490 Adult Development and Aging
associated with the broader literature on disease, aging, and
cognition.
Cardiovascular Disease, Aging, and
Cognitive Functioning
Familiarity with the literature on cardiovascular disease
or with risk factors for cardiovascular disease such as hyper-
tension, obesity, diabetes, cigarette smoking, and high
cholesterol and cognitive function is a prerequisite for under-
standing research in the area of cardiovascular disease and
behavior. (See the review by Waldstein & Elias, 2001.)
Hypertension, diabetes, smoking, and obesity have been as-
sociated with poorer cognitive functioning, although total
cholesterol and alcohol consumption have been associated
both with better and poorer cognition depending on •dose re-
lationshipsŽ and the speci“c cognitive measures employed
(see P. Elias, Elias, D•Agostino, Silbershatz, & Wolf, 1999;
Muldoon, Flory, & Ryan, 2001).
Because of the signi“cant volume of research on cardio-
vascular disease variables, we focus on studies of older
populations and of interactions of disease factors with age
(cross-sectional) or aging (longitudinal). We restrict our re-
view to hypertension because it has received the greatest
amount of attention and because it serves as a model, or gen-
eral paradigm, for studies of the cumulative impact of aging
and disease, or risk for disease, on cognitive functioning.
Hypertension and Age: Main Effects
It is well-known that age and aging are associated with de-
clines in cognitive functioning. It is also clear that hyperten-
sion and increments in systolic and diastolic blood pressure
(DBP) are associated with lower levels of cognitive function-
ing across all ages. Hypertension affects almost all areas of
the cerebral vasculature. A wide range of abilities are ad-
versely affected, including psychomotor speed, visual con-
structive ability, learning memory, selective attention, ”uid
ability, and executive function (M. Elias & Robbins, 1991a;
Waldstein, 1995; Waldstein & Katzel, 2001). The most recent
summaries of hypothetical variables relating high blood pres-
sure and cognitive performance in explanatory models have
been provided in papers by Waldstein (1995) and Waldstein
and Katzel (2001). These mechanisms include genetic and
environmental factors, psychosocial variables, mood states
and traits, and a long list of biological factors including cere-
bral metabolism, blood ”ow, changes in endothelial dysfunc-
tion, cellular dysfunction, neurochemical dysfunction, white
matter disease, silent infarction, brain atrophy, and athero-
sclerosis. An important aspect of these models is that they
posit different mechanisms that cause blood pressure to im-
pact cognitive function. Although much of the evidence for
the validity of these models is indirect, they are consistent
with what is known about the physiological and structural
consequence of sustained hypertension and hypertension in
youth. Less comprehensive, but nevertheless important,
models for explaining why other cardiovascular risk fac-
tors and disease affect cognitive functioning may be seen
in the various chapters of the Waldstein and Elias (2001) text.
In the following section, we focus on the literature on
hypertension.Hypertension in Old AgeComprehensive reviews of the aging-hypertension literature
are available (M. Elias, Elias, D•Agostino, & Wolf, 2000;
Waldstein, 2000). Studies with very large prospective com-
munity samples show that blood pressure level in middle
age predicts cognitive functioning in old age (M. Elias,
Wolf, D•Agostino, Cobb, & White, 1993; Launer, Masaki,
Petrovitch, Foley, & Havlik, 1995). These reviews summa-
rize the many studies indicating that the cognitive function-
ing of older and very old persons is affected by hypertension
and the mounting evidence that high blood pressure in middle
age (M. Elias et al., 1993; Launer et al., 1995; Swan,
Carmelli, & LaRue, 1995) is a predictor of lowered levels of
cognitive functioning in old age, and that this is true even
when subjects are being treated with antihypertensive drugs
(M. Elias et al., 1993). Hypertension and blood pressure, as
well as diabetes mellitus and other risk factors, are also pre-
dictors of Alzheimer•s disease (Guo, Viitanen, Fratiglioni, &
Winblad, 1996), although it is not yet clear if high blood
pressure is a cause or consequence of Alzheimer•s disease.
Additional studies with controls for blood pressure-related
comorbidities are needed. It also appears that a drop in blood
pressure from middle- to old age may be a predictor of lower
levels of performance in old age (Swan, Carmelli, & LaRue,
1998), but this work needs to be replicated in studies that
employ multiple waves of longitudinal testing.Early Longitudinal DataThe emphasis on hypertension by aging interactions appears
to have been in”uenced by Busse•s (1969) de“nition of
primary agingas changes inherent to the aging process that
are irreversible and secondary agingas caused by disease
that are positively correlated with age but usually reversible
(M. Elias et al., 1990). The narrower translation of this
model, such that it speaks to hypertension and primary aging,
has been de“ned as the •classic age by hypertension modelŽ