Study indicates longer reproductive life span experienced by U.S. women
Researcher analyzes factors driving the increase in age at natural menopause
April 22, 2021
Science Daily/Texas Tech University Health Sciences Center
As females age, their bodies typically undergo two significant changes that generally occur during adolescence and middle age. The first, known as menarche, is the time during puberty when a girl begins having monthly menstruation cycles, which often tends to range from 8-13 years of age. She enters the second change, known as menopause, 12 months following her last menstruation cycle when her ovarian function ceases, usually sometime in her 40s or 50s.
The time after menarche and prior to menopause is known as a woman's reproduction life span and marks the years when she is most able to bear children. For many women, these events occur naturally. However, women can enter menopause earlier than expected due to other issues. Women that undergo radiation therapy for cancer typically stop menstruating, as do women who undergo surgical menopause procedures such as having their ovaries removed.
Because each woman experiences these life stages at different times, one woman's reproductive life span is generally shorter or longer than that of another, sometimes significantly so. Duke Appiah, Ph.D., from the Texas Tech University Health Sciences Center (TTUHSC) Graduate School of Biomedical Sciences, said those differences can affect much more than a woman's reproductive health.
For instance, Appiah said, researchers have known a link exists between the duration of a woman's reproductive life span and her overall metabolic health, but they haven't known why. Part of that link, he opined, could be caused by a woman being naturally exposed to estrogen and various estrogen compounds. Estrogens can be beneficial because they can help protect or delay the onset of certain health issues. However, they also have been associated with some diseases, and women that normally have less estrogen and remain that way through menopause are more likely to develop heart disease or osteoporosis.
"If the reproductive life span is longer, then that means they still have exposure to the natural estrogens, which will also help delay some diseases like cardiovascular disease and osteoporosis, and to some extent, even cancer," Appiah said.
But why do some women who have longer reproductive life spans, and therefore longer exposure to estrogens, still develop metabolic issues?
It's a question Appiah and a group of collaborators set out to address in a research letter to the Journal of the American Medical Association (JAMA). The letter, "Trends in Age at Natural Menopause and Reproductive Life Span Among U.S. Women, 1959-2018," was published in JAMA's April 8 issue. Appiah's collaborators included Chike C. Nwabuo, M.D., MPH, from Johns Hopkins University; Imo A. Ebong, M.D., M.S., from the University of California, Davis; Melissa F. Wellons, M.D., MHS, from Vanderbilt University Medical Center; and Stephen J. Winters, M.D., from the University of Louisville.
Appiah, an assistant professor of public health at the TTUHSC and director of the university's master's program in public health, said women who enter menopause at age 40-45 years have a higher risk of developing cardiovascular disease, whereas those who become menopausal after the age of 50 experience a higher risk of breast cancer.
"These characteristics have clinical significance, but we wanted to see in the United States over the past 60 years, if there have been any changes in age at menopause, reproductive life span and to age at menarche," Appiah explained. "If it was changing, we wanted to find out what factors are possibly associated with these changes. Not many studies have been done in the U.S. to look at trends in age at menopause. If we can see some of the factors which are associated with or are driving having natural menopause at an earlier age, perhaps we can intervene."
Appiah said many of the previous studies are outdated and used data from shorter time periods such as 1910-1950. None of these studies investigate the link between age at menopause and the development of metabolic health issues. They also failed to address factors that may cause a woman to enter menopause earlier in her life.
To collect data for his study, Appiah used successive surveys spanning the 1959-1962 National Health Examination Survey I (NHES I) through the National Health and Nutrition Examination Survey (NHANES) for 2017-2018. The NHANES is a biennial survey conducted by the Centers of Disease Control and Prevention to generally evaluate the health of children and adults in the U.S. In addition to providing a significantly larger sample size, the NHANES provides a cross-sectional sample of the non-institutionalized U.S. adult population. It includes a detailed demographic and behavioral questionnaire, a physical examination, laboratory testing and a list of all prescription medications used by the respondent.
Using this data, Appiah was able to analyze 7,773 women aged 40 to 74 years at the time of the survey and who had reached natural menopause. From the 1959-1962 NHES I to the 2015-2018 NHANES, the mean age at which women reached natural menopause increased from 48.4 years to 49.9 years and the mean age at menarche fell from 13.5 years to 12.7 years. This resulted in an increase of the mean reproductive life span from 35.0 years to 37.1 years.
In multivariable adjusted models Appiah saw that race and ethnicity (Black and Hispanic), poverty, current and former smoking status and hormone therapy use were associated with earlier age at natural menopause and a shorter reproductive life span. Factors such as more years of education and use of oral contraceptives were associated with women who reached natural menopause at a later age and had longer reproductive life span.
Appiah said other factors not assessed in their study such as lifestyle and behavior factors, improved access to health care, nutrition, obesity and environmental factors may be related to the increasing trends in age at natural menopause and reproductive life span.
