Tuesday, April 11, 2023

Impact of coronavirus on states’ fertility rates tracked with economic, social, and political divides

Those that leaned blue, were more urban, and had greater income inequality saw steepest declines

Peer-Reviewed Publication

NYU LANGONE HEALTH / NYU GROSSMAN SCHOOL OF MEDICINE

Experts have found that at the start of the COVID-19 outbreak in early 2020, Americans chose not to become pregnant as they grappled with stay-at-home restrictions, anxiety, and economic hardship. Now, a new study led by researchers at NYU Grossman School of Medicine shows that some states actually experienced steeper decreases in fertility than others.

The findings revealed that nine months after the pandemic began, there were 18 fewer births a month per 100,000 women of reproductive age across the U.S. compared with the year before. However, after the second wave in 2021, fertility fell by roughly 9 monthly births per 100,000 women, which was similar to the rate at which national fertility had been decreasing prior to the pandemic.

“Our findings suggest that while the overall national fertility rate rebounded remarkably quickly after the initial COVID-19 wave, the initial declines by state were as polarized as the country as a whole,” said study co-lead author Sarah Adelman, MPH, a research associate in the Department of Pediatrics at NYU Langone Health.

According to the state-specific results, New York State experienced a massive fertility rate decline following the first wave, plunging from a pre-pandemic annual trend of 4 fewer monthly births per 100,000 women of reproductive age to roughly 76 fewer monthly births per 100,000 women. Delaware saw about 64 fewer monthly births for the same number of women and Maryland about 55 fewer monthly births per 100,000 women. Like they had been in New York, annual fertility rate decreases in these states were in the single digits prior to the coronavirus outbreak.

By contrast, following the first wave, Idaho, Montana, and Utah experienced a boost of up to 56 additional births each month per 100,000 women of reproductive age. This is despite the fact that fertility rates in these areas had also been trending downward in the years leading up to the pandemic.

Adelman says that while previous research has documented national fertility-rate declines following COVID-19, the new study, publishing online April 11 in the journal Human Reproduction, goes a step further, comparing changes among individual states and examining factors that may account for the different rates. 

For the research, the study team analyzed data from the U.S. Centers for Disease Control and Prevention Bureau of Vital Statistics, the 2020 U.S. Census, and from the University of Virginia 2021 population estimates, to calculate fertility rate trends after each COVID-19 wave. The team then examined whether coronavirus case rates or other factors were the main drivers of fertility rate changes.

Contrary to their expectation, the severity of the coronavirus wave in each state appeared to have had little bearing on changes in that state’s fertility rate, the researchers say. Rather, demographic factors like racial composition and economic factors, including greater income inequality, higher percentage of college-degree earners, and large drops in employment at the start of the pandemic, negatively impacted rates.

The research team then examined states’ political leaning and a measure called the social distancing index (SDI), which tracked changes in people’s mobility following the first wave. They found that states with stronger social distancing responses and that were politically liberal had larger fertility rate declines following the first wave of the pandemic. When plotted on a graph, politically liberal places such as New York and the District of Columbia had the highest SDIs and lowest fertility rates, while more conservative states such as Idaho and Montana had the reverse.

“These results suggest that changes in a state’s fertility rates were not driven by COVID-19 cases themselves but rather by existing social, economic, and political disparities,” said co-lead author Mia Charifson, MA, a doctoral student in the Department of Population Health at NYU Langone.

“While these issues have always been linked with decisions about having children, they were clearly magnified by the pandemic, highlighting the need to address underlying social factors that constrain people’s ability to grow their families, especially during times of crisis,” added study senior author Linda Kahn, PhD, MPH.

Kahn, an assistant professor in the Departments of Pediatrics and Population Health at NYU Langone, cautions that since the researchers used state-level, population-wide data in their study, their findings cannot explain choices made by individuals.

Future research, she says, might examine more personal factors that influence decisions around pregnancy during times of crisis, such as student debt, job security, and access to childcare, in addition to existential concerns about climate change and political instability.

Funding for the study was provided by National Institutes of Health grants R00ES030403 and R01ES032808. Further funding was provided by the National Science Foundation Graduate Research Fellowship Program 20-A0-00-1005789. 

In addition to Adelman, Charifson, and Kahn, other NYU Langone investigators involved in the study were Eunsil Seok, PhD; Shilpi Mehta-Lee, MD; Sara Brubaker, MD; and Mengling Liu, PhD.

