Total serum cholesterol levels and mortality risk as a function of age. A report based on the Framingham data.
Level 3 - non-randomized controlled study
Prospective observational cohort study evaluating survival across age strata.
What was done
Researchers analyzed biennial examination data collected between 1948 and 1980 for 5,209 men and women in the Framingham Heart Study. Cox proportional hazards regression models evaluated survival after ages 40, 50, 60, 70, and 80 years to assess associations between total serum cholesterol, lipoprotein subfractions (LDL and HDL measured from 1968 to 1973), and all-cause, coronary heart disease (CHD), and non-CHD mortality.
What was found
The association between total cholesterol and all-cause mortality was positive at age 40, negligible at ages 50 to 70, and negative at age 80 years. CHD mortality was significantly positively associated with cholesterol at ages 40, 50, and 60, but attenuated to non-significantly positive at age 70 and non-significantly negative at age 80. Non-CHD mortality was significantly negatively related to cholesterol at ages 50 years and above. The inverse association with mortality in the oldest age group was driven by lower LDL levels rather than protective HDL levels. The abstract does not provide exact numeric hazard ratios, risk estimates, or confidence intervals.
Why it matters
This study demonstrated that the relationship between serum cholesterol and mortality attenuates and may reverse with advancing age. It cautions against automatically extrapolating lipid-lowering trial results from middle-aged populations to older adults without dedicated randomized trial evidence.
Limits
As an observational cohort, residual confounding and reverse causation remain potential biases, even though modified analyses attempted to account for pre-existing severe illness. Subfraction analyses (HDL and LDL) were only available for a subset of the follow-up period (measured 1968-1973), and the abstract provides no specific point estimates or confidence intervals.
Cited by
- supports In the Framingham Heart Study, after age 50, mortality increased as total cholesterol dropped.