NIH Gender and Pain Conference - April 1998 - Home Page

 

Some common diseases affect one sex more frequently or more severely than the other.   These include:

OSTEOARTHRITIS: Women use more varied coping strategies.

OSTEOARTHRITIS: Osteoarthritis (OA), the "wear and tear" disorder of the joints, affects 40% of middle aged adults and up to 70% of older adults. Some forms of OA are more common in women than men. OA of the knee, for example, is twice as common in women as in men. By contrast, OA of the hips affects men and women equally.

  
Pain is the most common symptom of OA. The extent of joint damage does not necessarily predict the amount of pain persons with OA feel, according to Francis J. Keefe, Ph.D., professor of health psychology at Ohio University, Athens, Ohio. One person with moderate OA, he said, may report little pain and be quite active, even able to play golf or tennis. Another may report severe pain and sometimes use a wheelchair.
 

Pain is the most common symptom of osteoarthritis

    
Keefe and his colleagues asked 41 women and 30 men with OA to keep daily pain diaries. The women reported 40% more OA pain and more severe pain. But they coped more actively with it. They spoke more about their pain with others, looked for distractions, sought spiritual support, and asked for help. Women's energetic coping efforts, he said, paid off: the day after experiencing severe OA pain, they were less likely to report negative moods than men were.

The researchers also asked persons with OA and their spouses to perform a series of routine household activities, such as picking up clothes from the floor. They then studied the couple's interaction. Women with OA talked more about their pain, and showed more non-verbal indicators of pain than did men with OA. Husbands of women with OA were more likely to use humor and other strategies to encourage their partners to carry out the activities.

The research team also videotaped 19 persons with OA performing ordinary daily tasks. Patients and their spouses viewed the tapes separately and rated their partner's pain in each activity. Women recognized pain in their partners better than men did. But they proved no better than men in picking up pain signals in anyone other than their own spouse.

"Pain occurs in a social context," Keefe said. "When one partner has a chronic illness, a couple may benefit from training in role playing and couples' communication." Men might benefit, he said, from adopting women's more expressive style of active coping. Seeking support and talking about one's needs helps persons of both sexes.

HEART DISEASEBefore age 50, women have more chest pain but less heart disease than men do. Women over age 50 have more silent heart disease than men do.

    
Women in their premenopausal years experience chest pain more often than men. But they are far less likely than men to have underlying heart disease, said Noel Bairey-Merz, M.D., medical director of the Preventative and Rehabilitative Cardiac Center at Cedars-Sinai Medical Center, Los Angeles, California. Postmenopausal women, she said, are more likely than men to have silent heart disease.
 

Heart disease is different in women than men

    
Half of the young women with chest pain so severe that their doctors send them to a cardiac catheterization laboratory for further study, she said, prove to have normal arteries in the heart. That is true for only 17% of men with similar symptoms.
    
Even when these healthy women are told they are fine, she said, they often do not get better. "Something clearly is wrong with them that we currently are not addressing," she said. Determining that is the goal of the Women's Ischemic Syndrome Evaluation (WISE) study, a 4-year, multicenter NIH-funded program begun in 1997.
    
Something is clearly wrong
    
Preliminary findings suggest that female hormones may play a contributory role. Both premenopausal women with high estrogen levels and postmenopausal women using estrogen replacement therapy, Bairey-Merz said, had more frequent and more severe chest pain that was not caused by heart disease.

In another study reported at the conference, David Sheps, M.D., professor and chair of cardiology at the James H. Quillen College of Medicine at East Tennessee State University in Johnson City, Tennessee, and his colleagues, explored differing perceptions of chest pain, or angina, in men and women with heart disease. Some 170 men and 26 women participated in the study. They were matched for age, disease severity, and other factors.

All participants kept symptom diaries for 48 hours. They then completed separate daylong tests of mental and physical stress.

On the mental stress day, they took a battery of psychological exams. Among them was a public speaking challenge: participants had to give a talk about a hassling life experience. The physical stress day included an upright bicycle exercise test and similar exertion. On both days, participants wore devices to monitor heart activity, had blood drawn, and had x-ray studies of heart functioning.

Women reported chest pain more often in daily life and on the mental stress day, but no more often after exercise stress. The researchers identified several factors that might account for this discrepancy.

