English - Home page

ISS
Istituto Superiore di Sanità
EpiCentro - L'epidemiologia per la sanità pubblica
Istituto Superiore di Sanità - EpiCentro


Nutritional Status, Dietary Habitus, Physical Activity, and Self-Perceived Body Image of Pre-Adolescents in Catania, Sicily, 2002

Alberto Perra1, Antonino Bella2, Yllka Kodra2, Mario Cuccia3, and the participants and instructors of the Epidemiology in Action course 2002

 

1Institut de Veille Sanitaire, Paris and the EPIET training program

2Laboratory of Epidemiology and Biostatistics, Istituto Superiore di Sanità, Rome

3Epidemiology and Prevention Service, Local Health Authority 3, Catania, Sicily

 

In 1998, the World Health Organization declared obesity to be a global epidemic (1). In addition to increasing obesity among adults in Italy and elsewhere, childhood obesity is also increasing at alarming rates. Children who are overweight or obese are at greater risk of adult obesity and other adult health problems than their normal-weight counterparts (2). Furthermore, healthy patterns of eating and physical activity begin in childhood  (2,3).

To further examine the situation in Italy, a population-based study of children in their first year of middle school was undertaken in Catania, the second-largest city in Sicily. The study was conducted by participants of the second annual Epidemiology in Action course in collaboration with health and school officials of the Province of Catania.

 

A list of the 222 first-year classes from all 39 middle schools of Catania and the number of students enrolled in each class were obtained from school authorities. A cumulative population list was developed, and 30 classes were selected, with the probability of selection proportionate to their size. Parents in the chosen classes were notified and given the possibility of refusing to have their children participate.

 

A self-administered questionnaire was distributed the day of the survey to all children in the chosen classes. Its completeness was reviewed by the interviewers, and the children were weighed and measured in light clothing using each school’s balance and altimeter. Balances were standardized at the beginning of the session. Data were entered and analyzed in Epi-Info Version 6.04. Confidence intervals were calculated taking into account the design effect resulting from the cluster survey design. In the analyses, adjustments were made in the weight of each child to account for clothing (600 g), and body mass index (BMI) was calculated using recently published tables for children and adolescents (4). On the basis of the sex- and age-specific tables, children were categorized into four groups: underweight, normal weight, overweight, and obese.  The number of working adults in the household was used as a proxy for socioeconomic status.

 

Of the 695 children enrolled in the selected classes, 597 (86%) were present on the day of the study, of whom 576 (96%) completed questionnaires and were weighed and measured; the remaining 21 refused to participate. The mean age was 11.8 years (range 10.5-14.6 years). A total of 56% were males, and 95% reported that there was at least 1 working adult in the household.

 

A total of 11% of children were underweight (95% CI 8%-14%), 54% were normal weight (95% CI 50%-59%), 27% (95% CI 24%-30%) were overweight) and 7% (95% CI 5%-10%) were obese. Distribution did not differ by sex or by economic status, as measured by the presence of at least one wage-earning adult in the family.

 

Virtually all (97%) of the children reported engaging in physical activity at school, although in the vast majority of schools, they did so only twice a week (Table). A substantial percentage (84%) participated in non-organized activities, most commonly soccer (41%) bicycle riding (39%), and running (29%); the median number of times per week in which they participated in such activities was 3. A lesser percentage (59%) participated in organized sports, with a median number of times/week of 2. A total of 47% reported that they walked at least part of the way to or from school, although only 10% of these reported walking >30 minutes, the minimum time suggested according to guidelines for physical activity among adolescents in Italy (5).

 

Few children (1.4%) reported that they had not watched television the previous day; the median number of hours spent in front of the television the previous day was 3 hours and 45 minutes, with 14% stating that they had watched more than 7 hours. Most (72%) also reported watching television on weekend mornings. In addition, during the week, they spent a median of 55 minutes at the computer or playing video games.

 

Although virtually all children reported that they ate lunch, 22% did not eat breakfast (Table). A total of 7% did not eat a morning snack; the same proportion did not consume an afternoon snack. When asked how often they had consumed fruits and vegetables in the past week, only 52% had eaten fruits and 25% had eaten vegetables on a daily basis; 9% reported they had not eaten fruits and 10% that they had not eaten vegetables during the previous week. With respect to content of snacks, 65% consumed pre-packaged snacks, processed meats, or carbonated beverages at least once a day, while 8.5% consumed such snacks at least twice a day.

