Why Sex Matters: The New Science of Gender-Specific Medicine*
(*Will it/should it make a difference in the way we take care of patients?)
Marianne J. Legato, M.D.
Founder/Director of The Partnership for Gender-Specific Medicine at Columbia University
1950-1992: “Women’s Health” Emerges
Emergence of feminism. Public Health Service Task
Force on Women’s Health: 1985. women in clinical research. 19901992.
NIH mandates inclusion of Women’s Health Equity Acts FDA mandates inclusion of
establish the Office of Research on Women’s Health at the NIH: 1992. women in trials of new drugs wherever appropriate: 1997
Women’s health is not a feminist, political or commercial issue. It is an intellectual imperative. The data of the last 15 years have shown us that there are significant and widespread differences between the sexes in every system of the body.
GENDER SPECIFIC MEDICINE:
The science of how normal human function and the experience of the same diseases differs between men and women.
Gender-specific medicine is not “women’s health”. It holds that
Using the variable of sex in scientific investigation helps us pose questions we otherwise never would have asked.
The new data prompt a reconsideration of our essentially male models of health and the pathophysiology of disease. The sex of the patient is a fundamental consideration in planning the prevention, detection and treatment of illness.
What Do We Know About The Differences Between Men and Women?
The Skeleton
Age of peak bone density.
Daily pattern of bone turnover.
Impact of disease (diabetes, Bone architecture. Sports injuries.
eating disorders hypertension) on bone density.
BRAIN
Brain anatomy. Intellectual abilities. Is our sense of gender “hardwired” into our brains? Stress. Problem solving.
Pain
Are women more sensitive to pain than men? Response to pain killers. Anatomical differences in the nervous system. Hormones and pain.
Best Developed Body of Gender Specific Data in Medicine.
CARDIOVASCULAR DISEASE:
Size, shape and electrical system of heart differs
in men and women.
Frequency of palpitations: higher in women. Gender significantly modifies the risk factors,
testing modalities, symptoms, therapeutic options and outcomes of coronary artery disease.
How Gender-Specific Research Changes Practice: The WISE* Study
Non-endothelial-dependent microvascular dysfunction is associated with decreased functional capacity in women.
How do we detect myocardial ischemia in women without significant obstructive CAD?
Associated with adverse outcome Disordered vascular smooth muscle and endothelial interactions
DASI scores Markers of inflammation Anemia assessment Greater use of pharmacologic stress testing?
Gender and the Normal Lung
Even when adjusted for body size, women’s lungs are smaller than those of men, although their hemoglobin levels are lower. Residual volume, vital capacity lower in females than in males.
At midcyle, progesterone stimulates breathing and oxygen and carbon dioxide diffuse more easily.
Profile of Lung Cancer in American Women*
In 2003, lung cancer will claim more lives than breast, prostate and colon cancers combined. Men: higher risk of squamous cell CA. Women: higher incidence of small cell lung cancer; spreads rapidly and has a poor prognosis. Women’s cancers are more likely to be peripheral and men more central, hindering early detection in women compared with men.
*Society for Women’s Health Research. Lung Cancer on the Rise in Women. Health News Digest.com
DRUG METABOLISM
Simply reducing dose for women and
differently in men and women.
children is not enough to ensure safety.
Many common medications are metabolized Oral contraceptives, menstrual cycle and
hormonal replacement therapy influence how some drugs are metabolized.
Response of Men and Women to Antidepressant Medications
The menstrual cycle affects our responses to antidepressants:
At midcycle, Desyrel and Norpramin levels double. Caffeine elimination prolongs late in the cycle; OC’s prolong caffeine elimination.
As estrogen levels peak, serotonin levels in plasma peak; women may need pulse dosing of antidepressants.
Pregnant women clear lithium faster. Women respond better to MAOI’s; men to tricyclics in treatment of depression.
How We Defend Ourselves in a Hostile World
The Immune System:
Women have a more vigorous immune system than men. Estrogen stimulates the immune system: is this the reason for higher frequency of autoimmune diseases in women? How men and women fight infections. Men and parasites. Stress and the immune system.
More Than Just the Hole in the Doughnut.
The GI Tract:
Saliva.
GERD Bowel transit time. Bile composition. The enteric nervous system: “the second brain”. Gender and obesity.
What has gender-specific
research
taught us about men?
The Vulnerability of Men
Negotiating Intrauterine Life
More males are conceived, but more are fatally flawed: why?
The fleet but impulsive Y-bearing spermatozoa Parental age and gap in parental ages Pesticides Stressed mothers abort male more than female fetuses
Males have a much higher incidence of developmental disability than females Females have the advantage of two X chromosomes
The Adolescent Male
Develops judgment and controls impulsivity much later in adolescence than girls Has a much higher incidence of risk taking and thus death by violence/accidents Much more likely to successfully suicide
The Mature Male: Why Do Men Die Sooner?
Men are more likely to suffer severe chronic disease and fatal illness than women and to suffer them at an earlier age.
Onset of coronary artery disease is a decade sooner than is the case for women and death rate is 2X that of women until the oldest age.
Men’s cancer death rate is 1.5 x that of women.
Incidence of 7 out of 10 most common infections is higher in men. Is men’s larger stature a handicap? Does it demand more cell replication to keep tissues intact and functional so that telomere erosion leads to cell death?
Is Our Sex-Specific Treatment of Men and Women Flawed?
Are the demands we make on boys, who develop verbal, judgmental and cognitive skills later than girls, too harsh? What are the consequences of our efforts to encourage “male” behavior? Is the tendency of many societies to offer males nutritional, vocational and educational advantages an evolutionarily selected trait that compensates for the relatively greater vulnerability of men? Are some of the most characteristic features of men, i.e., their willingness to take risks, the superior ability of men to negotiate three dimensional space, the ability of testosterone to mute pain, less useful in this era than millions of years ago?
Important Questions
Why should we change the way we have always done business?
(We have doubled life expectancy since 1900. Are men and women sufficiently different to warrant emphasizing gender in treatment?)
Will practicing GSM improve patient morbidity and mortality?
(Do we have those data? And if not, how hard are they to get?)
Where Do We Go From Here?
Does putting the new information about gender into medical practice improve patient outcome? How can we go about finding out?
The Gender-Specific Medical Practice
Establishing guidelines. Developing instruments to assess outcome. Pooling outcome data . Revising guidelines to reflect outcome data. Education of professional and lay communities.