Android fat distribution

Example of android fat accumulation in a male

Android fat distribution describes the distribution of human adipose tissue mainly around the trunk and upper body, in areas such as the abdomen, chest, shoulder and nape of the neck.[1] This pattern may lead to an "apple-shaped" body or central obesity, and is more common in males than in females. Thus, the android fat distribution of men is about 48.6%, which is 10.3% higher than that of premenstrual women.[2] In other cases, an ovoid shape forms which does not differentiate between men and women.Generally during early adulthood, females tend to have a more peripheral fat distribution such that their fat is evenly distributed over their body. However, it has been found that as females age, bear children and approach menopause, this distribution shifts towards the android pattern of fat distribution [3] resulting in a 42.1% increase in android body fat distribution in postmenstrual women.[2] This is to help centre a woman's gravity making her more stable when carrying offspring.[1]

Android fat distribution is contrasted with gynoid fat distribution; fat around the hips, thighs and bottom, causing a "pear-shape". This more female-patterned fat distribution [4] has been linked to risk factors for cardiovascular disease, in both males and females.[5] Android fat tends to be associated with cellulite, and lumpy appearance of the skin - usually undesired by women. This article will look at cosmetic implications of such subcutaneous fat such as liposuction.[6]

Jean Vague, a physician from Marseilles was one of the first individuals to bring to attention the increased risk of developing certain diseases in individuals with an android distribution compared to a gynoid distribution. For example, Diabetes and Gout. There are other health consequences beyond these, including psychological consequences.

Biology

Android fat is readily mobilized by deficits in energy balance. It is stored in different depots to gynoid fat.

Android fat cells are mostly visceral - they are large, deposited deep under the skin and are highly metabolically active. The hormones they secrete have direct access to your liver.[7] The presence of fat in the trunk and upper body in males is facilitated by testosterone. Testosterone circulation causes fat cells to deposit around the abdominal and gluteofemoral region, whereas in women oestrogen circulation leads to fat deposits around areas such as thighs, breasts and buttocks.[8] Therefore, measuring a person's oestrogen to testosterone ratio can reveal their predicted gynoid to android fat distribution.[9] Android fat develops as a back-up source of energy when the male body is experiencing an imbalance, whereas gynoid fat develops after puberty, in order to better prepare the body for supporting a potential infant.[1] 50% of the variance in abdominal fat mass observed in humans is due to genetic factors [10]

The cellular characteristics of adipose tissue in android and [gynoid] obese women are different. Android type have larger fat (Hypertrophy) cells whereas gynoid type have increase number of fat cells (Hyperplasia). This allows for hypertrophic obesity and hyperplastic obesity.[11] Two different receptors, alpha and beta fat cell receptors, vary in their ability to facilitate or inhibit fat mobilization. Alpha-receptors are predominately in the lower body thus more abundant in gynoid patterns and Beta-receptors are predominantly in the upper body and so more abundant in android patterns.[12]

Causes

Hormonal disorders or fluctuations can lead to the formation of a lot of visceral fat and a protruding abdomen. Medications such as protease inhibitors that are used to treat HIV and AIDS also form visceral fat. Android fat can be controlled with proper diet and exercise.[13] A poor diet with lack of exercise is likely to increase android fat level.

Health Consequences

Differences in body fat distribution are found to be associated with high blood pressure, high triglyceride, lower high-density lipoprotein (HDL) cholesterol levels and high fasting and post-oral glucose insulin levels [14]

The android, or male pattern, fat distribution has been associated with a higher incidence of coronary artery disease, in addition to an increase in resistance to insulin in both obese children and adolescents.[15] Studies have also related central abdominal obesity (indicated via increased waist-hip ratio) with increases in peripheral fasting insulin levels.

Android fat is also associated with a change in pressor response in circulation. Specifically, in response to stress in a subject with central obesity the cardiac output dependent pressor response is shifted toward a generalised rise in peripheral resistance with an associated decrease in cardiac output.

