% of people with HCV can be cured. These recommendations create a new framework for policy makers, government o cials, health workers, and patients. The emphasis of the guidelines is on low-income and middle-income countries that have disproportionately high rates of HCV, but implementation should be global.

The guidelines recommend population-wide HCV serology testing for all groups with a history of high HCV rates, and for those with increased exposure through behaviour and other risk factors. Nucleic acid testing is recommended after a positive HCV result, to detect HCV RNA before treatment. For people infected with HCV, alcohol assessment is the rst stage of care. For those with moderate to high alcohol intake, behavioural

support and intervention should be o ered to reduce alcohol consumption. Liver brosis and cirrhosis should also be assessed with the aspartate aminotransferase to platelet ratio index or FIB4 tests. Assessment for antiviral treatment should be undertaken for all people infected with HCV. Many new drugs for treatment are in development, and several emerging compounds are due to be licensed imminently. But it is too early for the guidelines to recommend combinations.

The cost and pricing of drugs is contentious. Critics have singled out Gileads Sovaldi (sofosbuvir), at US$84 000 for a 12 week course, as una ordable for most of the 32 million people infected with HCV in the USA. By contrast, a 48 week course of pegylated-interferon and ribavirin treatment in Egypt costs $2000. Government agencies and health-care providers need to work together with drug companies on new licensing agreements to make sure that treatment is within reach of all, so that people living with HCV are properly screened, cared for, and treated. The Lancet

For the WHO guidelines see http://www.who.int/hiv/pub/

hepatitis/hepctreatment guidelinespub/en/

For the Global Burden of Disease Study 2010 see http://

www.thelancet.com/themed/global-burden-of-disease

See Review page 1325

Ram

on A

ndra

de 3

DCie

ncia

/Scie

nce

Phot

o Li

brar

y Gr

ange

r Woo

tz/B

lend

Imag

es/C

orbi

s