Table 1.

Cox Proportional Hazard Regression of Life Span

Group	Parameter Estimate	Hazard Ratio	Lower 95% Confidence Limit	Upper 95% Confidence Limit
CR vs CON	−0.399 (0.241)	0.671	0.418	1.076
MET vs CON	−0.017 (0.040)	0.983	0.908	1.065
PF–MET vs CON	−0.010 (0.035)	0.990	0.926	1.060

Note: CON = control; CR = calorie restriction; MET = metformin; PF–MET = pair fed to metformin.