Study Finds Any Extra Steps Count: Even Sedentary Lifestyles Benefit from Increased Daily Walking

You’ve likely encountered the recommendation that adults should strive for 10,000 steps daily. While this guideline offers a straightforward directive, it overlooks the diversity of human lifestyles and physical compositions.

A global team of researchers has uncovered that even individuals with predominantly sedentary habits can mitigate the adverse effects of prolonged sitting by integrating more steps into their daily routines.

The prevalence of sedentary lifestyles is on the rise, with established connections to heightened risks of cardiovascular disease (CVD), elevated susceptibility to cancer and diabetes, and a reduced lifespan. Conversely, individuals with higher step counts and brisk walking paces tend to experience diminished risks.

Yet, it remained uncertain whether markedly sedentary individuals could mitigate these concerning health risks through daily step increments.

The study revealed that irrespective of sedentary tendencies, higher step counts correlated with reduced CVD risk and mortality rates. Consequently, those confined to desk-bound roles need not despair entirely, although researchers emphasize the importance of overall sedentary time reduction.

“This is by no means a get out of jail card for people who are sedentary for excessive periods of time,” says population health scientist Matthew Ahmadi from the University of Sydney in Australia.

“However, it does hold an important public health message that all movement matters and that people can and should try to offset the health consequences of unavoidable sedentary time by upping their daily step count.”

Ahmadi and his team scrutinized data from 72,174 volunteers enrolled in the UK Biobank, an extensive longitudinal dataset established in 2006 to track participants’ health metrics over at least three decades.

Each participant contributed an average of 6.9 years’ worth of general health data. Utilizing wrist accelerometers worn for seven days, researchers estimated physical activity levels, including step counts and sitting durations.

The median daily sedentary duration stood at 10.6 hours. Individuals surpassing this threshold were categorized as having ‘high sedentary time,’ while those falling below were labeled as having ‘low sedentary time.’

The study excluded participants whose initial two years of data might have been influenced by poor health, limiting the findings to generally healthy individuals for the first two years of data collection. It remains uncertain whether the dataset included participants with disabilities impacting their step counts.

The research revealed that accumulating between 9,000 and 10,000 steps daily proved optimal for counteracting the effects of a highly sedentary lifestyle, reducing incident CVD risk by 21 percent and mortality risk by 39 percent.

Regardless of sedentary behavior, researchers found that half of the benefits manifested at approximately 4,000 to 4,500 daily steps.

“Any amount of daily steps above the referent 2,200 steps per day was associated with lower mortality and incident CVD risk, for low and high sedentary time,” Ahmadi and colleagues conclude.

“Accruing between 9,000 and 10,000 steps a day optimally lowered the risk of mortality and incident CVD among highly sedentary participants.”

Ambitious survey of human diversity yields millions of undiscovered genetic variants

A massive US programme that aims to improve health care by focusing on the genomes and health profiles of historically underrepresented groups has begun to yield results.

Analyses of up to 245,000 genomes gathered by the All of Us programme, run by the US National Institutes of Health in Bethesda, Maryland, have uncovered more than 275 million new genetic markers, nearly 150 of which might contribute to type 2 diabetes. The work has also identified gaps in genetics research on non-white populations. The findings were published on 19 February in a package of papers in Nature1,2Communications Biology3 and Nature Medicine4.

They are a “nice distillation of the All of Us resource — what it is and what it can do”, says Michael Inouye, a computational genomicist at the University of Cambridge, UK. “This is going to be the go-to data set” for genetics researchers who want to know whether their findings are generalizable to a broad population or apply to only a limited one, he adds.

Bridging the gap

Researchers have long acknowledged the lack of diversity in the genomes available for them to study, says Jibril Hirbo, a geneticist at Vanderbilt University Medical Center in Nashville, Tennessee, who studies the genetics of health disparities. One study5 that looked at data gathered up until January 2019 found that 78% of people in most large-scale genomic studies of disease were of European descent. This has exacerbated existing health disparities, particularly for non-white individuals, Hirbo says. When researchers choose genetic or molecular targets for new medicines or create models to predict who is at risk of developing a disease, they tend to make decisions on the basis of non-diverse data because that’s all that has been available.

The All of Us programme, which has received over US$3.1 billion to date and plans to assemble detailed health profiles for one million people in the United States by the end of 2026, aims to bridge that gap, says Andrea Ramirez, the programme’s chief data officer. It began enrolling people in 2018, and released its first tranche of data — about 100,000 whole genomes — in 2022. By April 2023, it had enrolled 413,000 anonymized participants, 46% of whom belong to a minority racial or ethnic group, and had shared nearly 250,000 genomes. By comparison, the world’s largest whole-genome data set, the UK Biobank, has so far released about half a million genomes, around 88% of which are from white people.

The All of Us data set is “a huge resource, particularly of African American, Hispanic and Latin American genomes, that’s massively missing from the vast majority of large-scale biobank resources and genomics consortia”, says Alicia Martin, a population geneticist at Massachusetts General Hospital in Boston.

In addition to the genomes, the database includes some participants’ survey responses, electronic health records and data from wearable devices, such as Fitbits, that report people’s activity, “making this one of the most powerful resources of genomic data”, Martin says.