There are differences in android and gynoid fat distribution among individuals, which relates to various health issues among individuals. Android body fat distribution is related to high cardiovascular disease and mortality rate. People with android obesity have higher hematocrit and red blood cell count and higher blood viscosity than people with gynoid obesity. Blood pressure is also higher in those with android obesity which leads to cardiovascular disease.[16]

Women who are infertile and have polycystic ovary syndrome show high amounts of android fat tissue. In contrast, patients with anorexia nervosa have increased gynoid fat percentage [17] Women normally have small amounts of androgen, however when the amount is too high they develop male psychological characteristics and male physical characteristics of muscle mass, structure and function and an android adipose tissue distribution. Women who have high amounts of androgen and thus an increase tendency for android fat distribution are in the lowest quintiles of levels of sex-hormone-binding globulin and more are at high risks of ill health associated with android fat [18]

High levels of android fat have been associated with obesity [19] and diseases caused by insulin insensitivity, such as diabetes.[20] Insulin responsiveness is dependent on adipose cell size. The larger the adipose cell size the less sensitive the insulin. Diabetes is more likely to occur in obese women with android fat distribution and hypertrophic fat cells.[11] It is not just general obesity that is a consequence of android fat distribution but also other health consequences. There are connections between high android fat distributions and the severity of diseases such as acute pancreatitis - where the higher the levels of android fat are, the more severe the pancreatitis can be.[21] An increase in android fat distribution is positively correlated with foot pain and disability associated with foot pain.[22] Foot pain is reported to be the second most common musculoskeletal symptom in children who are obese. Even adults who are overweight and obese report foot pain to be a common problem.[23][24]

Psychological consequences

Body fat can impact on an individual mentally, for example high levels of android fat have been linked to poor mental wellbeing, including anxiety, depression and body confidence issues. On the reverse, psychological aspects can impact on body fat distribution too, for example individuals classed as being more extraverted tend to have less android body fat.[25]

Waist Hip Ratio

See Gynoid fat distribution

Central obesity is measured as increase by waist circumference or waist-hip ratio. Increase in waist circumference > 102 cm (40 in.) in males and > 88 cm (35 in.) in females. However increase in abdominal circumference may be due to increasing in subcutaneous or visceral fat, and it is the visceral fat which increases the risk of coronary diseases. The visceral fat can be estimated with the help of MRI and CT scan.

In females, measures of Waist to Hip ratio have been observed as an evolutionary sign of attractiveness and reproductive success.[26] A females waist being smaller than her hips by a ratio of 0.7 is considered most attractive[26] as it indicated readiness to give birth to offspring, and overall health to ensure survival of offspring. Waist to hip ratio is determined by an individual's proportions of android fat and gynoid fat. A small waist to hip ratio indicates less android fat, high waist to hip ratio's indicate high levels of android fat.

As WHR is associated with a woman's pregnancy rate, it has been found that a high waist-to-hip ratio can impair pregnancy, thus a health consequence of high android fat levels is its interference with the success of pregnancy and in-vitro fertilisation.[27] Body fat distribution is also related to the sex ratio of offspring. Women with large waists (a high WHR) tend to have an android fat distribution caused by a specific hormone profile, that is, having higher levels of androgens. This leads to such women having more sons.[28]

Liposuction

Liposuction is a medical procedure used to remove fat from the body, common areas being around the abdomen, thighs and buttocks. Liposuction does not improve an individual's health or insulin sensitivity [29] and is therefore considered a cosmetic surgery.[30] liposuction improves quality of life in everyday activities and issues regarding ones psychological state or social life after liposuction are less serious.[31] of individuals particularly It has been found that abdominal exercise alone cannot reduce android fat around the trunk and abdomen [32] so liposuction is often a short term solution.

