Age-related changes in cardiovascular disease risk factors of hypercholesterolemic children

Childhood cardiovascular risk factors, a predictor of late adolescent overweight

Background:

We conducted a prospective study to elucidate the effects of increased cardiovascular risk factors on future weight gain and also the relation between body mass index (BMI) and other cardiovascular risk factors in children and adolescents.

Materials and Methods:

This study was conducted on 1525 nonobese children and adolescents with an age range of 3-16 years old, participating in the 1^st phase and follow-up phases of Tehran Lipid and Glucose Study. The subjects were evaluated 4 times with a 3-year time interval regarding lipid profile status and BMI, and other cardiovascular disease (CVD) risk factors. All the cases had a BMI <85% and had been appraised in at least two evaluation points.

Results:

Cardiovascular risk factors, high-density lipoprotein (HDL) (P = 0.019), low-density lipoprotein (P = 0.016), triglyceride (TG) (P < 0.001), and blood pressure (BP) (P = 0.001); had significant effects on weight gain. There was also no difference between boys and girls and no age trend for increasing weight in both groups. The associations between BMI with cardiovascular risk factors were assessed cross-sectionally. For both sexes, BMI was significantly correlated to systolic and diastolic BP and TG (P = 0.05). For girls, BMI was significantly related to HDL (P = 0.05) regardless to age, but in boys, the relation of BMI with HDL only increased with age (P = 0.05).

Conclusion:

Increased CVD risk factors are predictors of future overweight in childhood and adolescent and increased weight is linked significantly with dyslipidemia and hypertension in this age group.

Calcium and Dairy Intake and Measures of Obesity in Hyper- and Normocholesterolemic Children

OBJECTIVE

Calcium intake has been inversely associated with body weight and body fatness in adults and, to a lesser extent, in children. Dairy intake has been inversely associated with metabolic syndrome in overweight but not normal-weight adults. We assessed whether intakes of calcium and dairy foods were associated with measures of obesity in hypercholesterolemic (HC) and normocholesterolemic (non-HC) children at baseline and over 1 year.

RESEARCH METHODS AND PROCEDURES

Non-obese 4- to 10-year-old HC and non-HC children (342) completed three 24-hour dietary recalls and provided measures of relative weight (BMI and BMI z scores) and adiposity (sum of skinfolds, trunk skinfolds) at baseline, 3, 6, and 12 months. Cross-sectional and longitudinal regression analyses, stratified by cholesterol risk status (HC vs. non-HC) and age (4 to 6 years and 7 to 10 years) and adjusted for potential confounders, were conducted.

RESULTS

After adjusting for age, sex, energy intake, and percentage energy from fat, calcium intake was inversely associated with BMI, sum of skinfolds, and trunk skinfolds at baseline and over 1 year in the 7- to 10-year-old non-HC children. Results from the regression models also indicated an inverse relation between intake of dairy foods and measures of obesity at baseline in these children. Calcium or dairy intake was not associated with measures of obesity in HC children or in the 4- to 6-year-old non-HC children.

DISCUSSION

These results suggest a complex relation among intake of calcium and dairy foods, measures of obesity, age, and serum cholesterol in children. Older children without risk of metabolic syndrome may benefit most from increased calcium intake.

A life course approach to diet, nutrition and the prevention of chronic diseases

OBJECTIVE

To briefly review the current understanding of the aetiology and prevention of chronic diseases using a life course approach, demonstrating the life-long influences on the development of disease.

DESIGN

A computer search of the relevant literature was done using Medline-'life cycle' and 'nutrition' and reviewing the articles for relevance in addressing the above objective. Articles from references dated before 1990 were followed up separately. A subsequent search using Clio updated the search and extended it by using 'life cycle', 'nutrition' and 'noncommunicable disease' (NCD), and 'life course'. Several published and unpublished WHO reports were key in developing the background and arguments.

SETTING

International and national public health and nutrition policy development in light of the global epidemic in chronic diseases, and the continuing nutrition, demographic and epidemiological transitions happening in an increasingly globalized world. RESULTS OF REVIEW: There is a global epidemic of increasing obesity, diabetes and other chronic NCDs, especially in developing and transitional economies, and in the less affluent within these, and in the developed countries. At the same time, there has been an increase in communities and households that have coincident under- and over-nutrition.

CONCLUSIONS

The epidemic will continue to increase and is due to a lifetime of exposures and influences. Genetic predisposition plays an unspecified role, and with programming during fetal life for adult disease contributing to an unknown degree. A global rise in obesity levels is contributing to a particular epidemic of type 2 diabetes as well as other NCDs. Prevention will be the most cost-effective and feasible approach for many countries and should involve three mutually reinforcing strategies throughout life, starting in the antenatal period.

Factor analysis of possible risks for hypertension in a black South African population

To date only a small number of studies have investigated the pattern of associations within a set of hypertension risks. The objective of this study was therefore to examine the interrelation of main hypertension risks in an African population by using factor analysis in order to detect underlying risk patterns. Subjects aged 16-70 years (N=963) were recruited from 37 randomly selected sites throughout the North West Province during 1996-1998. Exclusion criteria were pregnancy, lactation, casual visitors, drunkenness and treatment for chronic diseases, such as hypertension. Subjects with blood pressures exceeding 140/90 mmHg were classified as hypertensive. Children aged 10-15 years were also recruited from 30 randomly selected schools during 2000-2001 (N=694). Children were classified as hypertensive when an average systolic or diastolic blood pressure greater than or equal to the 90th percentile for age and sex was encountered, while correcting for height. The following hypertension risks were measured: urbanisation, obesity, plasma fibrinogen, lipids, insulin, serum gamma glutamyl-transferase, dietary intake, smoking and alcohol consumption. From 23 risks the factor analysis disclosed five factors that explained 56.2% of the variance in the male and 43.5% of the variance in the female group: an urban malnutritional phenomenon, the metabolic syndrome X, a hypercholesterolaemic and obesity complex, an alcoholic hypertriglyceridaemia, and central and peripheral cardiovascular hypertensive effects. In conclusion, South Africans migrating from rural to urban areas adapt to a new lifestyle with numerous risks, resulting in conditions like malnutrition, the metabolic syndrome X, dyslipidaemia, alcoholism, obesity and increased peripheral vascular resistance. For successful prevention of hypertension in a population in transition, a whole risk pattern should be corrected, rather than an individual risk by implementing lifestyle modification programmes.

