------------------------------------------------------------------------------------------------- log: C:\MyDocs\MPH\Text\SecondEdition\WebDoFiles\5.11.1.EsophagealCa.log log type: text opened on: 30 Dec 2007, 20:57:59 . * 5.11.1.EsophagealCa.log . * . * Estimate age-adjusted risk of esophageal cancer due to dose of alcohol. . * . use C:\WDDtext\5.5.EsophagealCa.dta, clear . * . * Show frequency tables of effect of dose of alcohol on esophageal cancer. . * . tabulate cancer alcohol [freq=patients] , column +-------------------+ | Key | |-------------------| | frequency | | column percentage | +-------------------+ Esophageal | Alcohol (g/day) Cancer | 0-39 40-79 80-119 >= 120 | Total -----------+--------------------------------------------+---------- No | 386 280 87 22 | 775 | 93.01 78.87 63.04 32.84 | 79.49 -----------+--------------------------------------------+---------- Yes | 29 75 51 45 | 200 | 6.99 21.13 36.96 67.16 | 20.51 -----------+--------------------------------------------+---------- Total | 415 355 138 67 | 975 | 100.00 100.00 100.00 100.00 | 100.00 . * . * Analyze the Ille-et-Vilaine data using logistic regression model (5.24) . * . xi: logistic cancer i.age i.alcohol [freq=patients] i.age _Iage_1-6 (naturally coded; _Iage_1 omitted) i.alcohol _Ialcohol_1-4 (naturally coded; _Ialcohol_1 omitted) Logistic regression Number of obs = 975 LR chi2(8) = 262.07 Prob > chi2 = 0.0000 Log likelihood = -363.70808 Pseudo R2 = 0.2649 ------------------------------------------------------------------------------ cancer | Odds Ratio Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- _Iage_2 | 5.109602 5.518316 1.51 0.131 .6153163 42.43026 _Iage_3 | 30.74859 31.9451 3.30 0.001 4.013298 235.5858 _Iage_4 | 51.59663 53.38175 3.81 0.000 6.791573 391.9876 _Iage_5 | 78.00528 81.22778 4.18 0.000 10.13347 600.4678 _Iage_6 | 83.44844 91.07367 4.05 0.000 9.827359 708.5975 _Ialcohol_2 | 4.196747 1.027304 5.86 0.000 2.597472 6.780704 _Ialcohol_3 | 7.441782 2.065952 7.23 0.000 4.318873 12.82282 _Ialcohol_4 | 39.64689 14.92059 9.78 0.000 18.9614 82.8987 ------------------------------------------------------------------------------ . vce Covariance matrix of coefficients of logistic model e(V) | _Iage_2 _Iage_3 _Iage_4 _Iage_5 _Iage_6 _Ialcoho~2 -------------+------------------------------------------------------------------------ _Iage_2 | 1.1663772 _Iage_3 | 1.0404166 1.0793391 _Iage_4 | 1.0403396 1.045788 1.070392 _Iage_5 | 1.0408953 1.0474958 1.0477758 1.0843291 _Iage_6 | 1.0400501 1.0459703 1.0467592 1.0503511 1.1911028 _Ialcohol_2 | -.00076529 .00003712 .00211802 .00644926 .01458804 .05992005 _Ialcohol_3 | -.00393971 -.00649123 -.00370223 .00110691 .01501861 .04098138 _Ialcohol_4 | .00975405 .02784946 .03011624 .04080362 .04726457 .04199017 _cons | -1.0399109 -1.0467994 -1.048726 -1.0548871 -1.0617639 -.0436303 e(V) | _Ialcoho~3 _Ialcoho~4 _cons -------------+------------------------------------ _Ialcohol_3 | .07707024 _Ialcohol_4 | .0422443 .14162954 _cons | -.03881739 -.07358771 1.085457 . lincom _Ialcohol_4 - _Ialcohol_3 ( 1) - _Ialcohol_3 + _Ialcohol_4 = 0 ------------------------------------------------------------------------------ cancer | Odds Ratio Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- (1) | 5.327606 1.95176 4.57 0.000 2.598339 10.92367 ------------------------------------------------------------------------------ . end of do-file . exit, clear