Annemarie wrote:
What I am actually trying to do is loop through a list of 6500 patients.
Each patient has an exposure_time i.e. the period of time in days during
which they are at risk for a fracture. For each age category (see
below), I want to add up a cumulative time at risk. So for ages 51-75, I
want to come out with a number that contains the total exposure_time for
all patient in that age category.
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If you want to distribute the time at risk to the appropriate age groups
you might want to study [ST] stset, [ST] stsplit, and possibly [R]
poisson. That is: If you observe a person from age 74 to age 77, the
time at risk is two years in the 51-75 agegroup and one year in the 76+
agegroup.
Whether this is relevant depends on the aims of the study; if it is not,
ignore it.
Svend
__________________________________________
Svend Juul
Institut for Folkesundhed, Afdeling for Epidemiologi
(Institute of Public Health, Department of Epidemiology)
Vennelyst Boulevard 6
DK-8000 Aarhus C, Denmark
Phone: +45 8942 6090
Home: +45 8693 7796
Email: [email protected]
__________________________________________
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