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What We Know About Childhood Obesity

Definitions of overweight and obesity

  • The human body is a delicate balance of water, proteins, carbohydrates, fats, vitamins and minerals. When people consume more calories from food than they expend through physical activity, they throw off this balance and cause their bodies to store the excess calories as fat. In extreme cases of fat buildup and weight gain, overweight and obesity result – posing serious threats to physical and mental health. (1)
  • Overweight and obesity is classified according to a measurement called the Body Mass Index (BMI). BMI is defined as a person's weight in kilograms divided by his height in meters squared (kg/m 2). (2) Among adults, a BMI between 25 and 30 signifies overweight, and a BMI greater than 30 signifies obesity. (4)
  • Overweight among youths is diagnosed according to gender and age-specific BMI growth curves. (3) An overweight child is defined as having a BMI at or above the 95th percentile, and a child at risk of becoming overweight has a BMI between the 85th and 95th percentiles. (2) There is no established definition of obesity in children and adolescents. (2)

Facts and figures: How fat is our nation?

  • Almost 2/3 of U.S. adults aged 20-74 years are overweight, including 30% who are obese, according to the 1999-2000 National Health and Nutrition Examination Survey (NHANES). (4) In the past 3 decades, adulthood obesity incidence has increased 100%. (4)
  • Among persons aged 6-19, an estimated 15%, or 9 million youths, are overweight. (2) In the past 3 decades, the numbers have more than tripled for children aged 6-11 (from 4% in 1971-74 to 15% in 1999-2000) and doubled for adolescents aged 12-19 (from 6% to 15%). (2)
  • In addition to the 15% of youths who are overweight, data suggest that another 15% are at risk of becoming overweight (BMI between the 85 th and 95 th percentiles). (6)

Financial implications: Obesity = profound economic burden

  • In 2000, the costs of obesity in the United States were estimated at $117 billion – $61 million due to direct healthcare costs (i.e. preventive, diagnostic, and treatment services for obesity and related diseases) and $56 million on indirect costs (i.e. wages lost because of illness or disability, and future earnings lost because of premature death). (13)
  • Among children and adolescents, the annual cost of treating obesity-related diseases has increased more than threefold, from $35 million in 1979-1981, to $127 million in 1997-1999. (8)
  • According to the Centers for Disease Control and Prevention, a 10% weight loss could reduce an overweight person's lifetime medical costs by $2,200-$5,300. (10)

Trends and disparities in race, ethnicity, socioeconomic status, and gender

  • Obesity has spread rapidly across race, gender, and class lines, but its prevalence has increased disproportionately among African-American, Hispanic, and Native American children. (11)
    • In contrast to the 12-13% of Caucasian youth who are overweight, 24% of Mexican-American youth, 20% of non-Hispanic African-American children and 24% of African-American adolescents are overweight. (6) An estimated 38-39% of Native American youth are at risk of becoming overweight, according to a 1999 Aberdeen Indian Health Service study. (14 )
    • Prevalence is particularly high among Mexican-American boys (>27% of children and teens) and African-American girls (22% of children and 27% of adolescents). (9)
  • While a lower level of parental income and education increases the risk of being overweight among Caucasian children, higher socioeconomic status does not necessarily protect from overweight and obesity among African-American and Hispanic children. (11)

Health consequences: Links between childhood overweight, chronic disease, and premature death

  • Excess weight can exert a profound and immediate effect on physical, mental, emotional, and social development:
    • Compared with normal-weight youths, overweight children and adolescents suffer disproportionately from such chronic conditions as diabetes, asthma, high blood pressure, high cholesterol, atherosclerosis, bone/joint problems, and sleep apnea. (3,12,14,16,18-24)
    • Overweight kids experience intense social stigmatization. (14,25) Particularly among adolescent Caucasian girls, Hispanic girls, and boys of all races, childhood overweight is associated with lower self-esteem, a tendency to withdraw from others, increased loneliness, sadness, and nervousness, and increased use of alcohol and tobacco. (26)
    • Severely overweight children are more than 5 times as likely as their healthy counterparts to have a lower health-related quality of life, i.e., their ability to move around, play sports, and perform in school, as well as their levels of fear and sadness, and the quality of their relationships with peers. (30)
  • Overweight youths have an estimated 70-80% chance of becoming obese adults. (14,15,17,26) People who suffer the burdens of excess weight during childhood are at continued and elevated risk for chronic diseases and premature death during adulthood. (13) Obesity contributes to 4 of the 10 leading causes of death among U.S. adults: coronary heart disease, stroke, Type 2 diabetes, and cancer (1) :
    • Heart disease and stroke account for almost 40% of deaths in the U.S., costing the nation an estimated $351 billion in 2003. (27) Obese adults are at ever-increasing risk for hypertension, dyslipidemia, atherosclerosis, coronary heart disease, left ventricular hypertrophy, stroke, and kidney failure. (16,19)
    • Cancer is the 2nd leading cause of death in the United States. (16) Excess weight, poor diet, and physical inactivity greatly increase the chances of developing cancers of the breast, colon, prostate, endometrium (lining of the uterus), cervix, ovary, kidney, gallbladder, and potentially the liver, pancreas, rectum, and esophagus. (13,28)
    • Diabetes is a major cause of kidney failure, limb amputation, and acquired blindness. (18) Although Type 2 diabetes is considered an adult disease, doctors have seen a sharp rise in the occurrence of Type 2 in childhood, concurrent with the childhood obesity epidemic. (19) 1 in every 3 children born in 2000 will develop Type 2 diabetes if current trends continue. (5)
    • Obesity is also a significant risk factor for the following diseases: asthma, kidney failure, gallbladder disease, urinary incontinence, and osteoarthritis . (13,19-21,29)
    • According to Dr. George Blackburn, associate director of the Division of Nutrition at Harvard Medical School, “We must…intensify efforts for early identification and early prevention of overweight and obesity, or we are going to have the first generation of children who are not going to live as long as their parents.” (31)