Nov. 5, 2013 -- intro: American girls are hitting puberty sooner, according to a new study that suggests obesity could be driving the early development.

The study of more than 1,200 girls found that the median age of breast development ranged from 8.8 to 9.7 years, depending on race, with heavier girls developing breasts sooner than their thinner counterparts.

"Girls with earlier maturation are at risk for lower self-esteem and higher rates of depression," the study authors wrote in their report, published Monday in the journal Pediatrics. "They are more likely to be influenced by older peers and more deviant peers, and initiate intercourse, substance use and other norm-breaking behaviors at younger ages."

Childhood obesity has more than doubled in the past 30 years, according to the U.S. Centers for Disease Control and Prevention, rising from 7 percent in 1980 to 18 percent in 2010. More than one-third of children and teens are now overweight or obese. And the problem only gets worse. More than two-thirds of American adults are overweight or obese, according to the CDC.

While these statistics are quoted so often that they make most people's eyes glaze over, the effects of obesity reach far beyond clothing size and cardiovascular health. Obesity can affect family relationships and income, too.

Read on to learn about eight other ways carrying those extra pounds may influence the way you live.

quicklist: 1 category: Surprising Effects of Obesity title: More Migraines url: text: A study published in the journal Neurology revealed what a real headache extra weight can be. Johns Hopkins researchers surveyed nearly 4,000 people to find that the higher their body mass index, the greater their chances were of having episodic migraines. Those who were obese were 81 percent more likely to experience at least 14 migraine headaches each month compared with people who were a healthy weight. Obese women over the age of 50 suffered from chronic headaches the most.

quicklist: 2 category: Surprising Effects of Obesity title: More Cancer url: text: The National Cancer Institute associates 34,000 new cases of cancer in men and 50,000 in women each year with obesity.

Right now the link between excess weight and cancer is purely circumstantial and not necessarily cause-and-effect, but experts have floated some theories about why more body fat tracks with higher rates of cancer.

"It could be that excess fat cells increase hormonal activity or they increase growth factors that lead to tumor growth," said Dr. Raul Seballos, vice chairman of preventive medicine at the Cleveland Clinic.

Obese people are at higher risk for all cancers, Seballos said. They are often diagnosed in later stages of cancer than thinner people and are more likely to die from the disease. Some emerging data looking at weight-loss surgery patients suggest that some of this risk can be diminished by losing weight.

quicklist: 3 Category: Surprising Effects of Obesity Title: Infertility Increases url: text: Overweight women have a harder time getting pregnant. One Indian study of 300 morbidly obese women found that more than 90 percent of them developed polycystic ovarian disease, a condition associated with infertility, over a three-year period.

As with cancer, the association between obesity and infertility isn't entirely clear.

"Obesity is an inflammatory state, and that alone might decrease fertility," said Dr. Marc Bessler, director of the Center for Weight Loss and Metabolic Surgery at New York Presbyterian Hospital. "It may also be the result of hormone changes produced by the fatty tissue."

Bessler said that many of his heavier patients experienced difficulty getting pregnant. And many infertility clinics don't accept female patients with high body mass indexes given their diminished chances of conceiving. However, Bessler said some of his patients become pregnant just months after weight-loss surgery once they had dropped a few pounds.

quicklist: 4 category: Surprising Effects of Obesity title: Premature Birth Risk url: text: For heavier women who do get pregnant, the worries aren't over. A new study in the Journal of the American Medical Association found that obesity increased a woman's chance of having a preterm baby, especially when her body mass index is 35 or higher. The study's authors speculate that having too much fat may inflame and weaken the uterine and cervical membranes. Whatever the reason, it can have devastating effects. Premature birth is the leading cause of infant death and long-term disabilities.

quicklist: 5 category: Surprising Effects of Obesity title: Less Shut-Eye url: text: Sleep and excess weight do not make good bedfellows. Nearly 80 percent of older, obese Americans report having problems sleeping, a recent American Sleep Foundation survey found.

Poor sleep contributes to a host of diseases, including diabetes, heart disease and, ironically, obesity itself. Numerous studies, including the Harvard Nurses' Study, link short sleep to expanding waistlines. The Harvard Nurses' Study found that those who slumbered less than five hours a night were 15 percent more likely to gain weight than those who enjoyed at least seven hours of sleep.

Dr. Donald Hensrud, a nutritionist and preventive medicine expert in the department of endocrinology, diabetes, metabolism and nutrition at the Mayo Clinic, said one of the most immediate health dangers for many obese people is sleep apnea, a condition in which a person gasps or stops breathing momentarily while asleep.

"Sleep apnea can be caused by increased fat around the neck area that presses down and closes off the soft tissues of the airways while a person is lying down, especially on his back," Hensrud said. "This means the person does not get good quality sleep, has less oxygen in the blood stream, and the heart has to work harder."

quicklist: 6 category: Surprising Effects of Obesity title: Tough Love url: text: Though fat people are often the butt of jokes, obesity stigma is no laughing matter.

A Yale study found that weight is the No. 1 reason people are bullied at any age, and those who are bullied have lower self-esteem, higher levels of depression and increased risk of suicide than those who are not.

The main source of ridicule, according to the Yale researchers: Loved ones.

"More than 40 percent of children who seek treatment for weight loss say they have been bullied or teased by a family member," said the study's lead author, Rebecca Puhl. "When we asked obese women who stigmatized them the most, 72 percent said it was someone in their family."

Puhl said discussions with loved ones about their burgeoning weight often came across as judgmental and derogatory, even when intentions were good. However, offering support and encouragement is the most effective approach to help someone struggling to drop pounds.

quicklist: 7 category: Surprising Effects of Obesity title: Medical Gap url: text: The No. 2 source of stigma, after loved ones?

Puhl said her studies have found that 67 percent of overweight men and women report being shamed or bullied in the doctor's office. And 50 percent of doctors found that fat patients were "awkward, ugly, weak-willed and unlikely to comply with treatment" while 24 percent of nurses said they were repulsed by their obese patients.

A negative reception from a health care provider is especially detrimental to obese people, Puhl stressed, because they already contend with a greater number of health problems than average.

"Besides jeopardizing discussions between patients and health care providers, someone who is obese is more likely to avoid the doctor altogether even when they have a problem," she said.

However Puhl noted that the knife cuts both ways. Her studies reveal that people are less apt to follow doctor's orders and more likely to switch to a new provider if their physician is overweight.

quicklist: 8 category: Surprising Effects of Obesity title: Shrinking Wallet url: text: Wider waistbands seem to widen the pay gap.

One George Washington University School of Public Health study found a strong connection between greater obesity and shrinking wages. Examining data from the 2004 National Longitudinal Survey of Youth, the researchers discovered that wages among the obese were $8,666 less for females and $4,772 lower for males compared with their thinner counterparts. In 2008, the researchers found wages were $5,826 less for obese females -- a 14.6 percent penalty over normal-weight females.

Slimmer females, especially, do seem to have fatter wallets. In a University of Florida study, women who weighed 25 pounds less than the group average, earned $15,572 a year more than women of normal weight and women who tipped the scales at 25 pounds above the average weight earned an average of $13,847 less than an average-weight female. They found no such disparity among men.