Scheduled childbirth may greatly reduce preeclampsia, a leading cause of maternal death

Scheduled labor inductions or Cesarean deliveries may prevent more than half of at-term preeclampsia cases, according to new research published in Hypertension journal

Peer-Reviewed Publication

AMERICAN HEART ASSOCIATION

Research Highlights:

  • Analysis found that more than half of preeclampsia cases that occur during weeks 37-42 of pregnancy (called at-term preeclampsia) may be prevented with timed birth, such as a scheduled induction or Cesarean delivery.
  • Planned labor inductions and Cesarean deliveries are already widely practiced for a range of reasons, however, they are seldom considered as an intervention to prevent at-term preeclampsia, which may be life-threatening.

DALLAS, April 10, 2023 — More than half of all preeclampsia cases that occur during weeks 37-42 of pregnancy (at-term) may be prevented with timed birth, such as a scheduled induction or Cesarean delivery, according to new research published today in Hypertension, a peer-reviewed journal of the American Heart Association.

Preeclampsia is the most dangerous form of high blood pressure (≥140/90 mm Hg) during pregnancy, and it is a leading cause of maternal death worldwide. Preeclampsia is potentially life-threatening and affects 1 in 25 pregnancies in the United States. The condition is typically diagnosed after 20 weeks of pregnancy. Symptoms include headaches, vision changes and swelling of the hands, feet, face or eyes for the mother; or a change in the well-being of the baby. Preeclampsia also indicates that there is an increased risk of developing heart health complications for women later in life.

Preterm delivery may be considered an option for women who develop preeclampsia during weeks 20-36 of pregnancy; however, most preeclampsia occurs during the time frame called at-term, which is between 37-42 weeks of pregnancy. While screening for preeclampsia is routine during pregnancy, there are limited treatment options that are proven safe and effective. Low-dose aspirin more than halves the risk of preterm preeclampsia among women at risk, however, aspirin does not affect the risk of at-term preeclampsia , which is three times more common than preterm preeclampsia and associated with more complications for mothers and babies.

Timed birth strategies, including induced labor and Cesarean deliveries that are planned in advance, are already widely practiced for various reasons. However, they are seldom used as an intervention to prevent at-term preeclampsia.

“Timed birth is achievable in many hospitals or health centers,” said lead study author Laura A. Magee, M.D., a professor of women’s health at King’s College in London, “so our proposed approach to prevent at-term preeclampsia has huge potential for global good in maternity care.”

Researchers examined more than 10 years of health records for nearly 90,000 pregnancies at two hospitals (King’s College Hospital, London and Medway Maritime Hospital, Gillingham) in the U.K. There were 57,131 pregnancies with health records at 11 to 13 weeks (between 2006 and 2017), in which there were 1,138 cases of at-term preeclampsia; and 29,035 pregnancies at 35 to 36 weeks (between 2016 and 2018), in which there were 619 cases of at-term preeclampsia. In the analysis, researchers evaluated risk of preeclampsia and potential benefits of timed birth for both groups with standard clinical criteria for preeclampsia and a risk prediction model (computer program that predicts risk of preeclampsia based on various individual factors, such as maternal history, blood pressure, ultrasound and blood tests).  

The majority of women in the dataset were in their early 30s, self-identified as white and had a body mass index at the upper limits of normal. About 10% of the women in the analysis also self-identified as smokers; fewer than 3% had a medical history of high blood pressure, Type 2 diabetes or an autoimmune disease; and only 3.9% reported a family history of preeclampsia.

At-term preeclampsia occurred with similar frequency when participants screened during the first trimester were compared with those screened during the third trimester. On average, women included in the study delivered at 40-weeks, and two-thirds of all participants experienced spontaneous onset of labor. About one-fourth of the women included in the analysis had Cesarean deliveries.

The analysis indicates that, when utilizing risk-modeling in place of standard clinical screening, timed birth may prove to be an effective intervention for reducing by more than half the risk of at-term preeclampsia.

“Our findings suggest that over half of the cases of at-term preeclampsia may be prevented by timed (planned) birth,” said Magee. “It is important to note that being at higher risk of at-term preeclampsia was associated with earlier spontaneous onset of labor, so women at the highest risk were already less likely to deliver close to their due date.”

