We all must have come across the phase: this is why women live longer than men. These are all over the social media, where men are performing more often than not, some experiments, without gears, just for fun, "in the name of science". The caption reads: this is why women live longer. However, is there really a science to it, other than the fact that women choose to do things more safely?

In the United States, women have a life expectancy of about 80, whereas men have 75. Women outlive men and this holds true regardless of the country women live, the money they make, and other factors. In fact, it is true for most other mammals too.

Dr Dena Dubal, a professor of neurology at the University of California, San Francisco told the New York Times, "It is a very robust phenomenon all over the world, totally conserved in sickness, during famines, during epidemics, even during the times of starvation."

But what are the reasons? These reasons are often more complicated and less established. It is important to note that only because women are outliving men does not mean they are living a better life. In fact, women tend to have shorter health spans, which means the number of healthy years in a person's life is less in women than men, confirmed Bérénice Benayoun, an associate professor at the U.S.C. Leonard Davis School of Gerontology.

As per a 2021 study titled, Sex differences in frailty: Comparisons between humans and preclinical models, found that women are more physically grail than men in old age. They are also more vulnerable, especially after menopause and are at more risk of developing cardiovascular issues and Alzheimer's disease because of age.

The key is in figuring out what makes one sex more resilient or vulnerable.

Genetics

For things which do not find easy explanations, scientists look for their answers in genes. Many research, including a 2020 study titled, The sex with the reduced sex chromosome dies earlier: a comparison across the tree of life, suggests that the XX set of female sex chromosomes may impact longevity. However, there has not been any clarity on how it affects longevity.

Another 2018 study titled, Female XX sex chromosomes increase survival and extend lifespan in aging mice, which was conducted by Dr Dubal's lab, looked at genetically manipulated mice with different combinations of sex chromosomes and reproductive organs. It was found that those with two X chromosomes and ovaries lived longest, followed by mice with two X chromosomes and testes. Mice with XY chromosomes had shorter life spans.

"There was something about the second X chromosome that was protecting the mice from dying earlier in life, even if they had testes. What if there was something on that second X chromosome that was in some ways a sprinkle of the fountain of youth," says Dr Dubal. While scientists have not yet looked at this factor in humans, Dr Dubal suggests that humans have the same hormones and sex chromosomes, and similar reproductive system that could corroborate the similar findings in people.

Hormones

Plenty research has shown that estrogen is responsible for longevity also effect on the immune system. The data also shows that before menopause, the female immune system tends to do better. In fact Dr Benayoun said that males tend to do much worse in response to infection.

Another 2017 study titled, Ages at Menarche and Menopause and Reproductive Lifespan As Predictors of Exceptional Longevity in Women: The Women's Health Initiative, found that women who experienced menopause later in life over the age 50 lived longer than those who experienced it earlier.

Lifestyle and Behavior

There are also disparity in behavioral patterns between men and women. This includes smoking, drinking heavily, which can contribute significantly to mortality. Women also have more "health promoting behavior", believe experts. Women are also more likely to socialize than men and thus it protects them from detrimental effects of social isolation and loneliness. In fact, a 2023 analysis published in Jama Network, titled, Widening Gender Gap in Life Expectancy in the US, 2010-2021, found that women are less likely to die by drug overdose or suicide.

If you think that injections of botulinum toxin -- commonly known as Botox -- are only used to make skin wrinkle-free, you may be mistaken.

A new study led by US researchers has shown that Botox injections can act as a “rescue therapy” to treat conditions such as finger ulcers, digital ischemia, and gangrene that are difficult to manage with standard therapies.

Finger ulcers (or digital ulcers) are painful open sores, while acute digital ischemia causes the fingers to become extremely painful, cold, and sometimes pale or bluish in color. Gangrene is the dangerous death of body tissue (necrosis), often turning skin black, green, or purple.

These debilitating complications, often associated with conditions like lupus, rheumatoid arthritis, systemic sclerosis, or bacterial infections, are caused by reduced blood flow to the fingers and heal poorly.

Botox injections, which work by reducing blood vessel constriction and improving circulation, may help achieve complete healing of lesions in more than 85 percent of such patients, according to a study recently published in JAMA Dermatology.

