Table 1.

Risk factors for hearing loss

	Risk	Evidence	Comments
Personal factors
Age	+++	***	High age is strongly related to hearing loss
Male sex	++	***	Men lose more hearing than women
Hereditary conditions	++	***	Explains a great part of the individual variation in hearing loss
Socioeconomic factors	+	**	Low social class, income and education related to reduced hearing
Ethnicity	+	**	White Caucasians lose more hearing than Afro-Americans
Health factors
Ear disease	++	***
Cardiovascular disease	+	*
Hypertension	+	*
Diabetes	+	*
Smoking	+	*
Cholesterol	?	*
Triglycerides	?	*
Occupations
Industrial workers	++	**	Depending on noise exposure level and use of protection
Shipyard workers	++	**
Construction workers	++	**
Offshore workers	+	*
Professional divers	+	**
Fire fighters	+	**
Military workers	++	**
Civil aviation workers	+	**
Railway workers	+	**
Farmers	++	**
Musicians	+	**
Kindergarten employees	+	*	Probably too low noise exposure
Noise exposure
Continuous noise	+/+++	***	High risk with unprotected noise exposure L ex, 8h > 90 dB. Low risk <85 dB
Impulse noise	+++	***
Gunfire	++	***
Leisure-time noise	+	**	Probably of minor importance at a group level
Hearing protection	−	**
Other exposures
Vibration	+	*	Vibration may increase the NIHL
Chemicals	+	*	Styrene, CS2, toluene, lead, mercury and CO
Medication	+/+++	***	Cisplatin, aminoglycosides

Risk assessment: +++, severe risk; ++, moderate risk; +, low risk; ?, uncertain risk; −, reduced risk

Level of evidence: ***, high; **, medium; *, low