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Older women may become more sensitive to pain than men – study

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New research suggests that gender differences in pain perception may become more disparate with age.

The study found that the brain system which enables us to inhibit our own pain changes with age, and that gender-based differences in those changes, may lead older females to be more sensitive to moderate pain than males as older adults.

Researchers used fMRI scans to examine brain responses in men and women who had rated the intensity and unpleasantness of pain during exposure to increasing levels of heat.

The results, published recently in The Journal of Pain, suggested that established gender differences in pain perception could likely be traced at least in part to this brain network, and offered new evidence that those gender differences may become more disparate with age.

“The most novel part of this study is looking at gender by age,” said lead study author Michelle Failla, assistant professor in the College of Nursing at The Ohio State University.

“Most of the work characterising which regions in the brain respond to pain have been done in people aged 18 to 40. We want to understand what’s happening between the ages of 30 and 90-years-old because that’s when people are beginning to experience chronic pain.”

Plenty of previous research has shown that females are more sensitive to pain than males, but the brain regions and functions behind the gender differences in pain perception have mostly remained a mystery. And in later adulthood, when risk for chronic pain is higher and our tolerance for pain drops, even less about the brain’s role in pain perception is known.

In this study, the researchers specified that they holistically examined gender-based differences that may relate not just to biological sex, but also to social factors that influence how people respond to pain.

The imaging component of the study zeroed in on the descending pain modulatory system (DPMS), a hub of brain regions that communicate with each other to engage signal transmission – including activation of opioid receptors – that enables us to reduce our own pain.

The study sample included 27 females and 32 males between ages 30 and 86 who were asked to report when applied heat reached levels of just-noticeable, weak and moderate pain and to rate how unpleasant each level felt. Researchers used the fMRI imaging to observe DPMS activity that corresponded with each participant’s individual pain response.

“There are different brain regions involved in those distinctions between perception of pain intensity and unpleasantness, so we thought it was important to look at both and see how those brain regions are recruited during pain,” said Failla, also an investigator in the Center for Healthy Aging, Self-Management and Complex Care in Ohio State’s College of Nursing.

Results showed that a few regions within the brain’s pain modulatory system did indicate a gender-by-age difference: At the moderate pain level, men showed an increased DPMS response with older age, while as women aged, the DPMS response decreased. A decreased response in the brain is presumed to translate into a lower ability to harness our own physiological functions to reduce our pain.

Presumed is a key word: While the DPMS is believed to have a significant role in pain sensitivity and tolerance, researchers are still working toward describing exactly how it works and how an intact versus dysfunctional system shows up in scans.

“We don’t know exactly what is an optimum DPMS response,” Failla said. “Are we seeing it activated to catch up with your pain, or is it already working, meaning the pain could have been worse?”

The researchers are continuing this work, which includes investigating brain activity in people who may have a difficult time articulating the pain that they’re feeling – such as people with dementia or autism.

The more scientists can learn about the brain’s role in pain perception, the better the chances are for more effective pain management, Failla said.

“Pain is such an individual experience. In science we’re moving toward individual factors that can influence pain specifically and what makes it different for each person,” she said. “This could then identify a mechanism we can target, or even just give us a better understanding that there are different levels of innate abilities to modulate pain.”

This study was conducted at Vanderbilt University Medical Center and was supported by a National Institute on Aging grant awarded to co-authors Todd Monroe of Ohio State and Ronald Cowan of the University of Tennessee Health Science Center.

Other co-authors include Paul Beach of Emory University, Sebastian Atalla of the University of North Carolina, and Mary Dietrich and Stephen Bruehl of Vanderbilt University.

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Sitting still for long periods increases mortality risk, says study

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Sitting for long hours without breaks can increase risk mortality risk in older women, a new study shows.

The research, published in the Journal of the American Heart Association (JAHA), has data showing that older women who sat for 11.7 hours or more per day increased their risk of death by 30 percent, regardless of whether they exercised vigorously.

The study examined measurements of sitting and daily activity collected from hip devices worn for up to seven days by 6,489 women, aged 63 to 99, who were followed for eight years for mortality outcomes.

This data was collected  as part of a long-term national project known as the Women’s Health Initiative (WHI), which began in 1991 and is ongoing, led by Andrea LaCroix, Ph.D., M.P.H., Distinguished Professor at the Herbert Wertheim School of Public Health.