In past research, Appiah has shown that menopause is associated with metabolic conditions, which also influence the development of certain diseases. More importantly, he said, his work has shown that researchers tend to be more concerned about the age at which women reach menopause when they actually need to identify factors that are causing women to reach menopause at an earlier age because those factors tend to be more important.
"This study was to give some empirical evidence to some of my past studies, but then for future studies, I'm still looking at how age and menopause is associated with cardiac structure and function, for instance, how the heart beats, how the heart becomes bigger with age," Appiah said. "This paper has given perspective to some of my past work, and it's also given some direction to my future work, whereby I'll look at whether age at natural menopause and length of reproductive life span is a marker for overall health in women."
https://www.sciencedaily.com/releases/2021/04/210415090803.htm
Poor iodine levels in women pose risks to fetal intellectual development in pregnancy
April 22, 2021
Science Daily/University of South Australia
An increasing number of young women are at increased risk of having children born with impaired neurological conditions, due to poor iodine intake.
Dietary changes, including a growing trend towards the avoidance of bread and iodised salt, as well as a reduced intake of animal products containing iodine can contribute to low iodine levels.
A small pilot study undertaken by the University of South Australia (UniSA) comparing iodine levels between 31 vegan/plant-based participants and 26 omnivores has flagged the potential health risk.
Urine samples showed iodine readings of 44 ug/L in the plant-based group, compared to the meat eaters' 64 ug/L level. Neither group came close to the World Health Organization's recommended 100 grams per litre.
Participants from both groups who chose pink or Himalayan salt instead of iodised salt had severely deficient iodine levels, averaging 23 ug/L.
The findings have been published in the International Journal of Environmental Research and Public Health.
While the study was undertaken in South Australia, it builds evidence on a 2017 US study that found nearly two billion people worldwide were iodine deficient, resulting in 50 million experiencing clinical side effects.
UniSA research dietitian Jane Whitbread says adequate iodine is essential for fetal intellectual development.
"Mild to moderate iodine deficiency has been shown to affect language development, memory and mental processing speeds," Ms Whitbread says.
"During pregnancy, the need for iodine is increased and a 150mcg supplement is recommended prior to conception and throughout pregnancy. Unfortunately, most women do not take iodine supplements before conceiving. It is important to consume adequate iodine, especially during the reproductive years."
Dietary sources of iodine include fortified bread, iodized salt, seafoods including seaweeds, eggs, and dairy foods.
Concerns about the link between poor iodine status and impaired neurological conditions in newborns prompted the mandatory fortification of non-organic bread with iodised salt in 2009 in Australia.
It has since been reported that women who consume 100g of iodine-fortified bread every day (approximately three pieces) have five times greater chance of meeting their iodine intake compared to women who don't consume that much. The average amount of bread consumed by women in this study was one piece of bread.
The growing preference of Himalayan salt over iodized table salt may also be problematic, Ms Whitbread says. A quarter of women in the study reported using the pink salt which contains an insignificant level of iodine.
Another issue is that plant-based milks have low levels of iodine and are not currently fortified with this nutrient.
Neither group met the estimated average requirement (EAR) for calcium.
The vegan/plant-based group also did not reach the recommended levels for selenium and B12 without supplementation, but their dietary intake of iron, magnesium, vitamin C, folate and fibre was higher than the meat eaters. This reflects the inclusion of iron-rich soy products, wholemeal foods, legumes, and green leafy vegetables in their diet.
The researchers recommended that both new salts and plant milks be fortified with iodine as well as a campaign to raise awareness about the importance of iodine in the diet, especially for women in their reproductive years.
They also called for a larger study sample to determine iodine status of Australian women.
https://www.sciencedaily.com/releases/2021/04/210422093858.htm
Disrupted sleep is linked to increased risk of early death, particularly in women
April 19, 2021
Science Daily/European Society of Cardiology
For the first time, a study has shown a clear link between the frequency and duration of unconscious wakefulness during night-time sleep and an increased risk of dying from diseases of the heart and blood vessels, and death from any cause, particularly in women.
The study of 8001 men and women, which is published today (Tuesday) in the European Heart Journal, found that women who experienced unconscious wakefulness most often and for longer periods of time had nearly double the risk of dying from cardiovascular disease during an average of between 6 and 11 years' follow-up, when compared to the risk in general female population. The association was less clear in men, and their risk of cardiovascular death increased by just over a quarter compared to the general male population.
Unconscious wakefulness, also known as cortical arousal, is a normal part of sleep. It occurs spontaneously and is part of the body's ability to respond to potentially dangerous situations, such as noise or breathing becoming obstructed. Pain, limb movements, trauma, temperature and light can also be triggers.
