Homocysteine-Lowering by B Vitamins Slows the Rate of Accelerated Brain Atrophy in Mild Cognitive Impairment

Suplemen vitamin B6, B12 dan asam folat akan menurunkan kadar homosistein. Penurunan kadar homosistein akan memperlambat atrofi otak, sehingga menjaga fungsi kognitif pada usia lanjut. Apakah suplemen ini dapat juga mencegah Alzheimer?

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Homocysteine-Lowering by B Vitamins Slows the Rate of Accelerated Brain Atrophy in Mild Cognitive Impairment: A Randomized Controlled Trial
A. David Smith, Stephen M. Smith, Celeste A. de Jager1, Philippa Whitbread, Carole Johnston, Grzegorz Agacinski, Abderrahim Oulhaj, Kevin M. Bradley, Robin Jacoby, Helga Refsum

Background
An increased rate of brain atrophy is often observed in older subjects, in particular those who suffer from cognitive decline. Homocysteine is a risk factor for brain atrophy, cognitive impairment and dementia. Plasma concentrations of homocysteine can be lowered by dietary administration of B vitamins.
Objective
To determine whether supplementation with B vitamins that lower levels of plasma total homocysteine can slow the rate of brain atrophy in subjects with mild cognitive impairment in a randomised controlled trial (VITACOG, ISRCTN 94410159).
Methods and Findings
Single-center, randomized, double-blind controlled trial of high-dose folic acid, vitamins B6 and B12in 271 individuals (of 646 screened) over 70 y old with mild cognitive impairment. A subset (187) volunteered to have cranial MRI scans at the start and finish of the study. Participants were randomly assigned to two groups of equal size, one treated with folic acid (0.8 mg/d), vitamin B12(0.5 mg/d) and vitamin B6 (20 mg/d), the other with placebo; treatment was for 24 months. The main outcome measure was the change in the rate of atrophy of the whole brain assessed by serial volumetric MRI scans.
Results
A total of 168 participants (85 in active treatment group; 83 receiving placebo) completed the MRI section of the trial. The mean rate of brain atrophy per year was 0.76% [95% CI, 0.63–0.90] in the active treatment group and 1.08% [0.94–1.22] in the placebo group (P = 0.001). The treatment response was related to baseline homocysteine levels: the rate of atrophy in participants with homocysteine >13 µmol/L was 53% lower in the active treatment group (P = 0.001). A greater rate of atrophy was associated with a lower final cognitive test scores. There was no difference in serious adverse events according to treatment category.
Conclusions and Significance
The accelerated rate of brain atrophy in elderly with mild cognitive impairment can be slowed by treatment with homocysteine-lowering B vitamins. Sixteen percent of those over 70 y old have mild cognitive impairment and half of these develop Alzheimer's disease. Since accelerated brain atrophy is a characteristic of subjects with mild cognitive impairment who convert to Alzheimer's disease, trials are needed to see if the same treatment will delay the development of Alzheimer's disease.

Rising Stroke Rates Among Middle-Aged Women in the United States

Peningkatan prevalensi obesitas dan sindroma metabolik menyebabkan peningkatan prevalensi stroke pada wanita

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Stroke. 2010;41:1371

Weight of the Obesity Epidemic
Rising Stroke Rates Among Middle-Aged Women in the United States
Amytis Towfighi, MD; Ling Zheng, PhD Bruce Ovbiagele, MD

From the Department of Neurology (A.T., L.Z.), University of Southern California, Los Angeles, Calif; and the Department of Neurology (B.O.), University of California at Los Angeles, Los Angeles, Calif.