The paper is the first to apply a novel and validated machine-learned algorithm called CHAP to examine total sitting time and length of sitting bouts in relation to the risk of death.

Study co-author Steve Nguyen, PhD., M.P.H., a postdoctoral fellow at the University of California San Diego Herbert Wertheim School of Public Health and Human Longevity Science, said: “Sedentary behaviour is defined as any waking behaviour involving sitting or reclining with low energy expenditure.

“Previous techniques for calculating sedentary behaviour used cut points that identified low or absent movement. The CHAP algorithm was developed using machine-learning, a type of artificial intelligence, that enhanced its ability to accurately distinguish between standing and sitting.”

Fine-tuning “sitting” enabled Nguyen to parse total sitting time and usual sitting bout durations.

Sedentary behaviour is a health risk because it reduces muscle contractions, blood flow and glucose metabolism.

Exercise cannot undo these negative effects, according to the study, whether women participated in low or high amounts of moderate-to-vigorous intensity physical activity, they showed the same heightened risk if they sat for long hours.

LaCroix explained: “When you’re sitting, the blood flow throughout your body slows down, decreasing glucose uptake. Your muscles aren’t contracting as much, so anything that requires oxygen consumption to move the muscles diminishes, and your pulse rate is low.

“If I take a brisk long walk for an hour but sit the rest of the day, I’m still accruing all the negative effects on my metabolism.”

Based on the research, LaCroix makes the following recommendation: “The risk starts climbing when you’re sitting about 11 hours per day, combined with the longer you sit in a single session. For example, sitting more than 30 minutes at a time is associated with higher risk than sitting only 10 minutes at a time. Most people aren’t going to get up six times an hour, but maybe people could get up once an hour, or every 20 minutes or so. They don’t have to go anywhere, they can just stand for a little while.”

However, Nguyen points out that not all sitting is the same.

“Looking beyond conditions like cardiovascular disease, we start thinking about cognitive outcomes, including dementia,” he said.

“There are cognitively stimulating activities that can result in sedentary behavior, like sitting while studying a new language. Is sedentary behavior in that context overall bad for a person? I think it’s hard to say.” Nguyen has recently received a National Institute of General Medical Sciences K99 award for 12 months of mentored research to look at protein signatures of physical activity and how they relate to dementia.

LaCroix added: “We’ve created this world in which it’s so fascinating to sit and do things. You can be engrossed by TV or scroll on your Instagram for hours. But sitting all the time isn’t the way we were meant to be as humans, and we could reverse all of that culturally just by not being so attracted to all the things that we do while sitting.”

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High risk of hospital readmission after surgery among older Americans

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A study finds an increased risk of hospital readmission for older Americans within 180 days of undergoing major surgery — a risk that is particularly acute for individuals who are frail or have dementia.

The findings from researchers at the University of Yale, were published in the journal JAMA Network Open.

Previous research by the same team demonstrated that major surgery is a common event for older Americans and also demonstrated a heightened mortality risk within one year of major surgery for people who are age 65 and older.

The new study is the first to describe both the short-term risk (within 30 days) and longer-term risk (within 180 days) of hospital readmission for older Americans who have recently had major surgery.

The study looked at hospital readmission among a nationally representative sample of 1,477 older Americans, not living in nursing homes, who had at least one major surgery between 2011 and 2018. More than one in four (27.6 per cent) had a readmission to the hospital within 180 days after major surgery; nearly one in eight (11.6 per cent) were readmitted within just 30 days.

Dr. Robert D. Becher, associate professor of surgery at Yale School of Medicine and co-senior author of the study, commented: “Prior to now, data on longer-term readmissions after major surgery in older persons have been lacking. This is problematic, as older persons undergoing major surgery represent a large and growing population.

“These readmission rates are high. And this study adds to our understanding of what it means to recover from major surgery as an older person.”

The numbers are even higher for those with geriatric-specific conditions such as frailty and dementia. Frail patients were readmitted within 180 days at a rate of 36.9 per cent; patients with probable dementia were readmitted at a rate of 39 per cent; and patients 90 years old and older were readmitted at a rate of 36.8 per cent.

Dr. Thomas M. Gill, the Humana Foundation Professor of Geriatric Medicine at Yale and co-senior author of the study, said: “These findings reenforce the importance of enhanced preoperative recognition of frailty and dementia in older persons and may inform patient and family expectations — and surgical decision making — about postoperative trajectories in the setting of these geriatric conditions.”

