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Genetic influence and environmental factors

Going through puberty is already a challenging time for any teen, the addition of genetic and environmental factors can interfere with the progression to adulthood. Genetic factors account for half of the variations of pubertal timing. Enviromental factors are extrenly important to progressing of puberty. One of the first observed environmental effects is that puberty occurs later in children raised at higher altitudes. The most important of the environmental influences is clearly nutrition, but a number of others have been identified. These factors all affect timing of female puberty and menarche more clearly than male puberty.

Hormones

There is theoretical concern, and animal evidence, that environmental hormones and chemicals may affect aspects of prenatal or postnatal sexual development in humans.[77] Large amounts of incompletely metabolized estrogens and progestagens from pharmaceutical products are excreted into the sewage systems of large cities, and are sometimes detectable in the environment. Sex steroids are sometimes used in cattle farming but have been banned in chicken meat production for 40 years. Although agricultural laws regulate use to minimize accidental human consumption, the rules are largely self-enforced in the United States. Significant exposure of a child to hormones or other substances that activate estrogen or androgen receptors could produce some or all of the changes of puberty.

Harder to detect as an influence on puberty are the more diffusely distributed environmental chemicals like PCBs (polychlorinated biphenyl), which can bind and trigger estrogen receptors. More obvious degrees of partial puberty from direct exposure of young children to small but significant amounts of pharmaceutical sex steroids from exposure at home may be detected during medical evaluation for precocious puberty, but mild effects and the other potential exposures outlined above would not.

Researchers[76] have hypothesized that early puberty onset may be caused by certain hair care products containing estrogen or placenta, and by certain chemicals, namely phthalates, which are used in many cosmetics, toys, and plastic food containers.

Bisphenol A (BPA) is a chemical used to make plastics, and is frequently used to make baby bottles, water bottles, sports equipment, medical devices, and as a coating in food and beverage cans. Scientists are concerned about BPA's behavioral effects on fetuses, infants, and children at current exposure levels because it can affect the prostate gland, mammary gland, and lead to early puberty in girls. BPA mimics and interferes with the action of estrogen—an important reproduction and development regulator. It leaches out of plastic into liquids and foods, and the Centers for Disease Control and Prevention (CDC) found measurable amounts of BPA in the bodies of more than 90 percent of the U.S. population studied. The highest estimated daily intakes of BPA occur in infants and children. Many plastic baby bottles contain BPA, and BPA is more likely to leach out of plastic when its temperature is increased, as when one warms a baby bottle or warms up food in the microwave.[78]

Steroids

As kids turn into teens and puberty starts to begin there is a lot going on in a teens mind. Am I big enough? Am I pretty enough? Why does she/ he look like that and I don’t? These are all common thoughts in a teens mind as their bodies start to change. A common environmental factor that teens and even adults are willing to try, are steroids. “Steroids are artificial hormones that can improve strength and muscle mass”

These steroids are not the kinds of steroids your body naturally produces to help you fight stress and grow bigger during puberty. The steroids that are illegal are called anabolic steroids. “Anabolic steroids are artificially produced hormones that are the same as, or similar to, androgens, the male-type sex hormones in the body” A person’s body knows the right amount of steroids the body needs so adding extra steroids into the body is extremely harmful.

Anabolic steroids are taken in many different forms such as pills, powders, or injections. Since steroids can be injected, given in a form of a shot, an increased risk of illnesses can be passed through needles that are shared or dirty. Some of these illnesses include HIV/AIDS and hepatitis. Hepatitis is a serious liver disease There are many dangers to steroids. The minor side effects include acne, oily hair, red or purple spots on the body, swelling of the legs and feet, and persistent bad breath. “Also a teen who takes steroids might not grow as tall as he or she was supposed to grow” Here is a list of some of the long- lasting, more serious effects: •	premature balding •	dizziness •	mood swings, including anger and sadness •	seeing or hearing things that aren't there (hallucinations) •	extreme feelings of mistrust or fear (paranoia) •	problems sleeping •	nausea •	vomiting •	trembling •	high blood pressure that can damage the heart or blood vessels over time •	aching joints •	greater chance of injuring muscles and tendons •	jaundice or yellowing of the skin; liver damage •	trouble peeing •	increased risk of developing heart disease, stroke, and some types of cancer

Some of the health risks that target girls are increased facial hair growth, deeper voice, shrinking of the breasts, and period changes. Some of the health risks that target boys include the shrinkage of the testicles and penis problems, pain when urinating (peeing), and breast development As you can see, steroids are a huge detriment to your health and should be avoided at all costs. Not only does it affect your physical health but it also does damage to your behaviors and attitudes. Stay away from steroids!

Nutritional influence

Maintaining a healthy and balanced diet relates to the age a teen will start puberty. Nutritional factors are the strongest and most obvious environmental factors affecting timing of puberty.[71] Even though it is known that weight gain effects early pubertal development, poor childhood nutrition leads to delays in the start of puberty

Obesity Influence

“Rapid weight gain during infancy is associated with accelerated growth and early pubertal development” Scientific researchers have linked early obesity with an earlier onset of puberty in girls. They have cited obesity as a cause of breast development before nine years old and menarche before twelve years of age.[79] Menarche is a girls first menstrual cycle. Early puberty in girls can be a harbinger of later health problems.[80]

A 2010 study published in Pediatrics, conducted by Frank Biro noticed that girls are starting puberty a lot younger than past decades. His team examined about 1,200 girls ages 7 and 8 in Cincinnati, New York and San Francisco. They noticed that approximately 10 percent of white girls and 23 percent of black girls had started developing breasts at age 7. In 1997 only 5 percent of white girls and 15 percent of black girls were developing breast at this age Starting puberty earlier could give the teen a higher risk of breast cancer than girls who develop later in life

Also as study was conducted using data from the National Comorbidity Survey Replication and examined how early and late menarche affects a girl’s rick for anxiety problems later in life. The outcome of this study was that early onset to puberty increases the risk for a lifetime diagnosis of posttraumatic stress disorder (PTSD), specific phobias (SP), social anxiety disorder (SAD) oppose from late timing only increases rates of SAD

This phenomenon could be blamed due to “the modern American diet, which includes many processed, high-fat foods” Even though being overweight increases the likelihood that a girl will start puberty earlier it is the opposite for boys, they could start later.

