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But among people at high genetic risk for dementia, these potentially modifiable factors – not smoking, not having depression or diabetes, getting regular physical activity, avoiding social isolation, and following a healthy diet – may not have protective associations, according to research published in Nature Medicine.
Recent analyses have indicated that eliminating known modifiable risk factors for dementia at a population level could prevent one-third of dementia cases, but prevention trials “have yielded inconsistent results so far,” wrote first author Silvan Licher, MD, of the department of epidemiology at Erasmus University Medical Center Rotterdam (the Netherlands) and his colleagues.
“Prior studies have mostly focused on the risk of dementia associated with an individual protective factor, yet the combination of multiple factors may yield more beneficial effects than the individual parts,” they wrote. “Combining data about a number of factors is also important because it takes into account the multifactorial nature of late-life dementia. We used data from the Rotterdam Study to determine to what extent a favorable profile based on modifiable risk factors is associated with a lower risk of dementia among individuals at low, intermediate, or high genetic risk.”
Grouped by APOE genotype
Patients who were apolipoprotein E epsilon-4 allele (APOE4) carriers (i.e., APOE2 and 4, APOE3 and 4, or two APOE4) were classified as having high genetic risk (n = 1,747). Other APOE genotypes were considered intermediate risk (n = 3,718 with two APOE3 alleles) or low risk (n = 887 with either two APOE2 alleles or APOE2 and 3).
The researchers measured six potentially modifiable lifestyle or health factors that “have been implicated in a lower risk of dementia.” Modifiable risk scores ranged from 0 to 6. Participants were classified as having an unfavorable profile (0-2 protective factors), an intermediate profile (3-4 protective factors), or a favorable profile (5-6 factors).
The researchers calculated the relative risk of developing dementia using a Cox proportional hazards model and the absolutely risk using competing risk models.
In all, 56.2% of the participants were women, the average age was about 69 years, and patient characteristics were similar across the categories of APOE risk. APOE4 carriers received dementia diagnoses at a younger age, more often had a parental history of dementia, and had higher total cholesterol levels, compared with noncarriers. In all, 915 people received a dementia diagnosis, of whom 739 received a diagnosis of Alzheimer’s disease. The other 2,644 participants died free from dementia. The median follow-up was 14.1 years.
“Dementia risk was significantly higher among participants at high or intermediate APOE risk, compared with those at low APOE risk,” the researchers said. In addition, the risk of dementia increased in participants who had fewer protective factors. Those with 0-2 protective factors had a 29% higher risk of dementia, compared with participants with 5 or 6 protective factors, after adjusting for age, sex, level of education, parental history of dementia, history of stroke, systolic blood pressure, and total and high-density lipoprotein cholesterol.
Lifestyle benefits tended to be greater in younger participants
“APOE genotype significantly modified the association between protective factors and dementia,” the authors said. Compared with participants with protective modifiable risk profiles, participants with unfavorable modifiable risk profiles had greater risk for dementia in the low–APOE risk group (hazard ratio, 2.51) and intermediate–APOE risk group (HR, 1.39), but not in the high–APOE risk group.
“Protective associations of favorable risk profiles against dementia tended to be stronger in younger individuals than in older individuals and were most pronounced for younger individuals at low APOE risk,” Dr. Licher and colleagues said. In a sensitivity analysis that used a polygenic risk score for Alzheimer’s disease based on 27 variants other than APOE to determine participants’ genetic risk, the patterns were “attenuated yet largely comparable,” they wrote. Patterns also remained consistent when the researchers used an ideal cardiovascular health score to indicate modifiable health profiles.
“Our results confirm that individuals with a favorable profile have a lower risk of dementia than those with intermediate or unfavorable profiles based on modifiable risk factors,” they said. Unlike in a subgroup analysis of data from the FINGER study, however, “this study found that a favorable profile could not offset high APOE risk.”
The findings may have implications for clinical trial design and suggest that APOE4 carriers may need to be targeted earlier in the disease process to influence their risk for dementia.
“On the positive side, results from this study show that avoiding an unhealthy lifestyle could potentially prevent or postpone the onset of dementia in most individuals in the population (73%), namely those at low and intermediate genetic risk,” the investigators wrote. “Among these, the majority were categorized has having a favorable profile (66%), yet room for improvement is still substantial.”
The study lacked data on hearing impairment and did not capture shifts to more adverse or optimal lifestyles during follow-up. In addition, the results are based on relatively small samples in each risk category, and the estimates had wide confidence intervals. The population was older and mostly of European descent, which limits the generalizability of the findings, the authors noted.
