E. coli infection linked to long-term health problems

ScienceDaily (Nov. 19, 2010) — People who contract gastroenteritis from drinking water contaminated with E. coli are at an increased risk of developing high blood pressure, kidney problems and heart disease in later life, finds a study published on the British Medical Journal website.

The findings underline the importance of ensuring a safe food and water supply and the need for regular monitoring for those affected.

It is estimated that E. coli O157:H7 infections cause up to 120,000 gastro-enteric illnesses annually in the US alone, resulting in over 2,000 hospitalisations and 60 deaths. However, the long term health effects of E. coli infection in adults are largely unknown.

So a team of researchers in Canada assessed the risk for hypertension, renal impairment and cardiovascular disease within eight years of gastroenteritis from drinking contaminated water.

They used data from the Walkerton Health Study -- the first study to evaluate long term health after an outbreak of gastroenteritis in May 2000 when a municipal water system became contaminated with E. coli O157:H7 and Campylobacter bacteria.

Study participants were surveyed annually and underwent a physical examination and laboratory assessment to track their long term health.

Of 1,977 adult participants, 1,067 (54%) experienced acute gastroenteritis of whom 378 sought medical attention.

Compared with participants who were not ill or only mildly ill during the outbreak, participants who experienced acute gastroenteritis were 1.3 times more likely to develop hypertension, 3.4 times more likely to develop renal impairment, and 2.1 times more likely to have a cardiovascular event, such as a heart attack or stroke.

The authors conclude: "Our findings underline the need for following up individual cases of food or water poisoning by E. coli O157:H7 to prevent or reduce silent progressive vascular injury."

They add: "These long term consequences emphasise the importance of ensuring safe food and water supply as a cornerstone of public health."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by BMJ-British Medical Journal, via EurekAlert!, a service of AAAS.

Journal Reference:

W. F. Clark, J. M. Sontrop, J. J. Macnab, M. Salvadori, L. Moist, R. Suri, A. X. Garg. Long term risk for hypertension, renal impairment, and cardiovascular disease after gastroenteritis from drinking water contaminated with Escherichia coli O157:H7: a prospective cohort study. BMJ, 2010; 341 (nov17 2): c6020 DOI: 10.1136/bmj.c6020

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Short and long sleep in early pregnancy linked to high blood pressure in the third trimester

ScienceDaily (Oct. 2, 2010) — A study in the Oct. 1 issue of the journal Sleep found that getting too little or too much sleep in early pregnancy is associated with elevated blood pressure in the third trimester. The study suggests that improving prenatal sleep hygiene may provide important health benefits.

Results show that the mean systolic blood pressure in the third trimester was 114 mm Hg in women with a normal self-reported nightly sleep duration of nine hours in early pregnancy, 118.05 mm Hg in women who reported sleeping six hours or less per night, and 118.90 mm Hg in women with a nightly sleep duration of 10 hours or more in early pregnancy. After adjustments for potential confounders such as age, race and pre-pregnancy body mass index, mean systolic blood pressure was 3.72 mm Hg higher in short sleepers and 4.21 mm Hg higher in long sleepers. Similar results also were found for diastolic blood pressure.

"Both short and long sleep duration in early pregnancy were associated with increased mean third trimester systolic and diastolic blood pressure values," said principal investigator and lead author Dr. Michelle A. Williams, professor of epidemiology in the School of Public Health at the University of Washington and co-director of the Center for Perinatal Studies at Swedish Medical Center in Seattle, Wash.

The study also found an association between sleep duration and preeclampsia, a condition that involves pregnancy-induced hypertension along with excess protein in the urine. The risk of developing preeclampsia was almost 10 times higher (adjusted odds ratio = 9.52) in very short sleepers who had a nightly sleep duration of less than five hours during early pregnancy. Overall, about 6.3 percent of participants were diagnosed with either preeclampsia or pregnancy-induced hypertension without proteinuria.

"If our results are confirmed by other studies, the findings may motivate increased efforts aimed at exploring lifestyle approaches, particularly improved sleep habits, to lower preeclampsia risk," said Williams.

According to the National Heart, Lung, and Blood Institute, systolic blood pressure -- the top number in a blood pressure reading -- is the force of blood in the arteries as the heart beats. A systolic blood pressure reading is considered to be "high" if it is 140 or more millimeters of mercury.

The Eunice Kennedy Shriver National Institute of Child Health and Human Development reports that preeclampsia is a syndrome that occurs after the 20th week of pregnancy. It should be monitored closely by a medical professional because it can have a severe impact on the health of the mother and her baby.

The study involved 1,272 healthy, pregnant women who completed a structured interview at 14 weeks gestation, on average. Sleep duration in early pregnancy was evaluated by the question, "Since becoming pregnant, how many hours per night do you sleep?" Only about 20.5 percent of women reported a sleep duration of nine hours per night, which was used as the "normal" reference category because prior research indicates that pregnant women tend to have longer sleep duration patterns. About 55.2 percent of women reported sleeping seven to eight hours per night, 13.7 percent slept six hours or less and about 10.6 percent slept 10 hours or more.

After delivery, data on maternal blood pressures at routine prenatal care visits were abstracted from participants' medical records, providing an average of 12 blood pressure values for each participant. Women with pre-gestational chronic hypertension were excluded from the study. Mean systolic blood pressures were 111.8 mm Hg and 111.4 mm Hg in the first and second trimesters, and 114.1 mm Hg in the third trimester.

