Is women’s respiratory health going up in a puff of smoke?

Chronic respiratory diseases are rising sharply among women worldwide, driven by increasing exposure to smoking, pollution, and other risk factors. Yet women are more likely than men to be misdiagnosed, underdiagnosed, or face barriers to early treatment.

The number of chronic obstructive pulmonary disease cases among women is projected to increase to 260 million by 2050. Photo: Michael Starkie

As the rate of chronic respiratory diseases—conditions affecting the lungs and airways—continues to rise globally, women increasingly comprise a growing proportion of fresh cases. This is largely due to environmental factors such as indoor and outdoor pollution, and behavioural patterns such as increased smoking and tobacco use.

In the case of chronic obstructive pulmonary disease (COPD), which accounts for nearly 80% of chronic respiratory disease cases globally, prevalence and mortality rates are rising more rapidly in women than in men. The condition causes restricted airflow and breathing problems and is sometimes referred to as emphysema or chronic bronchitis.

In other lung-related diseases, such as asthma and pulmonary hypertension (a condition that affects blood vessels in the lungs), women are increasingly at a higher risk than men. Researchers have also noted genetic biomarkers and physiological differences that can make women more susceptible to lung disease.

Yet, while efforts are being made in some cases to tailor screening, women are less likely to have their conditions caught at an early stage and more likely to be misdiagnosed than men, according to physicians and public health officials.

Global modelling of COPD prevalence published in JAMA Network projects that the number of cases among women will increase to 260 million by 2050, compared with 177 million in 2020, a relative increase of over 47%. In contrast, global COPD prevalence among men is expected to increase from 303 million in 2020 to 331 million in 2050, a relative increase of just 9.4%.

The modelling also found that by 2050 the number of people with COPD in low- and middle-income countries (LMICs) is projected to be more than double that in high-income countries, highlighting the urgent need to prioritise accessible, affordable solutions that address the gender imbalance.

The impact of lung conditions on women

There are a range of biological, social, and environmental factors that mean lung diseases, especially COPD, are likely to affect women for different reasons and with different outcomes when compared with men.

COPD was often considered to be a disease that primarily affected men, but this perception has shifted as smoking rates among women have increased, explains Dr Ioanna Tsiligianni, a researcher, general practitioner, and associate professor in general practice and public health at the Faculty of Medicine, University of Crete.

“Women smoke more. But it’s not only that they smoke more; they [also] have lungs that are smaller, so the [consequence] of smoking is greater.”

She says there is also greater understanding of the impact of smoking on women’s lungs. “Women smoke more. But it’s not only that they smoke more; they [also] have lungs that are smaller, so the [consequence] of smoking is greater.”

Women generally experience less first-hand smoke exposure but are at greater risk of significant lung impairment and more severe symptoms with the same level of exposure, according to the International Primary Care Respiratory Group (IPCRG). The JAMA study found that “to develop COPD it has been demonstrated that females require less cumulative smoking exposure than males.” Women, correspondingly, are likely to be diagnosed at younger ages then men. Exposure also includes that of biomass smoke in both domestic and occupational environments.

“For many lung diseases, gender influences how the disease manifests,” says Dr MeiLan Han, chief of pulmonary and critical care at the University of Michigan. “For example, in COPD, women seem to have more serious symptoms than men,” she says, explaining that women report greater shortness of breath than men for the same degree of airway obstruction.

In both COPD and asthma, women's symptoms can be affected by hormonal changes—such as those occurring during menstruation or pregnancy—which may increase airway inflammation. This could help explain why more women than men develop asthma after puberty and why they often experience more severe symptoms, according to Asthma + Lung UK.

Women are increasingly at higher risk of developing asthma than men. Photo: Andrej Lišakov

Women also have different comorbidities than men, experts point out, which can make treatment more complicated. For example, several studies have looked at possible connections between inhaled corticosteroids prescribed for COPD patients and incidence of fractures and osteoporosis, which is more common in older women. In some cases, as one study found, doctors might need to prescribe anti-resorptive medications, which increase bone strength, as part of treatment for COPD to prevent these outcomes.

Women also are more likely to have depression or anxiety, which can be exacerbated by illnesses such as COPD and in turn lead to worse symptoms.

Rapid increase in Asia Pacific

According to Global Burden of Disease data, East Asia and the Pacific had the largest number of COPD cases in 2020. By 2050, they are expected to rank second and third globally, surpassed only by sub-Saharan Africa. Over the same period, the number of women with COPD is expected to rise in every region except Europe and Central Asia.

“You’ve got a double whammy in the Asia Pacific region—an increase in the prevalence of COPD in women [as well as] issues relating to lower incomes, access to healthcare, and affordability of medicines.”

Given the projected growth in COPD globally and the groups at risk, it is unsurprising that the Asia Pacific region is especially vulnerable, explains Amanda Barnard, president of the International Primary Care Respiratory Group.

“You’ve got a double whammy in the Asia Pacific region—an increase in the prevalence of COPD in women [as well as] issues relating to lower incomes, access to healthcare, and affordability of medicines,” says Barnard, who is also an emeritus professor and former associate dean of rural and Indigenous health at the Australian National University School of Medicine.

