Men account for 61% of COVID-19 related deaths in in England and Wales. We asked experts why.
Medically reviewed by Dr Roger Henderson and words by Zia Sherrell
Gender differences exist in many health conditions, and COVID-19 is no different. It appears that with regards to the novel coronavirus, men’s health is less robust.
This global phenomenon is particularly visible in some countries. In Thailand, males account for a massive 81% of COVID-19 related deaths, in England and Wales, it’s 61%.
What are the reasons for the considerable difference between the sexes? We spoke to Dr Anthony Kaveh, MD, physician anesthesiologist, and integrative medicine specialist.
“Men are disproportionately affected by COVID-19 than women. From preliminary data, possible reasons include behavioural, baseline health, and genetic differences between men and women,” says Dr Kaveh.
Let’s look at what we know about COVID-19 infections among men and women. But first, a little about how and why the sexes are different.
Men and women have vastly different biological characteristics, that develop thanks to our chromosomes. A chromosome is a bundle of coiled DNA, found in the nucleus of almost every cell in the body. Humans have 23 pairs of chromosomes.
The sex chromosomes determine whether you develop as a male or female.
In humans, women have two larger X chromosomes (XX), whereas men have a single X chromosome and a much smaller Y chromosome (XY) that has relatively fewer gene copies.
When an embryo is developing in the womb, these chromosomes dictate the future sex of the baby.
One of the genes found on the Y chromosomes, the SRY gene, starts testicular development in an XY embryo. The testicles begin to make testosterone which directs the embryo to develop as a male.
In an XX embryo, there is no SRY gene, so instead, an ovary develops which makes female hormones.
This basic, biological variation between the sexes can affect COVID-19 infection rates.
The effects of hormones
Although essential for male health, testosterone levels are also linked to a range of medical conditions.
Oestrogen is a predominantly female hormone that provides protective effects from conditions, including heart disease. Men cannot benefit from its positive health effects, as they only produce low levels.
However, Dr Kaveh says that “The immunologic effects of oestrogen in protecting against COVID-19 are theoretical and don’t yet provide a mechanism to explain our observations.”
Oestrogen is a predominantly female hormone that provides protective effects from conditions.
Testosterone could have a role to play in COVID-19 infection rates. High levels of testosterone can suppress an immune response. Researchers found that women and men with lower levels of testosterone had higher antibody responses to an influenza vaccine.
Genetics and immunity
The X chromosome has about 900 genes, the Y chromosome, just 55. Women have a genetic advantage with two X chromosomes because if there is a mutation in one, the other gene provides a buffer.
Men have more sex-linked diseases such as the blood clotting disorder, haemophilia, and suffer from an increased rate of metabolic disorders. The protective XX effect explains why male death rates are frequently higher.
The female immune system is stronger.
The female immune system is stronger. Concerning COVID-19 infections, Dr Kaveh says “Genetic factors are often considered, including the more active female immune system. While a more “active” immune system would make sense to protect against COVID-19, it would be expected to worsen the cytokine storm we observe in severe COVID-19 infection.”
However, there is no evidence to support that cytokine storms, which are potentially lethal, excessive immune responses, are more common in women.
If more men are testing positive for COVD-19, could the simple reason be that more men are tested than women? In fact, it seems the opposite is true.
“Within the context of our early statistics, women are tested more frequently than men, but men have more positive tests. This may reflect a male “stoicism” that leads to delayed care,” says Dr Kaveh.
Men are not as likely as women to seek medical attention. The Centers for Disease Control and Prevention (CDC) reported that women were 33% more likely than men to visit a doctor, even excluding pregnancy-related visits.
Women are tested more frequently than men, but men have more positive tests.
It seems like the reason for higher infection and death statistics in men is not due to a bias in testing.
“Obesity, diabetes, hypertension, and smoking are also predictors of COVID-19 hospitalisation, but the breakdown is difficult to correlate,” said Dr Kaveh.
People of either sex are more likely to suffer from complications from coronavirus if they have certain pre-existing health conditions, or engage in behaviours such as smoking and excessive alcohol consumption.
These health conditions and behaviours tend to be more common in men, which could affect the imbalance that we see in COVID-19 infections.
The association between risk factors and infection rate are not yet fully understood. “For example, hypertension is more common in men until menopause, at which point female rates quickly rise,” explains Dr Kaveh. In this case, we should be seeing an increase in the COVID-19 infection rate for women who have reached menopausal age, yet this is not the case.
The association between risk factors and infection rate are not yet fully understood.
“Obesity, a risk factor for diabetes, affects women more than men globally. However, diabetes is slightly more prevalent in men. These comorbid conditions don’t fully explain the COVID-19 observations, and neither does smoking,” says Dr Kaveh.
Smoking is a risk factor for all respiratory diseases and also of lung cancer which is another COVID-19 risk factor.
In China, about 50% of men smoke and only 2% of women. These figures could contribute to the high ratio of male deaths which are more than double the rate of female deaths.
These differences in smoking and death rates are not as extreme in other countries. Risky behaviour cannot fully explain sex bias in COVID-19 infections.
The gender impact on COVID-19
As yet, it seems like there is no definitive answer as to why more men are suffering severe COVID-19 infections. More research is needed.
“We are still very early in our global epidemiological observations of COVID-19. More complete data in the coming months will hopefully provide more clues to explain our observations,” concluded Dr Kaveh.