Week of April 17, 2004; Vol. 165, No. 16
When It's No Longer Baby Fat
Janet Raloff, Science News
Nutritionists and epidemiologists have been documenting a disquieting trend: Increasingly, children are plump by the time they enter school—and they get fatter as they grow.
We're not talking cute baby fat here. Globally, some 22 million children under age 5 are truly overweight—many of them are to the point of being obese. In the United States, "the term pandemic is appropriate for describing the current status of childhood obesity," observed Sue. Y.S. Kimm and Eva Obarzanek in commentary they authored a few years back in Pediatrics.
FILL 'ER UP. While eating baby food, the high chair set doesn't tend to develop obesity in large numbers. It's after age 2, when children begin eating what the rest of their family does, that many children start to put on extra pounds.
Though some of these children will suffer ridicule for their supersized physiques, aesthetics is not the health community's primary concern. Pediatric obesity has developed into "the most serious and prevalent nutritional disorder in the United States," noted the University of Michigan's Albert P. Rocchini in the New England Journal of Medicine 2 years ago. Not only does obesity have a substantial effect on blood pressure, putting individuals at risk of heart disease, but it also greatly increases the odds that kids will develop type 2 diabetes, the form once known as adult-onset diabetes.
In fact, type 2 diabetes and early signs of it—such as poorly controlled blood sugar concentrations—have both been showing up at high rates among the grade school set. Not surprisingly, studies have shown that the kids exhibiting these metabolic impairments are usually heavy to obese. When such epidemiological data are considered "in conjunction with both the current worldwide epidemic of childhood obesity and the evidently high incidence [of impaired blood sugar control] in severely obese children, it appears that there is an emerging pediatric epidemic of type 2 diabetes," concluded Rocchini.
It's against this backdrop that two new papers offer more disturbing news. The first finds that 40 percent of New York preschoolers surveyed in the government's neighborhood nutrition program for impoverished women, infants, and children (WIC) were overweight. In general, the youngsters started fattening up after age 2—when they started sharing meals with the rest of their families, notes report coauthor Jennifer A. Nelson of the Medical and Health Research Association of New York City.
A second study interviewed adult African-American women from impoverished backgrounds and probed for the attitudes about nutrition and bodyweight they had picked up from their mothers during childhood. Several beliefs emerged: Because food is hard to come by, be grateful for what's available and eat it all. Quantity of food is as important as variety. Being slim suggests something is wrong.
Diane B. Wilson of Virginia Commonwealth University in Richmond, who led the study, concludes that mothers' attitudes and actions have an important and lasting role in shaping how their children—especially their daughters—view food and eating.
This is important, she notes, because her earlier research with teenage girls showed that, compared with whites, "black girls have a larger ideal body size. They do not seek to be skinny minis." Unfortunately, says Wilson, many black females fail to maintain a normal body weight. Instead, collectively, black U.S. women "have the highest incidence of obesity" and suffer several chronic diseases as a result.
Limiting the nation's trend toward more obesity in upcoming generations, Wilson's data suggest, may require that today's moms become role models for healthy eating and fitness. Says Wilson: "That's the most powerful thing they can do—even beyond what they tell their kids." Owing to the time pressures and distractions facing so many parents today, she concedes that for most women, finding the time and energy to become examples of healthy eating and exercise is no easy task.
Pudginess begins early
Nelson notes that people administering New York's WIC program—which offers nutrition advice and vouchers for specific foods according to a nutritionist's analysis for each family—had observed that many children in the program were overweight. "So, we decided to do a quick survey" to test the observations and get a sense of whether WIC families were eating healthful meals.
In the March American Journal of Public Health, Nelson and her coworkers report findings on 557 children ages 2 to 4. Their families were among 1,255 surveyed while enrolling or reenrolling in WIC at one of 18 program centers during one month in 2001. These New York centers served low-income neighborhoods in four of the city's five boroughs.
Height and weight data from the children were attached to the questionnaires. Parents answered questions about milk drinking in the household, fruit and vegetable consumption, and general levels of exercise. The questionnaires also recorded demographic data, such as race and nation of birth. Names were removed from the questionnaires to preserve anonymity.
The survey data showed that 64 percent of 2-year-olds were normal weight, as were roughly half of the 3- and 4-year-olds. For each age group, some 4 to 5.5 percent of children were underweight. The rest were heavier than the standard weight of children of their height, age, and gender, based on reference tables from the federal Centers for Disease Control and Prevention.
The researchers found that "the increase in overweight began at about age 2.5 years." The data show that at 2 years, some 14 percent of children were extremely overweight for their height. By age 3, more than 25 percent of children were in this top category.
The survey also showed that 73 percent of families served their children whole milk when low-fat or skim milk would have met their calcium needs. Moreover, 44 percent of families reported serving fruits or vegetables "less than once a day," and 13 percent of families said their preschoolers didn't get formal exercise even twice a week.
