To characterize the epidemiology and genetics of apolipoproteins A-I, A-II, B, C-II, C-III, and E in a population of Mexican-Americans in Starr County, Texas.

BACKGROUND:

Evidence has established that the distribution and burden of several common chronic diseases among Mexican-Americans differ from that in the general population. These diseases include diabetes (almost exclusively noninsulin dependent diabetes), hypertension, and gallbladder disorders. While progress was made towards an elucidation of their epidemiology within this population, there was a paucity of data regarding other cardiovascular risk factors, most notably, the distribution of lipoproteins and their constituent apoproteins. With regard to the apolipoproteins, there were only minimal data from any population dealing with their distribution and relationships in the general population or pedigrees. This project provided as complete a profile on the distribution of metabolic cardiovascular risk factors as could be claimed for any other study of comparable size and provided baseline values for apo A-I, A-II, B, C-II, C-III and E.

DESIGN NARRATIVE:

One thousand randomly selected individuals were given a complete physical examination. From those 1,000, 100 probands with gallbladder disease were selected. Approximately 1,200 first degree relatives of the probands were invited to participate in the study and given a physical examination. Additionally, 100 control individuals, their spouses and first degree relatives were followed longitudinally for five years. Blood samples were obtained for determination of total cholesterol, LDL cholesterol, HDL2 and HDL3 cholesterol, and genetic markers. Data were collected on age, sex, body mass and fat distribution, diet, smoking, and alcohol consumption. Annual follow-up assessed the dynamics of changes in apolipoprotein levels and profiles and those factors which contributed to their change. The random and longitudinal data were combined with pedigree data to determine the effects of major genes, polygenes, and the environment on the variability of each apolipoprotein and on the relationship between these and other risk factors. An assessment was made in 100 individuals of the contribution of genetic variability at the DNA level in determining apolipoprotein levels.

Participation in prior survey of Starr County, Texas where 1,004 representative individuals of the population aged 15 and older were selected. The community was first mapped and random blocks selected. All individuals in households on selected blocks were enumerated and then 1 age eligible individual from each household was selected for a complete physical evaluation. From these, 250 individuals were identified as probands and their, primarily, first degree relatives were selected for the same examination. 1,254 individuals were seen in this phase.

These individuals became eligible for the more complete profiling of apolipoproteins funded by the referenced grant.

Mexican American residents of Starr County, Texas.