However, variations between countries grouped into regions according to socioeconomic development and geographic proximity suggest that while mainly benefitting women’s lives and health at first, progress in gender equality helps men to live longer too, eventually narrowing the gender gap in life expectancy.

Lead author Dr Cat Pinho-Gomes, Honorary Research Fellow at The George Institute for Global Health, UK in partnership with Imperial College London, said the results — published in the lead up to International Women’s Day — suggest that addressing longstanding gender inequality and empowering women might help extend longevity for both women and men.

“Many of the factors that determine how long you will live — like working and living conditions, exposure to pollution, access to health care, education, income, and social support — are layered with gender differences around the world,” she said.

“As countries make greater progress towards gender equality and women are afforded the opportunity to participate more fully in in political, economic, and social life, the whole of society reaps the rewards.”

According to the latest report by the World Economic Forum, global events such as the rising cost of living, the COVID-19 pandemic, the climate emergency and large-scale conflict and displacement are stalling progress towards gender parity. This may, in turn, jeopardise socioeconomic development and improvement in living and working conditions, curbing the gains in life expectancy that have occurred over the past decades.

To investigate whether gender equality was associated with life expectancy (LE) for women and men and assess the gender gap in life expectancy across the globe, the researchers used a modified global gender gap index (mGGGI), based on the index developed by the World Economic Forum (WEF), and applied it across 156 countries between 2010 and 2021.

The WEF’s Global Gender Gap Index benchmarks the current state and evolution of gender parity across four key dimensions (Economic Participation and Opportunity, Educational Attainment, Health and Survival, and Political Empowerment). For this study, the health dimension was excluded because it includes healthy life expectancy, which was the subject of this study.

Among the three dimensions included in this study (i.e., political, economic, and educational), gender equality in education had the strongest association with longer LE for both women and men.

“This suggests investing in education is paramount, particularly in low- and middle-income countries, where many girls are still denied access to education and resources are limited,” added Dr Pinho-Gomes.

“Even high-income countries — where substantial progress has been made to address gender inequalities in recent years — investing in gender equality may still benefit life expectancy, particularly for men. This study confirmed what we had already seen for countries in the EU using a different index, reinforcing the validity of our findings.”

“The weaker association between gender equality in the political domain and the gender gap in LE raises concerns about how gender equality is being implemented by political systems worldwide,” she said.

“As we’ve seen from the recent resignations of high-profile female politicians, women still experience significant challenges in this field, including discrimination, balancing private, family and political life, gaining support from political parties, and securing campaign funding.”

Overall, in 2021, each ten percent increase in the mGGGI was associated with a 4.3-month increase in women’s LE and a 3.5-month increase in men’s LE, leading to an 8-month wider gender gap, but there was considerable variation between geographical regions.

“Our study has important implications for policy makers across the globe, particularly as the world gradually recovers from the myriad shocks caused by the COVID-19 pandemic, which had a gendered impact across multiple domains of life,” added Dr Pinho-Gomes.

“This International Women’s Day, let’s not forget that the evidence demonstrates that enhancing women’s representation across multiple sectors contributes to wealthier and, hence, healthier societies for all.”

“In a drop of seawater, there will be about 1,000 to 10,000 E. huxleyi cells, and about 10 million viruses,” said Kay Bidle, a professor in the Department of Marine and Coastal Sciences at Rutgers School of Environmental and Biological Sciences (SEBS) and a senior author on the study. “They’re all in a sort of arms race against each other and we are studying it to see how it plays out and impacts Earth’s carbon cycle.”

Reporting in Science Advances, the researchers said they discovered, through observations both in the ocean and in the laboratory, that the chalk (calcium carbonate) plates, called coccoliths, are a previously unrealized central player in viral infections that can collapse phytoplankton blooms the size of some countries within weeks.

“Coccoliths can act as catalysts for death, delivering viruses directly to algae cells for successful infection,” said Christopher Johns, a doctoral student in the Department of Marine and Coastal Sciences at SEBS and lead author on the study.

E. huxleyi is a one-celled species of phytoplankton, which, like trees, performs photosynthesis. In the case of phytoplankton, they convert carbon dioxide dissolved in ocean water into organic compounds, and at the same time produce oxygen.

“The phytoplankton in the oceans contribute about half of Earth’s oxygen, with the other half coming from land plants,” Bidle said. “Every other breath you take is from phytoplankton.”