As liposuction can lower a person's waist-hip ratio by removing fat from locations where android fat accumulates, it can give the appearance of a more attractive body shape, and imitate an indication of reproductive health. Another method of reducing android fat is Laparoscopic Adjustable Gastric Banding which has been found to significantly reduce overall android fat percentages in obese individuals.[33]

Individual Differences

Cultural Differences

Cultural differences in the distribution of android fat have been observed in several studies. Compared to Europeans, South Asian individuals living in the UK have greater abdominal fat.[34] Asian Indians living in the USA have high levels of body fat in contrast to their muscle mass and BMI [35] Newborn babies in India also show similar differences in their body fat distribution.[36] There is a difference in wait-to-hip ratio (WHR’s) between Indian people and Africans living in South Africa such that Indians have greater WHR’s compared to African people.[37]

A difference in body fat distribution was observed between men and women living in Denmark (this includes both android fat distribution and gynoid fat distribution), of those aged between 35 to 65 years, men showed greater body fat mass than women. Men showed a total body fat mass of 6.9 kg and women showed a total body fat mass of 4.5 kg.[38] These observed difference could be due to a difference in muscularity.[39] Australian Aborigines who live a hunter gatherer lifestyle, have been noted to have high levels of obesity (with an android fat distribution) when they switch to a Westernized lifestyle. This is because in comparison to their previous lifestyle where they would engage in strenuous physical activity daily and have meals that are low in fat and high in fiber, the Westernized lifestyle has less physical activity and the diet includes high levels of carbohydrates and fats.[40]

Age related changes

Android fat distributions change across life course. The main changes in women are associated with menopause. Premenopausal women tend to show a more gynoid fat distribution than premenopausal women - this is associated with a drop in oestrogen levels. An android fat distribution becomes more common post-menopause, where oestrogen is at its lowest levels.[41][42] Older men show android fat distributions more often than younger men [43] which may be due to lifestyle changes, or hormonal changes related to age.[44] Older adults have a greater waist-to-hip ratio than young adults which indicates high levels of android fat in older adults. Computed tomography studies show that older adults have a two-fold increase in visceral fat compared to young adults.These changes in android fat distribution in older adults occurs in the absence of any clinical diseases.[45]

