A prospective case-controlled study of 197 men, 50-60 years old, selected at random from a population at risk from hyperlipidaemia to examine the relationship between hyperlipidaemia and sensorineural hearing loss

Abstract

Hyperlipidaemia has been reported as an aetiological factor in sensorineural hearing loss. Reports on this subject have been retrospective, lacked adequate controls, or have been based on a series of cases which may represent incidental findings as hyperlipidaemia is prevalent in the normal population. The published evidence that hyperlipidaemia causes hearing problems is contradictory and warrants further controlled trials: A prospective case-controlled study was conducted of 197 men between 50 and 60 years old selected at random from a population at risk from ischaemic heart disease or hyperlipidaemia. Hearing thresholds, relevant variables and--on two occasions--their fasting cholesterol levels, were recorded. The control subjects were recruited from patients undergoing nasal surgery for either internal or external structural abnormalities. All study and control groups were also compared with the National Study of Hearing (NSH) data. When hearing thresholds were grouped together as 0.5, 1, 2 and 4 kHz, 0.5, 1, 2 kHz or 4, 6 and 8 kHz there were no statistically significant differences except at 4, 6 and 8 kHz in the worse hearing ear where the at risk group had better hearing thresholds, P = 0.0475. However, the differences which existed became reduced across all frequencies when the subgroup with fasting lipids > 6.5 mmol/l was compared with the at risk group as a whole against the NSH data.