Figure 1. Relative Risk Nomogram.

Family hx = % of parents and siblings with a history of dementia; RR = Relative risk; AVLT PR SS = Auditory Verbal Learning Test percent retention scaled score. In order to use the nomogram, a straight line should be drawn connecting the desired age and family history proportion (percent of first degree relatives with a positive history) to the intermediate relative risk estimate. Then a second straight line should be drawn from the intermediate relative risk estimate through the AVLT percent retention scaled score to the final relative risk estimate. The final relative risk estimate represents relative risk of developing cognitive impairment over the future five year period compared to the reference patient described in text.

Calculation of the 95% Confidence Interval for the final relative risk ratio of the nomogram is as follows: 95% Confidence Interval = exp (score ± 1.96 x std) score = [age (.097083) + % family history (.010761) + AVLT SS (-.164692)] - 5.634305 std = square root of var var = [(age famhx AVLT SS) - (75 0 10)] x E1 x E2 E1 = algebraic matrix as follows:

$$\left[\begin{array}{ccc}\hfill .00016834& \hfill .00000209& \hfill -0.00001142\\ \hfill .00000209& \hfill .00002680& \hfill -0.00000581\\ \hfill -.00001142& \hfill -.00000581& \hfill 0.00114522\end{array}\right]$$

E2 = algebraic matrix as follows:

$$\left[\begin{array}{c}\mathrm{age}-75\hfill \\ \text{family history}-0\hfill \\ \text{AVLT scaled score - 10}\hfill \end{array}\right]$$