References

  1. 1 2 3 Thornhill. The Evolutionary Biology of Human Female Sexuality. ISBN 9780195340983.
  2. 1 2 Ley, CJ; Lees, B; Stevenson, JC (1992). "Sex-and menopause-associated changes in body-fat distribution". American Journal of Clinical Nutrition 55 (5): 950–954.
  3. ↑ Wells, JCK (2007). "Sexual dimorphism of body composition.". Best Practice & Research Clinical Endocrinology & Metabolism 21 (3): 415–430. doi:10.1016/j.beem.2007.04.007.
  4. ↑ Bray, GA (2004). "Medical Consequences of Obesity". The Journal of Clinical Endocrinology & Metabolism 89 (6): 2583–2589. doi:10.1210/jc.2004-0535.
  5. ↑ Wiklund, P; Toss, F; Weinehall, L; Hallmans, G; Franks, PW; Nordström, A; Nordström, P (2008). "Abdominal and Gynoid Fat Mass Are Associated with Cardiovascular Risk Factors in Men and Women". Journal of Clinical Endocrinology & Metabolism 93 (11): 4360–4366. doi:10.1210/jc.2008-0804.
  6. ↑ Orringer, J. S., Alam, M., & Dover, J. S. (2014). Body Shaping, Skin Fat and Cellulite: Procedures in Cosmetic Dermatology Series. Elsevier Health Sciences.
  7. ↑ "How does the type of fat you have affect your risk of disease?". weight-loss.yoexpert. Retrieved 21 March 2016. |first1= missing |last1= in Authors list (help)
  8. ↑ Furnham, A., Tan, T., & McManus, C. (1997). Waist-to-hip ratio and preferences for body shape: A replication and extension. Personality and Individual Differences, 22(4), 539-549.
  9. ↑ Kirchengast, S., Gruber, D., Sator, M., Hartmann, B., Knogler, W., & Huber, J. (1997). Menopause-associated differences in female fat patterning estimated by dual-energy X-ray absorptiometry. Annals of human biology, 24(1), 45-54.
  10. ↑ Ali, A; Crowther, N (2005). "Body fat distribution and insulin resistance". South African Medical Journal 95 (11): 878–880.
  11. 1 2 Sutherland, H.W; Stowers, J.M (1978). Carbohydrate Metabolism in Pregnancy and the Newborn. ISBN 978-3-540-08798-4.
  12. ↑ Plowman, Sharon; Smith, Denise (2008). Exercise Physiology for Health, Fitness, and Performance. ISBN 978-0-7817-8406-1.
  13. ↑ "Liposuction Info: Fat Cells and Your Anatomy". liposuction4you. Retrieved 21 March 2016.
  14. ↑ Ali, A; Nigel, C (2005). "Body fat distribution and insulin resistance". South African Medical Journal (95): 878–880.
  15. ↑ Aucouturier, J; Meyer, M; Thivel, D; Taillardat, M; Duché, P (2009). "Effect of android to gynoid fat ratio on insulin resistance in obese youth". Archives of Pediatrics & Adolescent Medicine 163 (9): 826–831. doi:10.1001/archpediatrics.2009.148.
  16. ↑ Wysocki, M; Krotkiewski, M; Braide, M; Bagge, U (3 January 1991). "Hemorheological disturbances, metabolic parameters and blood pressure in different types of obesity". Atherosclerosis 88 (1): 21–28. PMID 1878007.
  17. ↑ Kirchengast, S; Huber, J (2004). "Body composition characteristics and fat distribution patterns in young infertile women". Fertility and Sterility 81 (3).
  18. ↑ BJORNTORP, PER (1996). "The android woman – a risky condition". Journal of Internal Medicine 239: 105–110.
  19. ↑ Lewis, G; Carpentier, A; Adeli, K; Giacca, A (2003). "Disorded fat storage and mobilization in the pathogenesis of unsulin resistance and type 2 diabetes". Endocrine Reviews 23: 20–229.
  20. ↑ Blouin, K; Boivin, A; Tchernof, A. "Androgens and body fat distribution". Journal of Steroid Biochemistry and Molecular Biology 108 (3): 272–280.
  21. ↑ Mery, C. M., Rubio, V., Duarte-Rojo, A. E. S., Suazo-Barahona, J., Peláez-Luna, M., Milke, P., & Robles-Díaz, G. (2002). Android fat distribution as predictor of severity in acute pancreatitis. Pancreatology, 2(6), 543-549.
  22. ↑ Tanamas, S., Wluka, A., Berry, P., Menz, H., Strauss, B., & Davies-Tuck, M. et al. (2012). Relationship between obesity and foot pain and its association with fat mass, fat distribution, and muscle mass. Arthritis Care Res, 64(2), 262-268.
  23. ↑ Hill, C., Gill, T., Menz, H., & Taylor, A. (2008). Prevalence and correlates of foot pain in a population-based study: the North West Adelaide health study. Journal Of Foot And Ankle Research, 1(1), 2. http://dx.doi.org/10.1186/1757-1146-1-2
  24. ↑ Steele JR, Mickle KJ, Munro B. Fat flat frail feet: how does obesity affect the older foot. XXII Congress of the International Society of Biomechanics; 2009.
