Specifically the authors evaluated 796 participants (avg 65yo) in the Singapore Longitudinal Aging Study. After taking into account just about everything, high homocysteine & low folate were linked to decrease in physical and functional ability, as measured by Performance Oriented Mobility Assessment and self-reports of instrumental activities of daily living.
However, we need to assess the link between homocysteine, folate & physical/functional decline since all the conclusions drawn suggest a decline but no proof as to which caused the other, eg did an increase homocysteine & folate decrease cause the decline in function or did the decline in physical function cause the increase in homocysteine & decrease in folate? As an observational study, this can only suggest hypotheses for us to research but is clearly no proof of cause & effect. Something to mull over . . .