Age and sex related alterations of serum lipids and relative distribution of individual lipid in HDL, VLDL and LDL were studied on 230 subjects of healthy adults (114 males, 116 females) including 26 octogenarian and 13 nonagenarian in Kochi district. The lipids in serum lipoprotein separated by electrophoresis on agarose were determined by use of scanning densitometer after visualization by enzymatic reagents.
The levels of total cholesterol (TCh), total phospholipid (TPL) and total triglyceride (TTG) showed continuous increase with aging, to a peak in the seventies, then decreased by eighties and nineties. Each concentration of the lipids in nineties was 168.8, 174.5 and 96.2mg/dl respectively. In every age group, the levels of TCh and TPL in females were slightly higher than those in males, but TTG level of females was lower than that of males.
HDL-C (%) of TCh did not alter in each age group, and showed 24.6% in eighties and 25.4% in nineties. LDL-C (%) increased after seventies, showed 67.6% at eighties and 68.5% at nineties. VLDL-C (%) decreased after eighties. In males, HDL-C (%) increased with aging and showed the highest value of 28.9% at nineties, but in females, it declined gradually with advancing age.
HDL-PL (%) of TPL gradually decreased to seventies, then increased after eighties and beyond. LDL-PL (%) increased gradually with aging and VLDL-PL (%) decreased after eighties.
HDL-TG (%) of TTG showed no marked change in every age group. VLDL-TG (%) remained almost 60% between the ages from thirties to seventies, but markedly decreased to 38.8% at eighties and 23.1% at nineties, while LDL-TG (%) was nearly 30% to seventies and increased to 50.0% in eighties and 67.3% in nineties.
The amount of lipids in HDL was almost constant in each age group. The content of lipids in VLDL and LDL increased to a peak in seventies and then decreased at eighties and beyond, but the amount of lipids in LDL after eighties was still higher than those of under sixties.
In conclusion, total concentration of each lipid, relative distribution of individual lipid in HDL, VLDL and LDL and lipid composition of each lipoprotein fractions significantly changed with aging, particularly altered at eighties and nineties largely due to the marked change in triglyceride concentration. From our observation of crosssectional changes with age in serum lipoproteins, the age of seventies may be a turning point of the biochemical aging process.
