One of the largest studies into the risk factors for age-related hearing loss has found that smoking and body mass index (BMI) are two of the main culprits whereas alcohol has a protective effect, but high levels of work noise remain the biggest risk.
The study led by Dr. Erik Fransen, of the University of Antwerp in Belgium, found that smoking, being over-weight and occupational noise are risk factors in the most common type of hearing loss.
However moderate alcohol consumption, one glass of wine, spirit or beer, was found to have a protective effect but the effect of heavy drinking was not considered.
The study involved nine audiological centers in seven countries and involved a total of 4,083 people between 53 and 67 years old.
Participants filled out a questionnaire on their exposure to potential environmental risk factors and their medical history and their hearing was also tested - the data was then analyzed for associations between potential risk factors and hearing loss.
While the effects of smoking and alcohol consumption have been studied before, previous research results were not found to be conclusive but this latest research offers the most convincing evidence to date.
Dr. Fransen says hearing loss is proportional to how much you smoke and your body mass index (BMI) and starts getting worse once you have smoked regularly for more than one year.
Dr. Fransen says unlike some parts of the body, once damage has occurred, there is no prospect of recovery.
Smoking and obesity can harm the hearing in the way they damage other organs - by disrupting the flow of blood around the body, and as Dr. Fransen suggests creating a lack of oxygen and a failure to remove toxic waste from the ear.
This latest research also confirms that exposure to noise contributes to hearing loss in later life - according to the World Health Organization (WHO) exposure to excessive noise is the major avoidable cause of permanent hearing loss worldwide.
Fransen and his colleagues conclude though hearing loss has always been considered an inevitable part of ageing, more and more studies seem to indicate this is not necessarily true as a healthy lifestyle can be beneficial for hearing conservation at higher ages.
The study is published online in Springer's Journal of the Association for Research in Otolaryngology (JARO) and was presented this week at the International Society of Audiology Congress in Hong Kong.
Another research project involving more than 5,000 civil servants also found that smoking in middle age was linked to a decline in memory and verbal reasoning ability.
This study was conducted jointly between the University of Paris and University College London.