Abstract
BACKGROUND: Good physical capability is an important part of healthy biological ageing. Several factors influencing physical capability have previously been reported. Long-term reports on physical capability and the onset of clinical disorders and chronic diseases are lacking. Decrease in physical capacity has been shown to increase mortality. This study focuses on the prevalence of chronic diseases. The primary objective of the study was to reveal the association between physical capability and morbidity. Secondary objectives included the validity of self-reported physical capability and the association between baseline physical capability and mortality. METHODS: The OSTPRE (Kuopio Osteoporosis Risk Factor and Prevention Study) prospective cohort involved all women aged 47-56 years residing in the Kuopio Province, Finland in 1989. Follow-up questionnaires were mailed at five-year intervals. Physical capability questions were first presented in 1994. From these women, we included only completely physically capable subjects at our baseline, in 1994. Physical capability was evaluated with five scale self-reports at baseline and in 2014 as follows: completely physically capable, able to walk but not run, can walk up to 1000 m, can walk up to 100 m and temporarily severely incapable. The prevalences of selected chronic diseases, with a minimum prevalence of 10% in 2014, were compared with the change in self-reported physical capability. Additionally, associations between long-term mortality and baseline physical capability of the whole 1994 study population sample were examined with logistic regression. The correlation of self-reported physical capability with functional tests was studied cross-sectionally at the baseline for a random subsample. RESULTS: Our study population consisted of 6219 Finnish women with a mean baseline age of 57.0 years. Self-reported physical capability showed statistically significant correlation with functional tests. Cardiovascular diseases and musculoskeletal disorders show the greatest correlation with decrease of physical capability. Prevalence of hypertension increased from 48.7% in the full physical capability group to 74.5% in the "able to walk up to 100 metres" group (p < 0.001). Rheumatoid arthritis showed a similar increase from 2.1 to 7.4% between these groups. Higher baseline body mass index (BMI) decreases long-term capability (P < 0.001). Women reporting full physical capability at baseline had a mortality rate of 15.1%, in comparison to 48.5% in women within the "able to walk up to 100 m" group (p = 0.357). Mortality increased steadily with worsening baseline physical capability. CONCLUSIONS: The results of this study show that chronic diseases, particularly cardiovascular and musculoskeletal disorders, correlate with faster degradation of physical capability in the elderly. Similar results are shown for increase in BMI. We also demonstrate that the risk of mortality over a 20-year period is higher in individuals with poor baseline physical capability.