Dominik Linz, associate professor in the cardiology department at Maastricht University Medical Center (The Netherlands), explained: "A common trigger for nocturnal arousals is obstructive sleep apnoea when breathing stops and the arousal system ensures the activation of our body to change our sleep position and to reopen the upper airway. Another cause of arousals can be 'noise pollution' during the night by, for example, night-time aircraft noise. Depending on the strength of the arousal, a person might become consciously aware of the environment, but often that is not the case. Typically, people will feel exhausted and tired in the morning because of their sleep fragmentation but will not be aware of the individual arousals."
Previous research has shown that sleep duration, either too short or too long, is associated with increased risks of death from cardiovascular or other causes. However, until now, it was unknown whether there was also a link with the arousal burden (a combination of the number of arousals and their duration) during a night's sleep and the risk of death.
In a collaboration between a team led by associate professor Mathias Baumert from the School of Electrical and Electronic Engineering at the University of Adelaide (Australia) and Prof. Linz, researchers looked at data from sleep monitors worn overnight by men and women taking part in one of three studies: 2782 men in the Osteoporotic Fractures in Men Sleep Study (MrOS), 424 women in the Study of Osteoporotic Fractures (SOF), and 2221 men and 2574 women in the Sleep Heart Health Study (SHHS). The average ages in the studies were 77, 83 or 64 years, respectively. The participants were followed up over a period of several years, which ranged from an average of six years (SOF) to 11 years (MrOS).
After adjusting for factors that could affect the results such as total sleep duration, age, medical history, body mass index (BMI) and smoking habits, the researchers found that women had an arousal burden that was lower than men. However, those who had an arousal burden that accounted for more than 6.5% of their night's sleep had a greater risk of dying from cardiovascular disease than women with a lower arousal burden: double the risk in SOF and 1.6 times the risk in SHHS. Their risk of dying from all causes was also increased by 1.6 times in SOF and 1.2 times in SHHS.
Taking the women from both studies together, those with an arousal burden of more than 6.5% had a 12.8% risk of dying from cardiovascular disease, nearly double that of women of a similar age in the general population who had a risk of 6.7%. The risk of dying from any cause was 21% among women in the general population, which increased to 31.5% among women in the two studies with an arousal burden of more than 6.5%
Men with an arousal burden accounting for more than 8.5% of their night's sleep had 1.3 times greater risk of dying from cardiovascular disease (MrOS) or any cause (SHHS), compared to men with lower arousal burdens, but findings for increased risk of death from any cause in MrOS or cardiovascular disease in SHHS were not statistically significant.
When the researchers looked at all the men in both studies, those with an arousal burden of more than 8.5% had a risk of 13.4% and 33.7% of dying from cardiovascular disease or any cause, respectively, compared to the risk in the general population of men of similar ages of 9.6% and 28%, respectively.
Prof. Linz said: "It is unclear why there is a difference between men and women in the associations, but there are some potential explanations. The triggers causing an arousal or the body's response to arousal may differ in women compared to men. This may explain the relatively higher risk of cardiovascular death in women. Women and men may have different compensatory mechanisms for coping with the detrimental effects of arousal. Women may have a higher arousal threshold and so this may result in a higher trigger burden in women compared to men."
He said that older age, BMI and the severity of sleep apnoea increase arousal burdens. "While age cannot be changed, BMI and sleep apnoea can be modified and may represent an interesting target to reduce arousal burdens. Whether this will translate into lower risks of dying from cardiovascular disease warrants further study. For me as a physician, a high arousal burden helps to identify patients who may be at higher risk of cardiovascular disease. We need to advise our patients to take care of their sleep and practice good sleep 'hygiene'. Measures to minimise noise pollution during the night, lose weight and treat sleep apnoea could also help to reduce the arousal burden."
Prof. Baumert said: "In order to include assessment of arousal burdens into routine strategies for reducing the risk of cardiovascular disease, we need easily scalable, widely accessible and affordable techniques to estimate the duration and fragmentation of sleep and to detect arousals. Wearable devices for measuring activity and changes in breathing patterns may provide important information."
Limitations of the study include that it was conducted in older, mainly white people and so its findings cannot be extrapolated to other races or younger men and women. The researchers did not consider the possible effect of medications; monitoring of the participants' sleep was conducted on a single night and so does not take account of night-to-night variations. Finally, it can only show there is an association between greater sleep arousal burden and increased risk of death, not that sleep arousals cause the increased risk.
In an accompanying editorial Professor Borja Ibáñez, clinical research director at the Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid (Spain), and colleagues, who were not involved in the research, write that a strength of the study is that the arousal burden was measured objectively with sleep monitors, rather than being self-reported by the participants. They point out that disruption of the body's natural circadian rhythm is known to be involved in the development of often undetected fat accumulation in arteries and this could be a possible mechanism for the increase in the risk of cardiovascular problems.
