Association between measures of morbidity and locomotor disability: diagnosis alone is not enough.

This study examines the relationship between different measures of morbidity and locomotor disability in early old age. Data from a community health survey of 858 people aged approximately 58 years living in the West of Scotland were examined for associations between morbidity and locomotor disability. The relationships between presence of chronic conditions, severity and pain from chronic conditions, reported symptoms, self-reported health and locomotor disability were examined using logistic regression. After adjusting for several measures of morbidity, sex and social class, frequency of pain from cardiovascular conditions (OR 5.49, 95%CI 2.64-11.39), frequency of pain from musculo-skeletal conditions (OR 2.79, 95% CI 1.76-4.44) and self-assessed health compared to other people the same age (OR 2.76, 95% CI 1.64-4.65) were the most important predictors of locomotor disability. Inclusion of frequency of pain greatly increased the strength of associations of chronic conditions with locomotor disability. Simple measures of morbidity may mask important associations between particular conditions and locomotor disability. In particular the findings suggest that for surveys of the correlates of locomotor disability, collateral information on the frequency of pain associated with chronic conditions and self-reported health relative to other people of the same age provides additional explanatory power.