Background The association between coronary heart disease (CHD) and social
status has differed among societies in strength and direction. As years of
schooling is a major determinant of socioeconomic status and dyslipidaemia
a major CHD determinant, the purpose of this investigation is to estimate t
he association of years of schooling with plasma lipids and lipoproteins am
ong samples from five countries representing different cultures, socio-poli
tical systems and stages of economic development.
Methods Men and women from Chinese, Polish, Russian, Israeli and US samples
were studied. Years of schooling were analysed both as a multi-category or
dinal variable and divided into two strata: less than the equivalent of hig
h school and greater than or equal to high school equivalence. Pasting plas
ma cholesterol. low density lipoprotein (LDL) cholesterol, high density lip
oprotein (HDL) cholesterol and triglycerides were compared across years of
schooling strata within each country. Lipid levels were computed unadjusted
and then adjusted for age and lipid risk factor variables.
Results Total cholesterol, LDL cholesterol, and triglycerides varied direct
ly with years of schooling in Chinese, Polish and Russian men, and in contr
ast varied inversely with years of schooling among US white men. The HDL ch
olesterol varied inversely with years of schooling for Chinese, Polish, and
Russian men, but varied directly with years of schooling among US white me
n. The lipid differences between men of high versus low years of schooling
were not explained by age, body mass index, smoking, alcohol consumption or
blood pressure medication use. Findings were less consistent for women and
for Israelis and US blacks of both genders.
Conclusions Lipid and lipoprotein levels consistent with atherogenicity var
ied directly with years of schooling in Chinese, Polish, and Russian sample
s. Opposite trends were present in US whites. These findings are consistent
with a hypothesized influence of social status on CHD risk differing among
populations in relation to stages in societal economic development.