 Limitations for the research included that no interventions were provided to participants; researchers calculated potential risk only through risk modeling. In addition, the study did not examine the potential for preeclampsia after delivery. Although this was an observational study using modeling to predict risk reduction for at-term preeclampsia, the researchers noted that strengths of the study include the large population of women represented and that labor induction and Cesarean delivery are widely available options. However, randomized clinical trials, studies where individuals are chosen at random to receive treatment versus no treatment or an alternate treatment, are needed to evaluate the safety and effectiveness of timed birth as an appropriate intervention to reduce at-term preeclampsia.

In February 2023, the American Heart Association released a scientific statement, Optimizing Prepregnancy Cardiovascular Health to Improve Outcomes in Pregnant and Postpartum Individuals and Offspring, which details the benefits of early interventions to support pre- and interpregnancy (during pregnancy) cardiovascular health. The statement highlighted interventions related to diet, smoking cessation and weight reduction that may reduce the frequency of adverse pregnancy outcomes at birth (such as hypertensive disorders of pregnancy, pre-term birth, small-for-gestational-age birth or gestational diabetes). Additional research is needed to better understand the relationship between comprehensive prepregnancy cardiovascular health care and the frequency of adverse pregnancy outcomes.

Co-authors are David Wright, Ph.D.; Argyro Syngelaki, Ph.D.; Peter von Dadelszen, D.Phil.; Ranjit Akolekar, M.D.; Alan Wright, Ph.D.; and Kypros H. Nicolaides, M.D. Authors’ disclosures are listed in the manuscript.

The study was funded by grants from the Fetal Medicine Foundation in the U.K. Support was also provided by PerkinElmer, Life Analytical Sciences, Roche Diagnostics and Thermo Fisher Scientific.

Studies published in the American Heart Association’s scientific journals are peer-reviewed. The statements and conclusions in each manuscript are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. The Association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific Association programs and events. The Association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance providers and the Association’s overall financial information are available here

Additional Resources:

About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. We are dedicated to ensuring equitable health in all communities. Through collaboration with numerous organizations, and powered by millions of volunteers, we fund innovative research, advocate for the public’s health and share lifesaving resources. The Dallas-based organization has been a leading source of health information for nearly a century. Connect with us on heart.orgFacebookTwitter or by calling 1-800-AHA-USA1.

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Non-biological factors and social determinants of health important in women’s CVD risk assessment

A new American Heart Association scientific statement notes that current CVD risk assessments fall short for women from diverse races and ethnicities other than white

Peer-Reviewed Publication

AMERICAN HEART ASSOCIATION

Statement Highlights:

  • A new American Heart Association scientific statement reviews research about racial and ethnic differences in cardiovascular risk factors among women in the U.S.
  • In addition to traditional risk factors, women of underrepresented races or ethnicities experience challenges in the diagnosis and treatment of cardiovascular conditions due to language barriers, discrimination, difficulties in acculturation or assimilation, lack of financial resources or health insurance, or lack of access to health care.
  • Women of racial and ethnic backgrounds other than white have been underrepresented in research, therefore, current risk calculators have limitations for Black, Hispanic/Latina, American Indian/Alaska Native and Asian women in the U.S.
  • Expanding cardiovascular risk assessment calculators to include social determinants of health and non-biological variables is necessary to address cardiovascular disease among women of underrepresented races or ethnicities.

DALLAS, April 10, 2023 — Non-biological factors and social determinants of health are important to include in CVD risk assessment for women, particularly for women of diverse races and ethnicities other than white, according to a new American Heart Association scientific statement published today in Circulation, the Association’s flagship, peer-reviewed journal.

“Risk assessment is the first step in preventing heart disease, yet there are many limitations to traditional risk factors and their ability to comprehensively estimate a woman’s risk for cardiovascular disease,” said Jennifer H. Mieres, M.D., FAHA, vice chair of the scientific statement writing committee and a professor of cardiology at the Zucker School of Medicine at Hofstra Northwell in Hempstead, N.Y. Of note, large patient data registries used to develop cardiovascular risk assessment formulas or algorithms lack racial and ethnic diversity, so they may not accurately reflect risk for women of underrepresented groups.

2022 American Heart Association presidential advisory deemed it critical to understand the impact of race and ethnicity on cardiovascular risk factors in women in order to incorporate those specific risks into prevention plans and reduce the high burden of CVD among women from diverse backgrounds. This new scientific statement responds to the presidential advisory as a review of the current evidence on racial and ethnic differences in cardiovascular risk factors for women in the U.S.