Lifestyle factors may benefit only people with low genetic risk
“The authors’ key finding was that modifiable lifestyle risk factors were able to reduce dementia risk only in people who did not have an APOE4 allele and hence were at lower genetic risk,” said Kenneth Rockwood, MD, professor of geriatric medicine and neurology at Dalhousie University in Halifax, N.S., and his coauthors, in an accompanying editorial.
The findings contrast with those of another recent population-based study using data from the UK Biobank (JAMA. 2019;322[5]:430-7. doi: 10.1001/jama.2019.9879), which suggested that modifiable factors affect dementia risk regardless of genetic risk.
Together, these studies “tell us that ... we must better understand outcomes in those most at risk,” they said. “We might begin by recognizing that aging is essential, rather than incidental, to dementia disease expression.” Future research should focus on people living with frailty, who often are excluded from trials and are at high risk for dementia. Older adults who develop delirium also may be an ideal target group of patients at increased risk for dementia.
“Reducing the extent of disease expression in people prone to developing dementia late in life is difficult. Studies investigating whether dementia can be prevented at all, such as the Rotterdam study, and then whether it can be prevented in the people at greatest risk, can be commended for their clear-eyed approach,” Dr. Rockwood and colleagues said.
The Rotterdam Study is funded by Erasmus Medical Center and University, as well as a variety of Dutch organizations, institutes, and government ministries, and the European Commission. The authors had no competing interests.
Dr. Rockwood is president and chief science officer of DGI Clinical, which has contracts with pharmaceutical and device manufacturers related to individualized outcome measurement.
SOURCES: Licher S et al. Nat Med. 2019 Aug 26. doi: 10.1038/s41591-019-0547-7; and Rockwood K et al. Nat Med. 2019 Aug 26. doi: 10.1038/s41591-019-0575-3.
The study by Dr. Licher and associates shows a clinically significant impact of a healthy lifestyle in reducing dementia. But what is surprising is that the effect was not seen in genetically higher-risk people.
If anything, the results strengthen our recommendations to people interested in lowering their risk for dementia with lifestyle modification. Bear in mind that APOE testing is not done routinely, so the vast majority of our patients do not know their APOE genotype. Since a healthy lifestyle can benefit the majority of the population (around 75%), even if it is less or ineffective in the APOE4 carrier group (about 25% of the population), it is certainly something to recommend. Of course, health care professionals already recommend heart healthy habits, which have an equivalent benefit, and sadly, adherence is relatively low. Adding that lifestyle modification may help prevent dementia might improve patient compliance. Starting healthy lifestyles as early in life as possible may be the key. It is less effective if we wait until we already have memory loss.
Finally, the study results regard relative risk, a concept that many fail to fully grasp. A person can still get dementia in any of the categories, including the “best one” (low genetic and lifestyle risk). It’s a matter of the odds being better or worse, but there is no guarantee of a positive or negative outcome.
Richard J. Caselli, MD, is professor of neurology at the Mayo Clinic Arizona in Scottsdale and associate director and clinical core director of the Arizona Alzheimer’s Disease Center, Phoenix. He made these comments in an interview.
The study by Dr. Licher and associates shows a clinically significant impact of a healthy lifestyle in reducing dementia. But what is surprising is that the effect was not seen in genetically higher-risk people.
If anything, the results strengthen our recommendations to people interested in lowering their risk for dementia with lifestyle modification. Bear in mind that APOE testing is not done routinely, so the vast majority of our patients do not know their APOE genotype. Since a healthy lifestyle can benefit the majority of the population (around 75%), even if it is less or ineffective in the APOE4 carrier group (about 25% of the population), it is certainly something to recommend. Of course, health care professionals already recommend heart healthy habits, which have an equivalent benefit, and sadly, adherence is relatively low. Adding that lifestyle modification may help prevent dementia might improve patient compliance. Starting healthy lifestyles as early in life as possible may be the key. It is less effective if we wait until we already have memory loss.
Finally, the study results regard relative risk, a concept that many fail to fully grasp. A person can still get dementia in any of the categories, including the “best one” (low genetic and lifestyle risk). It’s a matter of the odds being better or worse, but there is no guarantee of a positive or negative outcome.
Richard J. Caselli, MD, is professor of neurology at the Mayo Clinic Arizona in Scottsdale and associate director and clinical core director of the Arizona Alzheimer’s Disease Center, Phoenix. He made these comments in an interview.
The study by Dr. Licher and associates shows a clinically significant impact of a healthy lifestyle in reducing dementia. But what is surprising is that the effect was not seen in genetically higher-risk people.