They continue: "Even though many knowledge gaps on the relationship between sleep and CVD [cardiovascular disease] remain to be studied in the coming years, this study provides solid evidence supporting the importance of sleep quality for a better CV health. Further evidence combining comprehensive sleep evaluation with biological sampling and long-term follow-ups will be desirable . . . What remains to be determined is whether an intervention aiming at improving sleep quality is able to reduce the incidence of CV events and mortality. While awaiting these trials, we wish you sweet dreams."
https://www.sciencedaily.com/releases/2021/04/210419195248.htm
Health benefits of breastfeeding, for mother: Lactation and visceral, pericardial fat
April 9, 2021
Science Daily/Texas Tech University Health Sciences Center
As demonstrated by multiple studies over the years, women who breastfeed have a lower risk for developing cardiovascular disease and diabetes when compared to those who don't or can't. However, the mechanisms by which these risks are reduced for lactating women are still not fully understood.
Duke Appiah, Ph.D., an assistant professor of public health at the Texas Tech University Health Sciences Center and director of the university's master's program in public health, said the presence of excess fat, specifically visceral and pericardial fat could help explain this finding. Using that hypothesis, Appiah and a team of researchers recently completed a study titled, "The Association of Lactation Duration with Visceral and Pericardial Fat Volumes in Parous Women: The CARDIA Study." The Journal of Clinical Endocrinology & Metabolism published the results in its February issue.
The Appiah team included Cora E. Lewis, M.D., and James M. Shikany (University of Alabama at Birmingham); David R. Jacobs, Jr., Ph.D., and Myron Gross, Ph.D., (University of Minnesota); Jeff Carr, M.D., (Vanderbilt University Medical Center); and Charles P. Quesenberry, Jr., Ph.D., Stephen Sidney, M.D., and senior research scientist Erica P. Gunderson, Ph.D., (Kaiser Permanente Northern California). The National Institute of Diabetes and Digestive and Kidney Diseases provided funding to Gunderson, the study's senior author, for creating the pregnancy-related derived variables, and for the analysis of lactation and the development of cardiometabolic diseases in Coronary Artery Risk Development in Young Adults (CARDIA) study women.
Visceral fat, often referred to as active fat, potentially can increase the risk of developing dangerous health issues such as cardiovascular disease, heart attacks, Type 2 diabetes, stroke, breast and colorectal cancer and Alzheimer's disease. Though it can build up in the arteries, visceral fat typically is stored within the abdominal cavity near critical organs such as the stomach, liver and intestines.
Pericardial fat, a deposit of fatty tissue located on the outside of the heart, also may influence certain cardiovascular conditions.
"We know these two organ-related fats contribute to diabetes as well as cardiovascular disease, so we wanted to see how breastfeeding influences these types of fat," Appiah explained. "If breastfeeding does affect these fats, then it means it could provide a physiologic mechanism by which we can understand how breastfeeding actually affects these two main diseases. That was basically the motivation for this study."
Because these fats are related to insulin production and other cardio metabolic factors, Appiah said weight change could influence the relationship between breastfeeding and these fats. For instance, the visceral fat that builds up around the abdomen tends to also include adipokines, which are cytokines produced by fatty tissue. Adipokines also secrete hormones, which influence the insulin sensitivity of the muscles. When the amount of visceral fat increases, so too does the competition for insulin binding sites, which increases the risk of developing insulin resistance or glucose intolerance.
An increase in pericardial fat also puts additional weight on the heart and can affect its contractivity, or how it beats, which also could influence other cardiovascular diseases. Though many studies have looked at visceral fat, or abdominal fat, and its influence on cardiometabolic health, Appiah said not as much is known about pericardial fat.
"However, there is still enough science showing that the more pericardial fat you have, the more likely you are to get cardiovascular disease," Appiah said. "What this really means is that breastfeeding affects weight gain, and so women who breastfeed typically will not gain more weight, which will also influences less fat buildup in the abdomen or around their heart."
Gunderson said previous studies on women in the 30-year CARDIA study have shown lactation duration is associated with a 50% lower relative risk of progression to Type 2 diabetes in women, independent of their metabolic profiles and body size before pregnancy, social factors and lifestyle behaviors. Lactation also may prevent future development of cardiovascular disease in women by reversing hypertriglyceridemia during pregnancy through the removal of excess fatty acids in the production of breast milk and by preventing the lowering of high-density lipoprotein cholesterol after delivery.
"This lower pericardial fat was mediated only partially by subsequent weight gain, indicating that there are powerful systemic metabolic changes independent of overall adiposity," Gunderson said. "Thus, lower fat deposition in the heart and other organs might potentially explain the protective benefits of lactation to prevent cardiovascular disease in women."
To generate data for his research, Appiah used the CARDIA study, with which he also is affiliated. CARDIA, sponsored by the National Institutes of Health-National Heart Lung and Blood Institute, is a long-term study of cardiovascular disease that includes more than 5,000 Black (48%) and white (52%) adult women who were aged 18 to 30 years when the study began in 1985-1986.
