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<table width="100%" summary="page for infert"><tr><td>infert</td><td align="right">R Documentation</td></tr></table>

<h2>Infertility after Spontaneous and Induced Abortion</h2>

<h3>Description</h3>


<p>This is a matched case-control study dating from before the
availability of conditional logistic regression.
</p>


<h3>Usage</h3>

<pre>infert</pre>


<h3>Format</h3>



<table summary="Rd table">
<tr>
 <td align="right">
    1.  </td><td align="left"> Education  </td><td align="left"> 0 = 0-5  years </td>
</tr>
<tr>
 <td align="right">
        </td><td align="left">            </td><td align="left"> 1 = 6-11 years </td>
</tr>
<tr>
 <td align="right">
        </td><td align="left">            </td><td align="left"> 2 = 12+  years  </td>
</tr>
<tr>
 <td align="right">
    2.  </td><td align="left"> age        </td><td align="left"> age in years of case </td>
</tr>
<tr>
 <td align="right">
    3.  </td><td align="left"> parity     </td><td align="left"> count </td>
</tr>
<tr>
 <td align="right">
    4.  </td><td align="left"> number of prior </td><td align="left"> 0 = 0 </td>
</tr>
<tr>
 <td align="right">
        </td><td align="left"> induced abortions </td><td align="left"> 1 = 1 </td>
</tr>
<tr>
 <td align="right">
        </td><td align="left">            </td><td align="left"> 2 = 2 or more </td>
</tr>
<tr>
 <td align="right">
    5.  </td><td align="left"> case status</td><td align="left"> 1 = case </td>
</tr>
<tr>
 <td align="right">
        </td><td align="left">            </td><td align="left"> 0 = control </td>
</tr>
<tr>
 <td align="right">
    6.  </td><td align="left"> number of prior </td><td align="left"> 0 = 0 </td>
</tr>
<tr>
 <td align="right">
        </td><td align="left"> spontaneous abortions </td><td align="left"> 1 = 1 </td>
</tr>
<tr>
 <td align="right">
        </td><td align="left">            </td><td align="left"> 2 = 2 or more </td>
</tr>
<tr>
 <td align="right">
    7.  </td><td align="left"> matched set number </td><td align="left"> 1-83 </td>
</tr>
<tr>
 <td align="right">
    8.  </td><td align="left"> stratum number </td><td align="left"> 1-63</td>
</tr>

</table>



<h3>Note</h3>


<p>One case with two prior spontaneous abortions and two prior induced
abortions is omitted.
</p>


<h3>Source</h3>


<p>Trichopoulos et al. (1976)
<EM>Br. J. of Obst. and Gynaec.</EM> <B>83</B>, 645&ndash;650.
</p>


<h3>Examples</h3>

<pre>
require(stats)
model1 &lt;- glm(case ~ spontaneous+induced, data=infert,family=binomial())
summary(model1)
## adjusted for other potential confounders:
summary(model2 &lt;- glm(case ~ age+parity+education+spontaneous+induced,
                data=infert,family=binomial()))
## Really should be analysed by conditional logistic regression
## which is in the survival package
if(require(survival)){
  model3 &lt;- clogit(case~spontaneous+induced+strata(stratum),data=infert)
  print(summary(model3))
  detach()# survival (conflicts)
}
</pre>


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