 

Children were asked whether they felt they wanted to gain weight, lose weight, or remain the same.  Data by weight category are presented in the Figure. While most of those who were overweight or obese wanted to lose weight, 47 % of those of normal weight and 5% of those who were underweight also reported that they wanted to lose weight. Normal weight girls were more likely than boys to want to lose weight; in the normal weight category, 51% of girls and 17% of boys wanted to lose weight, while in the underweight category, the corresponding figures were 8% for girls and 11% for boys.

 

Editorial Note

Luigi Greco

Department of Pediatrics, University Federico II, Naples, Italy

 

The job of an epidemiologist is to conduct studies on major health problems that assist in the planning and implementation of  public health interventions. Their work does not end with the completion of a study, even though such studies lead to a significant increase in knowledge about the subject.

 

The study done on schoolchildren in Catania provides a general picture of overweight and obesity in this population. Levels were, respectively 27% and 7%, values that are significantly higher than the expected based on statistical distribution of body mass index.

 

A number of factors have contributed to the high levels of overweight and obesity currently being observed in Italy and elsewhere. The methods by which the human body accumulates and stores fat is regulated by a complex homeostatic mechanism involving hormones and other factors that tend to accumulate energy (and thereby stimulate food consumption) and those that tend to limit the accumulation of energy and therefore decrease consumption (6). The equilibrium between these factors and the complex molecular cascades that they influence result in a specific body target for each individual, defined as the ideal amount of lean and fat mass in times of adequate food availability.

 

It is important to consider that hunger, the desire to obtain food, and to continuously hunt, have been powerful selective pressure throughout human history and remain so in the animal world. However, the food supply in Italia and much of the Western world has changed enormously within the past 50 years in terms of the regular availability as well as the quantity and types of food available, even as the genetic programming of the human body that regulates storage and use of energy remains that set in motion thousands of years ago.

 

In addition to the dramatic increases in caloric intake in recent years, another factor contributing to overweight and obesity in Italian children is that they consume much less energy than did previous generations at the same age:

  • Less energy is needed to stay warm during the winter; children have warmer clothes and live in heated environments (consumption of approximately 500 calories less per day)

  • They do much less physical activity (consumption of 200-300 fewer calories/day)

  • After-school activities are increasingly sedentary (videogames, computers, television)

  • Less calories are needed to digest foods; many of today’s foods are pre-cooked, processed, etc

  • They consume foods of higher caloric density.

Yet another factor contributing to the current prevalence of overweight and obesity is that the majority of overweight children are large children of large parents, in whom genetic growth potential is fully expressed. In the past,  their ancestors were not able to fully manifest this potential because of a variety of environmental factors; today, the factors limiting full expression of human growth potential (scarcity of calories, lack of an equilibrium between intake and availability, infections and illnesses, and low caloric density of available foods) have largely disappeared in the western world. As a result the population has grown more in all dimensions, including body mass.

In view of the many genetic factors that determine nutritional status, there is nonetheless much that can be done to prevent overweight and obesity. Measures that should be taken include:

- choose foods with lower caloric density

- limit total caloric intake

- limit saturated fats and cholesterol

- engage in physical activity at least two hours a day

In reality, engaging in such practices should help avoid the need to resort to difficult-to-sustain diets in children, which cause considerable suffering and have a high likelihood of failure in the long run.

 

References

1.  World Health Organization, Obesity: Preventing and Managing the Global Epidemic, Report of a WHO Consultation on Obesity, Geneva, 1997.

2.  Edmunds L, Waters E, Elliott EJ.  Evidence based paediatrics: Evidence based management of childhood obesity. BMJ 2001 Oct 20;323(7318):916-9

3.  Williams CL, Hayman LL, Daniels SR et al. Cardiovascular Health in Childhood : A Statement for Health Professionals From the Committee on Atherosclerosis, Hypertension, and Obesity in the Young (AHOY) of the Council on Cardiovascular Disease in the Young, American Heart Association.  Circulation. 2002;106:143

4.  Cole TJ, Bellizzi MC, Flegal KM, Dietz WH. Establishing a standart definition for child overweight and obesity worldwide: international survey. BMJ 2000;320:1240-1243.

5.  Prevenire l’obesità in Italia. Indicazioni metodologiche per la realizzazione di intervento di educazione alimentare. 108-110. Maggio 2001.

6.  Hoppin AG, Kaplan LM. The leptin era: new insight into the mechanisms of body weight homeostasis. J Pediatr Gastroenterol Nutr. 1999 Sep;29(3):250-64. Review.