Air pollution last year caused the premature death of nearly half a million babies in their first month of life, with most of the infants being in the developing world, data shows.
Exposure to airborne pollutants is harmful also for babies in the womb. It can cause a premature birth or low birth weight. Both of these factors are associated with higher infant mortality.
Nearly two-thirds of the 500,000 deaths of infants documented were associated with indoor air pollution, particularly arising from solid fuels such as charcoal, wood, and animal dung for cooking.
The discovery is reported in the State of Global Air 2020 report, which examined data on deaths around the world alongside a growing body of research that links air pollution with health problems.
Medical experts have warned for years of the impacts of dirty air on older people and on those with health conditions, but are only beginning to understand the deadly toll on babies in the womb.
Katherine Walker, principal scientist at the Health Effects Institute, which published the report, said: “We don’t totally understand what the mechanisms are at this stage, but there is something going on that is causing reductions in baby growth and ultimately birth weight. There is an epidemiological link, shown across multiple countries in multiple studies.”
Babies born with a low birth weight are more susceptible to childhood infections and pneumonia. The lungs of pre-term babies can also not be fully developed.
“They are born into a high pollution environment, and are more susceptible than children who went to term,” said Dan Greenbaum, president of the Health Effects Institute in the US.
Beate Ritz, professor of epidemiology at UCLA, (University of California, Los Angeles), who was not involved with the study, said the indoor air pollution in cities across India, south-east Asia and Africa was comparable to that of Victorian London.
“This is not the air pollution we see in modern cities [in the rich world] but that which we had 150 years ago in London and other places, where there were coal fires indoors. Indoor air pollution has not been at the forefront for policymakers, but it should be,” Ritz said.
She pointed out that the harm to children went beyond the deaths; reducing air pollution would also lessen harm to survivors. “There is also damage to the brain and other organs from this pollution, so just surviving is not enough – we need to reduce air pollution because of the impact on all these organs too,” she said.
Some of these effects are likely to have existed, unnoticed, for centuries, as people have long cooked upon fires in enclosed spaces, an activity that causes particulate matter to be breathed in, particularly by women and children, who spend more time in
By mid-October, the coronavirus had killed almost 17,000 more American men than women, according to data from the Centers for Disease Control and Prevention. For every 10 women claimed by the disease in the United States, 12 men have died, found an analysis by Global Health 50/50, a U.K.-based initiative to advance gender equality in health care.
That disparity was one of many alarming aspects of the new virus. It bewildered those unfamiliar with the role of gender in disease.
But the specialized group of researchers who study that relationship was not surprised. It prepared an array of hypotheses. One possible culprit was male behavior. Perhaps men were more likely to be exposed to the virus due to social factors; a disproportionately male workforce, for instance, could place more men in contact with infected people. Or men’s lungs might be more vulnerable because they were more likely to smoke in the earliest countries to report the differences.
What has become more evident, 10 months into this outbreak, is that men show comparatively weaker immune responses to coronavirus infections, which may account for those added deaths.
“If you look at the data across the world, there are as many men as women that are infected. It’s just the severity of disease that is stronger in most populations in men,” Franck Mauvais-Jarvis, a Tulane University physician who studies gender differences in such diseases as diabetes. In such cases, biology can help explain why.
Women generally have stronger immune systems, thanks to sex hormones, as well as chromosomes packed with immune-related genes. About 60 genes on the X chromosome are involved in immune function, Johns Hopkins University microbiologist Sabra Klein told The Washington Post in April. People with two X chromosomes can benefit from the double helping of some of those genes.
Akiko Iwasaki, who studies immune defenses against viruses at Yale University, wanted to see how sex differences might play out in coronavirus infections. She and her colleagues cast a proverbial net into the immune system to fish out schools of microscopic fighters.
“We did a holistic look at everything we can measure immunologically,” Iwasaki said, listing a litany of the molecules and cells that form the body’s bulwark against pathogens: “cytokines, chemokines, T cells, B cells, neutrophils. Everything that we had access to.”
In male patients, the T-cell response was weaker, the scientists found. Not only do T cells detect infected cells and kill them, they also help direct the antibody response. “It’s like a master regulator of immune response. And when you have a drop in T cells, or in their ability to become activated, you basically lose the conductor of an orchestra,” Iwasaki said.
The power of the immune system wanes as people age, regardless of sex. But what is a gentle decline for women is an abrupt dive off a cliff for men: Iwasaki’s work indicates the T-cell response of men in their 30s and 40s is equivalent to that of a woman in her 90s.