What traditional risk formulas miss about women in general

Traditional formulas to determine cardiovascular disease risk include Type 2 diabetes, blood pressure, cholesterol, family history, smoking status, physical activity level, diet and weight. These formulas do not account for sex-specific biological influences on cardiovascular risk or medications and conditions that are more common among women than men.

Female-specific factors that should be included in assessing cardiovascular risk are:

  • Pregnancy-related conditions, such as preeclampsia (dangerous high blood pressure that develops late in pregnancy), preterm delivery, gestational diabetes, gestational high blood pressure or miscarriage. According to the Association of Black Cardiologists, 2 out of 3 women who experience preeclampsia will die of heart disease.
  • Menstrual cycle history, such as age at first period and at menopause.
  • Types of birth control and/or hormone replacement therapy used.
  • History of chemotherapy or radiation therapy.
  • Polycystic ovarian syndrome (PCOS) – a condition that results in hormone imbalance and irregular ovulation. PCOS affects up to 10% of women of reproductive age and is associated with higher risk for cardiovascular disease.
  • Autoimmune disorders – women are twice as likely as men to develop autoimmune disorders such as rheumatoid arthritis or lupus. These conditions are associated with faster build-up of plaque in the arteries, higher risk of cardiovascular disease and worse outcomes after heart attacks and strokes.
  • Depression and posttraumatic stress disorder – both are more common among women and associated with a higher risk of developing CVD.

“The delivery of equitable cardiovascular health care for women depends on improving the knowledge and awareness of all members of the health care team about the full spectrum of cardiovascular risk factors for women, including female-specific and female-predominant risk factors,” said Mieres, who is also the chief diversity and inclusion officer at Northwell Health.

Importance of social determinants of health in risk assessment

Social determinants of health play a significant role in the development of CVD among women, with disproportionate effects on women from diverse racial and ethnic backgrounds. These determinants include economic stability, neighborhood safety, working conditions, environmental hazards (such as exposure to air pollution), education level and access to quality health care. The impact of social factors is recognized in how they affect behavioral risk factors, such as smoking status, physical activity, diet and proper medication use.

“It is critical that risk assessment be expanded to include social determinants of health as risk factors if we are to improve health outcomes in all women,” said Laxmi S. Mehta, M.D., FAHA, chair of the writing group and director of preventative cardiology and women’s cardiovascular health at The Ohio State University Wexner Medical Center in Columbus, Ohio. “It is also important for the health care team to consider social determinants of health when working with women on shared decisions about cardiovascular disease prevention and treatment.”

Differences in women’s cardiovascular disease risk by race and ethnicity

Although cardiovascular disease is the leading cause of death for all women, the statement highlights significant racial and ethnic differences in cardiovascular risk profiles:

  • Non-Hispanic Black women (an umbrella term encompassing African American, African and Caribbean) in the U.S. have the highest prevalence of high blood pressure in the world, above 50%. They are also more likely to develop Type 2 diabetes; have obesity or extreme obesity; and to die of smoking-related diseases. Non-Hispanic Black women are disproportionately affected by traditional risk factors and experience the onset of CVD at younger ages. Social determinants of health are a key driver for this disparity, as detailed in the AHA’s 2022 Cardiovascular Disease Statistical Update.
  • Hispanic/Latina women (referring to women of any racial and ethnic background whose ancestry is from Mexico, Central America, South America, the Caribbean or other Spanish-speaking countries) have a higher rate of obesity compared with Hispanic/Latino men. Hispanic/Latina women born in the U.S. also have higher rates of smoking than those who were born in another country and immigrated to the U.S. Paradoxically, despite higher rates of Type 2 diabetes, obesity and metabolic syndrome, CVD death rates are 15-20% lower in Hispanic/Latina women than among non-Hispanic white women. It’s possible that this “Hispanic paradox” is due to grouping diverse Hispanic subcultures together in research data, which does not account for different levels of risk among individual subgroups of Hispanic/Latino people or the possibility of healthy immigrant bias.
  • American Indian and Alaska Native women (a diverse population including hundreds of federally recognized and non-recognized tribes across the U.S.) have a higher rate of tobacco use than other groups, with 1 in 3 American Indian or Alaska Native women currently smoking. Type 2 diabetes is the primary risk factor for heart disease among American Indian women; however, rates vary by region, with up to 72% prevalence among American Indian women in Arizona, and just over 40% among those in Oklahoma, North Dakota and South Dakota. Unfortunately, understanding the cardiovascular health of American Indian/Alaska Native people is challenging due to small sample sizes in national data, racial and/or ethnic misclassification or other factors.
  • Asian American women (having origins in the Far East, Southeast Asia or the Indian subcontinent) have varied rates of CVD risk within Asian subgroups: high blood pressure rates are 30% among Chinese women and 53% among Filipino women; rates of low HDL (good) cholesterol and high triglycerides are highest among Asian Indian and Filipino women; and Type 2 diabetes prevalence is highest among Southeast Asian women. The BMI level for increased risk of Type 2 diabetes is lower for Asian people than for other racial groups. Asian Americans are less likely to be overweight or have obesity compared to other racial groups, however, at the same BMI they have higher rates of high blood pressure, CVD and Type 2 diabetes. Higher body fat levels and the distribution of body fat may explain these differences: Recent research shows that Asian people generally have a higher percentage of body fat than non-Hispanic white people of the same age, sex and body mass index. In addition, studies have shown that Chinese, Filipino and Asian Indian people have more abdominal fat compared with non-Hispanic white and Black people.

“When customizing CVD prevention and treatment strategies to improve cardiovascular health for women, a one-size-fits-all approach is unlikely to be successful,” Mieres said. “We must be cognizant of the complex interplay of sex, race and ethnicity, as well as social determinants of health, and how they impact the risk of cardiovascular disease and adverse outcomes in order to avert future CVD morbidity and mortality.”

Future cardiovascular disease prevention guidelines may be strengthened by urging culturally specific lifestyle recommendations tailored to the cultural norms and expectations that influence behaviors, beliefs and attitudes about diet, physical activity and healthy weight, according to the statement. The writing committee calls for community-based approaches, faith-based community partnerships and peer support in encouraging a healthy lifestyle to improve the primary prevention of cardiovascular disease among women from underrepresented groups. The statement also urges more research to address gaps in our knowledge about risk factors among women, including gathering data specific to subgroups of each race and ethnicity.

This scientific statement was prepared by the volunteer writing group on behalf of the American Heart Association’s Cardiovascular Disease and Stroke in Women and Underrepresented Populations Committee of the Council on Clinical Cardiology; the Council on Cardiovascular and Stroke Nursing; the Council on Hypertension; the Council on Lifelong Congenital Heart Disease and Heart Health in the Young; the Council on Lifestyle and Cardiometabolic Health; the Council on Peripheral Vascular Disease; and the Stroke Council. American Heart Association scientific statements promote greater awareness about cardiovascular diseases and stroke issues and help facilitate informed health care decisions. Scientific statements outline what is currently known about a topic and what areas need additional research. While scientific statements inform the development of guidelines, they do not make treatment recommendations. American Heart Association guidelines provide the Association’s official clinical practice recommendations.

Additional co-authors are Gladys P. Velarde, M.D., FAHA; Jennifer Lewey, M.D., M.P.H.; Garima Sharma, M.D.; Rachel M. Bond, M.D.; Ana Navas-Acien, M.D., Ph.D.; Amanda M. Fretts, M.P.H., Ph.D.; Gayenell S. Magwood, Ph.D., R.N., FAHA; Eugene Yang, M.D.; Roger S. Blumenthal, M.D., FAHA; and Rachel-Maria Brown, M.D. Authors’ disclosures are listed in the manuscript.

The Association receives funding primarily from individuals. Foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific Association programs and events. The Association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance providers, and the Association’s overall financial information are available here.

Additional Resources:

About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. We are dedicated to ensuring equitable health in all communities. Through collaboration with numerous organizations, and powered by millions of volunteers, we fund innovative research, advocate for the public’s health and share lifesaving resources. The Dallas-based organization has been a leading source of health information for nearly a century. Connect with us on heart.orgFacebookTwitter or by calling 1-800-AHA-USA1.

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Evictions and infant and child health outcomes

JAMA Network Open

Peer-Reviewed Publication

JAMA NETWORK

About The Study: This systematic review surveyed 11 studies reporting associations between direct experience of and proximity to evictions and adverse birth outcomes. Evidence suggests that childhood exposure to evictions was associated with harms to neurodevelopment and overall health. In the context of a rental housing affordability crisis, ongoing racial disparities in evictions, and continuing harm to millions of families, health care practitioners and policy makers have an integral role to play in supporting safe, stable housing for all.

