Just like their parents, children have been getting heavier.
A federal report released last week, compiled from 30 years of children’s weight data, shows that the proportion of overweight children and adolescents has been increasing since 1965. And the most dramatic increase in the proportion of overweight children has occurred since 1980, according to the study published in this month’s Archives of Pediatrics and Adolescent Medicine.
Over three decades, the percentage of the most-overweight children has roughly doubled. The study defined as overweight those children who fell in the 95th percentile for body-mass index, a calculation in which weight in kilograms is divided by height in meters squared.
Because children’s bodies can change so much during growth, the 95th percentile is perhaps the best definition of overweight, according to the researchers who conducted the study.
The researchers, from the federal Centers for Disease Control and Prevention, based their study on comparable, standardized data from five national surveys by the federal government between 1963 and 1991. The most recent data, collected from 1988 to 1991, came from the third National Health and Nutrition Examination Survey, known as NHANES III. The surveys each studied between 3,000 and 14,000 children ages 6 to 17.
For children ages 6 to 11, the incidence of being very overweight increased in 30 years from 5.2 percent of the population to 10.8 percent for boys and 10.7 percent for girls. For the 12- to 17-year-olds, the prevalence increased a similar amount, although more dramatically for boys than for girls.
In the most recent study, NHANES III, children 6 to 17 who fell at or above the 95th percentile in weight-for-height represented about 11 percent of that age group, or about 4.7 million children.
The childhood weight-gain trend parallels that among adults, who are now less physically active and eat more high-calorie foods compared with adults in the past, the researchers note.
