Increasing physiological and psychological impairments with age does not mean that ageing is equivalent with illness, diseases or dependency. In fact, earlier studies could not explore that a type or the pathogenesis of diseases is only caused by the ageing process (Steinhagen-Thiessen & Borchelt 1996). Brody and Schneider (1986) distinguished between age-dependent and age-related diseases. Age-dependent diseases are involved in the ageing process and cause the exponentially increasing mortality risk with advanced age, for instance heart and cerebrovascular diseases. Age-related diseases like musculoskeletal diseases are relating temporally with age and have no causal effect on the increasing individual.