The women scored higher than the men did on psychological measures, such as "harm avoidance." They had lower levels of beta endorphins, brain chemicals related to feelings of well being. When challenged with a heat stimulus, they reported feeling pain sooner than the men did. These findings, Sheps and his colleagues say, suggest that men and women attend to and view certain symptoms differently.

MIGRAINE HEADACHESOne in 5 women and one in 17 men have migraines.

About one in 5 women and one in 17 men in the U.S. report experiencing migraine headaches, according to Rami Burstein, Ph.D., assistant professor of anesthesia and neurobiology at Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts. Before puberty, Burstein said, migraines are more common in boys than girls.

Migraines cause dull pain, typically worse on one side of the head. Some people become extremely sensitive to light and experience nausea. Migraines usually last from 2 to 6 hours.

    
In women, migraines often occur at the time of ovulation, near menstruation, and in pregnancy. This fact has prompted attention to hormonal factors. One theory is that shifts in hormone levels may be a trigger: birth control pills make migraines worse in some women, better in others. During pregnancy, some women's migraines disappear, but other women get them for the first time. Migraines usually appear before age 35, but some women develop them only after menopause. In both women and men, other triggers include lack of sleep, hunger, stress, red wine, bright light, and heat.
 

Women's migraines may be linked to hormonal changes

    
Burstein and his colleagues have explored gender differences in a wide variety of bodily functions before, during, and after migraine attacks. They have tried to correlate their findings with the location of the pain, how often it occurs, how long it lasts, how severe it is, how it affects sensations of vision, smell, touch, and hearing, and what factors may have set it off.

Migraines prove to be quite complex, Burstein said, affecting nerve cells both in the brain and at the skin surface, for instance. Differentiating the different components of migraine pain, he said, may allow a more precise diagnosis and more rational treatment.

CHRONIC REPRODUCTIVE ORGAN PAIN: Medications that relieve pain in one sex may not benefit the other.

Medications used for many common pain syndromes benefit men with chronic pain of the reproductive organs, but rarely help women with chronic pelvic pain, according to Ursula Wesselmann, M.D., Ph.D., assistant professor of neurology at the Johns Hopkins University School of Medicine, Baltimore, Maryland.

She and her colleagues at the Hopkins pain clinic compared 39 women with chronic, non-cancerous, pelvic pain and 25 men with chronic, non-cancerous, testicular pain. Each patient received one of 4 different types of medication known to relieve other pain syndromes. The medications included antidepressants, anticonvulsants, membrane stabilizing agents, and opioids. A larger percentage of men than women improved in each case. With antidepressants, the most frequently used medication, for instance, 9 of 11 men improved. Only 4 of 28 women did so.

Both women and men with these disorders, Wesselmann said, experience deep pain that often is hard to localize. Such pain often triggers changes in blood pressure, nausea, and sweating, making people feel quite ill. Both men and women, she said, often find the pain embarrassing and hard to talk about, even with a physician. As a result, some delay seeking help or don't assertively pursue the help they need.

Pelvic pain in women that lasts at least 6 months at the same location generally is thought to have a gynecological source, Wesselmann said, although physicians sometimes are not able to pinpoint it. A disorder such as endometriosis, an inflammation of the lining of the uterus, causes some women a great deal of pain, even when little disease is present. Yet some women with extensive disease have no pain.

    
Many of the women Wesselmann studied had undergone numerous surgical procedures, including hysterectomies, pelvic exploration, and treatment for endometriosis, before coming to the pain clinic still seeking relief. Studies of large groups of women, she noted, suggest that women have a 5% risk of having pelvic pain in their lifetime. The risk rises to 20% in women with pelvic inflammatory disease.
 

Women have a 5% lifetime risk of pelvic pain.

    
Chronic testicular pain is most common in men in their late 30s. This pain is defined as pain in one or both testes that lasts at least 3 months. In one in 3 men, there is no obvious cause. In the others, bicycle accidents, vasectomies, infections, tumors, and other medical disorders are identified as the trigger.

The men in the Hopkins study had undergone fewer surgical procedures on average than the women. Male urologists may be more reluctant to remove reproductive organs in male patients, Wesselmann suggested, than male gynecologists to remove reproductive organs in women. Wesselmann was one of many speakers to point out that different attitudes held by physicians towards pain in men and women potentially influence both diagnosis and treatment. This phenomenon, she and others agreed, needs more study.