An urgent need

A study in Nature on type 2 diabetes2 is an example of the power of using a database that includes diverse genomes, Ramirez says. The condition, which affects about one in ten people in the United States, can be caused by many distinct biological mechanisms involving various genes. The researchers analysed genetic information from several databases, including All of Us, for a total of more than 2.5 million people; nearly 40% of the data came from individuals not of European ancestry. The team found 611 genetic markers that might drive the development and progression of the disease, 145 of which have never been reported before. These findings could be used to develop “genetically informed diabetes care”, the authors write.

In another of the studies3, researchers used All of Us data to examine pathogenic variants — that is, genetic differences that increase a person’s risk of developing a particular disease. They found that, among the genomes of people with European ancestry, 2.3% had a pathogenic variant. Among genomes from people with African ancestry, however, this fell to 1.6%.

Study co-author Eric Venner, a computational geneticist at Baylor College of Medicine in Houston, Texas, cautions that there should be no biological reason for the differences. He says that the disparity is probably the result of more research having been conducted on people of European ancestry; we simply know more about which mutations in this population lead to disease. In fact, the researchers found more variants of unknown risk in the genomes of people with non-European ancestry than in those with European ancestry, he adds. This underscores the urgent need to study non-European genomes in more detail, Venner says.

Updating models

Gathering and using more genomic and health data from diverse populations will be especially important for generating more accurate ‘polygenic risk scores’. These provide a picture of a person’s risk of developing a disease as a result of their genetics.

To calculate a score for a particular disease, researchers develop an algorithm that is trained on thousands of genomes from people who either do or don’t have the disease. A person’s own score can then be calculated by feeding their genetic data into the algorithm.

Previous research6 has shown that the scores, which might soon be used in the clinic for personalized health care, tend to be less accurate for minority populations than for majority ones. In one of the current papers4, researchers used the more-inclusive All of Us data to improve the landscape: they calibrated and validated scores for 23 conditions and recommended 10 to be prioritized for use in the clinic, for conditions including coronary heart disease and diabetes. Martin applauds these efforts, but she hopes that future studies address how physicians and others in the clinic interpret these scores, and whether the scores can improve a person’s health in the long term because of the treatment decisions they elicit.

The All of Us programme plans to release a tranche of data every year, representing new enrolees and genomes, including one later in 2024, Ramirez says. It’s excellent that diverse data are coming in, Hirbo says, adding that he would like to see existing algorithms that were trained mainly on the genomes of people of European ancestry updated soon. “The models are still way behind,” he says.


New Study Reveals Surprising Cooling Trend in Himalayan Glaciers Amidst Global Warming

Research recently published in the peer-reviewed journal Nature Geoscience reveals a surprising trend amidst the escalating global temperatures due to climate change: glaciers surrounding the world’s tallest mountains are experiencing a slight cooling during the warm season. The study, conducted at the Pyramid International Observatory, situated about 3.1 miles above sea level on the southern face of Mount Everest in the Khumbu Valley, presents intriguing insights into high-elevation climate dynamics.

For nearly four decades, the observatory has diligently collected data on various meteorological parameters, including air temperature, precipitation, humidity, and wind speed. The analysis of this extensive dataset uncovered a peculiar pattern: a decline in maximum daytime temperatures during the warmer months from May to October, amounting to approximately 0.040°C per year over the past 15 years.New Study Reveals Surprising Cooling Trend in Himalayan Glaciers Amidst Global Warming

Upon scrutinizing the data further, scientists corroborated this cooling trend with observations from neighboring weather stations across the southernmost regions of the Tibetan plateau. Surprisingly, the phenomenon wasn’t confined to Mount Everest; it spanned across the entire Himalayan range. This revelation contradicts prior assumptions, as a recent report indicated accelerated melting of Himalayan glaciers between 2010 and 2019, implying an overall warming trend in line with global climate trends.

Experts attribute this unexpected cooling to katabatic winds, a well-understood meteorological phenomenon. As sunlight warms the glaciers during the day, the air near the surface heats up and ascends, creating a vacuum that draws cold air downwards from the surrounding peaks. This process generates local katabatic winds, which peak in the afternoon, often exceeding speeds of 100 mph. With rising global temperatures amplifying this effect, the intensified katabatic winds contribute to the observed cooling trend by facilitating the descent of colder air.

New Study Reveals Surprising Cooling Trend in Himalayan Glaciers Amidst Global Warming

Interestingly, researchers speculate that these chilly winds might have mitigated glacier melt to some extent, counteracting potentially more severe outcomes. However, the study highlights a caveat: while daytime temperatures exhibit a cooling trend, nighttime temperatures during colder months (November to April) are on the rise. This nuanced interplay results in a deceptive impression of temperature trends, ultimately underscoring the inevitability of glacier melt amidst climate change.

The intricate relationship between glaciers and local climate dynamics underscores the critical role of ice in modulating temperature variations. Glacier ice acts as a thermal buffer, absorbing heat during the day and releasing it at night, thereby tempering temperature extremes in the vicinity. Consequently, temperature readings farther away from the glacier provide a more accurate reflection of daily temperature fluctuations, which significantly influence glacial melting processes.

