Children participating in a dietary clinical trial were studied to (1) assess physical activity patterns in boys and girls longitudinally from late childhood through puberty and (2) determine the association of level of physical activity on systolic blood pressure, low-density lipoprotein cholesterol, and BMI.In the Dietary Intervention Study in Childhood, a randomized clinical trial of a reduced saturated fat and cholesterol diet in 8- to 10-year-olds with elevated low-density lipoprotein, a questionnaire that determined time spent in 5 intensity levels of physical activity was completed at baseline and at 1 and 3 years. An estimated-metabolic-equivalent score was calculated for weekly activity; hours per week were calculated for intense activities. We hypothesized that weekly self-reported physical activity would be associated with lower systolic blood pressure, low-density lipoprotein, and BMI over 3 years. Longitudinal data analyses were performed for each outcome (systolic blood pressure, low-density lipoprotein, and BMI) by using generalized estimating equations with estimated-metabolic-equivalent score per week as the independent variable adjusted for visit, gender, and Tanner stage (BMI was included in models for systolic blood pressure and low-density lipoprotein).The initial study cohort comprised 663 youths (362 boys [mean age: 9.7 years] and 301 girls [mean age: 9.0 years], of whom 623 (94%) completed the 3-year visit. For every 100 estimated-metabolic-equivalent hours of physical activity, there was a decrease of 1.15 mmHg of systolic blood pressure. There was a 1.28 mg/dL decline in low-density lipoprotein for a similar energy expenditure. For BMI, an analysis of intense physical activity showed that for every 10 hours of intense activity, there was a trend toward significance with a 0.2 kg/m2 decrease.Children with elevated cholesterol levels who lead a more physically active lifestyle have lower systolic blood pressure and a trend toward lower low-density lipoprotein over a 3-year interval. Long-term participation in intense physical activity may reduce BMI as well.
Prevention of cardiovascular disease must begin in childhood, preferably before risk factors develop. Elevated low‐density lipoprotein cholesterol levels in children are likely to track over time and become high‐risk levels in adults. The Dietary Intervention Study in Children (DISC) was a multicenter, collaborative randomized trial in preadolescent children designed to test the efficacy and safety of a dietary intervention to lower saturated fat and cholesterol intake among growing children with elevated low‐density lipoprotein cholesterol. Numerous DISC results, which include findings on lipids‐lipoproteins, genetics, and nutrient adequacy, as well as descriptions of the behavioral intervention strategies, have been reported. A summary of practical findings and their potential clinical applications have not previously been published. Highlights of key lessons learned from DISC and translational applications of potential interest to nurses and other health care providers are presented.
Purpose of review The Barker hypothesis implicates the fetal in-utero environment as a significant determinant of risk for major chronic diseases, such as cardiovascular disease, stroke, hypertension, type 2 diabetes, and obesity later in life. Although the Barker hypothesis has gained increasing recognition since it was first introduced 20 years ago, it is still being met with skepticism because of the largely observational and cross-sectional nature of the studies on which it is primarily based. The purpose of this review is to re-examine the Barker hypothesis in the context of new information with a focus on prospective studies in humans and experimental observations made in laboratory animal models. Recent findings The debate on the Barker hypothesis continues, in part fueled by conflicting findings from different studies. While one study from the U.S. found no significant correlation between birth weights and blood pressure at ages 11 to 14 years, another large study of Filipino children found that the highest levels of blood pressure were present among those who were relatively thin at birth but who were later relatively heavy as adolescents. Two relatively recent review papers on the relationship between birth weights and blood pressure levels later in life also drew opposite conclusions. Even animal studies are not free of controversy. A study linking maternal malnutrition during the pre-implantation period of rat development to abnormalities in blastocyst formation was openly faulted for methodologic flaws in its statistical analysis. There is increasing evidence that birth weight per se cannot be viewed as a major culprit for this increased risk. Although the study of Filipino adolescents had methodologic weaknesses readily acknowledged by the authors, their findings still suggests that the postnatal condition of heavier body habitus during adolescence also played a significant role in blood pressure levels as well as smaller birth weights. A study of birth weight and later risk for type 2 diabetes found a higher prevalence of lower birth weight among those with type 2 diabetes, but in the same study, they found that the prevalence of diabetes was also higher among those with larger birth weight and high BMI in childhood. A recent review of the literature found no strong evidence to link birth weight to blood lipid levels later in life. Summary At present, the Barker hypothesis is in need of further scientific insight and stronger supporting evidence. The most recent publications on this subject are review papers and a book rather than original research that presents novel findings. Thus far, there is no information that provides any mechanistic insight into the relationship between the intra uterine milieu and adverse post-natal consequences. There are no unifying theories which link low birth weights to a variety of different outcomes later in life. Hence, there are regrettably more questions remaining than there are answers regarding the Barker hypothesis. It is timely to perhaps, apply some of the generally accepted principles for assessing causality to the available information on the fetal origins hypothesis. The next step might be to conduct studies that test this notion as an a priori hypothesis rather than as post hoc examination of cross-sectional data. The time has also come to further refine the hypothesis to encompass more than mere correlation between birth weight and risk for chronic disease later in life. Surely, life-long exposures to environmental factors such as dietary patterns, physical activity, and stress levels have to play either independent or effect modifying roles in the causal web of chronic disease. It is, therefore, timely to further refine the Barker hypothesis to a testable proposition, Barker Hypothesis-Version 2004.
Objective. To assess the relationship between energy intake from fat and anthropometric, biochemical, and dietary measures of nutritional adequacy and safety. Design. Three-year longitudinal study of children participating in a randomized controlled trial; intervention and usual care group data pooled to assess effects of self-reported fat intake; longitudinal regression analyses of measurements at baseline, year 1, and year 3. Participants. Six hundred sixty-three children (362 boys and 301 girls), 8 to 10 years of age at baseline, with elevated low-density lipoprotein cholesterol, who are participants of the Dietary Intervention Study in Children. Measures. Energy intake from fat assessed from three 24-hour recalls at each time point was the independent variable. Outcomes were anthropometric measures (height, weight, body mass index, and sum of skinfolds), nutritional biochemical determinations (serum ferritin, zinc, retinol, albumin, β-carotene, and vitamin E, red blood cell folate, and hemoglobin), and dietary micronutrients (vitamins A, C, E, thiamin, riboflavin, niacin, vitamins B-6, B-12, folate, calcium, iron, zinc, magnesium, and phosphorus). Results. Lower fat intake was not related to anthropometric measures or serum zinc, retinol, albumin, β-carotene, or vitamin E. Lower fat intake was related to: 1) higher levels of red blood cell folate and hemoglobin, with a trend toward higher serum ferritin; 2) higher intakes of folate, vitamin C, and vitamin A, with a trend toward higher iron intake; 3) lower intakes of calcium, zinc, magnesium, phosphorus, vitamin B-12, thiamin, niacin, and riboflavin; 4) increased risk of consuming less than two-thirds of the Recommended Dietary Allowances for calcium in girls at baseline, and zinc and vitamin E in boys and girls at all visits. Conclusions. Lower fat intakes during puberty are nutritionally adequate for growth and for maintenance of normal levels of nutritional biochemical measures, and are associated with beneficial effects on blood folate and hemoglobin. Although lower fat diets were related to lower self-reported intakes of several nutrients, no adverse effects were observed on blood biochemical measures of nutritional status. Current public health recommendations for moderately lower fat intakes in children during puberty may be followed safely.