The issue of hospital readmission looms large in the USS health care system for a variety of reasons.

In 2018 alone, readmission costs totalled more than $50 billion, the researchers said. This was driven, in part, by the nearly 3.8 million 30-day hospital readmissions that year. The vast majority of those patients are Medicare beneficiaries aged 65 and older.

“From a patient perspective, the most important outcome among older persons with multiple conditions is maintaining independence and function. And we know that being readmitted to the hospital after major surgery can negatively impact that independence and function,” Becher said.

“So these new data put into perspective just how common hospital readmissions, and their negative downstream consequences, are to older persons.”

The researchers said the next steps in their examination of the issue will be to further understand why vulnerable older persons have such high readmission rates and suggest meaningful ways to minimise the risk of readmission.

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Risk factors for frailty in old age different in men and women, finds study

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A study conducted by researchers at the Federal University of São Carlos (UFSCar) in Brazil and University College London (UCL), found the factors that increase the risk of frailty in old age to be different in men and women.

The study, which was funded by FAPESP, is published in the journal Archives of Gerontology and Geriatrics.

According to the results, osteoporosis, low weight, heart disease, and poor hearing increased the risk of frailty in men, while a high level of fibrinogen (a marker of cardiovascular disease) in the blood, diabetes and stroke were associated with a higher risk of frailty in women.

The findings were based on an analysis of data from 1,747 participants in the English Longitudinal Study of Ageing (ELSA), an ongoing population survey that explores the dynamic relationships between health, functioning, social networks and economic status in people aged 50 and over who reside in England. ELSA began in 2002. These participants were interviewed and assessed every four years between 2004 and 2016.

The researchers selected participants aged 60 or more who initially did not have frailty syndrome and were not classified as pre-frailty (with only one or two of the above factors).

Frailty syndrome is characterised by the presence of three or more of the following factors: involuntary weight loss, fatigue, muscle weakness, slow gait, and a low level of physical activity. It is more common in women than men, partly because of women’s greater life expectancy.

Tiago da Silva Alexandre, last author of the article and a professor in UFSCar’s Department of Gerontology, explained: “Frailty syndrome serves as a warning sign of the possibility of a negative outcome in an older person. We used to think of frailty as having a single pathway in the elderly, but our study shows there are several routes. The differences between men and women in this regard are important for policymakers to take into account. They should influence primary health care and could result in more gender-specific action plans and intervention for older people.”

Frailty syndrome has a phenotype, he explained – a set of easily identifiable signs and symptoms designed to identify older people with a heightened risk of falls, hospitalisations, incapacitation, and early death.

“Our study went back a few steps before this process begins to find out which characteristics may lead to frailty during the lives of these older people. When we think about aging and the quality of life in old age, it’s very important to identify the main risk factors so as to be able to foresee problems and formulate public policy for men and women,” he added.

According to Dayane Capra de Oliveira, first author of the article, although frailty as a tool is based on biology, sex-related differences in risk factors for development of the syndrome are mainly associated with the different social roles of men and women, and with their different degrees of access to resources during their lives.

“Another key aspect is that frailty is a multifactorial condition. While socioeconomic factors, skeletal muscle disorders, heart disease and low weight appear to underlie frailty in men, in women the process appears to be driven mainly by cardiovascular and neuroendocrine disturbances,” Oliveira said.

Differences and similarities

According to the researchers, while some risk factors for frailty are the same for men and women – including old age, low educational attainment, sedentarism and depression, for example – differences in body composition and fat deposition throughout life and especially in old age may lead directly or indirectly to the appearance of components of frailty, such as metabolic alterations that culminate in the development of diseases, which in turn increase the risk of frailty.

Alexandre said: “Our study is based on data for people now aged 60 or more and living in England. We don’t know how these sex-based differences will play out in future generations. However, the fact is that the men in the cohort we studied were more exposed to several kinds of working conditions considered risk factors for diseases. Their diet was less healthy. They didn’t go to the doctor as much as the women [so that there was less early diagnosis]. They drank more and were more exposed to other substances that increased the risk of cardiovascular disease and heart attack.”

Women are more affected by chronic diseases, which are not as lethal but can be incapacitating.

He added: “The sex-based differences are a lifelong backdrop and culminate in different ageing processes, different causes of death or disability, and different kinds of frailty in men and women.”

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