E. huxleyi is well-known for its ability to biomineralize calcium carbonate, similar to corals, by producing coccoliths, which are arranged on the cell surface to form an armored layer. These coccoliths are produced and then shed into the surrounding seawater in a continuous cycle.

For years, the function of these coccoliths has been poorly understood, according to Bidle. Researchers believed the chalk armor existed in part to protect phytoplankton from getting infected by viruses. And the discarded, free coccoliths were commonly thought of as passively drifting planktonic particles with little biological or ecological roles.

But in experiments conducted in laboratories on the Cook campus at Rutgers University-New Brunswick, Johns and other team members observed that the expelled coccoliths can find their way back to the E. huxleyi cells, reattach, and at the same time ferry viral particles, facilitating infection. This ability to propagate and catalyze infection is one unexpected role of the coccoliths with important potential ecosystem outcomes.

The discovery also has an important connection to climate change and the Earth’s carbon cycle, Bidle said. Infected E. huxleyi cells produce a sticky glue that can help aggregate particles into what is called “marine snow.” When marine snow sinks to the deep ocean, it helps to sequester and bury carbon, removing it from the atmosphere for centuries to millennia. Coccoliths are important in this process because they are heavier than seawater and help make particles sink faster and more rapidly into the deep ocean.

By assisting in the death of the phytoplankton, as well as in marine snow formation and sinking, the coccolith biominerals can ultimately have a positive impact on the removal of carbon dioxide from the upper ocean and atmosphere, Bidle said.

“This means the coccoliths facilitate the process of sequestering or sinking carbon into the deep ocean for thousands of years, making them important players in balancing the Earth’s carbon cycle,” Bidle said.

Other Rutgers researchers on the study include Associate Professor Heidi Fuchs; Karen Grace Bondoc-Naumovitz, a former postdoctoral fellow now at the University of Exeter in England; and Alexandra Matthews, a former undergraduate student, all within the Department of Marine and Coastal Sciences.

Researchers from the U.S. Department of Energy’s Oak Ridge National Laboratory, the University of California-Santa Barbara, and the University of North Carolina-Wilmington also were involved in the study.

CTE is a progressive neurodegenerative disease frequently found in contact sports athletes. However, many former contact sports athletes suffer from thinking problems and impulsive behavior in the absence of CTE, or with very mild CTE. This new study suggests that a separate type of brain damage, which can appear earlier than CTE, may underlie some of these symptoms.

“Damage to the white matter may help explain why football players appear more likely to develop cognitive and behavioral problems later in life, even in the absence of CTE,” said corresponding author Thor Stein, MD, PhD, a neuropathologist at VA Boston Healthcare System and assistant professor of pathology and laboratory medicine at Boston University Chobanian & Avedisian School of Medicine.

The researchers studied the brains of 205 deceased American football players donated to the Veterans Affairs-Boston University-Concussion Legacy Foundation (VA-BU-CLF) Brain Bank and measured levels of myelin, a component of white matter that covers, protects and speeds up the connections in the brain. They then interviewed family members on measures of cognition and impulsivity and then compared how career length and age of beginning tackle football related to levels of myelin, and how myelin levels related to cognition and impulsivity. In addition to more years of football played, the researchers found that starting tackle football at a younger age was also related to more white matter loss, independent of career length.

“These results suggest that existing tests that measure white matter injury during life, including imaging and blood tests, may help to clarify potential causes of changes in behavior and cognition in former contact sport athletes. We can also use these tests to better understand how repeated hits to the head from football and other sports lead to long term injury to the white matter,” said co-author Michael L. Alosco, PhD, associate professor of neurology.

The researchers hope these findings help reinforce the idea that more needs to be done to protect the brains of athletes, especially children, from repeated hits to the head.

These finding appear online in the journal Brain Communications.

This work was supported by grant funding from: NIA (AG057902, AG06234, RF1AG054156), NINDS (U54NS115266, K23NS102399, RF1NS122854), National Institute of Aging Boston University AD Center (P30AG072978); the United States Department of Veterans Affairs, Veterans Health Administration, BLRD Merit Award (I01BX005161); the Nick and Lynn Buoniconti Foundation, and BU-CTSI Grant Number 1UL1TR001430. The views, opinions and/or findings contained in this article are those of the authors and should not be construed as an official Veterans Affairs or Department of Defense position, policy or decision, unless so designated by other official documentation. Funders did not have a role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication.