Tenth categories of total and HDL cholesterol fail to independently predict death risk in middle-aged Turkish adults

OBJECTIVE
The aim of this study was to delineate in detail the longitudinal association of total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) levels with overall mortality in middle-aged participants of the biennial Turkish Adult Risk Factor study.

METHODS
Baseline lipid variables were analyzed in sex-specific deciles. A baseline age of 45 to 84 years as an inclusion criterion led to the enrollment of 2121 men and women. Cox regression analyses were performed.

RESULTS
Deaths were recorded in 237 and 306 women and men, respectively, during a mean 8.85±4.4 years of follow-up. After adjustment for age, smoking status, lipid-lowering and antihypertensive drug usage, prevalent diabetes, and coronary heart disease, and using the lowest decile as referent, neither TC (p trend=0.94 and 0.96, respectively), nor HDL-C categories (p trend=0.20 and 0.31, respectively) were significantly predictive of mortality in either gender. TC deciles exhibited a gender difference insofar as hazard ratios in females tended to be reciprocal to those in males in deciles 2 through 5.

CONCLUSION
The findings on TC deciles may be attributed to a comparatively higher death rate in the female (compared with male) bottom decile, reflecting the autoimmune process-induced elevated risk in the lowest decile. Observations on HDL-C confirmed presumed pro-inflammatory conversion in levels >50 mg/dL. These results have important clinical implications.