Lynfield, Y. L.  (1974)  Skin diseases in twins. Since those diseases are now known to be caused by pathogens (Odom et al., 2000), Kligman (knowingly or unknowingly) was the first to suggest an infectious causation for PB. As I have shown, we are still far from determining with certainty the exact causes of pattern baldness. First, some types of baldness have already been shown to be a result of infectious diseases such as influenza, typhus,Lymee meningitis, tick-borne encephalitis (Cimperman, 1999), HIV (Jan & Roudier-Pujol, 2000), scarlet fever, and pneumonia (Weigand, 1969). For many men, going bald is inevitable. Interestingly, D. follicularum has long been known to cause mange in animals, a disease characterized by inflammation, itching, thickening of the skin, and hair loss (Encyclopædia Britannica, 2001). Jaworsky and others (1992) observed activated T-cell infiltrates, mast cell degranulation, and fibroblast activation in the scalp of patients with PB. 0 1 2. Pattern baldness (PB), also called androgenetic alopecia, is characterized by a progressive patterned hair loss from the scalp, which begins usually during the twenties or thirties (Odom et al., 2000). Researcher and dermatologist Cato Mørk explains how hormones affect the manes of so many men. The fourth possibility is to take medication. Your email will never be shared with any outside parties. A paper by Herrera & Lynch (1990) reviewed the literature on baldness and heart disease, and concluded that the presence of PB does increase an individual’s risk of heart disease, but not as much as smoking or hypertension. (1992) Intrapair differences of physical aging and longetivity in identical twins. Hair plays no vital function in human physiology, as we can live perfectly well without having any hair (Bertolino & Freedberg, 1987). Table 2. They suggested that the inflammation might impair the normal hair cycle. The eagle eye is among the strongest in the animal kingdom, with an eyesight estimated at 4 to 8 times stronger than that of the average human. This topic, to my knowledge, had never been previously addressed. Journal of Clinical Epidemiology 46: 1213-1218. Trevisan, M., Farinaro, E., Krogh, V., Jossa, F., Giumetti, D., Fusco, G., Panico, S., Mellone, C., Frascatore, S., Scottoni, A., Mancini, M.  (1993) Baldness and coronary heart disease risk factors. Top Answer. It has been proposed that the same bacteria that cause periodontitis are the causative agents of heart disease (Mattila et al., 1989, cited in DeStefano, 1993). Since heart disease shows evidence of infectious causation (Ewald & Cochran, 2000), it is very probable that infection may be partly responsible for PB as well. (1996) also found a relationship between PB and heart disease. Have you ever spent time in the food court of a shopping mall just watching people? Diseases of the Skin. Table 1. Mostly bald, you’re an ape, descended from apes; your features and actions are carved or winnowed by natural selection. Ellis and others showed that a specific androgen receptor gene variation was present in over 98% of young subjects with premature balding and in 92% of older bald men, but only in 77% of controls. B. Researchers have found that the sebaceous glands of bald men have twice the number of testosterone receptors than those of controls, which makes their scalp more sensitive to androgen levels (Sawaya, 1986). They found significantly higher levels of lipoprotein (a) in patients with PB. When one begins to research the life of an eagle they can end up with all sorts of fascinating thoughts. Clinics in Dermatology 6: 108-118. There are four basic treatments available for individuals afflicted with PB to manage their baldness. They found that balding individuals had significantly higher levels of diastolic blood pressure, serum total cholesterol, and prevalence of hypercholesterolemia than participants without baldness. Odom, R. B., James, W. D., Berger, T. G.  (2000). Some people have a lot of hair and, well, some people don't! The bald eagle has been the national symbol of the United States since 1782. However, both of these drugs only work in a fraction of the subjects that use them. The numbers must be read as the maximum possible genetic involvement in the development of the disease, not as its actual genetic contribution to because pathogens or other common environmental factors may contribute significantly to the disease. This type of baldness is partly caused by the fact that humans have continuously growing hair, something most other mammals don’t have (poodles are an exception to this rule, Nuttall says). One recent study claims to be the first to have found an association between PB and a specific gene. New York: McGraw-Hill Book Company. What do Charles Darwin, Michael Jordan, and Yoda have in common? Ann Dermatol Venereol 127:1534-1536. Sure, there's a lot of variation among human populations. It is likely that genetic, infectious, and non-infectious environmental causes play a role in the development of the disease. Setty, L. R.  (1970)  Hair patterns of the scalp of White and Negro males. Some people have curly hair, while others have straight hair. The second drug is finasteride (Propecia), which is taken orally. Animals, like humans, do go bald. International Journal of Dermatology 39: 576-584. For people with hair follicles that are sensitive to DHT, even normal amounts of the hormone can result in hair follicles miniaturizing and eventually failing to grow, creating the horseshoe-shaped hair pattern that’s normal for bald men. Currently, it is believed that PB results from a combination of androgen levels and a genetic predisposition (Bertolino & Freedberg, 1987; Odom et al., 2000). Jaworsky, C., Kligman, A. M., Murphy, G. F.  (1992) Characterization of inflammatory infiltrates in male pattern alopecia: implications for pathogenesis. Find out why these majestic birds are so cool. Testosterone is produced in the testes and adrenal glands in males, and in much smaller quantities in the ovaries and adrenal glands of females. The human scalp normally contains 100,000 hairs that follow a specific growth cycle (Odom et al., 2000). In Montagna, W., Ellis, R. A. Hamilton (1942, cited in Hamilton, 1960) has shown that androgens are required in the development of PB, as men who have been castrated at an early age do not develop it. Who lose their hair? The notorious pesticide DDT – responsible for the decline of the honeybee, among others species – has also taken its toll on the U.S. eagle population. In addition to enjoying some yummy food, it can be fun simply to see the variety of people that walk by in a short time. Most of the skin on your body is actually covered with tiny hairs called vellus hairs that give your skin a slightly velvety, peach-fuzz look. Further support for the role of infection in PB came from Dr. William Regelson, an expert on aging from Virginia Commonwealth University’s medical school (Lord, 1998). As a Senior in college, I took a class on evolutionary medicine with Professor Paul Ewald. A review of the literature. Unless women start finding bald men attractive, and men with hair unactractive. New York: Academic Press, Inc. Hamilton, J. The microbes then are responsible for eliciting an immune system response, which results in the inflammation that is seen on the scalps of PB patients. Environment and resources effect every everything on this planet why should humans be any different. Second, there is growing evidence of the presence of inflammation in the scalp of balding individuals (Kligman, 1988; Young et al., 1991; Jaworsky et al., 1992; Piérard et al., 1996; Sueki et al., 1999; Mahé et al., 2000). The presence of immunoglobulins on the scalp indicates that an antigen is present, perhaps a microbe. Age range and incidence of hair patterns of the scalp of 300 Caucasian and 300 African American males. Further support for the increased risk of heart disease with PB came from Sasmaz and coworkers (1999) who analyzed the difference of lipid parameters in 41 men with PB and 36 age-matched controls. Since PB begins in areas that are most frequently exposed to the sun, Young and coworkers argued that light may excite porphyrin production by the resident flora, producing an inflammatory reaction. (1958)  Age, sex, and genetic factors in the regulation of hair growth in man: a comparison of Caucasian and Japanese populations. In 1972, the chemical DDT was restricted in many areas, allowing bald eagles to reproduce fully once again without trouble. Regelson speculated that the scalps of some individuals are sensitive to the mites, and thus become inflamed and interrupt the normal hair cycle. Sinclair, R.  (1998) Male pattern androgenetic alopecia. Baldness in men is related to the male hormone dihydrotestosterone, which causes old hairs on the scalp to be replaced by progressively shorter and thinner hairs in a … It can live up to 70 years. New York: WB Saunders Company. Finally, a review article by Mahé and others (2000) suggested a way in which to incorporate inflammation with the previously proposed hypothesis of PB: androgens and genetics. (2001) have found a significant association between PB and a gene that codes for an androgen receptor. The inflammations in the scalp were localized around the infundibulum and sebaceous glands, and numerous lymphocytes, macrophages, and mast cells were found in those areas. PB affects about 30% of Caucasian men in their thirties, 40% in their forties, and so on until age 70 (Sinclair, 1998). Smooth taught skin and sebum oils and waxes contribute to being shiny, so even if say your face is not normally shiny the above combination makes the skin on the head shiny. Even though some people believe that Bald eagles can carry away large pets or humans, the truth is that a Bald eagle can only lift around five pounds. Piérard, G. E., Piérard-Franchimont, C., Nikkels-Tassoudji, N., Nikkels, A. F., Saint Léger, D.  (1996)  Improvement in the inflammatory aspect of androgenetic alopecia. Dermatology in General Medicine. A longitudinal study conducted in Italy with 872 men set out to examine the relationship between PB and heart disease over a 15-year period (Trevisan et al., 1993). A quarter of all men are either bald or going bald by age 30, and hair loss eventually affects two-thirds of men. However, baldness has been shown to have negative psychosocial effects (Cash, 1992) so many individuals choose to do something about it. For my final project, I decided to explore male pattern baldness from an evolutionary perspective. Other studies further support the presence of inflammation in PB. Therefore, humans evolved to fill their mobile needs by losing the fur over the course of generations. Sasmaz, S., Senol, M., Ozcan, A., Dogan, G., Tuncer, C., Akyol, O., Sener, S.  (1999) Journal of the European Academy of Dermatology and Venereology 12: 123-125. In the simplest definition, sebum is the body’s attempt at protecting the skin. This is what determines their length and thickness. DDT had caused problems for the bald eagle because it altered the bird's nervous system. Browse the library of TED talks and speakers, 100+ collections of TED Talks, for curious minds. Furthermore, he noted that bald people often report scaling and itching during the early stages, presumably because of the inflammation. (Eds)  The Biology of Hair Growth. Why are humans Eagles predators? It is only by considering all three possible causes for a disease that we are able to fully comprehend its etiology and find ways to treat it, or ultimately, prevent it from developing in the first place. The androgen receptor is a steroid receptor that determines the sensitivity of cells to androgens (Janne et al., 1993, cited in Ellis et al., 2001). You asked about animals. In addition, studies should examine the effects of anti-inflammatory drugs such as aspirin on reducing inflammation of the scalp. Hair loss or fur loss can be seen in several animals, including coatis, Andean bears and cats of various species. (2001)  Polymorphism of the androgen receptor gene is associated with male pattern baldness. The second possibility is to obtain a wig or toupee to cover the bald spot. They also found higher levels of total cholesterol and LDL-cholesterol in PB subjects. A. In Caucasian women, it is less common, although not as rare as previously thought. He reasoned that over generations of males picking less hairy mates, the overall population, of both males and females, became less hairy due to genetic mixing. Ellis et al. (1969)  Alopecias—diagnostic and pathogenic considerations. That’s why we tend to give people we don’t know epithets like “the blond one”, or in trying to jog someone’s memory we might say, “he had brown hair.” When a man no longer has hair and he is bald, women tend to look directly at the man’s face. In general, hairy mammals have that hair for a reason, and face strong evolutionary pressure to keep their hair. Why these majestic birds are so cool in Wonderopolis is less common, although not rare. 3,994 males for a period of 15 years of pattern baldness shorter and the telogen phase which. 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