Development of Vascular Risk Factors in Relation to Cognition
Objectives To investigate the development of vascular risk factor levels at four points over 15 years in relation to late-life cognitive functioning.
Design Longitudinal population-based study.
Setting The Hoorn Study, a community-based cohort study of glucose metabolism and cardiovascular risk.
Participants Three hundred eighty individuals without dementia (mean baseline age 57.7 ± 5.5).
Measurements Four extensive medical examinations were conducted over 15 years. Cognition was assessed in detail at the fourth examination. The time course of vascular risk factors across the examinations was compared between individuals in the highest tertile (good performance) and those in the lowest tertile (poor performance) of cognitive functioning on three cognitive domains (memory, information processing speed, and attention and executive functioning (A&EF)).
Results Individuals with poor information processing speed had higher levels of systolic blood pressure at baseline (mean difference (standard error) 11.6 (2.6) mmHg, P < .001) than those with good information processing speed. Individuals with poor A&EF had a higher waist:hip ratio (3.03 (1.15), P = .009), glycosylated hemoglobin (0.29% (0.10%), P = .005) and total cholesterol:high-density lipoprotein cholesterol ratio (0.38 (0.19), P = .04) at baseline than individuals with good A&EF, although the differences in vascular risk factor levels between the poor and good cognition group diminished with increasing age.
Conclusion High blood pressure, adiposity, hypercholesterolemia, and hyperglycemia at midlife are associated with late-life cognitive dysfunction, but for most risk factors, this relationship gradually attenuates with increasing age. These results suggest that timing of vascular treatment strategies to prevent cognitive impairment is critical.
The relationship between cardiovascular risk factors and cognitive decline in older individuals is increasingly being recognized. Several longitudinal population-based studies have shown that midlife obesity and midlife hypertension are associated with risk of dementia later in life. In contrast, studies on these risk factors in older populations did not observe these associations or even found reverse associations with cognitive dysfunction (for review). The complex interplay between age, duration of exposure, selective survival, and changes in risk factor levels over time may explain this. Risk factors such as blood pressure (BP) and body weight tend to rise in middle age but decrease in very old age. In addition, the levels of vascular risk factors may change during the dementia process well before dementia becomes clinically manifest. To further unravel the relationship between vascular risk factors, age, and cognition, longitudinal studies that assess vascular risk factors over multiple time points between midlife and late life are necessary.
Obesity, hypertension, hypercholesterolemia, and impaired glucose metabolism are well-known risk factors for dementia, whereas less is known about the association with milder decrements in late-life cognitive functioning. More insight into risk factors for these milder cognitive decrements is needed, because treatment to prevent impaired cognitive functioning may be most effective in early stages. The current study investigated vascular risk factor levels at four time points over 15 years in relation to cognition in older individuals without dementia. Cognitive functioning was assessed in detail, addressing cognitive domains particularly sensitive to cognitive decline in the context of cardiovascular disease.
Abstract and Introduction
Abstract
Objectives To investigate the development of vascular risk factor levels at four points over 15 years in relation to late-life cognitive functioning.
Design Longitudinal population-based study.
Setting The Hoorn Study, a community-based cohort study of glucose metabolism and cardiovascular risk.
Participants Three hundred eighty individuals without dementia (mean baseline age 57.7 ± 5.5).
Measurements Four extensive medical examinations were conducted over 15 years. Cognition was assessed in detail at the fourth examination. The time course of vascular risk factors across the examinations was compared between individuals in the highest tertile (good performance) and those in the lowest tertile (poor performance) of cognitive functioning on three cognitive domains (memory, information processing speed, and attention and executive functioning (A&EF)).
Results Individuals with poor information processing speed had higher levels of systolic blood pressure at baseline (mean difference (standard error) 11.6 (2.6) mmHg, P < .001) than those with good information processing speed. Individuals with poor A&EF had a higher waist:hip ratio (3.03 (1.15), P = .009), glycosylated hemoglobin (0.29% (0.10%), P = .005) and total cholesterol:high-density lipoprotein cholesterol ratio (0.38 (0.19), P = .04) at baseline than individuals with good A&EF, although the differences in vascular risk factor levels between the poor and good cognition group diminished with increasing age.
Conclusion High blood pressure, adiposity, hypercholesterolemia, and hyperglycemia at midlife are associated with late-life cognitive dysfunction, but for most risk factors, this relationship gradually attenuates with increasing age. These results suggest that timing of vascular treatment strategies to prevent cognitive impairment is critical.
Introduction
The relationship between cardiovascular risk factors and cognitive decline in older individuals is increasingly being recognized. Several longitudinal population-based studies have shown that midlife obesity and midlife hypertension are associated with risk of dementia later in life. In contrast, studies on these risk factors in older populations did not observe these associations or even found reverse associations with cognitive dysfunction (for review). The complex interplay between age, duration of exposure, selective survival, and changes in risk factor levels over time may explain this. Risk factors such as blood pressure (BP) and body weight tend to rise in middle age but decrease in very old age. In addition, the levels of vascular risk factors may change during the dementia process well before dementia becomes clinically manifest. To further unravel the relationship between vascular risk factors, age, and cognition, longitudinal studies that assess vascular risk factors over multiple time points between midlife and late life are necessary.
Obesity, hypertension, hypercholesterolemia, and impaired glucose metabolism are well-known risk factors for dementia, whereas less is known about the association with milder decrements in late-life cognitive functioning. More insight into risk factors for these milder cognitive decrements is needed, because treatment to prevent impaired cognitive functioning may be most effective in early stages. The current study investigated vascular risk factor levels at four time points over 15 years in relation to cognition in older individuals without dementia. Cognitive functioning was assessed in detail, addressing cognitive domains particularly sensitive to cognitive decline in the context of cardiovascular disease.