As one of the longest and continuous studies of its kind, the CARDIA study has continued to monitor these participants for more than 30 years and has aided researchers in understanding how factors that appear in early adulthood can increase the risk of cardiovascular disease later in life.
"There are not many studies out there which actually have followed young women all through their birth years and measured cardiovascular risk factors on all of them," Appiah said. "It also includes cumulative measures of lactation, which made CARDIA more unique to address this research because it's not just one episode of breastfeeding that is important. We wanted to look at the entire reproductive lifespan and CARDIA was the best study to do that."
Gunderson, who also is a professor of health systems science at the Kaiser Permanente Bernard J. Tyson School of Medicine, said the CARDIA data enabled the research team to account for biomarkers and metabolic risk factors before pregnancy that might influence future adiposity and cardiovascular health.
"After accounting for lifestyle behaviors and other risk factors across the life course, the lower visceral and pericardial fat among women with longer lactation persisted," Gunderson said. "This indicates lactation may have effects that persist many years through midlife."
After their initial enrollment in the study in 1985-1986, women in the CARDIA study update their measurements and other history approximately every five years, giving investigators a clearer picture of a woman's entire reproductive lifespan. The results, as Appiah discovered in his research, show that women who breastfed more over the duration of their reproductive years experienced less weight gain and tended to have less fat buildup around the abdomen or around the heart.
Appiah said these results support some of the findings made by the American College of Pediatricians (ACP), which recommends breastfeeding exclusively for the first six months of a child's life, and then combining breastfeeding with age-appropriate food between six months and 12 months the food can be mixed. However, ACP also recommends that women should breastfeed for two years or longer if they are able.
"Now we are showing that, yes, breastfeeding more is actually beneficial to a woman's health and can help to prevent cardiovascular disease," Appiah added. "This study is providing more proof for some of these recommendations that have been given previously."
Appiah said there are other issues related to lactation that his team is investigating, including looking at how lactation influences cytokines and other hormones.
"We know that these fats produce adipokines and other cytokines that are associated with plaque buildup in the arteries," Appiah said. "Therefore, we want to look at how these cytokines may be influenced by lactation. We also want to look at how lactation may affect left ventricular structure and function independent of pericardial fat. Those are the next steps for this project."
https://www.sciencedaily.com/releases/2021/04/210409093601.htm
A mother's fat intake can impact infant infectious disease outcomes
Findings show types of fats matter when it comes to gut well-being
April 14, 2021
Science Daily/University of British Columbia Okanagan campus
A team of UBC Okanagan researchers has determined that the type of fats a mother consumes while breastfeeding can have long-term implications on her infant's gut health.
Dr. Deanna Gibson, a biochemistry researcher, along with Dr. Sanjoy Ghosh, who studies the biochemical aspects of dietary fats, teamed up with chemistry and molecular biology researcher Dr. Wesley Zandberg. The team, who conducts research in the Irving K. Barber Faculty of Science, explored the role of feeding dietary fat to gestating rodents to determine the generational effects of fat exposure on their offspring.
"The goal was to investigate how maternal dietary habits can impact an offspring's gut microbial communities and their associated sugar molecule patterns which can be important in immune responses to infectious disease," says Dr. Gibson, who studies gut health and immunity as well as causes of acute or chronic diseases like inflammatory bowel disease.
Their study suggests that the type of fat consumed during breastfeeding could differentially impact an infant's intestinal microbial communities, immune development and disease risk.
The three main classes of fatty acids include saturated (SFA), found in meats and dairy products, monounsaturated fats (MUFA), found in plant-based liquid oils, and polyunsaturated fatty acids (PUFAs), found in some nuts, fish and shellfish. PUFAs are further characterized as either n-3 PUFAs or n-6 PUFAs, based on the number and positions of double bonds in the acyl chain.
Previous research has determined both n-3 PUFAs and n-6 PUFAs can have a negative impact on intestinal infections such as Enteropathogenic E. coli, Clostridium difficile, salmonella and gastrointestinal illnesses from eating poorly prepared or undercooked food or drinking contaminated water. In contrast, diets rich in MUFAs and SFAs have been shown to be largely protective against these infections.
Dr. Gibson's latest research states the beneficial properties of milk fat, or saturated fats, during the pre-and postnatal period might improve protection against infectious intestinal disease during adulthood particularly when a source of n-3 PUFAs are combined with saturated fats.
"Our findings challenge current dietary recommendations and reveal that maternal intake of fat has transgenerational impacts on their offspring's susceptibility to intestinal infection, likely enabled through microbe-immune interactions," says Dr. Gibson.
Global consumption of unsaturated fatty acids has increased significantly between 1990 and 2010, she adds, while people are consuming lower amounts of saturated fats during pregnancy because of recommendations to reduce saturated fat intake.