The authors acknowledged that "the poor nutrition and health habits uncovered in this survey can be linked only indirectly to the level of overweight among the children." Moreover, it wasn't initially clear whether these children were representative of the city's low-income preschoolers as a whole. However, notes coauthor Mary Ann Chiasson, "after we did our survey, the New York City Department of Health did a survey of elementary school children in the city" that turned up comparable data. It too found that among children starting as young as kindergarteners, only about half were normal weight, and some 4 percent underweight. The rest were overweight to obese.
"So, unfortunately, the [preschoolers] we surveyed in the WIC population are apparently similar to other kids in New York City after all," Chiasson says.
At this point, population-wide factors driving obesity can only be guessed at, Nelson and Chiasson say. They note, however, that kids get little exercise, rates of sedentary activities such as television viewing are high, and stressed-out parents increasingly rely on timesaving, high-calorie convenience foods.
The good news: Nelson observes that her team's new study does "suggest there's a moment of opportunity around age 2" to intervene before children get onto the fat track.
Chiasson says that their agency is looking to expand the parental-education component of the WIC program in New York and offer parents more help in identifying healthy recipes for preschoolers. "We're also working to get more green-market coupons for mothers" so that they can better afford the fruits and vegetables that growing children need, she says. And if her group can scare up the money, Chiasson hopes to offer some children a pedometer as tool for motivating them to increase their activity. "We've been trying it with staff who have young children, and they love it," she notes.
Wilson says she began probing motivations behind eating behaviors after reading studies indicating that children as young as 5 years are aware of dieting and body image. To see such young kids focused on body shape and calories "was very disturbing to me," she says. This prompted her to explore, through focus groups, what messages about food that moms, particularly low-income African-Americans, might be communicating to their daughters.
For her study, she recruited 21 adult women in South Carolina, ages 25 to 65 years. Open-ended discussions covered topics such as:
Words of wisdom your mom passed on about healthy eating.
Things moms communicated about eating through behavior rather than words.
Concerns mothers might have shared about a daughter's weight—such as whether the child was too thin or too fat.
Any concerns regarding the participants' own weights or dieting habits.
Current similarities to and dissimilarities from their mothers' eating habits and body satisfaction.
The women generally had come from families for whom food was scarce. Many participants recalled being taught to be grateful for whatever was available—which usually meant produce from the garden. Because many of the women also came from big families, most learned to shun wastefulness and finish what was on her plate, because extra food wouldn't be coming after mealtime.
Although concerns about being overweight weren't generally discussed while these women were growing up, some of the younger women told Wilson they occasionally saw their mothers diet to lose weight. However, a general attitude in their community had been that weight loss connoted sickness or other problems, whereas weight gain suggested happiness.
At some level, that's consistent with what Cincinnati researchers reported several years ago on mothers' perceptions of their children's weights. In cooperation with a WIC program there, Amy E. Baughcum of Children's Hospital Medical Center and her colleagues focused on 622 children between the ages of 2 and 5 years. They found that obesity was common in moms with limited education and in their offspring. However, although nearly every obese mother regarded herself as such, "the majority of mothers did not view their overweight children as overweight, and this misperception was more common in mothers with less education," the researchers reported in Pediatrics.
Wilson and her colleagues conclude from her team's focus-group discussions that childhood poverty and deprivation can have lasting repercussions that most nutrition scientists haven't realized. For instance, her group reports in the April Journal of Cultural Diversity that "the key importance of food availability in the childhood diets of many of our respondents may result in a tendency to choose foods that are easily accessed, such as those sold in 'fast food' restaurants and vending machines." Moreover, the fact that many of the participants didn't have variety in their diets as children may have fostered complacency about that issue as it affected their own children.
Observes Wilson: Ethnic values, income, family dynamics, the type and availability of role models—all can shape the lessons children learn at home about what, when, and how much to eat. Indeed, she concludes, "more and more, we're finding that eating is culturally based. And that means we're going to have to start studying it through that lens."
Time to run
MOVE IT, KIDS. One way to keep fat off is to exercise. With many schools dropping recess time and extracurricular sports, children aren't burning as many calories most days as they used to. That makes it more important than ever for parents to ensure that their kids get plenty of active play outside of school, the American Academy of Pediatrics says.
Tsung O. Cheng of George Washington University Medical Center agrees. In the April 3 Lancet, he observes that Chinese children "are different from those in other developing countries" in that they are usually excused from household chores so they can study. Because a college education "is seen as the passport to a high-paying job," most parents push their kids to spend all their spare time with homework and computers rather than playing games and engaging in sports. The bottom line, Cheng says: "Participation in physical activities is almost nonexistent" for Chinese youth, leading to sedentary children and escalating rates of obesity.
Last summer, the American Academy of Pediatrics issued a policy statement to physicians on preventing childhood obesity. After reviewing the depressing trends among the nation's young people, the academy offered a list of recommendations. Although the advice is aimed at doctors, parents and policymakers could learn from it.
The list recommends:
Identifying at-risk children early, by plotting their body mass index (BMI) annually. BMI offers the best gauge for what's normal weight and what's not, and how to interpret BMIs for children can be identified on charts at a federal Web site (http://www.cdc.gov/nccdphp/dnpa/bmi/bmi-for-age.htm).
Encouraging breastfeeding, since several studies have shown that the longer a child is breast-fed the lower his or her risk of childhood obesity.
