In The News: January 2014

A recent study in the New England Journal of Medicine measured glucose and hemoglobin A1c levels from over 2,000 participants without dementia to examine the relationship between glucose and future risk of dementia.*

Participants were from a study that included 839 men and 1,228 women whose mean age at baseline was 76 years; 232 participants had diabetes, and 1,835 did not. During a median follow-up of 6.8 years, dementia developed in 524 participants. Among participants without diabetes, higher average glucose levels within the preceding 5 years were related to an increased risk of dementia. Diabetics with higher average glucose levels were also related to an increased risk of dementia.

The study, funded by the National Institutes of Health, concluded that, “Higher glucose levels may be a risk factor for dementia, even among persons without diabetes.”

A recent issue of the Journal of the American Heart Association features a report by Finnish researchers that associates higher omega-3 fatty acid levels with healthier brains. The background of the study, performed at the University of Eastern Finland, is that the consumption of tuna or other broiled or baked fish, but not fried fish, is linked to fewer subclinical brain abnormalities on magnetic resonance imaging (MRI).*

The team investigated the association between plasma phospholipid omega-3 fatty acids, objective biomarkers of exposure, and subclinical brain abnormalities on MRI.

In the community-based Cardiovascular Health Study, 3,660 participants aged 65 or younger underwent brain MRI in 1992-1994, and 2,313 were rescanned 5 years later.

The conclusion of the report stated that, “Among older adults, higher phospholipid long-chain omega-3 PUFA content was associated with lower prevalence of subclinical infarcts and better white matter grade on MRI. Our results support the beneficial effects of fish consumption, the major source of long-chain omega-3 PUFAs, on brain health in later life.”

BMC Nephrology published the results of a meta-analysis of kidney disease patients, which found an association between supplementation with active forms of vitamin D and a lower risk of dying over follow-up.*

For their analysis, researchers selected 17 studies involving a total of 489,254 end stage renal disease patients receiving dialysis and three studies that included 2,603 chronic kidney patients not on dialysis. Subjects were treated with active vitamin D sterols that included alfacalcidol, doxercalciferol, calcitriol, maxacalcitol, falecalcitriol, or paricalcitol. Follow-up periods ranged from 12 to 140 months.

In comparison with no treatment, subjects who received active vitamin D compounds had an up to 39% lower risk of dying from all causes over follow-up. Pooled analysis of dialysis patients associated active vitamin D therapy with a 20% lower adjusted risk of dying, and among those not on dialysis, the risk was 41% lower.

Editor’s Note: When cardiovascular mortality was examined, active vitamin D was associated with a 41% lower adjusted risk of death over follow-up.

In an online issue of Neurology, the medical journal of the American Academy of Neurology, a study was recently published indicating that aging individuals with hardened arteries are more likely to have brain plaques associated with Alzheimer’s disease—even if the person does not have any signs of dementia.*

The study involved 91 people with an average age of 87 who did not have dementia. Researchers took scans of the participants’ brains to measure any plaques in the brain. The amount of stiffness in the participants’ arteries was measured about two years later. Half of all participants had beta-amyloid plaques. People with beta-amyloid plaques were more likely to have high systolic blood pressure, higher average blood pressure, and higher arterial stiffness as measured with the brachial-ankle method.

“This study adds to growing evidence that hardening of the arteries is associated with cerebrovascular disease that does not show symptoms. Now we can add Alzheimer’s type lesions to the list,” study author Timothy M. Hughes, PhD, of the University of Pittsburgh, said.

In the journal Diabetes Care, researchers report an association between greater magnesium intake and a lower risk of developing diabetes over a 6.9 year average period.*

The study included 2,582 men and women enrolled in the Framingham Heart Study Offspring cohort. Between 1991 and 1995, the subjects participated in examinations that included glucose tolerance testing and dietary assessment, and were followed through 1998 to 2001, when they were re-examined.

Thirty-six percent of the participants were classified as having metabolic impairment, defined as impaired fasting glucose, impaired glucose tolerance, insulin resistance or hyperinsulinemia, at the time of the 1991-1995 examinations. Among those without the condition, 18% developed metabolic impairment by the end of follow-up. Those without metabolic impairment whose magnesium intake from food and supplements was among the top one-fifth of participants had a 37% lower risk of becoming impaired over follow-up compared with those whose intake was among the lowest fifth.

Editor’s Note: In those classified as metabolically impaired at baseline, 16.6% became diabetic by the end of follow-up. Having a magnesium intake that was among the highest fifth lowered the risk of developing diabetes in this group by 32% in comparison with an intake that was lowest. When the entire study population was considered, those whose magnesium intake was highest had approximately half the risk of becoming diabetic over follow-up than subjects whose intake was lowest.

An article published in Breast Cancer Research and Treatment reports the results of a meta-analysis which found an association between higher serum levels of vitamin D and better prognosis for women with early stage breast cancer.*

For their analysis, Pamela J. Goodwin of the University of Toronto and her colleagues selected eight studies involving a total of 5,691 women diagnosed with breast cancer. Blood samples were collected, on average, within 90 days of diagnosis or shortly before treatment. Deficient levels of vitamin D were uncovered in 36.8% of the subjects. When the lowest versus highest categories of serum vitamin D were compared in a pooled analysis, women whose levels were low had a risk of recurrence that was more than double that of subjects whose levels were high and a risk of death that was 76% higher.