“These new findings are particularly important because therapeutic options remain limited for the cutaneous and vascular manifestations of systemic sclerosis and other autoimmune diseases,” said Dr. Netchiporouk, a scientist in the Infectious Diseases and Immunity in Global Health Program at the Research Institute of the McGill University Health Center.

Netchiporouk noted that the available vasodilator and immunosuppressive treatments are generally administered intravenously.

In contrast to Botox injections, these are also costly, minimally effective, and associated with significant adverse effects.

Also read: Botox Helped Her Burp: How Injectables Changed A 25-Year-Old's Life

The study also described the case of a 50-year-old man with a rare autoimmune disease that caused joint pain and digital necrosis (gangrene).

While traditional medications helped reduce his pain, he was forced to stop working, and the condition severely impacted his quality of life.

However, after receiving botulinum toxin injections, his pain was relieved, and sensation improved within 24 hours, and the necrosis began to improve within two weeks.

“This treatment has become an important tool, especially for patients with autoimmune vascular diseases that result in serious health consequences and for which there are few therapeutic options,” Netchiporouk said.

Also read: Why Regulatory Clarity Is Important for Safe Aesthetic Procedures in India

Botox: Safe, With Minimal Adverse Effects

The study, based on a systematic review and individual patient data meta-analysis of 30 published studies and one unpublished case involving 119 patients, found that only a few patients experienced adverse effects.

These were generally mild and short-lived, most commonly temporary muscle weakness or pain at the injection site.

“Our results show that botulinum toxin can improve blood circulation in the fingers and treat serious complications such as ulcers or gangrene, offering a safe and easy-to-administer alternative,” said Dr. Catherine Zhu, a dermatology resident at the McGill University Health Center.

Zhu added that the injections can be easily administered by rheumatologists and dermatologists in outpatient settings, reducing reliance on intravenous therapies that require hospitalization and increasing overall healthcare costs.

Importantly, in most cases, a single injection session was sufficient to achieve the desired response.

“Botulinum toxin can offer significant benefits with a favorable safety profile. It deserves further study to develop standardized protocols and optimize outcomes,” said Dr. Netchiporouk.

Even after being preventable and curable, tuberculosis (TB) retains its status as one of the deadliest infectious diseases more than 140 years after Robert Koch announced the discovery of Mycobacterium tuberculosis (Mtb) on March 24, 1882.

A major challenge is that millions of people carry it without knowing, and current tests often miss it. This is known as latent TB infection, where bacteria exist in an inactive state in the body.

While you do not feel sick, the infection can progress to active, contagious TB disease.

Ahead of World Tuberculosis Day, on March 24, scientists at the Indian Council of Medical Research-National Institute for Research in Tuberculosis (NIRT) in Chennai, reported developing an advanced blood test that can find TB even when it's hiding, and before it gets serious.

In the study, published in the Lancet journal eBioMedicine, the researchers explained about detecting circulating cell-free Mtb DNA in the plasma of individuals at high risk of developing TB disease via a dual target-based digital droplet PCR (ddPCR) assay.

The test was targeted at adults without a clear diagnosis of TB (asymptomatic or clinically diagnosed TB).

Using the test, the team led by Luke Elizabeth Hanna from NIRT's Department of Virology and Biotechnology, found TB in the blood up to 18 months before a person was diagnosed.

They identified eight out of 10 people at risk - all before they fell sick with the infectious disease.

“The new test performed better than all existing standard TB tests combined. This test could change how we fight TB - by finding it early, treating it faster, and stopping it from spreading,” said the team in the paper.

Tuberculosis: Advanced Blood Test

Detection of pathogen-derived cell-free DNA (cfDNA) has been gaining much attention in recent years for the diagnosis of several clinical conditions.

cfDNA is a liquid biopsy blood test that analyzes small, non-cellular DNA fragments circulating in the bloodstream.

The team found that the advanced blood test could find tiny traces of TB in the blood - even when a person feels completely healthy.

The test works by breaking a small blood sample into thousands of tiny droplets and searching each one for TB.

The study included 46 healthy household contacts of patients with pulmonary TB who developed TB within two years of follow-up, and 92 HHCs who did not progress to TB.

