Tuesday, April 14, 2009
Why Men Die Early
Why Men die earlier than Women
Coordinator WABA MWG
According to statistics, it is observed that women outlive men in the world today, and scientists have traditionally pointed to riskier behaviour on the part of men as the reason why. Another reason for the earlier demise of men may be that they are more prone to parasitic infections. In a study report, Ian P. F. Owens, from Imperial College London, writes, that "In those species where males die younger than females, the males suffer a disproportionately high rate of parasitism. This is most extreme in those species where male-male competition for mates is most severe. From the above thought, it is believed that male-biased mortality occurs not only as a result of death through risky behaviour, but also because males are more susceptible to parasitic diseases.
Owens believes testosterone may play a key role to make men more prone to infections. The male hormone is well-recognized as an immunosuppressant, and studies have shown men who are castrated (and thus no longer produce testosterone) live about 15 years longer than men who are not castrated. Testosterone may suppress the immune system, he continues, by changing the way men's bodies allocate important resources, such as taking energy away from the immune system and using it for other purposes.
Another explanation for the increased risk for parasitic infections among males, suggested is the simple fact that men are bigger than women and thus provide a larger target for parasites
• As of 2005, the average life expectancy in the U.S. was 80.4 for women and 75.2 for men. That means men, on average, die 5.2 years earlier than women.1
• Statistics show that being male is now the single largest risk factor for early mortality in developed countries.2
• A number of genetic-biological and socio-cultural factors contribute to the longevity gap between men and women. They include differences in sex hormones, sex chromosomes, immune response, iron in the blood, natural selection, cultural conditioning and how the sexes deal with their standing in society.
• How much of the longevity gap is due to biology and how much to environment or behaviour is a matter of debate among scientists but the best data we have today suggests that only about one-third of longevity is due to genes.
• Boys in the U.S are reported to have a 29 percent higher prenatal death rate3 and are 20 percent more vulnerable to infant mortality up to age one.4
• According to a study done in 2003 by the Institute for Social Research at the University of Michigan, men have higher age-adjusted death rates than women for the 15 leading causes of death in the U.S., with the exception of Alzheimer's disease.5
• Because men usually develop heart disease 10 to 15 years earlier than women do, they are more likely to die of it in the prime of life. About one-fourth of all heart-disease-related deaths occur in men aged between 35 to 65.6
• More American men than women are reported stricken with cancer. The age-adjusted invasive cancer incidence rate per 100,000 people in 2004 was 537.6 for men and 402.1 for women.7
• Men are 30% more likely to suffer a stroke than are women, making it the third-leading cause of death in men.8
• More than twice as many men die each year because of accidents as do women.9
• Men have a 30 percent higher risk of death from pneumonia than women.10
• Men's death rates are at least twice as high as women's for suicide, homicide and cirrhosis of the liver.11
• If men attempt suicide, they are more likely to succeed than women. Suicide was the eighth leading cause of death for males and the sixteenth leading cause of death for females in 2004.12
• Scientists believe that if everybody adopted a healthy lifestyle and medical advances in prevention, early detection and treatment of disease continue at their present pace, we could achieve an average life expectancy of 85 or 90.
• As obesity becomes more pervasive in the U.S., some predict that life expectancy may actually decrease.13
• Men are more prone to taking risks than women.14 There's also evidence that they are quicker to aggression15 and more likely than females to express their aggression physically.16
• Male drivers have a 77 percent higher risk of dying in a car accident than women, based on miles driven.17
• Men are much more likely to be incarcerated than women18 and are far more likely than women to be victims of violent crime.19
• If men attempt suicide, they are more likely to succeed than women.20
• About one-quarter of adult men currently smoke at least occasionally compared with one in five women21 which can lead to higher death rates from diseases like arteriosclerotic heart disease, lung cancer and emphysema.
• Men drink more and indulge in recreational drugs more often than women, both risk factors for long-term health problems and accidental death.
A study published in the July 2000 issue of Psychological Review reported that US females are more likely to deal with stress by seeking support than men. Statistically men in Cameroon die at a younger age than women for several reasons, including genetic and biologic factors. This relates to the fact that being male is now the single largest risk factor for early mortality in developing countries on the whole.
How much of the longevity gap is due to biology and how much to environment or behaviour remains a matter of debate among scientists. According to Thomas Perls, MD, women have been outliving men for centuries though the gap has changed over time, primarily due to the hazards of childbirth. Though medical science has become more successful in providing better outcomes for women delivering babies in the developed countries to increase the longevity gap, research needs to be carried in the developing countries to learn about the current real situation estimated at 5 years of outliving men.
The longevity gap varies by age, scientists have revealed. While boys die more frequently than girls in infancy, during childhood, and during each subsequent year of life, male mortality accelerates considerably during certain stages of life. Between ages 15 and 24 years, when testosterone is at its highest levels in men, they are four to five times more likely to die than women. The gap then narrows until late middle age when the death rate for men increases mainly due to heart disease, suicide, car accidents and illnesses related to smoking and alcohol use.
In 2005, the Centres for Disease Control and Prevention listed the 15 leading causes of death as the following:
• Heart disease
• Chronic lower respiratory diseases
• Alzheimer's disease
• Influenza and pneumonia
• Kidney disease
• Chronic liver disease and cirrhosis
• Parkinson's disease
Consider the following:
• Because men usually develop heart disease 10 to 15 years earlier than women do, they are more likely to die of it in the prime of life. About one-fourth of all heart-disease-related deaths occur in men ages 35 to 65.5
• More men than women are stricken with cancer. The age-adjusted invasive cancer incidence rate per 100,000 people in 2004 was 537.6 for men and 402.1 for women.6
• Men are 30% more likely to suffer a stroke than are women, making it the third-leading cause of death in men.7
• More than twice as many men die each year because of accidents as do women.8
• Men have a 30 percent higher risk of death from pneumonia than women.9
• Men's death rates are at least twice as high as women's for suicide, homicide and cirrhosis of the liver.10
• If men attempt suicide, they are more likely to succeed than women. Suicide was the eighth leading cause of death for males and the sixteenth leading cause of death for females in 2004.11
1. Sexual selection and the Male: Female Mortality Ratio; Daniel Kruger, PhD; Randolph Nesse, MD; Human Nature, 2004. 2: 66-85
2. Just Like a Woman: How Gender Science is Redefining What Makes Us Female Dianne Hales, Random House, Inc.
3. Thomas Perls, MD, Harvard Medical School, New England Centenarian Study (NECS).
4. David R. Williams, the Institute for Social Research, American Journal of Public Health, May 2003.
5. American Heart Association.
6. U.S. Cancer Statistics Working Group. United States Cancer Statistics: 1999-2004 Incidence and Mortality Web-based Report Version. Atlanta (GA): Department of Health and Human Services, Centers for Disease Control and Prevention, and National Cancer Institute.
7. Department of Health and Human Services (HHS).
8. Centres for Disease Prevention and Control.
9. University of Pittsburgh School of the Health Sciences.
10. Institute for Social Research at the University of Michigan.
11. Centres for Disease Control and Prevention, National Centre for Injury Prevention and Control. Injury Statistics Query and Reporting System.