Little Evidence That Diet, Lifestyle Cuts Alzheimer's Risk

Numerous studies have attempted to link specific behaviors and health conditions to the onset of Alzheimer's disease, but scientists still can't say for sure that anything you do or don't do will prevent the brain disorder, according to a new U.S. review of recent research. The U.S. National Institutes of Health convened a conference last spring to analyze 18 studies of potential risk factors, such as poor eating habits, chronic illness, smoking or little exercise, and development of Alzheimer's disease. "Although we are not dismissing the potential or important role that these major risk factors might play in the development of Alzheimer's disease, at this time, with what we have currently, we cannot confirm any risk associations," said study lead author Dr. Martha L. Daviglus, a professor of preventive medicine and medicine at the Northwestern University Feinberg School of Medicine in Chicago.

"So we need to conduct more research, if we want to have the evidence in hand," she added. The study, which summarizes the NIH conference results, is published in the May 9 online edition and September print issue of the Archives of Neurology. For now, older age is the leading known risk factor for Alzheimer's disease, the study noted. A gene variation is also tied to increased risk, it said. An estimated 5.3 million Americans struggle with Alzheimer's, a figure projected to grow as the country's Baby Boomer population ages, the authors said. The disease is responsible for between 60 and 80 percent of dementia cases. "What we're talking about here is something that is going to affect so many Americans in the years to come," said one expert, Catherine Roe, an instructor in neurology at Washington University School of Medicine in St. Louis. "In fact, there's going to be an explosion in the next 50 years, because everyone is living longer in general," she said.

The studies included in the NIH research review were conducted between 1984 and 2009 in English. Participants were at least 50 years old and living in developed countries. Some of the studies looked into dietary influences, such as folic acid intake, Mediterranean diet and nutritional supplements. Others looked for a link between health problems, such as diabetes or high cholesterol, and Alzheimer's. Still others explored levels of physical activity or alcohol consumption and risk of Alzheimer's disease. The NIH team found that, as a whole, the studies were "compromised by methodological limitations" that undercut the ability to draw a firm association between any particular behavioral habit and/or health condition and Alzheimer's.

Race Seems to Impact Rate of Kidney Function Decline

Among patients with kidney disease in the United States, certain racial/ethnic groups, including blacks and some Hispanics, get sicker faster than whites do, researchers have found. "Racial/ethnic differences are present early, before chronic kidney disease has been established," study co-author Dr. Carmen A. Peralta, of the University of California, San Francisco, said in a news release from the American Society of Nephrology. "The observed differences were not fully explained by traditional risk factors," which include cholesterol, weight, tobacco use, diabetes and high blood pressure, Peralta noted. The researchers reached their conclusions after examining the medical records of almost 5,200 adults in the United States whose kidneys initially worked normally.

Based on five years of follow-up data, the researchers used mathematical equations to estimate age-related changes in kidney function. The kidneys of blacks declined faster on an annual basis than those of whites, about 60 percent faster judging by one method, the study authors noted. Among Hispanic groups, kidneys declined faster among Dominicans, followed by Puerto Ricans. But other Hispanics, as well as Chinese Americans, didn't suffer from a faster rate of decline than whites. The research "reflects a new opportunity to study how to best identify persons at high risk and to investigate prevention strategies," Peralta said. The study was scheduled to be presented at the American Society of Nephrology's annual meeting, held this week in Denver.

High Cholesterol in Middle Age May Not Raise Dementia Risk for Women

For years, doctors have been saying that keeping your cholesterol levels in check as you age is good for your brain as well as your heart, but a new study suggests the connection between cholesterol and dementia later in life isn't quite so clear-cut. After more than 1,400 Swedish women followed for 32 years, Johns Hopkins researchers found that those with high cholesterol at mid-life were at no greater risk of developing Alzheimer's and other types of dementia than women with lower levels. In addition, the women whose cholesterol levels decreased the most from middle to older age were 2.5 times more likely to develop dementia than those whose levels increased or stayed the same.

Both cell and animal studies have suggested that high cholesterol contributes to Alzheimer's disease, the researchers noted, but they stressed that the relationship between cholesterol and dementia may vary over a lifetime. "Our findings highlight how risk factors can change over the course of a person's life span," said Michelle M. Mielke, an assistant professor of psychiatry at Hopkins and lead author of the study, which was published online Nov. 10 in the journal Neurology. "My biggest worry is that people will look at these results and decide that cholesterol doesn't matter, but that's not what we're saying," Mielke added.

"We know that high cholesterol is a very strong risk factor for cardiovascular disease and still needs to be treated with diet, exercise and possibly medication." Mielke added that it was unclear why a decline in cholesterol levels in old age was linked to a higher risk of dementia, but said it might be an early part of the disease process. "As people start to develop symptoms, they often forget to eat and start losing weight, and that may be why their cholesterol goes down." For the study, Mielke and her colleagues examined data from the Prospective Population Study of Women, which began in 1968 and consisted of 1,462 Swedish women between the ages of 38 and 60.