Editor’s Note: The authors remark that vitamin D, when activated, can alter the transcription and expression of specific genes, resulting in growth arrest, apoptosis, aromatase suppression, decreased inflammation, and inhibition of angiogenesis, invasion and metastasis, all of which help combat cancer.

In the journal Clinical Nutrition, researchers report the findings of a meta-analysis of randomized trials of folic acid supplementation in men and women with kidney disease, which concluded that treatment with the vitamin may help reduce the risk of cardiovascular disease, which is increased in this population.*

Xiaobin Wang and colleagues selected nine randomized trials for their analysis that examined the relationship between folic acid therapy and cardiovascular disease. Pooled analysis of the 8,234 subjects found a 10% lower risk of cardiovascular disease among those who received the vitamin in comparison with those who did not receive it. When trials involving patients who did not consume grains fortified with folic acid were separately examined, the risk was further reduced. The researchers also uncovered a greater benefit for folic acid supplementation in trials involving patients with advanced or end-stage disease, or which had a lower percentage of diabetics upon enrollment.

Editor’s Note: Folic acid is a B vitamin that helps reduce homocysteine which, when elevated, increases cardiovascular disease risk. Those with renal impairment suffer higher homocysteine levels.

The journal Health Affairs published a study by researchers at the University of Southern California, Harvard University, and other institutions, which concluded that delaying aging would be a better way to reduce disability than focusing on specific disease therapies.*

By employing a microsimulation of the future health and spending of older men and women, Dana Goldman and colleagues compared disease-specific scenarios with a delayed aging scenario. The team determined that delayed aging could add 2.2 years spent primarily in good health to average life expectancy, while addressing separate diseases would result in lesser improvements in health and longevity.

“In the last half-century, major life expectancy gains were driven by finding ways to reduce mortality from fatal diseases,” Dr. Goldman stated. “If we can age more slowly, we can delay the onset and progression of many disabling diseases simultaneously.”

Editor’s Note : “Even a marginal success in slowing aging is going to have a huge impact on health and quality of life,” added coauthor Jay S. Olshansky. “This is a fundamentally new approach to public health that would attack the underlying risk factors for all fatal and disabling diseases. We need to begin the research now.”

The journal Neurobiology of Aging describes a study conducted by researchers at the University of Montréal which uncovered an association between higher serum phylloquinone (vitamin K1) levels and better verbal episodic memory in older adults.*

The current investigation utilized data from 320 subjects between the ages of 70 to 85 years who were free of cognitive impairment upon enrollment in the Québec Longitudinal Study on Nutrition and Successful Aging, which recruited 1,793 men and women from 2003 to 2005. Follow-up interviews were conducted yearly for up to three years following enrollment. The current study’s subjects underwent cognitive evaluation between 2006 and 2008, and blood samples collected at this time period were analyzed for phylloquinone and other factors.

An association was found between higher vitamin K levels and the scores of three immediate free recall trials and 20 minute delayed free recall, which evaluated verbal episodic memory.

Editor’s Note: Episodic memory refers to the memory of events with their space-time context.

The Journal of Neuroimmunology published an article which reveals a benefit for calcitriol, the active form of vitamin D, in a mouse model of multiple sclerosis (MS).

Coleen E. Hayes and her associates tested the effect of calcitriol and vitamin D3 in mice with experimental autoimmune encephalitis, a disease in which demyelination of the nerves occurs as in MS. While vitamin D3 alone was not effective, the combination of calcitriol followed by supplementation with the vitamin resulted in improvement.*

“All of the animals just got better and better, and the longer we watched them, the more neurological function they regained,” Dr. Hayes reported. “The treatment shows potential to help halt the disease’s progress in humans, for whom currently available therapies have limited effectiveness. And in the long term they don’t halt the disease process that relentlessly eats away at the neurons. So there’s an unmet need for better treatments.”

Editor’s Note: The experimental treatment was more effective than methylprednisone, which is used to treat neurological problems experienced by MS patients.

JAMA Internal Medicine published an article which reported a lower risk of venous blood clots in association with the use of orally administered bioequivalent estradiol in comparison with conjugated equine (horse urine derived) estrogens for the treatment of menopausal symptoms.*

The investigation included 384 postmenopausal women who were enrolled in the Heart and Vascular Health Study, a case-control study of cardiovascular events involving subjects between the ages of 30 to 79 years. Subjects in the current study used oral horse urine derived estrogens or estradiol from 2003 to 2009. Sixty-eight women who had experienced venous thrombosis (deep vein thrombosis or pulmonary embolism), 67 women who had undergone a heart attack, and 48 subjects who had an ischemic stroke were matched for age and other factors with 201 control subjects. Among women who used horse urine derived estrogens, the risk of experiencing venous thrombosis was more than double that of subjects who used estradiol.

Editor’s Note: Analysis of plasma samples from 140 control subjects also indicated stronger propensity for blood clotting among those who used conjugated equine (horse urine derived) estrogens.