If anything, the results strengthen our recommendations to people interested in lowering their risk for dementia with lifestyle modification. Bear in mind that APOE testing is not done routinely, so the vast majority of our patients do not know their APOE genotype. Since a healthy lifestyle can benefit the majority of the population (around 75%), even if it is less or ineffective in the APOE4 carrier group (about 25% of the population), it is certainly something to recommend. Of course, health care professionals already recommend heart healthy habits, which have an equivalent benefit, and sadly, adherence is relatively low. Adding that lifestyle modification may help prevent dementia might improve patient compliance. Starting healthy lifestyles as early in life as possible may be the key. It is less effective if we wait until we already have memory loss.
Finally, the study results regard relative risk, a concept that many fail to fully grasp. A person can still get dementia in any of the categories, including the “best one” (low genetic and lifestyle risk). It’s a matter of the odds being better or worse, but there is no guarantee of a positive or negative outcome.
Richard J. Caselli, MD, is professor of neurology at the Mayo Clinic Arizona in Scottsdale and associate director and clinical core director of the Arizona Alzheimer’s Disease Center, Phoenix. He made these comments in an interview.
But among people at high genetic risk for dementia, these potentially modifiable factors – not smoking, not having depression or diabetes, getting regular physical activity, avoiding social isolation, and following a healthy diet – may not have protective associations, according to research published in Nature Medicine.
Recent analyses have indicated that eliminating known modifiable risk factors for dementia at a population level could prevent one-third of dementia cases, but prevention trials “have yielded inconsistent results so far,” wrote first author Silvan Licher, MD, of the department of epidemiology at Erasmus University Medical Center Rotterdam (the Netherlands) and his colleagues.
“Prior studies have mostly focused on the risk of dementia associated with an individual protective factor, yet the combination of multiple factors may yield more beneficial effects than the individual parts,” they wrote. “Combining data about a number of factors is also important because it takes into account the multifactorial nature of late-life dementia. We used data from the Rotterdam Study to determine to what extent a favorable profile based on modifiable risk factors is associated with a lower risk of dementia among individuals at low, intermediate, or high genetic risk.”
Grouped by APOE genotype
Patients who were apolipoprotein E epsilon-4 allele (APOE4) carriers (i.e., APOE2 and 4, APOE3 and 4, or two APOE4) were classified as having high genetic risk (n = 1,747). Other APOE genotypes were considered intermediate risk (n = 3,718 with two APOE3 alleles) or low risk (n = 887 with either two APOE2 alleles or APOE2 and 3).
The researchers measured six potentially modifiable lifestyle or health factors that “have been implicated in a lower risk of dementia.” Modifiable risk scores ranged from 0 to 6. Participants were classified as having an unfavorable profile (0-2 protective factors), an intermediate profile (3-4 protective factors), or a favorable profile (5-6 factors).
The researchers calculated the relative risk of developing dementia using a Cox proportional hazards model and the absolutely risk using competing risk models.
In all, 56.2% of the participants were women, the average age was about 69 years, and patient characteristics were similar across the categories of APOE risk. APOE4 carriers received dementia diagnoses at a younger age, more often had a parental history of dementia, and had higher total cholesterol levels, compared with noncarriers. In all, 915 people received a dementia diagnosis, of whom 739 received a diagnosis of Alzheimer’s disease. The other 2,644 participants died free from dementia. The median follow-up was 14.1 years.
“Dementia risk was significantly higher among participants at high or intermediate APOE risk, compared with those at low APOE risk,” the researchers said. In addition, the risk of dementia increased in participants who had fewer protective factors. Those with 0-2 protective factors had a 29% higher risk of dementia, compared with participants with 5 or 6 protective factors, after adjusting for age, sex, level of education, parental history of dementia, history of stroke, systolic blood pressure, and total and high-density lipoprotein cholesterol.
Lifestyle benefits tended to be greater in younger participants
“APOE genotype significantly modified the association between protective factors and dementia,” the authors said. Compared with participants with protective modifiable risk profiles, participants with unfavorable modifiable risk profiles had greater risk for dementia in the low–APOE risk group (hazard ratio, 2.51) and intermediate–APOE risk group (HR, 1.39), but not in the high–APOE risk group.
“Protective associations of favorable risk profiles against dementia tended to be stronger in younger individuals than in older individuals and were most pronounced for younger individuals at low APOE risk,” Dr. Licher and colleagues said. In a sensitivity analysis that used a polygenic risk score for Alzheimer’s disease based on 27 variants other than APOE to determine participants’ genetic risk, the patterns were “attenuated yet largely comparable,” they wrote. Patterns also remained consistent when the researchers used an ideal cardiovascular health score to indicate modifiable health profiles.
