# Sib-pair Command: lifetable

 Class Analysis and data manipulation command Name lifetable Arguments ( | 0) [ []] [cov ] [time].

Prints the life table for the quantitative trait end, where censor is the binary outcome trait, which is affected when end represents the date at which the individual first expressed the trait. The quantitative trait start represents the date of entry into the study of the individual. If start is the digit "0", then the start of the observation period is taken to be zero for all individuals (this option would usually be used with the time option, see below). The cohort stratum width is the bin width used to divide up the entry dates into the study. The period stratum width is the bin width used to divide up person years of followup.

A test for the presence of age-period-cohort interactions is calculated. One categorical covariate can be used to stratify the data and test for association.

The time modifier causes the start and end values to be treated as a continuous measure (eg age), rather than a Julian date.

Example:

```>> #
>> # Analyse the nickel data from Breslow and Day
>> # Statistical Methods in Cancer Research
>> # Volume II - The design and analysis of cohort studies
>> # IARC Scientific Publications No. 82
>> # 1987.
>> # Appendix VIII
>> #
>> set loc icd7 qua
>> set loc exposure qua
>> set loc dob qua
>> set loc jobstart qua
>> set loc start qua
>> set loc stop qua
>> run
>> set loc lungca aff . Lung cancer deaths (ICD7=162 or 163)
>> lungca=(icd7==162 or icd7==163)
>> set loc EXP1 aff . exposure 0-
>> set loc EXP2 aff . exposure 0.5-4.0
>> set loc EXP3 aff . exposure 4.5-8.0
>> set loc EXP4 aff . exposure 8.5-12.0
>> set loc EXP5 aff . exposure 12.5-
>> EXP1 = (exposure == 0.0)
>> EXP2 = (exposure >= 0.5 and exposure <= 4.0)
>> EXP3 = (exposure >= 4.5 and exposure <= 8.0)
>> EXP4 = (exposure >= 8.5 and exposure <= 12.0)
>> EXP5 = (exposure >= 12.5)
>> set loc EXP qua
>> EXP = EXP1 + 2*EXP2 + 3*EXP3 + 4*EXP4 + 5*EXP5
>> lifetable start stop lungca 100 10 time cov EXP

------------------------------------------------
Life table analysis for "lungca"
------------------------------------------------
"start" is start of observation period.
"stop" is end of observation period.
"EXP" is covariate.

Variable     Range                Strata    Stratum width
--------  ---------------------  --------    -------------
Start      23.7 --       70.7         1         100.0
Stop       33.7 --       97.8         5          10.0
Followed    0.4 --       48.7         5          10.0

Covariate levels ( 5)
1.00000    290
2.00000    225
3.00000    103
4.00000     41
5.00000     20

Covariate =    1.00000
Entered        Time Stratum    Riskset  Events   Person-time   Incidence
------------- -------------  ---------  ------  ------------  ----------
23.7 -         0.0 -         290       5         2720.  0.00183807
10.0 -         251      14         2277.  0.00614800
20.0 -         197      14         1619.  0.00864656
30.0 -         125       5          878.  0.00569790
40.0 -          58       4          308.  0.01300049
--------- -------  ------------  ----------
290      42         7802.  0.00538342
Covariate =    2.00000
Entered        Time Stratum    Riskset  Events   Person-time   Incidence
------------- -------------  ---------  ------  ------------  ----------
23.7 -         0.0 -         225      10         2080.  0.00480870
10.0 -         182      23         1504.  0.01529531
20.0 -         115      16          855.  0.01870698
30.0 -          58       1          373.  0.00268244
40.0 -          21       0          113.  0.00000000
--------- -------  ------------  ----------
225      50         4924.  0.01015333
Covariate =    3.00000
Entered        Time Stratum    Riskset  Events   Person-time   Incidence
------------- -------------  ---------  ------  ------------  ----------
23.7 -         0.0 -         103       9          909.  0.00989936
10.0 -          75      14          518.  0.02701423
20.0 -          32       2          202.  0.00988718
30.0 -          12       0           87.  0.00000000
40.0 -           6       2           27.  0.07356187
--------- -------  ------------  ----------
103      27         1744.  0.01548113
Covariate =    4.00000
Entered        Time Stratum    Riskset  Events   Person-time   Incidence
------------- -------------  ---------  ------  ------------  ----------
23.7 -         0.0 -          41       5          314.  0.01593775
10.0 -          24       5          194.  0.02577686
20.0 -          16       1           85.  0.01171428
30.0 -           3       1           15.  0.06793155
40.0 -           1       0            0.  0.00000000
--------- -------  ------------  ----------
41      12          608.  0.01973394
Covariate =    5.00000
Entered        Time Stratum    Riskset  Events   Person-time   Incidence
------------- -------------  ---------  ------  ------------  ----------
23.7 -         0.0 -          20       2          160.  0.01248709
10.0 -          12       4           73.  0.05491850
20.0 -           5       0           34.  0.00000000
30.0 -           1       0            3.  0.00000000
40.0 -           0       0            0.  0.00000000
--------- -------  ------------  ----------
20       6          270.  0.02224876

No interaction model LRTS =    22.0
Degrees of freedom =    16
Nominal P-value =     0.1429

No effect of covariate    =    33.3
Degrees of freedom =     4
Nominal P-value =     0.0000

```

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