Chemicals in Rugs, Cookware May Be Linked to Raised Cholesterol in Teens

Common chemicals found in everything from non-stick cookware to grease-resistant food packaging appear to be associated with increases in cholesterol levels in adolescents, a new study suggests. People are exposed to these chemicals known as perfluoroalkyl acids (PFAAs)in dust, drinking water, non-stain carpets, waterproof fabrics, microwave popcorn bags and a host of other household products. "This is the first study that takes an in-depth look at an association between these chemicals and health effects in children," said study author Stephanie J. Frisbee, research instructor in the Department of Community Medicine at West Virginia University School of Medicine in Morgantown.

The PFAA compounds in question include perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS). "We found a positive association between PFOA and PFOS and total [cholesterol] and LDL cholesterol," she said. As the blood levels of these chemical increased, so did cholesterol, Frisbee added. The American Chemical Council, an industry group, did not respond to repeated attempts by HealthDay to get comment on the findings. The report is published in the September issue of the Archives of Pediatrics & Adolescent Medicine. For the study, Frisbee's team looked at cholesterol levels in more than 12,000 children and adolescents who are part of the C8 Health Project.

This project resulted from the settlement of a class-action lawsuit against Dupont over the landfill dumping of chemicals that contaminated groundwater in six water districts in two states near the company's plant in Parkersburg, West Virginia, and exposed residents to levels of C8 (another name for PFOA) far higher than that of the general population. Among the participants, the average PFOA concentration was 69.2 nanograms per milliliter and average PFOS concentration was 22.7 nanograms per milliliter. Among 12- to 19-year-olds, the PFOA concentrations were higher than those seen in the general population, but PFOS concentrations were similar to those seen in samples from the general population, the researchers found.

Clues to Heart Attack, Stroke Risk From Fat-Filled Artery

A number of factors put patients with abnormal fatty deposits in an artery at high risk for heart attack, stroke and cardiovascular death, a new study shows. Patients in various stages of this condition atherothrombosis are at increased risk for heart attack and stroke stemming from reduced blood flow from the artery blockage, but some are at greater risk than others. In an analysis of more than 45,000 patients, the researchers found that patients with abnormal fatty deposits in an artery were at highest risk if they had a prior history of heart attack or other emergencies linked to an artery blockage.

Narrowing of the arteries in various locations also substantially increased the risk for patients with atherothrombosis, as did diabetes for all the patients even those with only the risk factors for atherothrombosis.Knowing that these factors boost the risk can help physicians take preventive action, according to the researchers, who are from the VA Boston Healthcare System, Brigham and Women's Hospital and Harvard Medical School in Boston. The researchers analyzed data from 45,227 patients enrolled in an international study known as Reduction of Atherothrombosis for Continued Health (REACH) between 2003 and 2004. They collected detailed information from the patients when they enrolled and conducted follow-ups one, two, three and four years later.

They found that 81.3 percent of the patients had hypertension, 70.4 percent had high  cholesterol levels in the blood, and 15.9 percent had polyvascular disease . In addition, 48.4 percent of the patients had "ischemic events" prior heart attacks, unstable angina or other problems related to the artery blockage, with 28.1 percent of those patients having had such an event within the previous year. During the follow-up period, 2,315 patients suffered cardiovascular death, 1,228 had a heart attack, 1,898 had a stroke, and 40 had a heart attack and a stroke on the same day. The researchers found that patients with atherothrombosis with a prior history of heart attacks and other events related to a blood vessel blockage had the highest rate of subsequent cardiac emergencies linked to blood flow problems.

Cholesterol Levels Fluctuate With Menstrual Cycle

Women's cholesterol levels vary throughout their menstrual cycle as their levels of estrogen rise and fall, a new study reveals. This means that to get a clear picture of a woman's cholesterol levels, doctors may need to take readings over several months before deciding whether the patient needs to have her levels lowered, the researchers noted. "Doctors who are looking at women high cholesterol have to take into account the phase of the menstrual cycle they are at when they take the measurement," said study co-author Enrique F. Schisterman, chief of the Epidemiology Branch at the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

"Practically, it's easier to recognize the beginning of a cycle," he said. "So if you do it consistently at the beginning of the cycle then you will get consistent measures over time." The report is published in the current online edition of the Journal of Clinical Endocrinology and Metabolism.For the study, Schisterman's group compared levels of estrogen with cholesterol and triglyceride levels in 259 healthy women, aged 18 to 44. Most of the women, had 14 or more measurements taken over two menstrual cycles. The women also charted the phases of their cycles using at-home fertility monitors that detect hormone levels indicating ovulation. Most of the women were physically active and did not smoke.

Only 5 percent had cholesterol levels higher than 200 mg/dL, which is borderline high-risk for heart disease. But, cholesterol levels among 19.7 percent of the women reached 200 mg/dL at least once. To make cholesterol readings more consistent and reliable, measurements should be taken at the same time each month for a couple of cycles, Schisterman added. "Practically, it's easier to recognize the beginning of a cycle," he said. "So if you do it consistently at the beginning of the cycle then you will get consistent measures over time."The report is published in the current online edition of the Journal of Clinical Endocrinology and Metabolism.