Chronic reproductive organ pain interfered more with daily activities in women than it did in men. Women reported that the pain caused them to lose time from work and to be less productive. This was true regardless of whether or not they also were depressed. Only depressed men reported similar interference with daily life. Of the 2 types of chronic reproductive organ pain, Wesselmann said, women's pain is the more complex. There is an urgent need, she said, to better understand its causes and improve its treatment.

FIBROMYALGIA: This still mysterious disorder affects 9 times more women than men.

Nine times more women than men have fibromyalgia (FM), a disorder causing widespread pain and fatigue, according to Laurence A. Bradley, Ph.D., professor of medicine at the University of Alabama, Birmingham, Alabama. Persons with FM report exquisite sensitivity to pressure stimulation both at specific locations, referred to as tender points, and at other sites on the body.

The lack of an obvious definitive cause for the disorder, the preponderance of women, and the long-held belief that women are more prone than men to "hysterical" disorders have served, Bradley said, to stigmatize persons with FM and to retard research. His research and that of other contemporary investigators suggest that FM has a biological basis.

Bradley and his colleagues studied pain perception, functional brain activity, and psychosocial factors, in 3 groups of women. They included:

  • 66 women being treated in a medical clinic for FM. These women met the standard classification measures for FM: they had widespread pain lasting at least 3 months at 11 or more of the 18 standard tender points. None had other rheumatic illnesses, chronic fatigue syndrome, or a history of neck or back surgery.
         
  • 40 women in the community who fit the same guidelines for FM, recruited via newspaper advertisements. None of these women had sought help for pain in the last 10 years.
        
  • 40 healthy women.

Pain perception: The researchers found that regardless of whether or not the women had sought health care, those with FM perceived a pressure stimulus as painful at lower intensity levels than healthy women did. Women with FM also distinguished different types of sensations better than healthy women. Their cerebrospinal fluid contained significantly higher levels of substance P, a chemical messenger of pain.

Functional brain activity: Studies using a device known as a single photon emission computerized tomographic (SPECT) scanner, showed differing activity in areas critical for pain perception in women with FM than in healthy women.

Psychological differences: Lifetime psychiatric diagnoses were higher in both women with FM in the patient group and those from the community group who sought medical care for pain in the 30 months after the study, than in women with FM who did not seek medical care and in healthy women.

These findings, Bradley said, suggest that abnormal pain perception in FM may stem from several biological abnormalities. While more attention to correcting these disorders is needed, he said, psychological factors also influence the likelihood that a person will seek medical care. Showing persons with FM how to focus less on their symptoms may improve their quality of life. Useful strategies may include psychotherapy, medications, and behavioral therapy.

TEMPOROMANDIBULAR DISORDERNot just a regional pain problem.

Seven times more women than men have Temporomandibular Disorder (TMD), a group of conditions involving pain and dysfunction of the temporomandibular joint in the jaw and surrounding muscles, according to William Maixner, D.D.S., Ph.D., co-director of the oral and maxillofacial pain program at the University of North Carolina, Chapel Hill, North Carolina. TMD is surprisingly common, he said, affecting an estimated one in 4 young adult women.

Persons with TMD, he and his colleagues found, are more sensitive to several types of painful stimuli than persons without the disorder. A heat stimulus applied to skin on the arm or the face, for example, caused more pain in persons with TMD than in healthy persons. When a heat stimulus was applied in a pulsating fashion to the hand, persons with TMD reached their maximum level of pain tolerance much faster than persons without TMD.

In another study, Maixner and his colleagues applied a tourniquet around the arms of both persons with TMD and persons who did not have the disorder but did have a toothache. The tourniquet procedure ordinarily has two effects: it makes the arm hurt, and it blunts the perception of pain elsewhere in the body.

Persons with toothaches responded as expected to the procedure: the intensity and unpleasantness of their tooth pain fell dramatically. But two-thirds of the TMD patients felt no change in their facial pain. Some experienced even more facial pain.

These findings suggest, Maixner said, that TMD probably is not simply a regional pain, like a toothache. Rather, it may represent a dysfunction in which pain transmitting regions in the central nervous system overreact to incoming signals.

TMD may lower quality of life by disturbing both sleep and mood, Maixner said. It even may be an early stage of fibromyalgia (FM), he suggested. Some 75% of persons with fibromyalgia--again, mostly women--also report TMD symptoms. The progression from TMD to FM, he said, may be linked to the degree of disruption in a person's pain regulatory systems.