“Our results confirm that individuals with a favorable profile have a lower risk of dementia than those with intermediate or unfavorable profiles based on modifiable risk factors,” they said. Unlike in a subgroup analysis of data from the FINGER study, however, “this study found that a favorable profile could not offset high APOE risk.”
The findings may have implications for clinical trial design and suggest that APOE4 carriers may need to be targeted earlier in the disease process to influence their risk for dementia.
“On the positive side, results from this study show that avoiding an unhealthy lifestyle could potentially prevent or postpone the onset of dementia in most individuals in the population (73%), namely those at low and intermediate genetic risk,” the investigators wrote. “Among these, the majority were categorized has having a favorable profile (66%), yet room for improvement is still substantial.”
The study lacked data on hearing impairment and did not capture shifts to more adverse or optimal lifestyles during follow-up. In addition, the results are based on relatively small samples in each risk category, and the estimates had wide confidence intervals. The population was older and mostly of European descent, which limits the generalizability of the findings, the authors noted.
Lifestyle factors may benefit only people with low genetic risk
“The authors’ key finding was that modifiable lifestyle risk factors were able to reduce dementia risk only in people who did not have an APOE4 allele and hence were at lower genetic risk,” said Kenneth Rockwood, MD, professor of geriatric medicine and neurology at Dalhousie University in Halifax, N.S., and his coauthors, in an accompanying editorial.
The findings contrast with those of another recent population-based study using data from the UK Biobank (JAMA. 2019;322[5]:430-7. doi: 10.1001/jama.2019.9879), which suggested that modifiable factors affect dementia risk regardless of genetic risk.
Together, these studies “tell us that ... we must better understand outcomes in those most at risk,” they said. “We might begin by recognizing that aging is essential, rather than incidental, to dementia disease expression.” Future research should focus on people living with frailty, who often are excluded from trials and are at high risk for dementia. Older adults who develop delirium also may be an ideal target group of patients at increased risk for dementia.
“Reducing the extent of disease expression in people prone to developing dementia late in life is difficult. Studies investigating whether dementia can be prevented at all, such as the Rotterdam study, and then whether it can be prevented in the people at greatest risk, can be commended for their clear-eyed approach,” Dr. Rockwood and colleagues said.
The Rotterdam Study is funded by Erasmus Medical Center and University, as well as a variety of Dutch organizations, institutes, and government ministries, and the European Commission. The authors had no competing interests.
Dr. Rockwood is president and chief science officer of DGI Clinical, which has contracts with pharmaceutical and device manufacturers related to individualized outcome measurement.
SOURCES: Licher S et al. Nat Med. 2019 Aug 26. doi: 10.1038/s41591-019-0547-7; and Rockwood K et al. Nat Med. 2019 Aug 26. doi: 10.1038/s41591-019-0575-3.
But among people at high genetic risk for dementia, these potentially modifiable factors – not smoking, not having depression or diabetes, getting regular physical activity, avoiding social isolation, and following a healthy diet – may not have protective associations, according to research published in Nature Medicine.
Recent analyses have indicated that eliminating known modifiable risk factors for dementia at a population level could prevent one-third of dementia cases, but prevention trials “have yielded inconsistent results so far,” wrote first author Silvan Licher, MD, of the department of epidemiology at Erasmus University Medical Center Rotterdam (the Netherlands) and his colleagues.
“Prior studies have mostly focused on the risk of dementia associated with an individual protective factor, yet the combination of multiple factors may yield more beneficial effects than the individual parts,” they wrote. “Combining data about a number of factors is also important because it takes into account the multifactorial nature of late-life dementia. We used data from the Rotterdam Study to determine to what extent a favorable profile based on modifiable risk factors is associated with a lower risk of dementia among individuals at low, intermediate, or high genetic risk.”
Grouped by APOE genotype
Patients who were apolipoprotein E epsilon-4 allele (APOE4) carriers (i.e., APOE2 and 4, APOE3 and 4, or two APOE4) were classified as having high genetic risk (n = 1,747). Other APOE genotypes were considered intermediate risk (n = 3,718 with two APOE3 alleles) or low risk (n = 887 with either two APOE2 alleles or APOE2 and 3).
The researchers measured six potentially modifiable lifestyle or health factors that “have been implicated in a lower risk of dementia.” Modifiable risk scores ranged from 0 to 6. Participants were classified as having an unfavorable profile (0-2 protective factors), an intermediate profile (3-4 protective factors), or a favorable profile (5-6 factors).
The researchers calculated the relative risk of developing dementia using a Cox proportional hazards model and the absolutely risk using competing risk models.