Persistent hypercholesterolemia is associated with the development of obesity among girls: the Bogalusa Heart Study

BACKGROUND

Obesity is associated with cardiovascular disease (CVD) risk factors. Cross-sectional data suggest that hypercholesterolemia is associated with the development of childhood obesity.

OBJECTIVE

The objective was to assess age-related changes in relative weight and the association between relative weight and CVD risk factors in hypercholesterolemic and nonhypercholesterolemic children who were nonobese at baseline.

DESIGN

Data on relative weight and CVD risk factors were extracted from the Bogalusa Heart Study for nonobese 5-6-y-old black and white hypercholesterolemic (LDL cholesterol > 75th percentile; n = 58) and nonhypercholesterolemic (LDL cholesterol < 60th percentile; n = 215) children (41% black, 52% girls) who were also assessed 3 and 6 y later. Changes in body mass index (BMI) and CVD risk factors were assessed as a function of age, sex, race, and cholesterol concentration.

RESULTS

BMI increased more in the hypercholesterolemic (n = 31) than in the nonhypercholesterolemic (n = 111) girls during the 6 y of follow-up but was not significantly different between hypercholesterolemic (n = 27) and nonhypercholesterolemic (n = 104) boys aged 5-12 y. Associations between BMI and the risk factors blood pressure, insulin, and blood lipids were observed to be stronger with increasing age and, in some cases, stronger in hypercholesterolemic children and girls.

CONCLUSIONS

Hypercholesterolemia is associated with increased relative weight in girls. The increased relative weight, even at an early age, is associated with a deleterious effect on blood lipids and other CVD risk factors in hypercholesterolemic children, although the strength of these associations is sex dependent.

Obesity in Auckland school children: a comparison of the body mass index and percentage body fat as the diagnostic criterion

OBJECTIVES

First, to determine obesity rates in Auckland school children according to their ethnic group using two different criteria: the body mass index (BMI) and percentage body fat (PBF) derived from bioelectrical impedance analysis (BIA). Second to examine the relationship between BMI and body composition across ethnic groups to determine if BMI references from European children accurately reflect obesity in other ethnic groups.

DESIGN

A total of 2273 Auckland school children, aged 5-10.9 y had their height, weight and bioelectrical impedance measured. Using these measurements, each child's BMI, fat free mass, fat mass and PBF were derived.

RESULTS

In all 14.3% of children were obese using the recommended definition of obesity (BMI) greater than the 95th percentile). There was no clinically significant difference in the relationship between BMI and body composition in different ethnic groups. Obesity rates varied with ethnicity (P<0.0001) and were higher in Pacific Island (24.1%) and Maori (15.8%) than in European children (8.6%). Obesity rates also varied with age (P<0.03), with the highest rates in older children. PBF levels were higher in females than males (P<0.0001). Using a definition of obesity based on percentage body fat (PBF>30%), obesity rates were higher in all ethnic groups.

CONCLUSIONS

Obesity rates are high in Auckland school children and there are clear differences in obesity rates in different ethnic groups. If BMI criteria are used to define obesity in our population, we recommend the same standards be used for children of all ethnicities.

The relation of overweight to cardiovascular risk factors among children and adolescents: the Bogalusa Heart Study

BACKGROUND

Although overweight and obesity in childhood are related to dyslipidemia, hyperinsulinemia, and hypertension, most studies have examined levels of these risk factors individually or have used internal cutpoints (eg, quintiles) to classify overweight and risk factors.

OBJECTIVE

We used cutpoints derived from several national studies to examine the relation of overweight (Quetelet index, >95th percentile) to adverse risk factor levels and risk factor clustering.

DESIGN

The sample consisted of 9167 5- to 17-year-olds examined in seven cross-sectional studies conducted by the Bogalusa Heart Study between 1973 and 1994.

RESULTS

About 11% of examined schoolchildren were considered overweight. Although adverse lipid, insulin, and blood pressure levels did not vary substantially with the Quetelet index at levels <85th percentile, risk factor prevalences increased greatly at higher levels of the Quetelet index. Overweight schoolchildren were 2.4 times as likely as children with a Quetelet index <85th percentile to have an elevated level of total cholesterol. Odds ratios for other associations were 2.4 (diastolic blood pressure), 3.0 (low-density lipoprotein cholesterol), 3.4 (high-density lipoprotein cholesterol), 4.5 (systolic blood pressure), 7.1 (triglycerides), and 12.6 (fasting insulin). Several of these associations differed between whites and blacks, and by age. Of the 813 overweight schoolchildren, 475 (58%) were found to have at least one risk factor. Furthermore, the use of overweight as a screening tool could identify 50% of schoolchildren who had two or more risk factors.

CONCLUSIONS

Because overweight is associated with various risk factors even among young children, it is possible that the successful prevention and treatment of obesity in childhood could reduce the adult incidence of cardiovascular disease.