There are many important factors in an adolescent’s nutrition, especially when going through puberty. There body needs more protein, iron, calcium, zinc, and foliate for healthy growth. They also need an increase in their daily caloric needs since when you go through puberty you are triggering a growths spurt. “Menstruating girls are at an especially high risk of iron deficiency.” Lastly, if your teen doesn’t receive enough calcium or protein during puberty they could have damage to their bone and muscle growth

Nutrition is extremely important because it affects your body and growth for the rest of your life. Everything you put into your body has a lasting effect. Your stomach is not a trashcan, handle it with care!

Exercise

The average level of daily physical activity has also been shown to affect timing of puberty, especially in females. A high level of exercise, whether for athletic or body image purposes, or for daily subsistence, reduces energy calories available for reproduction and slows puberty. The exercise effect is often amplified by a lower body fat mass and cholesterol.

Physical and mental illness

Chronic diseases can delay puberty in both boys and girls. Those that involve chronic inflammation or interfere with nutrition have the strongest effect. In the western world, inflammatory bowel disease and tuberculosis have been notorious for such an effect in the last century, while in areas of the underdeveloped world, chronic parasite infections are widespread. Mental illnesses occur in puberty. The brain undergoes significant development by hormones, which can contribute to mood disorders such as Major depressive disorder, bipolar disorder, dysthymia and schizophrenia. Girls aged between 15 and 19 make up 40% of anorexia nervosa cases.[81]

Bipolar disorder is a disease that people who have it can't control their moods as they swing from extreme highs to extreme lows. Everyone has up and downs but people with this disorder have no control over them and they flip-flop back and forth between moods. This is called mania. The brain has a difficult time keeping control of someone who battles with bipolar disorder. This disorder is believed to be genetic. This disorder can be treated with a combination of medicines. Even though there is no cure for bipolar disorder, if these conditions are treated a person with this disorder can live a full, productive life

Anorexia is an eating disorder that occurs when a person is afraid of gaining weight, so they do not eat. A human needs food and water to survive so as you can see this is not healthy. A person with this disorder believes that their body looks fat, even if they are thin. They usually develop mood swings of anger, and sadness due to lack of nutrients in their bodies

There is also another case of eating disorders, called bulimia. People with this disorder will binge, which means they will eat a huge amount of food and then purge. Purge means to try and get rid of the food eaten by vomiting, taking laxatives, and exercising A LOT. Teens sometimes develop this disease when something new or stressful comes into their life

There was a study conducted in Ireland to see the impact between pubertal timing and eating disorders. The results showed that girls who matured earlier showed the most eating concerns. They had the highest scores on bulimic symptoms and had the highest dissatisfaction about their bodies then the rest of the teens. Boys who matured later had more bulimic symptoms and negative attitudes about their bodies then boys who matured on time. Overall eating disorders were found to be more of a risk factor for girls in relation to pubertal timing but they are is still a risk for both, boys and girls

Stress and social factors

Some of the least understood environmental influences on timing of puberty are social and psychological. In comparison with the effects of genetics, nutrition, and general health, social influences are small, shifting timing by a few months rather than years. Mechanisms of these social effects are unknown, though a variety of physiological processes, including pheromones, have been suggested based on animal research.

The most important part of a child's psychosocial environment is the family, and most of the social influence research has investigated features of family structure and function in relation to earlier or later female puberty. Most of the studies have reported that menarche may occur a few months earlier in girls in high-stress households, whose fathers are absent during their early childhood, who have a stepfather in the home, who are subjected to prolonged sexual abuse in childhood, or who are adopted from a developing country at a young age. Conversely, menarche may be slightly later when a girl grows up in a large family with a biological father present.

More extreme degrees of environmental stress, such as wartime refugee status with threat to physical survival, have been found to be associated with delay of maturation, an effect that may be compounded by dietary inadequacy.

Most of these reported social effects are small and our understanding is incomplete. Most of these "effects" are statistical associations revealed by epidemiologic surveys. Statistical associations are not necessarily causal, and a variety of covariables and alternative explanations can be imagined. Effects of such small size can never be confirmed or refuted for any individual child. Furthermore, interpretations of the data are politically controversial because of the ease with which this type of research can be used for political advocacy. Accusations of bias based on political agenda sometimes accompany scientific criticism.

Another limitation of the social research is that nearly all of it has concerned girls, partly because female puberty requires greater physiologic resources and partly because it involves a unique event (menarche) that makes survey research into female puberty much simpler than male. More detail is provided in the menarche article.

Variations of sequence

The sequence of events of pubertal development can occasionally vary. For example, in about 15% of boys and girls, pubarche (the first pubic hairs) can precede, respectively, gonadarche and thelarche by a few months. Rarely, menarche can occur before other signs of puberty in a few girls. These variations deserve medical evaluation because they can occasionally signal a disease.

Conclusion

In a general sense, the conclusion of puberty is reproductive maturity. Criteria for defining the conclusion may differ for different purposes: attainment of the ability to reproduce, achievement of maximal adult height, maximal gonadal size, or adult sex hormone levels. Maximal adult height is achieved at an average age of 15 years for an average girl and 18 years for an average boy.