Promoting physical activity—from unstructured play at home to structured activity at schools, parks, day-care centers, and elsewhere.
Limiting television and video time to no more than 2 hours a day. Several studies have shown that more TV and video time increases a child's risk of weight gain. Researchers in China, for instance, reported 2 years ago in Biomedical And Environmental Sciences that "each hourly increment of television viewing was associated with a 1 to 2 percent increase in the prevalence of [pediatric] obesity."
Offering information and strategies that will teach habits to control weight gain—principally by eating nutritious foods and keeping exercise rates high—to parents, teachers, coaches, and others who influence children.
Encouraging families to not only promote snacks of fruits and vegetables, low-fat dairy foods, and whole-grain foods, but also to help them teach children when it's appropriate to indulge in between-meal eating.
American Academy of Pediatrics Committee on Nutrition. 2003. Policy statement: Prevention of pediatric overweight and obesity. Pediatrics 112(August):424-430. Available at http://pediatrics.aappublications.o.../full/112/2/424
Baughcum, A.E., et al. 2000. Maternal perceptions of overweight preschool children. Pediatrics 106(December):1380-1386. Available at http://www.cincinnatichildrens.org/NR/rdonlyres/
Cheng, T.O. 2004. Physical activity in young children. Lancet 363(April 3):1164. Available at http://www.thelancet.com/journal/
Kimm, S.Y.S., and E. Obarzanek. 2002. Childhood obesity: A new pandemic of the new millennium. Pediatrics 110(November):1003-1007. Extract available at http://pediatrics.aappublications.o...ract/110/5/1003
Ma, G.S., et al. 2002. Effect of television viewing on pediatric obesity. Biomedical and Environmental Sciences 15(December):291-297. Abstract.
Nelson, J.A., M.A. Chiasson, and V. Ford. 2004. Childhood overweight in a New York City WIC population. American Journal of Public Health. 94(March):458-462. Abstract available at http://www.ajph.org/cgi/content/abstract/94/3/458
New York City Department of Health and Mental Hygiene and Department of Education. 2003. Obesity begins early: Findings among elementary school children in New York City. NYC Vital Signs 2(June):1-2. Available at http://www.nyc.gov/html/doh/pdf/sur...hildobesity.pdf
Rocchini, A.P. 2002. Childhood obesity and a diabetes epidemic. New England Journal of Medicine 346(March 14)854-855. Extract available at http://content.nejm.org/cgi/content/extract/346/11/854
Sinha R., et al. 2002. Prevalence of impaired glucose tolerance among children and adolescents with marked obesity. New England Journal of Medicine 346(March 14):802-810. Available at http://content.nejm.org/cgi/content/full/346/11/802
Wilson, D.B., et al. 2004. From mothers to daughters: Intragenerational food and diet communication in an underserved group. Journal of Cultural Diversity 11(Spring/April).
Kimm, S.Y.S. . . . E. Obarzanek, et al. 2002. Obesity development during adolescence in a biracial cohort: the NHLBI growth and health study. Pediatrics 110(November):e54. Available at http://pediatrics.aappublications.o.../full/110/5/e54
______. 2001. Racial divergence in adiposity during adolescence: the NHLBI growth and health study. Pediatrics 107(March):e34. Available at http://pediatrics.aappublications.o.../full/107/3/e34
National Center for Chronic Disease Prevention and Health Promotion. Body Mass Index Calculator. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/nccdphp/dnpa/bmi/calc-bmi.htm
National Center for Chronic Disease Prevention and Health Promotion. BMI for Children and Teens (Also referred to as BMI-for-age). Centers for Disease Control and Prevention. Available at http://www.cdc.gov/nccdphp/dnpa/bmi/bmi-for-age.htm
Raloff, J. 2002. Surprise! Obesity (and Inactivity) Can Spur Cancers. Science News Online (Aug. 3). Available at http://www.sciencenews.org/articles/20020803/food.asp
Amy E. Baughcum
Department of Pediatrics
Children's Hospital Medical Center
3333 Burnet Avenue
Cincinnati, OH 45229
Tsung O. Cheng
Division of Cardiology
George Washington University Medical Center
2150 Pennsylvania Avenue, NW
Washington, DC 20037
Mary Ann Chiasson
Medical and Health Research Association of New York City, Inc.
40 Worth Street, Suite 720
New York, NY 10013
Sue Y.S. Kimm
Department of Family Medicine and Clinical Epidemiology
School of Medicine
University of Pittsburgh
Pittsburgh, PA 15261
Jennifer A. Nelson
Medical and Health Research Association of New York City, Inc.
40 Worth Street, Suite 720
New York, NY 10013
NYC Vital Signs
New York City Department of Health and Mental Hygiene
125 Worth Street
New York, NY 10013
Web site: http://www.nyc.gov/html/doh/
Division of Epidemiology and Clinical Applications
National Heart, Lung, and Blood Institute
National Institutes of Health
Bethesda, MD 20892
Diane B. Wilson
Box 980306, West Hospital 10th
Virginia Commonwealth University
Richmond, VA 23284