NEW YORK (NYTIMES) - Heart disease is the leading cause of death among men and women in the United States, killing nearly 700,000 people a year.

But studies have long shown that women are more likely than men to dismiss the warning signs of a heart attack, sometimes waiting hours or longer to call 911 or go to a hospital.

Now, researchers are trying to figure out why. They have found that women often hesitate to get help because they tend to have more subtle symptoms than men - but even when they do go to the hospital, healthcare providers are more likely to downplay their symptoms or delay treating them.

The US health authorities say that heart disease in women remains widely under-diagnosed and under-treated, and that these factors contribute to worse outcomes among women and heightened rates of death from the disease.

Most studies suggest that a major reason women delay seeking care - and are often misdiagnosed - is because of the symptoms they develop.

While chest pain or discomfort is the most common sign of a heart attack in both sexes, women who have heart attacks are far less likely than men to have any chest pain at all. Instead, they often have symptoms that can be harder to associate with cardiac trouble, like shortness of breath, cold sweats, malaise, fatigue, and jaw and back pain.

A report by the American Heart Association found that heart attacks are deadlier in women who do not exhibit chest pain, in part because it means both patients and doctors take longer to identify the problem.

But, when women suspect they are having a heart attack, they still have a harder time getting treated than men do. Studies show they are more likely to be told that their symptoms are not cardiovascular-related. Many women are told by doctors that their symptoms are all in their head.

One study found that women complaining of symptoms consistent with heart disease - including chest pain - were twice as likely to be diagnosed with a mental illness compared with men who complained of identical symptoms.

Women face longer waits, slower diagnoses

In a study published in May2022 in the Journal of the American Heart Association, researchers analysed data on millions of emergency room visits before the pandemic.

They found that women - and especially women of colour - who complained of chest pain had to wait an average of 11 minutes longer to see a doctor or nurse than men who complained of similar symptoms.

Women were less likely to be admitted to the hospital. They also received less thorough evaluations and were less likely to be administered tests like an electrocardiogram (ECG), which can detect cardiac problems.

Dr Alexandra Lansky, a cardiologist at Yale-New Haven Hospital, recalled one patient who had gone to multiple doctors complaining of jaw pain, only to be referred to a dentist, who extracted two molars. When the jaw pain did not go away, the woman went to see Dr Lansky, who discovered the problem was heart-related.

"She ended up having bypass surgery because the jaw pain was heart disease," said Dr Lansky, who directs the Yale Cardiovascular Research Center.

Over the years, the US health authorities have tried to address the gender gap in cardiovascular care through a variety of public service campaigns.

The federal government and the American Heart Association launched campaigns to increase awareness of heart disease and its symptoms in women, as did the Women's Heart Alliance, which started placing advertisements last year on Facebook, Instagram and thousands of radio and television stations.

Set to music by Lady Gaga, the group's ads urge women to "know the signs" of a heart attack, which they caution can be as vague as sweating, dizziness or unusual fatigue.

In January 2022, a group of scientists published a study delving into the factors that drive women to delay seeking care for their cardiac troubles.

They found that the absence of chest pain or discomfort was a major reason. The study, published in the journal Therapeutics and Clinical Risk Management, looked at 218 men and women who were treated for heart attacks at four different hospitals in New York before the pandemic.

It found that 62 per cent of the women did not have chest pain or discomfort, compared with just 36 per cent of the men. Many women reported shortness of breath, as well as gastrointestinal symptoms like nausea and indigestion. About a quarter of the men also reported having either shortness of breath or gastrointestinal distress.

Ultimately, 72 per cent of women who had a heart attack waited more than 90 minutes to go to a hospital or call 911, compared with 54 per cent of men. Slightly more than half of the women called a relative or a friend before dialling 911 or going to a hospital, compared with 36 per cent of the men.

Heart disease is rising in younger women

"There's a lack of understanding in both women and men that a heart attack does not have to cause chest pain or these incredible movie-like symptoms," said Dr Jacqueline Tamis-Holland, an author of the January 2022 study and a cardiologist at Mount Sinai Morningside in New York.

She said there were other reasons for the delays. One is that women do not consider themselves to be as vulnerable to heart disease as men. Previous studies have shown that they are more likely to dismiss their symptoms as stress or anxiety. They also tend to develop heart disease at later ages than men.

In Dr Tamis-Holland's study, the women who had heart attacks were, on average, 69, while the average age of the men was 61.

But younger women are not immune to heart disease. In fact, recent studies have found that heart attacks and deaths from heart disease have been rising among women between ages 35 and 54, in part because of an increase in cardiometabolic risk factors such as high blood pressure and obesity.

Experts say that more outreach and education is needed to help women and men recognise the signs and risk factors for heart disease.

But Dr Lansky said she also wants to empower people to become advocates for themselves, adding that people who suspect something is wrong with their health should not let a healthcare provider turn them away until they have answers.

"If you're not feeling right and you think that in the realm of possibilities is an issue with your heart, then you should spell it out," she said. "Say: 'I am concerned I may be having a heart attack, and I want an ECG just to be sure.' Nobody in the emergency department is going to say you can't have it. But sometimes they're just not thinking about it, so it's good to flag it."