"Although it has been known for decades that high-fat diets can directly alter inflammatory responses, recent studies have only just begun to appreciate how fatty acid classes may have discrete effects on inflammation, and can shift host responses to an infection," says Dr. Gibson.
Dietary fatty acids can impact inflammatory processes including defensive inflammatory responses following an intestinal infection. This can affect the severity of disease, making dietary fatty acids an important consideration in predicting disease risk, Dr. Gibson explains.
Researchers believe it's a combination of dietary fat-host interactions with the intestinal bacteriome that can determine the severity of these infections. The intestinal bacteriome, Dr. Gibson explains, is established during infancy and plays a critical role in aiding immune system maturation and providing a barrier against colonization with potential pathogens.
And Dr. Ghosh notes this latest research suggests current health guidelines should be reevaluated.
"Currently, Canadian dietary guidelines recommend nursing mothers replace foods rich in SFA with dietary PUFAs, with an emphasis on consuming n-6 and n-3 PUFAs," Dr. Ghosh says. "Given that PUFAs worsened disease outcomes in postnatal diet studies, in our views, these recommendations should be reconsidered."
While breast milk protein and carbohydrate concentrations remain relatively inert, fatty acid contents vary considerably and are influenced by maternal fat intake.
"Overall, we conclude that maternal consumption of various dietary fat types alters the establishment of their child's bacteriome and can have lasting consequences on their ability to respond to infection during adulthood," says Dr. Gibson. "At the same time, we show that maternal diets rich in SFA, provide a host-microbe relationship in their offspring that protects against disease."
It's important to understand that the intestinal bacteriome is established during infancy because it plays a critical role in aiding immune system maturation which can provide a barrier to potential pathogens, explains Dr. Zandberg. He also notes a healthy bacteriome is dependent on early-life nutrition.
"Sugars decorate important proteins in the gut," says Dr. Zandberg. "Their patterns are altered in the offspring due to the dietary choices of the mother during gestation and lactation. The change in patterns is associated with changes in the ability of the infant to fight off infectious disease in our model."
https://www.sciencedaily.com/releases/2021/04/210414100121.htm
Women accumulate Alzheimer's-related protein faster
March 25, 2021
Science Daily/Lund University
Alzheimer's disease seems to progress faster in women than in men. The protein tau accumulates at a higher rate in women, according to research from Lund University in Sweden. The study was recently published in Brain.
Over 30 million people suffer from Alzheimer's disease worldwide, making it the most common form of dementia. Tau and beta-amyloid are two proteins known to aggregate and accumulate in the brain in patients with Alzheimer's.
The first protein to aggregate in Alzheimer's is beta-amyloid. Men and women are equally affected by the first disease stages, and the analysis did not show any differences in the accumulation of beta-amyloid. Memory dysfunction arises later, when tau starts to accumulate. More women than men are affected by memory problems due to Alzheimer's, and it was for tau that the researchers found a higher rate of accumulation in women.
"Tau accumulation rates vary greatly between individuals of the same sex, but in the temporal lobe, which is affected in Alzheimer's disease, we found a 75% higher accumulation rate in women as a group compared to men," explains Ruben Smith, first author of the study.
The accumulation of tau is faster in patients who already have a pathological accumulation of beta-amyloid, and are in the early phase of the disease. The discovery that the accumulation rate of tau is higher in women remained even after adjusting for age and the levels of tau they had at the beginning. Together with data from three similar cohorts in the USA, the project contains 209 women and 210 men.
"The next step would be to examine why this accumulation is faster in women," says Sebastian Palmqvist, the researcher responsible for the cognitive assessment of the patients.
The study did not investigate the reasons for the higher rate of tau accumulation in women.
"Our study strongly indicates that the faster spread of tau makes women more prone to develop dementia because of Alzheimer's pathology compared to men. Future experimental studies will be important to understand the reasons behind this," concludes Professor Oskar Hansson.
https://www.sciencedaily.com/releases/2021/03/210325115423.htm
Women 'risk' grey hair to feel authentic
April 12, 2021
Science Daily/University of Exeter
Many women "risk" allowing natural grey hair to show in order to feel authentic, a new study shows.
Researchers from the University of Exeter surveyed women who chose not to dye their grey hair, and found a "conflict" between looking natural and being seen as competent.
Participants in the study -- mostly from English-speaking countries -- belonged to online groups whose members allow their natural grey hair to show, and the researchers noted "solidarity and sisterhood" among these women.
"We are all constrained by society's norms and expectations when it comes to appearance, but expectations are more rigorous for women -- especially older women," said lead author Vanessa Cecil, of the University of Exeter.
"The 'old woman' is an undesirable character in Western societies, being seen as incompetent or unpleasant -- if she is seen at all.
"In our study, we wanted to understand why some women choose natural grey hair.
"In the face of impossible standards to be natural and remain youthful forever, these women are doing what they can to retain status.
"Although many reported negative consequences such as being ignored or treated as less competent, they also felt happier to be 'flying my natural flag'.