Authors: Bruce Ramphal, Sc.B., of Harvard Medical School in Boston, is the corresponding author.

(doi: 10.1001/jamanetworkopen.2023.7612)

Embed this link to provide your readers free access to the full-text article  time http://jamanetwork.com/journals/jamanetworkopen/fullarticle/10.1001/jamanetworkopen.2023.7612?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=041123

About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.

Detecting stress in the office from how people type and click

Peer-Reviewed Publication

ETH ZURICH

In Switzerland, one in three employees suffers from workplace stress. Those affected often don’t realise that their physical and mental resources are dwindling until it’s too late. This makes it all the more important to identify work-​related stress as early as possible where it arises: in the workplace.

Researchers at ETH Zurich are now taking a crucial step in this direction. Using new data and machine learning, they have developed a model that can tell how stressed we are just from the way we type and use our mouse.

And there’s more: “How we type on our keyboard and move our mouse seems to be a better predictor of how stressed we feel in an office environment than our heart rate,” explains study author Mara Nägelin, a mathematician who conducts research at the Chair of Technology Marketing and the Mobiliar Lab for Analytics at ETH Zurich. Applied correctly, these findings could be used in future to prevent increased stress in the workplace early on.

Stressed people type and click differently

The ETH researchers proved in an experiment that stressed people type and move their mouse differently from relaxed people. “People who are stressed move the mouse pointer more often and less precisely and cover longer distances on the screen. Relaxed people, on the other hand, take shorter, more direct routes to reach their destination and take more time doing so,” Nägelin says.

What’s more, people who feel stressed in the office make more mistakes when typing. They write in fits and starts with many brief pauses. Relaxed people take fewer but longer pauses when typing on a keyboard.

The connection between stress and our typing and mouse behaviour can be explained with what is known as neuromotor noise theory: “Increased levels of stress negatively impact our brain’s ability to process information. This also affects our motor skills,” explains psychologist Jasmine Kerr, who researches with Nägelin and is a coauthor of the study.  

Simulating office stress as realistically as possible

To develop their stress model, the ETH researchers observed 90 study participants in the lab performing office tasks that were as close to reality as possible, such as planning appointments or recording and analysing data. They recorded the participants’ mouse and keyboard behaviour as well as their heart rates. In addition, the researchers asked the participants several times during the experiment how stressed they felt.

While some participants were allowed to work undisturbed, others also had to take part in a job interview. Half of this group were also repeatedly interrupted with chat messages. In contrast to earlier studies by other scientists, where the control group often did not have to solve any tasks at all and could relax, in the ETH researchers’ experiment, all participants had to perform the office tasks. 

“We were surprised that typing and mouse behaviour was a better predictor of how stressed subjects felt better than heart rate,” Nägelin says. She explains that this is because the heart rates of the participants in the two groups did not differ as much as in other studies. One possible reason is that the control group was also given activities to perform, which is more in line with workplace reality.

Data must be protected

The researchers are currently testing their model with data from Swiss employees who have agreed to have their mouse and keyboard behaviour as well as their heart data recorded directly at their workplace using an app. The same app also regularly asks the employees about their subjective stress levels. Results should be available by the end of the year.

However, workplace stress detection also raises some thorny issues: “The only way people will accept and use our technology is if we can guarantee that we will anonymise and protect their data. We want to help workers to identify stress early, not create a monitoring tool for companies,” Kerr says. In another study involving employees and ethicists, the researchers are investigating which features an app needs to have to meet these requirements and ensure responsible handling of sensitive data. 

Photonic filter separates signals from noise to support future 6G wireless communication

Multi-functional filter could help advance autonomous driving and the Internet of Things

Peer-Reviewed Publication

OPTICA

Peking University research team 

IMAGE: (FROM LEFT) RESEARCHERS HAOWEN SHU, ZIHAN TAO AND XINGJUN WANG PERFORMING AN EXPERIMENT TO TEST THEIR MICROWAVE PHOTONIC FILTER. view more 

CREDIT: PEKING UNIVERSITY RESEARCH TEAM

WASHINGTON — Researchers have developed a new chip-sized microwave photonic filter to separate communication signals from noise and suppress unwanted interference across the full radio frequency spectrum. The device is expected to help next-generation wireless communication technologies efficiently convey data in an environment that is becoming crowded with signals from devices such as cell phones, self-driving vehicles, internet-connected appliances and smart city infrastructure.

