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Original Research |
Columbia University, Institute of Human Nutrition and Department of Pediatrics, New York, New York
Address reprint requests to: Christine L. Williams, MD, MPH, Director, Childrens Cardiovascular Health Center, Columbia University, Institute of Human Nutrition, BHN 7-702, 3959 Broadway, Babies & Childrens Hospital of New York, New York, NY 10032. E-mail: chrisw320{at}aol.com
| ABSTRACT |
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Methods: Nine Head Start centers in Upstate N.Y. were assigned to either food service modification or control conditions. In addition, half of the centers assigned to the food service modification received supplemental nutrition education (FS/NU food service modification/nutritional education), while the remaining centers were provided with supplemental safety education materials (FS- food service modification only). The control preschool centers (CON) also received supplemental safety educational curricula for children but their food services remained unchanged. Children had serum cholesterol, as well as height and weight measured at the beginning and end of the school year. A generalized linear univariate procedure was used with percent change in total serum cholesterol as the outcome variable and intervention group as the primary independent variable.
Results: There was a significant decrease in total serum cholesterol among preschool children in food service intervention groups, (FS/NU and FS), compared to Controls (-6.0 versus -0.4 mg/dL). In addition to the significant difference in group means, children with elevated cholesterol at baseline were significantly more likely to have a cholesterol level in the normal range (<170mg/dL) at follow-up if they attended a preschool in the food service modification group. There was a 30% reduction in risk of elevated cholesterol in the latter compared to controls. Participation in the dietary intervention did not affect short-term growth.
Conclusions: A preschool heart health intervention, "Healthy Start," designed to reduce the total and saturated fat content of snacks and meals to recommended levels was effective in reducing serum cholesterol in the study population as a whole and specifically children at risk; i.e., those with initial elevated serum cholesterol.
Key words: intervention, preschool children, serum cholesterol, dietary fat
| INTRODUCTION |
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Interventions aimed at lowering the saturated fat content of the diet yield a decrease in total serum cholesterol in adults [1113]. A decrease in total cholesterol of as little as 10% can result in a 30% reduction in the incidence of coronary heart disease in the adult population [14]. Although it is not known how such a decrease in children affects their cardiovascular disease (CVD) risk as adults, there is a modest association between dietary fat intake and serum lipids in school age and preschool children [1517].
The results of a controlled multicomponent intervention on serum blood cholesterol in preschool children are reported below. The study was designed to promote heart healthy behaviors and decrease CVD risk factors in disadvantaged preschool children from upstate New York. The primary intervention was modification of the preschool food service to reduce the saturated fat content of meals and snacks. The study is notable because it deals with a very young population and because the dietary modification is not dependent on parental behavior modification. It was hypothesized that lowering the saturated fat content in a school menu that provides from one-third to two-thirds of a childs total nutritional intake would significantly lower blood cholesterol levels. In addition, we sought to determine if this effect could be enhanced in children who received a supplemental nutrition educational curriculum that included lessons on healthy eating. Notwithstanding the young age of the children (25 yrs.), it is possible that nutrition education could influence a childs food choices at home.
| MATERIALS AND METHODS |
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30% of total energy, and a saturated fatty acid intake of
10% of total energy. The program effectively lowered saturated fat intake in the intervention schools without compromising energy intake or nutritional content of the diet. A detailed report of the outcome of the food service intervention is provided elsewhere [19]. Teachers in the preschools assigned to the educational intervention (FS/NU) were provided with a skills-based, developmentally appropriate health curriculum which focused heavily on nutrition and other general health issues such as hygiene, body parts, etc. The teachers were trained and instructed in the use of the curriculum by the Healthy Start staff. The Control group had no modifications made to their food service. However, a curriculum component along with teacher training was provided to these schools similar to that provided to the FS/NU schools. The only difference was that this curriculum focused on safety and accident prevention and general health issues other than nutrition. Both nutrition and non-nutrition programs included a parent component which included "take home" papers describing activities that could be done at home to enhance the preschool learning experience. Parent meetings on health themes were also held 34 times during the year.
At the beginning of the program, in the fall of 1995, and at the end of the school year, in the spring of 1996, measurements of weight, height, and blood pressure were taken by the Healthy Start pediatric team and serum lipids were measured enzymatically using nonfasting finger stick samples analyzed with the Cholestech L*D*X* [2021].
The intervention groups were compared with respect to sociodemographic and baseline physical characteristics to identify potentially confounding variables. Additionally, baseline total cholesterol was examined by age, gender, ethnicity and baseline body mass index (BMI). T-tests compared group means and chi-square statistics compared distributions for categorical data.