  25. ↑ Davis, C., & Cerullo, D. (1996). Fat distribution in young women: Associations and interactions with behavioural, physical and psychological factors. Psychology, Health & Medicine, 1(2), 159-167.
  26. 1 2 Singh, D (1993). "Adaptive significance of female physical attractiveness: role of waist-to-hip ratio". Journal of Personality and Social Psychology 65: 293.
  27. ↑ Wass, P., Waldenström, U., Rössner, S., & Hellberg, D. (1997). An android body fat distribution in females impairs the pregnancy rate of in-vitro fertilization-embryo transfer. Human Reproduction, 12(9), 2057-2060.
  28. ↑ Abu-Rmeileh, N; Watt, G; Lean, M (2011). "sex differences of offspring-parents obesity: Angely hypothesis revisited". Human Biology 83 (4): 523–530.
  29. ↑ Wenk, G (7 February 2016). "Your Brain on Food". Psychology Today. Retrieved 2016-03-02.
  30. ↑ Nordqvist, Christian. "What is liposuction? What are the risks and benefits of havings liposuction?". Medical News Today. Knowledge Center. Retrieved 02/03/2016. Check date values in: |access-date= (help)
  31. ↑ Brorson, H; Ohlin, K; Olsson, G; Langstrom, G; Wiklund, I; Stvensson, H (2006). "Quality of life following liposuction and conservative treatment of arm lymphedema.". Lymphology 39: 8–25.
  32. ↑ Vispute, S. S., Smith, J. D., LeCheminant, J. D., & Hurley, K. S. (2011). The effect of abdominal exercise on abdominal fat. The Journal of Strength & Conditioning Research, 25(9), 2559-2564.
  33. ↑ Nadler, E. P., Reddy, S., Isenalumhe, A., Youn, H. A., Peck, V., Ren, C. J., & Fielding, G. A. (2009). Laparoscopic adjustable gastric banding for morbidly obese adolescents affects android fat loss, resolution of comorbidities, and improved metabolic status. Journal of the American College of Surgeons, 209(5), 638-644.
  34. ↑ McKeigue, PM; Shah, B; Marmot, MG (1991). "Relation of central obesity and insulin resistance with high diabetes prevalence and cardiovascular risk in South Asians". Lancet (337): 382–386.
  35. ↑ Banerji, MA; Faridi, N; Atluri, R; Chaiken, RL; Lebovitz, HE (1999). "Body composition visceral fat, leptin and insulin resistance in Asian Indian Men". J Clin Endocrinol Metab 84: 137–144.
  36. ↑ Bavdekar, A; Yajnik, CS; Fall, CHD; et al. (1999). "Insulin resistance syndrome in 8-year-old Indian children". Diabetes 48: 2422–2429.
  37. ↑ Ali, A., & Crowther, N. (2005). Body fat distribution and insulin resistance. SAMJ, 95(11), 878-880.
  38. ↑ Heitmann, BL (1991). "Body fat in the adult Danish population aged 35-65 years: an epidemiological study". International Journal of Obesity 15 (8): 535–545.
  39. ↑ Laulu, M; Simmons, D; Rush, E; Plank, L; Chandu, V (Dec 17, 2004). "Body size, body composition, and fat distribution: a comparison of young New Zealand men of European, Pacific Island, and Asian Indian ethnicities". The New Zealand Medical Journal: 117–1207.
  40. ↑ O'Dea, K. (1991). Westernization and non-insulin-dependent diabetes in Australian Aborigines. Ethnicity & Disease, 1(2), 171-187.
  41. ↑ Kirchengast, S., Gruber, D., Sator, M., Hartmann, B., Knogler, W., & Huber, J. (1997). Menopause-associated differences in female fat patterning estimated by dual-energy X-ray absorptiometry. Annals of human biology, 24(1), 45-54.
  42. ↑ Ley, C. J., Lees, B., & Stevenson, J. C. (1992). Sex-and menopause-associated changes in body-fat distribution. The American journal of clinical nutrition, 55(5), 950-954.
  43. ↑ Mueller, W. H., & Joos, S. K. (1985). Android (centralized) obesity and somatotypes in men: association with mesomorphy. Annals of human biology, 12(4), 377-381.
  44. ↑ Rimm, E. B., Stampfer, M. J., Giovannucci, E., Ascherio, A., Spiegelman, D., Colditz, G. A., & Willett, W. C. (1995). Body size and fat distribution as predictors of coronary heart disease among middle-aged and older US men. American Journal of Epidemiology, 141(12), 1117-1127.
  45. ↑ Schwartz, R., Shuman, W., Bradbury, V., Cain, K., Fellingham, G., & Beard, J. et al. (1990). Body Fat Distribution in Healthy Young and Older Men. Journal Of Gerontology, 45(6), M181-M185.
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