“This new microwave filter chip has the potential to improve wireless communication, such as 6G, leading to faster internet connections, better overall communication experiences and lower costs and energy consumption for wireless communication systems,” said researcher Xingjun Wang from Peking University. “These advancements would directly and indirectly affect daily life, improving overall quality of life and enabling new experiences in various domains, such as mobility, smart homes and public spaces.”

In the Photonics Research journal co-published by Chinese Laser Press and Optica Publishing Group, the researchers describe how their new photonic filter overcomes the limitations of traditional electronic devices to achieve multiple functionalities on a chip-sized device with low power consumption. They also demonstrate the filter’s ability to operate across a broad radio frequency spectrum extending to over 30 GHz, showing its suitability for envisioned 6G technology.

“As the electro-optic bandwidth of optoelectronic devices continues to increase unstoppably, we believe that the integrated microwave photonics filter will certainly be one of the important solutions for future 6G wireless communications,” said Wang. “Only a well-designed integrated microwave photonics link can achieve low cost, low power consumption and superior filtering performance.”

Stopping interference

6G technology is being developed to improve upon currently-deployed 5G communications networks. To convey more data at a faster rate, 6G networks are expected to use millimeter wave and even terahertz frequency bands. As this will distribute signals over an extremely wide frequency spectrum with increased data rate, there is a high likelihood of interference between different communication channels.

To solve this problem, researchers have sought to develop a filter that can protect signal receivers from various types of interference across the full radio frequency spectrum. To be cost-effective and practical for widespread deployment, it is important for this filter to be small, consume little power, achieve multiple filtering functions and be able to be integrated on a chip. However, previous demonstrations have been limited by their few functions, large size, limited bandwidth or requirements associated with electrical components.

For the new filter, researchers created a simplified photonic architecture with four main parts. First, a phase modulator serves as the input of the radio frequency signal, which modulates the electrical signal onto the optical domain. Next, a double-ring acts as a switch to shape the modulation format. An adjustable microring is the core unit for processing the signal. Finally, a photodetector serves as the output of the radio frequency signal and recovers the radio frequency signal from the optical signal.

“The greatest innovation here is breaking the barriers between devices and achieving mutual collaboration between them,” said Wang. “The collaborative operation of the double-ring and microring enables the realization of the intensity-consistent single-stage-adjustable cascaded-microring (ICSSA-CM) architecture. Owing to the high reconfigurability of the proposed ICSSA-CM, no extra radio frequency device is needed for the construction of various filtering functions, which simplifies the whole system composition.”

Demonstrating performance

To test the device, researchers used high-frequency probes to load a radio frequency signal into the chip and collected the recovered signal with a high-speed photodetector. They used an arbitrary waveform generator and directional antennas to simulate the generation of 2Gb/s high-speed wireless transmission signals and a high-speed oscilloscope to receive the processed signal. By comparing the results with and without the use of the filter, the researchers were able to demonstrate the filter’s performance.

Overall, the findings show that the simplified photonic architecture achieves comparable performance with lower loss and system complexity compared with previous programmable integrated microwave photonic filters composed of hundreds of repeating units. This makes it more robust, more energy-efficient and easier to manufacture than previous devices.

The researchers plan to further optimize the modulator and improve the overall filter architecture to achieve a high dynamic range and low noise while ensuring high integration at both the device and system levels.

Paper: Z. Tao, Y. Tao, M. Jin, J. Qin, R. Chen, B. Shen, Y. Wu, H. Shu, S. Yu, X. Wang, “Highly reconfigurable silicon integrated microwave photonic filter towards next-generation wireless communication,” Photonics Research, vol. 11, issue 5, pp. 682-694, (2023).

DOI: https://doi.org/10.1364/PRJ.476466


About Optica Publishing Group (formerly OSA)

Optica Publishing Group is a division of the society, Optica (formerly OSA), Advancing Optics and Photonics Worldwide. It publishes the largest collection of peer-reviewed and most-cited content in optics and photonics, including 18 prestigious journals, the society’s flagship member magazine, and papers and videos from more than 835 conferences. With over 400,000 journal articles, conference papers and videos to search, discover and access, our publications portfolio represents the full range of research in the field from around the globe.

About Photonics Research

Photonics Research disseminates fundamental and applied research progress in optics and photonics. Published by Chinese Laser Press and Optica Publishing Group and led by Editor-in-Chief Lan Yang, Washington University in St. Louis, USA. For more information, visit Photonics Research.