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      name:  <unnamed>
       log:  C:\MyDocs\MPH\LectureNotes\ClassDoLogData\Poisson\8.9.Framingham.log
  log type:  text
 opened on:  22 Jan 2010, 15:55:09

. *  8.9.Framingham.log 
. *
. *  Convert Framingham survival data setset to person-year data for 
. *  Poisson regression analysis.
. *
. set more on

. use  C:\WDDtext\2.20.Framingham.dta, clear

. *
. *  Convert bmi, scl and dbp into categorical variables that subdivide
. *  the data set into quartiles for each of these variables.
. *
. centile bmi dbp scl, centile(25,50,75)

                                                       -- Binom. Interp. --
    Variable |     Obs  Percentile      Centile        [95% Conf. Interval]
-------------+-------------------------------------------------------------
         bmi |    4690         25          22.8            22.7          23
             |                 50          25.2            25.1    25.36161
             |                 75            28            27.9        28.1
         dbp |    4699         25            74              74          74
             |                 50            80              80          82
             |                 75            90              90          90
         scl |    4666         25           197             196         199
             |                 50           225             222         225
             |                 75           255             252         256

. generate bmi_gr = recode(bmi, 22.8, 25.2, 28, 29)
(9 missing values generated)

. generate dbp_gr = recode(dbp, 74,80,90,91)

. generate scl_gr = recode(scl, 197, 225, 255, 256)
(33 missing values generated)

. *
. *  Calculate years of follow-up for each patient.
. *  Round to nearest year for censored patients.
. *  Round up to next year when patients exit with CHD
. *
. generate years = int(followup/365.25) + 1 if chdfate
(3226 missing values generated)

. replace years = round(followup/365.25, 1) if ~chdfate
(3226 real changes made)

. table sex dbp_gr, contents(sum years) row col

--------------------------------------------------
          |                 dbp_gr                
      Sex |     74      80      90      91   Total
----------+---------------------------------------
      Men |  10663   10405   12795    8825   42688
    Women |  21176   14680   15348   10569   61773
          | 
    Total |  31839   25085   28143   19394  104461
--------------------------------------------------

. table sex dbp_gr, contents(sum chdfate) row col

---------------------------------------------
          |              dbp_gr              
      Sex |    74     80     90     91  Total
----------+----------------------------------
      Men |   161    194    222    246    823
    Women |   128    136    182    204    650
          | 
    Total |   289    330    404    450   1473
---------------------------------------------

. generate age_in = age

. generate exit = age + years

. summarize age_in exit

    Variable |       Obs        Mean    Std. Dev.       Min        Max
-------------+--------------------------------------------------------
      age_in |      4699    46.04107    8.504363         30         68
        exit |      4699    68.27155    10.09031         36         94

. more
--Break--
r(1);

end of do-file

--Break--
r(1);

. centile bmi dbp scl, centile(25 50 75)

                                                       -- Binom. Interp. --
    Variable |     Obs  Percentile      Centile        [95% Conf. Interval]
-------------+-------------------------------------------------------------
         bmi |    4690         25          22.8            22.7          23
             |                 50          25.2            25.1    25.36161
             |                 75            28            27.9        28.1
         dbp |    4699         25            74              74          74
             |                 50            80              80          82
             |                 75            90              90          90
         scl |    4666         25           197             196         199
             |                 50           225             222         225
             |                 75           255             252         256

. table sex dbp_gr, contents(sum years ) row col

--------------------------------------------------
          |                 dbp_gr                
      Sex |     74      80      90      91   Total
----------+---------------------------------------
      Men |  10663   10405   12795    8825   42688
    Women |  21176   14680   15348   10569   61773
          | 
    Total |  31839   25085   28143   19394  104461
--------------------------------------------------

. exit, clear