Aim: On the basis of data from occupational medical examinations carried out during a 12-year period (1991—2002) for employees in the construction industry, associations between prevalence of cardiovascular risk factors or metabolic syndrome and hearing loss were to be analysed with respect to noise exposure. Method: Population: 81,412 males, 18—65 years old, audiometric examination (air conduction) without unilateral hearing loss, analysed on the basis of average hearing loss. Statistics: CHAID analysis of the data in 10-year age groups. Influencing factors: workplace noise exposure, systolic/diastolic blood pressure, obesity, selected metabolic parameters. Results: The decision trees for the 5 age groups are differently structured. 26—35 years: hearing loss is influenced most by BMI. In persons of normal weight, noise exposure higher than 90 dB(A) is the second most important influencing factor. Overweight people have higher levels of hearing loss if HDL or cholesterol levels are pathological. In the higher age groups, noise exposure is the factor which best predicts hearing loss but the decision trees are then branched differently for the different groups. 36—45 years: If noise exposure exceeds 90 dB(A) persons with elevated diastolic blood pressure sustain a significantly higher hearing loss than normotensives. If noise exposure is between 81 and 89 dB(A) hearing loss is influenced by BMI, several metabolic parameters and systolic blood pressure in that order. For noise exposure up to 80 dB(A) hearing loss is associated with the level of uric acid. 46—55 years: Employees exposed to noise levels of 81— 89 dB(A) with pathological levels of cholesterol and uric acid sustain most hearing loss. Conclusions: CHAID algorithms have the advantage of robustness and clarity. Factors influencing hearing loss — such as physiological and metabolic parameters — prove to be of different importance in different age groups. The earlier development of hearing loss in lower age groups is determined largely by metabolic status. This could yield a basis for preventive strategies.