ABSTRACTChildren in the eastern part of Finland have higher serum total and low-density lipoprotein from the western part of the country showed the greatest differences. Prepubescent boys 3 to 12 years old living in the west but with grandparents from the east had total and LDL cholesterol levels similar to those of boys living in and descended of grandparents from the east, despite their diet being of the western type. Thus, although diet is known to be a major determinant of serum cholesterol level,genetic factors also seem to play a role.