According to the authors, a number of mechanisms by which habitual short sleep duration may lead to increased blood pressure have been proposed. Because blood pressure is known to dip by an average of 10 to 20 percent during sleep, short sleep durations may raise the average 24-hour blood pressure and heart rate. This may lead to structural changes that gradually raise the pressure equilibrium of the entire cardiovascular system. Sleep restriction also may produce abnormalities in the levels of hormones such as endothelin and vasopressin, which play an important role in the cardiovascular system. The authors suspect that the association between long sleep duration and elevated blood pressures may be related to unmeasured confounders such as obstructive sleep apnea, depression or insulin resistance.

Williams noted that this study is the first step at filling an important gap in the scientific literature. Because most sleep studies exclude pregnant women, little is known about how insufficient sleep during gestation contributes to increased risks of medical complications of pregnancy.

"Moving forward, large-scale sleep studies should include pregnancy cohorts so that health care providers and mothers-to-be can more fully appreciate the health risks of insufficient sleep," she said.

Williams advises pregnant women and women who are planning to become pregnant to develop healthy habits that promote sufficient sleep. The tips she suggested include:

Establishing a consistent sleep scheduleFollowing a relaxing bedtime routineCreating a comfortable sleep environmentKeeping technological distractions such as the TV and computer out of the bedroomEating at least two to three hours before bedtimeExercising regularly during the dayAvoiding caffeine and alcohol before bedtime and giving up smoking

The study was supported by grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Academy of Sleep Medicine, via EurekAlert!, a service of AAAS.

Journal Reference:

Michelle A. Williams et al. Associations of early pregnancy sleep duration with trimester-specific blood pressures and hypertensive disorders in pregnancy. Sleep, (in press)

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

New study singles out factors linked to cognitive deficits in type 2 diabetes

ScienceDaily (Sep. 11, 2010) — Older adults with diabetes who have high blood pressure, walk slowly or lose their balance, or believe they're in bad health, are significantly more likely to have weaker memory and slower, more rigid cognitive processing than those without these problems, according to a new study published by the American Psychological Association.

These three health factors stood out from more than a dozen suspected to shape how Type 2 diabetes is frequently shadowed by cognitive impairment, including dementia. An analysis in September's Neuropsychology stresses that although these factors might not actually cause cognitive problems, their presence can warn doctors that such problems may exist or soon develop.

"Awareness of the link between diabetes and cognition could help people realize how important it is to manage this disease--and to motivate them to do so," said co-author Roger Dixon, PhD, of the University of Alberta.

Type 2 diabetes has been found by other researchers to nearly double the risk of dementia and Alzheimer's disease, said Dixon, who studies how health affects cognition in aging. As diabetes becomes more common, this heightened risk could dramatically hike the number of older people with dementia -- a double whammy of serious chronic disease. Among people older than 60, the U.S. prevalence of Type 2 diabetes is more than 23 percent, according to the National Institute of Diabetes and Digestive & Kidney Diseases. The Canadian prevalence is nearly 19 percent, according to the Public Health Agency of Canada.

An analysis of older Canadians living in British Columbia -- 41 with Type 2 diabetes (ages 55-81) and 458 matched healthy controls (ages 53-90) -- found that systolic blood pressure (the top number, or maximum pressure on artery walls during a single heartbeat), a low combination score for gait and balance, and a patient's own reports of poor health all played a statistically significant role in the relationship between diabetes and cognitive impairment relationship.

In other words, higher but still normal blood pressure, slower gait and shakier balance, and/or reporting one's self to be in bad health regardless of actual problems boosted the likelihood that someone with Type 2 diabetes had impaired cognition. The relationships were linear: For example, the worse the balance, the higher the likelihood of cognitive problems, as measured by mental speed (reaction time, switching time and perceptual speed), mental control and flexibility (executive functioning), and recall of recent learning (episodic memory).

The results highlight factors that may work indirectly, gradually and cumulatively to make older diabetics more likely to develop dementia. Researchers tested 13 different variables in all, in the areas of general fitness, emotional health, subjective and functional health, and lifestyle activities.

Mediating Factors

Because diabetes and hypertension often go together, Dixon said he was not surprised that high systolic blood pressure accounted for one-third to one-half of significantly worse scores on four tests. That finding, said the authors, suggests that diabetes and cognition may be connected via diabetics' vascular problems. For example, diabetes and hypertension may both play a role in a larger metabolic syndrome that includes high blood sugar and insulin resistance.

However, the other two factors raised new questions. Combined gait and balance had the greatest influence, accounting for between 32 percent and 62 percent of performance on seven cognitive tests. Diabetes might affect the specific nerves that control gait and balance, the authors wrote, or more broadly affect the overlapping brain areas that support both gait-balance and cognition.

Like blood pressure, what people said about their health accounted for about one-third to one-half of performance on five different cognitive tests. Negativity about one's health could reflect related factors such as stress or depression, which did not, in this study, directly mediate between diabetes and cognition. Self-reported health is "an important indicator of ways in which a cluster of health-related beliefs and behaviors can modulate the effect of this disease on cognitive adaptation," Dixon said.

"It's important to pay attention to the health beliefs of older adults, not because they are necessarily accurate or valid indicators of specific health status, but because they might track overall health," Dixon said.

Type 2 diabetes in adults accounts for 90 percent to 95 percent of all diagnosed cases of diabetes, according to the National Institute of Diabetes and Digestive & Kidney Diseases.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Psychological Association, via EurekAlert!, a service of AAAS.

Journal Reference:

McFall et al. Testing covariates of Type 2 diabetes-cognition associations in older adults: Moderating or mediating effects? Neuropsychology, 2010; 24 (5): 547 DOI: 10.1037/a0019246

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here