In all, 56.2% of the participants were women, the average age was about 69 years, and patient characteristics were similar across the categories of APOE risk. APOE4 carriers received dementia diagnoses at a younger age, more often had a parental history of dementia, and had higher total cholesterol levels, compared with noncarriers. In all, 915 people received a dementia diagnosis, of whom 739 received a diagnosis of Alzheimer’s disease. The other 2,644 participants died free from dementia. The median follow-up was 14.1 years.
“Dementia risk was significantly higher among participants at high or intermediate APOE risk, compared with those at low APOE risk,” the researchers said. In addition, the risk of dementia increased in participants who had fewer protective factors. Those with 0-2 protective factors had a 29% higher risk of dementia, compared with participants with 5 or 6 protective factors, after adjusting for age, sex, level of education, parental history of dementia, history of stroke, systolic blood pressure, and total and high-density lipoprotein cholesterol.
Lifestyle benefits tended to be greater in younger participants
“APOE genotype significantly modified the association between protective factors and dementia,” the authors said. Compared with participants with protective modifiable risk profiles, participants with unfavorable modifiable risk profiles had greater risk for dementia in the low–APOE risk group (hazard ratio, 2.51) and intermediate–APOE risk group (HR, 1.39), but not in the high–APOE risk group.
“Protective associations of favorable risk profiles against dementia tended to be stronger in younger individuals than in older individuals and were most pronounced for younger individuals at low APOE risk,” Dr. Licher and colleagues said. In a sensitivity analysis that used a polygenic risk score for Alzheimer’s disease based on 27 variants other than APOE to determine participants’ genetic risk, the patterns were “attenuated yet largely comparable,” they wrote. Patterns also remained consistent when the researchers used an ideal cardiovascular health score to indicate modifiable health profiles.
“Our results confirm that individuals with a favorable profile have a lower risk of dementia than those with intermediate or unfavorable profiles based on modifiable risk factors,” they said. Unlike in a subgroup analysis of data from the FINGER study, however, “this study found that a favorable profile could not offset high APOE risk.”
The findings may have implications for clinical trial design and suggest that APOE4 carriers may need to be targeted earlier in the disease process to influence their risk for dementia.
“On the positive side, results from this study show that avoiding an unhealthy lifestyle could potentially prevent or postpone the onset of dementia in most individuals in the population (73%), namely those at low and intermediate genetic risk,” the investigators wrote. “Among these, the majority were categorized has having a favorable profile (66%), yet room for improvement is still substantial.”
The study lacked data on hearing impairment and did not capture shifts to more adverse or optimal lifestyles during follow-up. In addition, the results are based on relatively small samples in each risk category, and the estimates had wide confidence intervals. The population was older and mostly of European descent, which limits the generalizability of the findings, the authors noted.
Lifestyle factors may benefit only people with low genetic risk
“The authors’ key finding was that modifiable lifestyle risk factors were able to reduce dementia risk only in people who did not have an APOE4 allele and hence were at lower genetic risk,” said Kenneth Rockwood, MD, professor of geriatric medicine and neurology at Dalhousie University in Halifax, N.S., and his coauthors, in an accompanying editorial.
The findings contrast with those of another recent population-based study using data from the UK Biobank (JAMA. 2019;322[5]:430-7. doi: 10.1001/jama.2019.9879), which suggested that modifiable factors affect dementia risk regardless of genetic risk.
Together, these studies “tell us that ... we must better understand outcomes in those most at risk,” they said. “We might begin by recognizing that aging is essential, rather than incidental, to dementia disease expression.” Future research should focus on people living with frailty, who often are excluded from trials and are at high risk for dementia. Older adults who develop delirium also may be an ideal target group of patients at increased risk for dementia.
“Reducing the extent of disease expression in people prone to developing dementia late in life is difficult. Studies investigating whether dementia can be prevented at all, such as the Rotterdam study, and then whether it can be prevented in the people at greatest risk, can be commended for their clear-eyed approach,” Dr. Rockwood and colleagues said.
The Rotterdam Study is funded by Erasmus Medical Center and University, as well as a variety of Dutch organizations, institutes, and government ministries, and the European Commission. The authors had no competing interests.
Dr. Rockwood is president and chief science officer of DGI Clinical, which has contracts with pharmaceutical and device manufacturers related to individualized outcome measurement.
SOURCES: Licher S et al. Nat Med. 2019 Aug 26. doi: 10.1038/s41591-019-0547-7; and Rockwood K et al. Nat Med. 2019 Aug 26. doi: 10.1038/s41591-019-0575-3.
FROM NATURE MEDICINE