Sample Selection, Recruitment, and Participation. The
municipal tax assessment list, containing names of householders
and residents in the city of London, Ontario (2011,
population 366,151), provided the sampling frame. Those
living in institutions, defined as nursing homes or chronic
care facilities, were not eligible. A stratified random sample
was drawn from the population. The strata were defined
by gender and six five-year age groups, starting with age
of 55, and the sampling rate was set to select 35 men and
women in each stratum. Those sampled were sent a letter
inviting their participation, and a follow-up call to recruit
and screen the respondents wasmade. Exclusion criteriawere
those who responded no to the question of their ability to
walk an 80 meter course. Thus, the target population the
noninstitutionalized population aged 55–85 years who selfreported
the ability towalk 80 meters.The university’s human
research review board approved the study, and each subject
signed informed consent.