"We also found that women chose to compensate for going grey by using other beauty practices -- so embracing grey isn't the same as embracing looking old.
"Grey-haired and youthfully glamorous is one thing, but in Western societies it's still not OK to look old."
Responses from the 80 participants, members of two Facebook groups about transitioning to natural grey hair, suggested the key trade-off was between authenticity and being seen as competent.
Women reported being shamed -- including by family and friends -- for being too natural ("let oneself go") but also wanted to avoid looking as if they have tried too hard to conceal their age ("mutton dressed as lamb").
Those who were supported by partners, family and friends had an "easier time" of the transition to grey, Cecil said.
Many women have chosen natural grey hair during COVID lockdowns -- both because hairdressers have been closed and due to spending less time in public, including at work.
"This appears to have accelerated a shift that was already happening, with more and more women choosing not to dye their hair," Cecil said.
https://www.sciencedaily.com/releases/2021/04/210412114815.htm
Stress from work and social interactions put women at higher coronary heart disease risk
April 9, 2021
Science Daily/Drexel University
Psychosocial stress -- typically resulting from difficulty coping with challenging environments -- may work synergistically to put women at significantly higher risk of developing coronary heart disease, according to a study by researchers at Drexel University's Dornsife School of Public Health, recently published in the Journal of the American Heart Association.
The study specifically suggests that the effects of job strain and social strain -- the negative aspect of social relationships -- on women is a powerful one-two punch. Together they are associated with a 21% higher risk of developing coronary heart disease. Job strain occurs when a woman has inadequate power in the workplace to respond to the job's demands and expectations.
The study also found that high-stress life events, such as a spouse's death, divorce/separation or physical or verbal abuse, as well as social strain, were each independently linked with a 12% and 9% higher risk of coronary heart disease, respectively.
The Drexel study used data from a nationally representative sample of 80,825 postmenopausal women from the Women's Health Initiative Observational Study, which tracked participants from 1991 to 2015, to find better methods of preventing cancer, heart disease and osteoporosis in women. In the current follow-up study, Drexel researchers evaluated the effect of psychosocial stress from job strain, stressful life events and social strain (through a survey), and associations among these forms of stress, on coronary heart disease.
Nearly 5% of the women developed coronary heart disease during the 14-year, seven-month study. Adjusting for age, time at a job, and socioeconomic characteristics, high-stress life events were associated with a 12% increased coronary heart disease risk, and high social strain was associated with a 9% increased risk of coronary heart disease. Work strain was not independently associated with coronary heart disease.
Coronary heart disease, the leading cause of death in the United States, occurs with the heart's arteries become narrow and cannot bring sufficient oxygenated blood to the heart. The latest work builds on earlier studies linking psychosocial stress to coronary heart disease by finding out how job strain and social strain work together to compound disease risk.
"The COVID-19 pandemic has highlighted ongoing stresses for women in balancing paid work and social stressors. We know from other studies that work strain may play a role in developing CHD, but now we can better pinpoint the combined impact of stress at work and at home on these poor health outcomes," said senior author Yvonne Michael, ScD, SM, an associate professor in the Dornsife School of Public Health. "My hope is that these findings are a call for better methods of monitoring stress in the workplace and remind us of the dual-burden working women face as a result of their unpaid work as caregivers at home ."
The study's authors say that future studies should look at the effects of shift work on coronary heart disease and explore the effects of job demands according to gender.
"Our findings are a critical reminder to women, and those who care about them, that the threat of stress to human health should not go ignored," said lead author Conglong Wang, PhD, a recent Dornsife graduate who conducted the research while at Drexel. "This is particularly pertinent during the stressors caused by a pandemic."
https://www.sciencedaily.com/releases/2021/04/210409124746.htm
Gut microbiota in Cesarean-born babies catches up
April 1, 2021
Science Daily/University of Gothenbur
Infants born by cesarean section have a relatively meager array of bacteria in the gut. But by the age of three to five years they are broadly in line with their peers. This is shown by a study that also shows that it takes a remarkably long time for the mature intestinal microbiota to get established.
Fredrik Bäckhed, Professor of Molecular Medicine at Sahlgrenska Academy, University of Gothenburg, has been heading this research. The study, conducted in collaboration with Halland County Hospital in Halmstad, is now published in the journal Cell Host & Microbe.
Professor Bäckhed and his group have previously demonstrated that the composition of children's intestinal microbiota is affected by their mode of delivery and diet. In the current study, the researchers examined in detail how the composition of intestinal bacteria in 471 children born at the hospital in Halmstad had developed.
The first fecal sample was collected when each child was a newborn infant. Thereafter, sampling took place at 4 months, 12 months, 3 years and 5 years. The scientists were thus able to follow the successive incorporation of various bacteria into the children's gut microbiota.