Background and Purpose— Recent US nationally representative data revealed that among individuals aged 45 to 54 years, women's stroke prevalence was double that of men's. The purpose of this study was to determine if the sex disparity existed previously.
Methods— We assessed sex-specific stroke and vascular risk factor prevalence among individuals aged 35 to 64 years who participated in the National Health and Nutrition Examination Surveys (NHANES), a cross-sectional, nationally representative survey conducted in 2 waves: 1988 to 1994 (n=7234) and 1999 to 2004 (n=6499).
Results— Women aged 35 to 54 years who participated in NHANES from 1999 to 2004 were 3 times more likely to have experienced a stroke compared with similarly aged women in NHANES 1988 to 1994 (1.8% versus 0.6%,P=0.003), but stroke prevalence among men did not change (0.9% versus 1.0%, nonsignificant). Among women, the prevalence of obesity (15.2% versus 17.9%, P=0.08), morbid obesity (12.8% versus 17.5%, P=0.003), abdominal obesity (47.4% versus 58.9%, P<0.0001), hypertriglyceridemia (22.91% versus 26.78%, P=0.035), and hypertension (33.04% versus 37.43%, P=0.03) was lower in NHANES 1988 to 1994 compared with the morerecent NHANES wave. Higher waist circumference was the only independent stroke risk factor for women aged 35 to 54 years in NHANES 1999 to 2004 (OR per 15-cm increase in waist circumference=1.02, 95% CI 1.00 to 1.04).
Conclusions— Stroke prevalence among women aged 35 to 54 years has tripled over the past 2 decades, at the same time remaining stable among men. Prevalence of obesity and 3 metabolic syndrome components increased; they may be key factors in the increase in women's stroke prevalence.

Low-Carbohydrate Diets and All-Cause and Cause-Specific Mortality

Diet rendah karbohidrat kaya sayuran menurunkan risiko kematian termasuk kematian akibat penyakit kardiovaskuler. Sebaliknya, diet rendah karbohidrat kaya sumber hewani meningkatkan risiko kematian pada pria dan wanita.

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Annals of Internal Medicine

September 7, 2010 vol. 153 no. 5 289-298

 

Low-Carbohydrate Diets and All-Cause and Cause-Specific Mortality
Two Cohort Studies
Teresa T. Fung, ScD; Rob M. van Dam, PhD; Susan E. Hankinson, ScD;Meir Stampfer, MD, DrPH; Walter C. Willett, MD, DrPH; and Frank B. Hu, MD, PhD

Abstract

Background: Data on the long-term association between low-carbohydrate diets and mortality are sparse.
Objective: To examine the association of low-carbohydrate diets with mortality during 26 years of follow-up in women and 20 years in men.
Design: Prospective cohort study of women and men who were followed from 1980 (women) or 1986 (men) until 2006. Low-carbohydrate diets, either animal-based (emphasizing animal sources of fat and protein) or vegetable-based (emphasizing vegetable sources of fat and protein), were computed from several validated food-frequency questionnaires assessed during follow-up.
Setting: Nurses' Health Study and Health Professionals' Follow-up Study.
Participants: 85 168 women (aged 34 to 59 years at baseline) and 44 548 men (aged 40 to 75 years at baseline) without heart disease, cancer, or diabetes.
Measurements: Investigators documented 12 555 deaths (2458 cardiovascular-related and 5780 cancer-related) in women and 8678 deaths (2746 cardiovascular-related and 2960 cancer-related) in men.
Results: The overall low-carbohydrate score was associated with a modest increase in overall mortality in a pooled analysis (hazard ratio [HR] comparing extreme deciles, 1.12 [95% CI, 1.01 to 1.24]; P for trend = 0.136). The animal low-carbohydrate score was associated with higher all-cause mortality (pooled HR comparing extreme deciles, 1.23 [CI, 1.11 to 1.37]; P for trend = 0.051), cardiovascular mortality (corresponding HR, 1.14 [CI, 1.01 to 1.29]; P for trend = 0.029), and cancer mortality (corresponding HR, 1.28 [CI, 1.02 to 1.60]; P for trend = 0.089). In contrast, a higher vegetable low-carbohydrate score was associated with lower all-cause mortality (HR, 0.80 [CI, 0.75 to 0.85]; P for trend ≤ 0.001) and cardiovascular mortality (HR, 0.77 [CI, 0.68 to 0.87]; P for trend < 0.001).
Limitations: Diet and lifestyle characteristics were assessed with some degree of error. Sensitivity analyses indicated that results were probably not substantively affected by residual confounding or an unmeasured confounder. Participants were not a representative sample of the U.S. population.
Conclusion: A low-carbohydrate diet based on animal sources was associated with higher all-cause mortality in both men and women, whereas a vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates.