Since 1948, residents of Framingham, Massachusetts, have participated in a program that
collects blood samples and clinical data to provide a rare and valuable database for
The purpose of this study is to support this national resource by aiding in its research
capacity. Specifically, researchers in this study will (1) investigate heart, lung, and
blood diseases; stroke; memory loss; joint disease; bone loss; deafness; cancer; blood
vessel diseases and other health conditions, and (2) examine DNA and its relationship to
risk of developing these disease and health conditions.
Approximately 330 families have participated in the Framingham Study. Participants will be
required to undergo a four-hour exam and to take that exam every two years thereafter.
During the exam, the Framingham investigators will (1) interview participants about medical
status, health issues, and lifestyles; (2) perform a regular physical exam; (3) obtain blood
and urine samples and administer a glucose-tolerance test; (4) supervise a brisk six-minute
treadmill walk; (5) administer an ultrasound procedure; and (6) review and obtain copies of
medical and hospital records. Participants will also be asked to complete a questionnaire at
home regarding dietary and health habits.
Many studies have shown that hematocrit (HCT) levels are associated with cerebrovascular
disease, cardiovascular disease (CVD), peripheral vascular disease, as well as all-cause
mortality. Twin studies have shown that HCT variation is largely determined by genetic
factors with heritability estimated as 40% - 65%. So far, no linkage analysis in humans
between HCT and DNA markers have been reported. The purpose of this protocol is to identify
chromosome regions that contain quantitative trait loci (QTL) involved in controlling HCT
levels. In the Framingham Study, a 10cM genome scan (about 400 markers) has been conducted
in 330 families. HCT was measured in the original cohort and Framingham offspring. These
data provide us the opportunity to undertake linkage analyses using variance component
method to map quantitative trait loci (QTL) of HCT.
- INCLUSION /EXCLUSION CRITERIA
The study population will include the members of the 330 Framingham Study families with