A complex process involving the hypothalamus, the pituitary gland and gonads triggers sex hormones that cause the physical changes that mark puberty. The causes of early-onset puberty, therefore, are many, including lifestyle and environmental factors. In rare cases, serious medical problems--more often seen in boys than in girls--can result in early-onset puberty, reports KidsHealth, an information website sponsored by the Nemours Foundation.
The University of Ottawa’s Institute of Population Health states that the age at which children begin puberty has seemingly been decreasing for at least the last 20 years. Puberty normally begins between the ages of 8 and 12 for girls and between ages 9 and 14 for boys. Early onset of puberty--also known as “precocious puberty” and “premature puberty”--begins before ages 8 and 9 for girls and boys, respectively.
Obesity
Research into the relationship between weight and early puberty in children has for a long time been inconclusive; however, the University of Michigan Health System credits obesity as a possible cause and the University of Maryland Medical Center reports that girls who are overweight are more likely to enter puberty early.
Hormonal Irregularities
A few medical conditions that affect hormones can cause precocious puberty in both boys and girls. Although they are rare, McCune-Albright syndrome, congenital adrenal hyperplasia and thyroid imbalances can create hormonal irregularities that lead to early-onset puberty. In addition, boys with excess production of male sex hormones, such as testosterone, have been known to start puberty early.
Environmental Agents
Research into environmental toxins and their effects on hormones has proven insightful into how a child’s environment can affect precocious puberty. Dr. Mary Wolff, along with colleagues at the Mount Sinai School of Medicine, published a report in March 2010 on the effects of certain chemicals found in a wide variety of everyday consumer products, including nail polishes, cosmetics, perfumes, lotions and shampoos. The results show a direct relationship between use of these products and early breast and pubic hair development in girls.
The Institute of Population Health at the University of Ottawa echoes these findings: young girls in Puerto Rico also experienced early breast development when exposed to the same class of chemicals; another case study reports premature puberty in young girls in Michigan caused by exposure to toxic chemicals found in common household items, fish and dairy items.
Genetics
Genes are known to play a role in the cause of early puberty in children. KidsHealth reports that 5 percent of boys who experience precocious puberty inherit the condition from either their fathers or maternal grandfathers, passed through their mothers. In girls, only 1 percent inherit the condition, however.
The condition congenital adrenal hyperplasia describes a group of inherited disorders that involve hormones produced by the adrenal glands. According to the MayoClinic.com, CAH affects children whose parents either have the condition or are carriers of the genetic mutation.
Another genetic mutation in boys is expressed as a disorder called familial gonadotropin-independent sexual precocity, which can result in the early production of testosterone and, thus, cause precocious puberty.
Other Rare Causes
A host of medical problems, diseases and disorders, although rare, can cause precocious puberty. Some of the conditions are injuries, obstructed blood flow, defects or abnormalities in the brain or spinal cord; the infections encephalitis and meningitis; radiation to the brain or spinal cord; spina bifida with hydrocephalus; and problems in the ovaries or thyroid glands.
Other factors include external sources of estrogen or testosterone such as those found in creams and ointments, and tumors in the brain, spinal cord, adrenal glands, pituitary gland, ovaries and cells that make sperm and testosterone.
Syndromes that involve glucose tolerance and insulin resistance, including diabetes and diabetes mellitus, also cause early-onset puberty in children.
References
- Nicholas A. Tritos and Christos S. Mantzoros: Syndromes of Severe Insulin Resistance
- University of Maryland Medical Center: Weight Control and Diet--Complications
- Dr. Om P. Ganda: Prevalence and Incidence of Secondary and Other Types of Diabetes
- Mount Sinai Medical Center: Exposure to Three Classes of Common Chemicals May Affect Female Development
- "Environmental Health Perspectives"; Investigation of Relationships between Urinary Biomarkers of Phytoestrogens, Phthalates, and Phenols and Pubertal Stages in Girls; Mary S. Wolff, et al; 2010