Plasma was obtained and subjected to testing using a ddPCR assay targeting two Mtb-specific insertion sequences, IS6110 and IS1081.

"Our findings support the diagnostic utility of ddPCR-based detection of circulating Mtb-derived cell-free DNA in plasma of individuals at high risk for progressing to active TB several months prior to clinical diagnosis," the ICMR-NIRT researchers said.

"These findings address important unmet diagnostic needs and indicate the potential of plasma-based Mtb ccfDNA detection to contribute to improved TB case detection and progress towards the WHO End TB goals," they added.

The WHO End TB Strategy

In 2024, an estimated 10.7 million people fell ill with TB worldwide, including 5.8 million men, 3.7 million women and 1.2 million children. TB is present in all countries and age groups, according to the World Health Organization (WHO).

The WHO aims to End TB by 2035, with a 95 percent reduction in deaths and a 90 percent reduction in incidence compared to 2015.

Down Syndrome is a common genetic disorder in which an extra copy of chromosome 21 (Trisomy 21) causes mild-to-moderate intellectual disabilities, developmental delays, and characteristic physical traits.

Every year, World Down Syndrome Day is observed on March 21 every year to raise public awareness about the condition, which deserves more than medical care.

The theme for World Down Syndrome Day 2026 is 'Together Against Loneliness,’ and it focuses on raising awareness of how loneliness disproportionately affects people with Down syndrome and other intellectual disabilities, as well as their families.

According to the UN data, the estimated incidence of Down syndrome is between 1 in 1,000 -- 1 in 1,100 live births worldwide. Each year, approximately 3,000 to 5,000 children are born with this chromosome disorder.

In India, about 30,000 babies are born with Down syndrome every year.

While Down Syndrome is not preventable, in a video post on the social media platform X, Dr. Neerja Gupta from AIIMS Delhi highlighted the importance of early detection, screening, and long-term support for better outcomes.

Dr. Gupta, Professor, Division of Genetics at AIIMS's Department of Pediatrics, also explained the causes of the condition and shared tests that can help eliminate the risks in future babies.

“Down syndrome is a common chromosomal disorder in which chromosome 21 is present in three copies instead of two. Normally, every human cell has 46 chromosomes. However, in Down syndrome, there are 47 chromosomes because the 21st chromosome is present in three copies instead of two,” she said.

Due to the increase in the number of chromosomes, the child may:

• presents with mild to moderate intellectual disability,
• have problems related to the heart,
• have problems of hearing,
• have vision problems
• have problems related to thyroid.

"The sooner we can catch them, the earlier we can begin the intervention, resulting in better health outcomes," Dr Gupta said.

Types Of Down Syndrome

Down syndrome can occur in three types, depending on how the extra copy of chromosome 21 is present. In all cases, chromosome 21 appears in three copies, but this can happen in different ways.

• Trisomy 21 -- the most common type, where all cells have three copies of chromosome 21.
• Translocation -- when part of chromosome 21 is attached to another chromosome. In this, the recurrence risk increases in the next child.
• Mosaic -- It occurs in about 1 percent of children with Down syndrome. In this type, there are two cell lines—some cells have the normal 46 chromosomes, while others have 47 chromosomes (with an extra copy of chromosome 21).

Down syndrome: Early Screening Tests

"As the mother’s age increases, the risk of Down syndrome also increases. Today, there are several prenatal tests available to detect this condition during pregnancy," the expert said.

• The chromosomal disorder can be identified by doing a chromosome test called Karyotyping.
• The NT scan (Nuchal Translucency scan) is an important test done between 11 to 13 weeks. The ultrasound test measures fluid at the back of the baby’s neck. Increased thickness may indicate a higher risk of Down syndrome.
• The Dual Marker Test -- a blood test done during early pregnancy (11–13 weeks), often in combination with the NT scan.
• The quadruple test -- a blood test done during the second trimester (usually 15–20 weeks of pregnancy) to screen for chromosomal abnormalities.

"In this, the DNA is seen in the fetal baby's stomach through the mother's blood, to check whether the chromosomal copies are in the right number or not," she said.

The expert noted that this screening test is highly accurate, but if the results indicate a high risk, diagnostic testing of the fetus is recommended.