Figure 3: Development of disability with age in seniors after age 68 subjects with low (0), moderate (1) and high (2-3) risk factors in 1986. The University of Pennsylvania Study, over 21 years, has followed seniors from age 68 in three strata: Low Risk, with no baseline risk factors of smoking, obesity, or lack of exercise; Moderate Risk, where one risk factor was present at baseline, and High Risk, where two or three risk factors were present at baseline. The lower line represents low risk subjects, the middle line moderate risk subjects, and the top line high risk subjects. Differences are major whether looked at by vertical differences, or by longitudinal ones (postponement). When contrasted with mortality rates, Compression of Morbidity by health risk factor status is demonstrated across these groups.