At birth, the infant's intestine has already been colonized by bacteria and other microorganisms. During the first few years of life, the richness of species steadily increases. What is now emerging is a considerably more detailed picture of this developmental trajectory.
One key conclusion is that the intestinal microbiota forms an ecosystem that takes a long time to mature. Even at 5 years of age, the system is incomplete. The maturation process can look very different from one child to another, and take varying lengths of time.
At the age of 4 months, the gut microbiota in the cesarean-born infants was less diverse compared with vaginally born infants. However, when the children were 3 and 5 years the microbiota diversity and composition had caught up and were largely normalized intestinal microbiota.
"Our findings show that the gut microbota is a dynamic organ, and future studies will have to show whether the early differences can affect the cesarean children later in life," Bäckhed says.
"It's striking that even at the age of 5 years, several of the bacteria that are important components of the intestinal microbiota in adults are missing in the children," he continues.
This indicates that the intestine is a complex and dynamic environment where bacteria create conditions for one another's colonization.
According to the researchers, the current study has broadened our understanding of how humans interact with the trillions of bacteria contained in our bodies, and of how these bacteria become established.
Lisa Olsson, a researcher at the University of Gothenburg and one of the first authors, adds:
"Children learn skills like walking and talking at different rates, and it turns out that the same applies to the maturity of the gut microbiota."
Fredrik Bäckhed again:
"By investigating and understanding how the intestinal microbiota develops in healthy children, we may get a reference point to explorie if the microbiota may contribute to disease in future studies," he concludes.
https://www.sciencedaily.com/releases/2021/04/210401112526.htm
Moderate daily caffeine intake during pregnancy may lead to smaller birth size
March 25, 2021
Science Daily/NIH/Eunice Kennedy Shriver National Institute of Child Health and Human Development
Pregnant women who consumed the caffeine equivalent of as little as half a cup of coffee a day on average had slightly smaller babies than pregnant women who did not consume caffeinated beverages, according to a study by researchers at the National Institutes of Health. The researchers found corresponding reductions in size and lean body mass for infants whose mothers consumed below the 200 milligrams of caffeine per day -- about two cups of coffee -- believed to increase risks to the fetus. Smaller birth size can place infants at higher risk of obesity, heart disease and diabetes later in life.
The researchers were led by Katherine L. Grantz, M.D., M.S., of the Division of Intramural Population Health Research at NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development. The study appears in JAMA Network Open.
"Until we learn more, our results suggest it might be prudent to limit or forego caffeine-containing beverages during pregnancy," Dr. Grantz said. "It's also a good idea for women to consult their physicians about caffeine consumption during pregnancy."
Previous studies have linked high caffeine consumption (more than 200 milligrams of caffeine per day) during pregnancy to infants being small for their gestational age (stage of pregnancy) or at risk for intrauterine growth restriction -- being in the lowest 10th percentile for infants of the same gestational age. However, studies on moderate daily caffeine consumption (200 milligrams or less) during pregnancy have produced mixed results. Some have found similar elevated risks for low birth weight and other poor birth outcomes, while others have found no such links. The current study authors noted that many of the earlier studies did not account for other factors that could influence infant birth size, such as variation in caffeine content of different beverages and maternal smoking during pregnancy.
For their study, the authors analyzed data on more than 2,000 racially and ethnically diverse women at 12 clinical sites who were enrolled from 8 to 13 weeks of pregnancy. The women were non-smokers and did not have any health problems before pregnancy. From weeks 10 to 13 of pregnancy, the women provided a blood sample that was later analyzed for caffeine and paraxanthine, a compound produced when caffeine is broken down in the body. The women also reported their daily consumption of caffeinated beverages (coffee, tea, soda and energy drinks) for the past week -- once when they enrolled and periodically throughout their pregnancies.
Compared to infants born to women with no or minimal blood levels of caffeine, infants born to women who had the highest blood levels of caffeine at enrollment were an average of 84 grams lighter at birth (about 3 ounces), were .44 centimeters shorter (about .17 inches), and had head circumferences .28 centimeters smaller (about .11 inches).
Based on the women's own estimates of the beverages they drank, women who consumed about 50 milligrams of caffeine a day (equivalent to a half cup of coffee) had infants 66 grams (about 2.3 ounces) lighter than infants born to non-caffeine consumers. Similarly, infants born to the caffeine consumers also had thigh circumferences .32 centimeters smaller (about .13 inches).
The researchers noted that caffeine is believed to cause blood vessels in the uterus and placenta to constrict, which could reduce the blood supply to the fetus and inhibit growth. Similarly, researchers believe caffeine could potentially disrupt fetal stress hormones, putting infants at risk for rapid weight gain after birth and for later life obesity, heart disease and diabetes.
The authors concluded that their findings suggest that even moderate caffeine consumption may be associated with decreased growth of the fetus.
https://www.sciencedaily.com/releases/2021/03/210325150122.htm