POSTMASTECTOMY PAINIt's often undertreated.

Most women recover uneventfully from surgery for cancer of the breast, but some develop chronic pain starting days to weeks after their surgery. About one in 20 to one in 5 experience long-lasting pain, according to different studies.

The pain typically affects the underarm, underside of the upper arm, and/or the chest wall, and sometimes, the shoulder. Women usually say this pain involves shock-like sensations overlying more continuous aching and burning. They describe it as "shooting," "stabbing," "piercing," and even "excruciating."

Since movement such as reaching or lifting often makes the pain worse, women commonly protect the affected arm. This habit frequently produces shoulder stiffness and further pain. Women may have trouble sleeping, dressing, and performing household chores. Chronic postmastectomy pain, unfortunately, often does not lessen with time.

Researchers are studying both causes and treatments for this pain syndrome, including medications, physical therapy to restore function, and behavioral strategies to aid in coping with the pain.

Some studies link the pain to surgical injury to a particular nerve in the underarm area. Researchers are exploring whether it is possible to spare this nerve without contributing to the further spread or recurrence of the cancer.

A study conducted in Finland found that chronic pain was more likely in women who remembered more postoperative pain. The researchers interviewed women with breast cancer 3 times in the year following their surgery. Those with chronic pain remembered having severe pain after the surgery, and their memory for it grew even stronger over time. By the end of the year, anxiety and depression returned to normal levels in women who had no chronic pain. It persisted, however, in those whose pain continued.

Researchers at the University of California, San Francisco, School of Nursing, including Christine Miaskowski, R.N., Ph.D., professor of nursing, who spoke at the gender and pain conference, studied 95 women who had breast cancer surgery. Nineteen reported postmastectomy pain. These women, the researchers found, often received inadequate pain relief.

Some physicians, they suggested, may be unfamiliar with the postmastectomy pain syndrome and its potential treatment. Existing medications, including tricyclic antidepressants, topical anesthetics, and anticonvulsants, all requiring prescriptions, they said, may ease this type of pain.

Richard Payne, M.D., professor of neurology, at the University of Texas M.D. Anderson Cancer Center, Houston, Texas, said at the conference that narcotic medications, that is, opioid drugs, may provide long term pain relief for some women. But further research is needed, he cautioned, to determine the most effective opioid medications, appropriate dosages, and best strategies to forestall the development of tolerance.

CANCERSevere pain may strike both sexes equally.

Having a severe, chronic pain condition may have a greater influence on the individual's experience of pain than does their sex, according to Dennis Turk, Ph.D., John and Emma Bonica Professor of Anesthesiology and Pain, at the University of Washington School of Medicine, Seattle, Washington.

Turk and Akiko Okifuji, Ph.D., research assistant professor of anesthesiology, studied 91 men and 52 women who sought treatment at a cancer center for chronic cancer pain. The group included persons with both localized cancer and cancer that had spread, or metastasized. The patients were comparable in age, education, and other measures, although they were not matched by type of cancer or stage.

The researchers found no significant male/female differences among the patients in pain severity, emotional distress, adaptation, or limitations in activities of daily life. The results were comparable to those seen in an earlier study of 428 consecutive patients, approximately equal numbers of men and women, at a pain treatment center.

The majority of pain patients, Turk said, regardless of diagnosis, fall into three categories:

  • Dysfunctional. These persons have high pain and emotional distress, and believe they have little control over their circumstances.
        
  • Interpersonally distressed. These persons have moderate pain and emotional distress, but perceive they receive little support.
        
  • Adaptive copers. These persons have low emotional distress and a "take-charge" attitude.

Proportionally fewer cancer patients were classified as dysfunctional than noncancer patients, Turk said. Fewer persons whose cancer had spread were interpersonally distressed than those in the other two groups. "There are very few patients with metastatic cancer and chronic pain," he observed, "who do not feel they get considerable support from others."

In contrast to most other conference speakers, Turk said he found no statistically significant differences between men and women with all types of chronic pain with regard to pain severity, adaptation, or effect of pain on their lives.

Differences within each sex, he said, proved greater than those between the sexes. "How people perceive and interpret their particular situation," he said, "may be more important than whether they are male or female."

 


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