HDL Level, Age, and Smoking are the Largest Determinants of Mortality Risk in Old People
An interesting epidemiological study here stratifies the contributions of various metrics to mortality in later life, age 70 and older. The authors find that the largest effects arise from HDL level, chronological age, and smoking. The largest single cause of death in our species is atherosclerosis, a progressive malfunction in clearance of cholesterol from blood vessel walls that leads to fatty plaques, narrowed arteries, stroke, and heart attack. HDL particles carry excess cholesterol from blood vessel walls back to the liver for excretion, and - thus over a lifetime - the more HDL in circulation one has, the greater the metabolic dysfunction needed to begin in earnest the development of atherosclerotic plaque.
The Duke Established Populations for Epidemiologic Studies of the Elderly (D-EPESE) is a longitudinal cohort of community-dwelling older adults designed to overcome the above-mentioned limitations. D-EPESE included 1507 participants, aged ≥71 years with biomarker data and 27 years of death data from the time of blood sample acquisition in 1992. This research aimed to identify clinical and molecular biomarkers that predict, and causally affect, longevity, from 186 clinically accessible measures that geriatricians and clinicians can, and frequently obtain in a clinic setting.
We studied the relationships of patient-reported outcomes and questionnaires, and clinically available medical tests with survival status and identified optimal predictors. We chose to explore 2-, 5- and 10-year longevity since these time horizons are clinically relevant for this cohort of mean age 78 years with mean life expectancy of 9.37 years (men) and 10.92 years (women). These time horizons are also relevant for clinical decision-making that considers the benefits and burdens of tests (e.g., colon, breast, and prostate cancer screening), and treatment (stringency of lipid and blood pressure lowering), based on life expectancy.
We identified a relatively small number of putative direct causes of longevity from among 186 clinically accessible variables, with 8 to 15 variables containing the totality of signal for each time horizon. Greater concentrations of small HDL particles, younger age, and fewer pack years of cigarette smoking were the strongest determinants of longevity at 2-, 5- and 10-years, respectively.
This seems interesting, but it is extraordinarily complicated. It would take me at least a day to evaluate this. Hopefully someone will do a youtube breaking this down.