Franco Salerno, the lead author of the study and an environmental scientist at the National Research Council, Institute of Polar Sciences, Milan, expresses relief at finally unraveling this complex phenomenon after nearly a decade of observation. He anticipates that the findings will pave the way for further research into local weather dynamics, shedding light on the intricate mechanisms shaping mountain climates.New Study Reveals Surprising Cooling Trend in Himalayan Glaciers Amidst Global Warming

Beyond its scientific implications, the study underscores the profound impact of glaciers on local mountain environments, particularly for climbers. The intensification of katabatic winds poses heightened risks for mountaineers, necessitating careful route assessment and navigation. Gordon Janow, director of the mountain climbing guide service Alpine Ascents, laments the increasing technical challenges and extended durations required for summit attempts, attributing these changes to the evolving mountain environment.

Moreover, the melting of glaciers, driven by these local weather phenomena, poses challenges not only in the Himalayas but also in mountains worldwide. Mount Rainier, a renowned training ground for mountaineers, exemplifies this trend, with changing terrain and increased hazards complicating ascent routes. Janow emphasizes the need for a nuanced understanding of contemporary mountain environments, cautioning against presumptions based on past experiences.

In essence, the research illuminates the complex interplay between climate change, local weather dynamics, and glacial responses, underscoring the need for comprehensive strategies to mitigate the impacts on mountain ecosystems and mountaineering activities alike.

Women with Fatty Liver Disease from Alcohol Consumption Face Higher Mortality Risk Than Men, Study Find

A recent study conducted by researchers from the Smidt Heart Institute at Cedars-Sinai and their colleagues has revealed that women diagnosed with fatty liver disease due to alcohol consumption are at nearly double the risk of mortality within a specific timeframe compared to men with the same condition.

The study, published in the esteemed Journal of Hepatology, underscores the imperative for women at risk of liver disease to abstain from excessive alcohol consumption.

Also termed steatotic liver disease, fatty liver disease develops when an excess of fat accumulates in the liver, potentially leading to enduring liver damage. This condition is also associated with an elevated risk of heart disease.

Dr. Susan Cheng, MD, MPH, the director of the Institute for Research on Healthy Aging in the Department of Cardiology at the Smidt Heart Institute and the lead author of the study, emphasized, “Steatotic liver disease is a significant and increasingly prevalent ailment, likely serving as an underlying precursor to numerous conditions, including those affecting the heart. We are increasingly concerned about steatotic liver disease as we observe its close correlation with established cardiovascular risk factors such as hypertension, high cholesterol, and diabetes.”

Recent medical discourse has introduced new terminology to classify distinct types of steatotic liver disease, including metabolic dysfunction-associated steatotic liver disease (MASLD), alcohol-related liver disease (ALD), and metabolic dysfunction-associated and alcohol-related liver disease (MetALD).

The investigators from Cedars-Sinai endeavored to investigate how these variants of steatotic liver disease might manifest differently in men and women.

Data spanning from 1988 to 1994, sourced from the National Health and Nutrition Examination Survey III, were scrutinized by the investigators. The study participants underwent comprehensive medical assessments, including questionnaires, physical examinations, and liver imaging scans, providing insights into alcohol consumption patterns, cardiometabolic risk factors, and liver health.

The analysis encompassed over 10,000 individuals aged 21 and above residing in the United States, with accessible data from liver scans and other medical evaluations. Approximately one-fifth of the cohort, totaling 1,971 individuals, exhibited steatotic liver disease, with MetALD accounting for over 75% of cases. While all forms of steatotic liver disease were approximately twice as prevalent in men compared to women, the data unveiled a significantly elevated risk of mortality among women over a median duration of 26.7 years. For instance, women diagnosed with MetALD faced an 83% higher risk of mortality compared to men without liver disease. Moreover, women afflicted with ALD confronted a mortality risk 160% greater than their male counterparts with ALD.

Dr. Alan Kwan, MD, a research instructor in the Department of Cardiology at Cedars-Sinai and a collaborator on the study, remarked, “These findings are particularly alarming against the backdrop of the COVID-19 pandemic, during which alcohol consumption and associated mortality, particularly among women, have surged.”

Indicators of underlying metabolic liver disease include being overweight or obese, prediabetes or diabetes, high blood pressure, or abnormal blood cholesterol levels. The investigators caution that women exhibiting these risk factors should be particularly vigilant regarding excessive alcohol consumption.

The Centers for Disease Control and Prevention defines moderate alcohol consumption for women as one drink per day or less.

The researchers intend to further explore why alcohol exerts a more pronounced impact on the female liver than the male liver and identify lifestyle modifications, beyond curtailing alcohol intake, that may mitigate a woman’s susceptibility to fatty liver disease.

They underscore that since the study relied on data collected between 1988 and 1994, additional research is imperative to ascertain how the prevalence of liver disease and alcohol consumption patterns may have evolved over time.

Dr. Yee Hui Yeo, MD, and Dr. Hirsh Trivedi, MD, both affiliated with Cedars-Sinai, also contributed to the study.