A generalized linear model (GLM) univariate procedure (SPSS) [22] was used to compare the percent change in cholesterol level from the beginning of the program to the end of the school year. The GLM procedure provides regression analysis and analysis of variance for one dependent variable (per cent change in total cholesterol) by factors and covariates. Intervention group was the primary factor of interest. Other potentially confounding variables were entered as factors (ethnicity, gender) or as covariates (BMI, age at baseline, and number of months between baseline and follow-up measures). Main effects models and 2-way interactions between intervention group and gender and ethnicity were evaluated. Additional analyses looked at total cholesterol defined categorically as: normal (<170 mg/dL), borderline high (170199 mg/dL) or high (
200 mg/dL) [23]. Data analyses were carried out by first comparing outcomes in the FS/NU and FS groups. Since no significant differences were found, FS/NU and FS groups were combined to evaluate the effect of the food service intervention on the outcome measure.
The difference in weight to height ratio between baseline and follow-up was examined using the generalized linear model, with age at baseline and time between measurements entered as covariates and with gender and ethnicity included as factors. The short-term effects of lowering dietary fat consumption on weight gain could be assessed with intervention group also entered as a factor in the model.
| RESULTS |
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200 mg/dL) did not differ significantly by age, gender, or ethnicity. Body mass index was categorized as normal, overweight, and obese; <85th, 85th95th, and >95th %-tiles, respectively, based on age and gender according to the year 2000 CDC growth charts [24]. There were no differences in total cholesterol by BMI.
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170 mg/dL declined 9.7% for the children in the food service modification groups. In contrast, the proportion of children with elevated cholesterol in the control group increased by 3.8%.
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170 mg/dL at baseline (Table 6). The relative risk of elevated TC in the food service modification groups compared to controls was significantly less than 1.0; 0.69 (95% CI = 0.57, 0.85). Thus, in the subpopulation of children with elevated baseline serum cholesterol, the food service intervention reduced the risk of elevated cholesterol by approximately 30%.
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| DISCUSSION |
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The results of childhood interventions designed to lower serum cholesterol level in a general population sample have varied, possibly as a function of the age group involved and the type and extent of the intervention. Several community and school based education interventions have focused on older children. The Finnish North Karelia youth project demonstrated an effect of the intervention among adolescents on serum cholesterol but this was a unique population with high baseline serum cholesterol levels and a baseline diet high in saturated fat [27]. Studies in U.S. populations include the "Know Your Body" (KYB) program [28] among New York elementary school children and the CATCH trial (Child and Adolescent Trial for Cardiovascular Health) [29] which included elementary school children from sites across the U.S. The KYB study found a small effect of the intervention on serum cholesterol, while the CATCH study found no demonstrable effect of the intervention.
There are several possible reasons why our study resulted in a significant reduction in serum cholesterol in contrast to the two U.S. studies referred to above. The preschool children in our study were much younger than children in the other intervention studies. They had far fewer food choices than elementary school children with respect to what was available to eat at meals and snacks. In addition, children in elementary school derive most of their calories from outside sources, eating only lunch at school. The preschool children in our study consumed a significant proportion of their total calories within the school setting. Also, because of their young age, they were less likely than elementary school children to get food and snacks for themselves outside of school. It is also possible that there may be variation by age as to the effect of lowering the saturated fat content of the diet, with younger children experiencing more of an impact. Finally, our food service intervention could have been more effective in changing the fat content of meals and snacks at school since we were dealing with small school populations with only one or two key food service personnel per school.
There have been several studies that have tested CVD interventions aimed at young children. Of particular note is the Finnish Special Turku Coronary Risk Factor (STRIP) Study [30] in which parents were counseled on child diet intake from the time the child was 7 months old. This cohort has now been followed more than 7 years. The STRIP intervention also significantly affected serum cholesterol levels in the children during the initial study period. In our investigation, there was a significant effect on short-term tracking in that children in the intervention group with a baseline elevated serum cholesterol had a 30% decreased risk of continued elevated cholesterol at follow-up compared to control children.
Our study did not demonstrate additional cholesterol lowering among preschool children who received supplemental nutrition education over and above that of the food service intervention. Since all the Head Start centers must, by law, provide nutrition education in the classroom, the added supplemental nutrition material we provided may not have been a large enough dose to make a difference in the outcome. Alternatively, the absence of an incremental effect could simply reflect the young age of the child, or the limited amount of time that was allocated to the supplemental education program in the classroom. Perhaps a longer educational experience is needed in children of preschool age to produce a change in behavior that is carried beyond the classroom. It is also feasible that the effect of the educational program is relatively small compared to the impact of the major environmental intervention of the food service modification.
The intervention did not significantly affect the childrens growth in the short-term in our population. There were no consistent differences in pounds per inch gained between the groups. These findings are comparable to those of others who found no adverse effects of a reduced fat diet on growth and development [26, 3132].
| CONCLUSION |
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Although the intervention described was relatively short term, extending over the course of a single school year, the results are encouraging in that a relatively simple intervention aimed at changing an important environmental component of school health (the food service) can result in a significant reduction in a major CVD risk factor in a young minority population.
| ACKNOWLEDGMENTS |
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Received February 20, 2003. Accepted September 10, 2003.
| REFERENCES |
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