Air pollution is responsible for about two million deaths in China per year. Photo: Cajeo Zhang

Although China is an obvious focus due to its size and high levels of pollution and smoking, India and Nepal are also struggling with growing cases of respiratory ailments. Cases of lung cancer have been increasing steadily in the region due to environmental and industrial pollution and increased smoking rates, with women making up a growing proportion of never smokers being diagnosed with lung cancer, Barnard says.

In addition, several studies have looked at the prevalence of genetic mutations in Asia that could contribute to greater susceptibility to both lung cancer and COPD and might require more specific biomarker testing. In the case of women, high exposure to smoke from domestic biofuels, especially in rural areas, contributes to more severe symptoms and higher mortality rates among women in these environments.

Confronting challenges in screening

Given most patients first present with respiratory problems in primary healthcare environments, it is important for physicians to consider COPD diagnoses for women as much as they do for men, Tsiligianni says. “We’re not trained to manage people based on gender; we’re trained to manage people based on disease,” she explains.

General practitioners need to understand the rise in the prevalence of COPD in women and know what is happening in their own country as occupational risk factors may vary from country to country.

Studies have found that women were less likely to be diagnosed with COPD and more likely to be diagnosed with asthma.

Barnard notes that although COPD may present differently in men and women, there is research evidence of gender bias in physician suspicion and preliminary diagnosis of COPD. Studies have found that women were less likely to be diagnosed with COPD and more likely to be diagnosed with asthma; asthma is generally less severe and can be reversible, whereas COPD cannot be reversed and is a progressive illness. Delayed or misdiagnosis of COPD in women often means they develop more advanced cases that are less receptive to treatment.

Early detection depends on evaluation of symptoms and asking questions about smoking, having morning cough, and experiencing shortness of breath, Barnard says. When health systems use community care workers or screening questionnaires, these symptoms can be easier to pick up, but policymakers also need to think about the structural problems that prevent women from seeking care, such as a tendency to prioritise healthcare for other family members over their own.

One country taking a comprehensive approach to identifying chronic respiratory diseases is China, which has around 100 million people living with COPD. The Chinese government has made significant investments in screening for those at high risk through a national programme that includes questionnaires and spirometry—a simple test used to measure how well the lungs work. Such population screening is a sensible exercise for a country the size of China, but represents a “huge undertaking” for smaller, lower-income countries that have more fragmented health systems, Barnard says.

Spirometry is considered the most evidence-based form of screening, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. Han of the University of Michigan is an advisor to GOLD on diagnosis and management strategies for COPD and says she is working on a statement about the value of universal spirometry.

She notes that researchers are beginning to think of COPD as starting in the womb. “Nicotine exposure in the womb can lead to long and tortuous airways [airways that are longer or more curved than average] and impact lung growth. We don’t do routine spirometry; so you don’t know what the trajectory is.”

From a prevention standpoint, she adds, if women realised they had impaired lung function at an early age, they might modify their behaviour to lower their risk.

Nicotine exposure in the womb can lead to long and torturous airways and impact lung growth. Photo: Lilartsy

Lung screening nevertheless must be weighed against other health needs, especially in LMICs. “There are huge issues about availability, about access, and about cost,” Barnard says. “I’ve done some work in Nepal, and you can certainly use a handheld spirometer. People do that; but even so, they probably [cost] around US$5,000 and if you’re a remote clinic and you’re trying to prioritise what equipment you need, that probably isn’t on the top of your list.”

One potential solution is finding ways to piggyback COPD on other screening programmes. In Australia, which has just started one on risk- and symptom-based lung cancer screening, primary care providers are working to make sure COPD is also picked up. “It’s about building it into that programme, which has political traction and funding,” Barnard says.

Tackling obstacles to care

Meanwhile, financial factors also make it more difficult for women with potential COPD to access care, especially in LMICs. This is true of nicotine replacement therapies and other medications that may or may not be covered by national programmes.

And while episodic illnesses are more affordable to treat, the ongoing nature of COPD can make it a significant financial burden. Sometimes, Barnard says, patients with a COPD diagnosis may buy their medication, use it until they feel better, and then stop.

“If there are limited resources to go around to pay for care, it is going to be the male breadwinner or the children—often the male children—who get priority over women.”

“We know that in LMICs, and even in high middle-income countries, women often put their health at the bottom of the list,” she says. “If there are limited resources to go around to pay for care, it is going to be the male breadwinner or the children—often the male children—who get priority over women.”

Stigma is also a concern, with women often feeling more embarrassment about being ill. As a result, many present to primary healthcare with more advanced illness.

With smoking a major risk factor for COPD and other respiratory diseases, the ability to put in place smoking cessation programmes is a key aspect of both treatment and prevention. Yet, women often find it more difficult to quit smoking due to a combination of physiological and psychological factors, according to Han and Tsiligianni, and may require a different approach.

Addressing the rising numbers of women with COPD and other chronic respiratory diseases, and reducing misdiagnosis, is a priority, especially for LMICs like those in the Asia Pacific.

Health systems with strapped finances will clearly need to find the most cost-effective ways of achieving this aim. Understanding structural differences in the way women seek healthcare, and improving education, will allow them to engage more productively with primary care at a point where outcomes are likely to be better.