Hearing as a predictor of falls and postural balance in older female twins.
BACKGROUND
The purpose of the present study was to examine, first, whether hearing acuity predicts falls and whether the potential association is explained by postural balance and, second, to examine whether shared genetic or environmental effects underlie these associations.


METHODS
Hearing was measured using a clinical audiometer as a part of the Finnish Twin Study on Aging in 103 monozygotic and 114 dizygotic female twin pairs aged 63-76 years. Postural balance was indicated as a center of pressure (COP) movement in semi-tandem stance, and participants filled in a fall-calendar daily for an average of 345 days after the baseline.


RESULTS
Mean hearing acuity (better ear hearing threshold level at 0.5-4 kHz) was 21 dB (standard deviation [SD] 12). Means of the COP velocity moment for the best to the poorest hearing quartiles increased linearly from 40.7 mm(2)/s (SD 24.4) to 52.8 mm(2)/s (SD 32.0) (p value for the trend = .003). Altogether 199 participants reported 437 falls. Age-adjusted incidence rate ratios (IRRs) for falls, with the best hearing quartile as a reference, were 1.2 (95% confidence interval [CI] = 0.4-3.8) in the second, 4.1 (95% CI = 1.1-15.6) in the third, and 3.4 (95% CI = 1.0-11.4) in the poorest hearing quartiles. Adjustment for COP velocity moment decreased IRRs markedly. Twin analyses showed that the association between hearing acuity and postural balance was not explained by genetic factors in common for these traits.


CONCLUSIONS
People with poor hearing acuity have a higher risk for falls, which is partially explained by their poorer postural control. Auditory information about environment may be important for safe mobility.
Viljanen
Anne
A
Department of Health Sciences, Finnish Centre for Interdisciplinary Gerontology, Finland. anne.viljanen@sport.jyu.fi
Kaprio
Jaakko
J
Pyykkö
Ilmari
I
Sorri
Martti
M
Pajala
Satu
S
Kauppinen
Markku
M
Koskenvuo
Markku
M
Rantanen
Taina
T
D000058:Accidental Falls / Q000706:statistics & numerical data*; D000368:Aged; D000375:Aging / Q000235:genetics / Q000502:physiology*; D001299:Audiometry; D016001:Confidence Intervals; D005260:Female; D005387:Finland; D006309:Hearing / Q000235:genetics; D034381:Hearing Loss / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic