Cholesterol screening and family history of vascular disease

A systematic review and meta-analysis on screening lipid disorders in the pediatric age group

Background:

Different viewpoints exist about lipid screening in all children or only in children with positive family history (FH) of premature cardiovascular diseases (CVDs) or hypercholesterolemia. This systematic review and meta-analysis aim to assess the effectiveness of lipid screening in children and adolescents according to the existence of positive FH of CVD risk factors.

Materials and Methods:

PubMed, Scopus, and Google scholar were searched to identify relevant papers that were published from November 1980 until 30 November 2013. Irrelevant studies were set aside after studying their title, abstract, and full text. Then, the relevant studies were assessed by using a quality appraisal checklist. We used random effect model for meta-analysis and calculating the total estimation of sensitivity, specificity, and the positive predictive value (PPV) of FH in predicting dyslipidemia among children and adolescents.

Results:

Overall, 17,214 studies were identified in the primary search, out of which 19 primary studies were qualified for study entry. The sensitivity of positive FH of premature CVD or dyslipidemia for predicting dyslipidemia among children varied between 15 and 93. Moreover, the effectiveness of screening children for dyslipidemia according to premature CVD or dyslipidemia in their relatives was low in 86.9% of the primary studies. The total estimation of sensitivity, specificity, and predictive value was 42.6, 59, and 20.7, respectively, according to the meta-analysis results.

Conclusion:

The present meta-analysis indicated that selecting target population for screening children and adolescents for dyslipidemia according to their FH has low sensitivity.

Evalution of Serum Lipid Profiles in Turkish Children Aged Two to Eighteen Years

OBJECTIVE

The purpose of this study was to evaluate dyslipidaemia in children according to age, gender, percentiles, mother's education level, breastfeeding duration and areas of residence.

METHODS

A total of 285 children (137 girls; 148 boys), aged between two and 18 years, were enrolled in this cross-sectional, epidemiologic study. Lipid profiles were assessed and its relation with sociodemographic features was evaluated.

RESULTS

Dyslipidaemia prevalence was 37.4% (n = 107). High very low-density lipoprotein cholesterol (VLDL-C) and low high-density lipoprotein cholesterol (HDL-C) levels are related with percentiles of the children (p = 0.006, p = 0.03, respectively). Gender was a significant factor for VLDL-C, which was higher in girls than boys (p = 0.04). Total cholesterol levels were high in 14 children (4.9%); 72 of the study group (25.3%) had high triglyceride levels; HDL-C levels were low in 52 children (18.2%).

CONCLUSION

All the parameters of dyslipidaemia are not so high in our region. However, as early detection of dyslipidaemia should begin in childhood, we should perform periodic checks to prevent cardiovascular risks.

Profiles of levels of lipids and dyslipidaemia in children from Beijing, China

BACKGROUND

There is limited data available on characteristics of profiles of lipids in children. The purpose of our investigation, therefore, was to determine the lipid profile, and analyze the prevalence of dyslipidaemia, in subgroups of children according to different gender, districts of residence, and ages in Beijing, China.

METHODS AND RESULTS

We included 18,944 school children, aged from 7 to 18 years, in our community-based cross-sectional study, measuring the levels of total cholesterol and triglyceride in capillary blood, and at the same time determining their weight and height. Weights, heights, circumference at the waist, and body mass index proved to be significantly greater for the boys than the girls. The levels of total cholesterol of boys and girls were 3.98 +/- 0.35, and 4.02 +/- 0.35 mmol/L, respectively, while the comparable levels of triglycerides were 1.08 +/- 0.52, and 1.18 +/- 0.66 mmol/L, respectively. The percentages of hypercholesterolaemia, hypertriglyceridaemia, combined dyslipidaemia, and hyperlipidaemia were 1.2, 8.8, 0.4, and 9.7%, respectively. The incidences of hypertriglyceridaemia, combined dyslipidaemia, and hyperlipidaemia of girls were higher than boys. The levels of triglycerides for boys aged from 11 to 18 years living in an urban setting were higher than those for boys living in rural settings, as were the levels of total cholesterol for boys aged from 12 to 16 years.

CONCLUSION

Our study provides the newest current profiles of lipids for children living in Beijing. We found significant influences of age, districts of residence, and genders on the levels of lipids, features which need further attention in the prevention and treatment of dyslipidaemia.

Evaluation of AAP guidelines for cholesterol screening in youth: Project HeartBeat!

BACKGROUND

The American Academy of Pediatrics (AAP) criterion for screening for hypercholesterolemia in children is family history of hypercholesterolemia or cardiovascular disease or BMI > or =85th percentile. This paper aims to determine the sensitivity, specificity, and positive predictive value (PPV) of dyslipidemia screening using AAP criteria along with either family history or BMI.

METHODS

Height, weight, plasma total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, and family history were obtained for 678 children aged 8, 11, and 14 years, enrolled from 1991 to 1993 in Project HeartBeat!. Sensitivity, specificity, and PPV screening of each lipid component using family history alone, BMI > or =85th percentile alone, or family history and/or BMI > or =85th percentile, were calculated using 2008 AAP criteria (total cholesterol, LDL-C, and triglycerides > or =90th percentile; HDL-C <10th percentile).

RESULTS

Sensitivity of detecting abnormal total cholesterol, LDL-C, HDL-C, and triglycerides using family history alone ranged from 38% to 43% and significantly increased to 54%-66% using family history and/or BMI. Specificity significantly decreased from approximately 65% to 52%, and there were no notable changes in PPV. In black children, cholesterol screening using the BMI > or =85th percentile criterion had higher sensitivity than when using the family history criterion. In nonblacks, family history and/or BMI > or =85th percentile had greater sensitivity than family history alone.

CONCLUSIONS

When the BMI screening criterion was used along with the family history criterion, sensitivity increased, specificity decreased, and PPV changed trivially for detection of dyslipidemia. Despite increased screening sensitivity by adding the BMI criterion, a clinically significant number of children still may be misclassified.

Screening and treatment for lipid disorders in children and adolescents: systematic evidence review for the US Preventive Services Task Force

OBJECTIVE

This was a systematic evidence review for the US Preventive Services Task Force, intended to synthesize the published evidence regarding the effectiveness of selecting, testing, and managing children and adolescents with dyslipidemia in the course of routine primary care.

METHODS

Literature searches were performed to identify published articles that addressed 10 key questions. The review focused on screening relevant to primary care of children without previously identified dyslipidemias, but included treatment trials of children with dyslipidemia because some drugs have only been tested in that population.

RESULTS

Normal values for lipids for children and adolescents are defined according to population levels (percentiles). Age, gender, and racial differences and temporal trends may alter these statistical cut points. Approximately 40% to 55% of children with elevated total cholesterol and low-density lipoprotein levels will continue to have elevated lipid levels on follow-up. Current screening recommendations based on family history will fail to detect substantial numbers (30%-60%) of children with elevated lipid levels. Drug treatment for dyslipidemia in children has been studied and shown to be effective only for suspected or proven familial monogenic dyslipidemias. Intensive dietary counseling and follow-up can result in improvements in lipid levels, but these results have not been sustained after the cessation of the intervention. The few trials of exercise are of fair-to-poor quality and show little or no improvements in lipid levels for children without monogenic dyslipidemias. Although reported adverse effects were not serious, studies were generally small and not of sufficient duration to determine long-term effects of either short or extended use.

CONCLUSIONS

Several key issues about screening and treatment of dyslipidemia in children and adolescents could not be addressed because of lack of studies, including effectiveness of screening on adult coronary heart disease or lipid outcomes, optimal ages and intervals for screening children, or effects of treatment of childhood lipid levels on adult coronary heart disease outcomes.

Epidemiology of dyslipidemia among schoolchildren in Sousse, Tunisia

In Tunisia, there is no available data on the CVD risk profile in the children population, although it is well known that risk factor development takes place during childhood. We undertook an epidemiological survey based on a representative sample of 1569 urban school children of Sousse in Tunisia to assess the prevalence of hypercholesterolemia and other lipid disorders. Prevalence of hypercholesterolemia (8.1%), high level of LDL-cholesterol (3.9%), high level of Lp(a) (14.5%), hypertriglyceridemia (1.3%) and hyper Apo B (3.4%) were found. These informations will be useful to set up a regional program of Heart Health promotion in schools.

Usefulness of the American Academy of Pediatrics recommendations for identifying youths with hypercholesterolemia

OBJECTIVE

To determine the usefulness of parent history of hypercholesterolemia and cardiovascular disease as a screening criterion for hypercholesterolemia in youths.

METHODS

Data were available from a population-based survey of 3665 Quebec youths aged 9, 13, and 16 years (81.2% of eligible subjects). Blood specimens were collected from 2475 subjects (54.8% of those eligible), and questionnaire data were obtained from 3048 parents (67.5% of those eligible). Lipids were measured in a Centers for Disease Control and Prevention standardized laboratory. Usefulness of parent history in identifying borderline/high low-density lipoprotein cholesterol (LDL-C) (> or =2.8 mmol/L [> or =110 mg/dL]) and high LDL-C (> or =3.4 mmol/L [> or =130 mg/dL]) was assessed according to test performance statistics (sensitivity, specificity, positive predictive value, and negative predictive value).

RESULTS

The prevalence of a positive parent history was 25.6%; 18.3% of subjects had borderline/high LDL-C, and 4.8% had high LDL-C. Sensitivity, specificity, positive predictive value, and negative predictive value of parent history were 33.1%, 76.0%, 23.7%, and 83.5%, respectively, for identifying borderline/high LDL-C; they were 40.7%, 75.1%, 7.7%, and 96.1% for identifying high LDL-C. Test performance statistics were not improved in subgroups defined according to age, gender, parent education, household income, family status, and family origin (French Canadian, other); neither were they improved by adding screening criteria (parent history of diabetes or hypertension, or youth overweight).

CONCLUSION

Parent history screening criteria offer little improvement over random population screening in identifying youths with hypercholesterolemia.

Biomarkers in disease and health

Biomarkers have considerable potential in aiding the understanding of the relationship between diet and disease or health. However, to assess the role, relevance and importance of biomarkers on a case by case basis it is essential to understand and prioritise the principal diet and health issues. In the majority of cases, dietary compounds are only weakly biologically active in the short term, have multiple targets and can be both beneficial and deleterious. This poses particular problems in determining the net effect of types of foods on health. In principle, a biomarker should be able to contribute to this debate by allowing the measurement of exposure and by acting as an indicator either of a deleterious or of an enhanced health effect prior to the final outcome. In this review, the examples chosen - cancer (stomach, colon/rectal, breast); coronary heart disease and osteoporosis - reflect three major diet-related disease issues. In each case the onset of the disease has a genetic determinant which may be exacerbated or delayed by diet. Perhaps the most important factor is that in each case the disease, once manifest, is difficult to influence in a positive way by diet alone. This then suggests that the emphasis for biomarker studies should focus on predictive biomarkers which can be used to help in the development of dietary strategies which will minimise the risk and be of greater benefit.

Nutrition in early life: somatic growth and serum lipids

This paper addresses the questions of whether early nutritional experience affects later somatic growth, the growth of the adipose tissue, or the levels of scrum lipids among well-nourished children. The analyses are based on data from three prospective studies. Postnatal nutrition and growth: there were differences in growth between breast-fed and formula-fed children. There was no association between linear growth and differences in food energy or macronutrient intake. Birth size and postnatal growth: there was no association between ponderal index (PI) at birth and body mass index (BMI) in the second year. For boys, the PI at 3 and 6 months of age was significantly positively correlated with BMI at the ages of 8 and 15 years, but not for girls. Childhood growth and lipids: there was no association between lipids at the age of 8 years and either birth weight or length, but children who had had a low PI at birth had higher lipid levels at the age 8 years. A positive association was found between serum lipids and abdominal fat and BMI. We conclude that, although early diet may influence growth rate beyond infancy, the evidence for fat patterning resulting from differences in fetal or early postnatal nutrition is still open to question.

Premature pubarche, ovarian hyperandrogenism, hyperinsulinism and the polycystic ovary syndrome: from a complex constellation to a simple sequence of prenatal onset

Adolescent girls with a history of premature pubarche have an increased incidence of functional ovarian hyperandrogenism [a form of polycystic ovary syndrome (PCOS)] at adolescence, which is usually associated with hyperinsulinemia and dyslipemia. The hyperinsulinemia and lipid disturbances can often be detected in the prepubertal period and throughout puberty, and are associated with an exaggerated ovarian androgen synthesis. Birthweight SD scores are lower in premature pubarche girls than in control girls, and particularly so in those girls who show hyperinsulinemia and subsequently develop ovarian hyperandrogenism. Therefore, although the mechanisms interlinking the triad of premature pubarche, hyperinsulinism and ovarian hyperandrogenism remain enigmatic, these data indicate that the triad may result, at least in part, from a common early origin, rather than from a direct interrelationship later in life.

A rational approach to treating hypercholesterolaemia in children. Weighing the risks and benefits

Because atherosclerosis is a continuous process throughout life, expert panels have suggested guidelines to reduce the risk of cardiovascular disease, starting from childhood. The guidelines focus on population-based measures and on treating hypercholesterolaemia in individual children. Low-fat diets in children have been widely debated. There is little evidence that growth is stunted or that nutritional deficiencies arise if the energy that is lost by limiting fat intake is substituted with other nutrients. Dietary fibre, plant sterols and fish oils have been used to modify lipid levels in children; however, the efficacy of these dietary adjuncts is limited. Bile acid-binding resins are the only approved drugs to lower cholesterol levels in children and appear to be well tolerated. However, compliance with resins is low because of unpalatability, so low dosages are preferred and vitamin supplementation is prudent. Data on HMG CoA reductase inhibitors and fibrates are insufficient to recommend these drugs at present. Drug treatment should be restricted to children who are at exceptionally high risk of disease, usually those with genetic dyslipidaemias.

Cholesterol screening in childhood: results of a 9-year follow-up study in Swiss and Italian children in Switzerland

Mass screening for blood cholesterol as part of routine preventive health care of children continues to be discussed in several countries. Results of longitudinal studies underline the importance of the predictive value of cholesterol levels assessed during childhood. Some countries have changed their recommendations during the past years to blood cholesterol screening for obese children only or for children of high risk families. In the Kindergarten-study Basel, a follow-up study on somatic, psychic and social development of Swiss and immigrant schoolchildren, cardiovascular risk factors were assessed at the ages of 5, 10 and 14 years. The age-specific levels of total and LDL-cholesterol found in our study were slightly higher and HDL-cholesterol lower than, for example, those found in the Bogalusa Heart Study. For total cholesterol no significant tracking correlations over the 5 and 9 year periods were found. Tracking of LDL- and HDL-cholesterol differed between nationalities and sexes. The total cholesterol/HDL-cholesterol index tracked slightly better. Italian girls showed the best 9-year tracking for HDL-cholesterol (r = 0.56). The differences between this and other studies can only partially be explained by different sampling and laboratory methods. Individual changes in cholesterol levels between the ages of 5 and 14 were marked. Sexual maturation was found to be of minor influence. Body mass index was the most consistent risk factor in our population. Changes of sex or growth hormone levels during puberty, but also changes of nutritional habits or physical activity might influence the individual cholesterol levels. Before recommendations on mass screening of cholesterol in children are made, the different longitudinal patterns of changes in cholesterol levels, and subpopulation-specific changes of nutritional habits and physical activity, should be discussed. The results of the Kindergarten study Basel suggest that attention should be paid to screening for obesity and to health education regarding nutrition and physical activity.

Relation of total homocysteine and lipid levels in children to premature cardiovascular death in male relatives

We assessed the relative importance of lipid, apo B, lipoprotein(a) [Lp(a)], and total homocysteine (tHcy) levels in children in relation to premature cardiovascular disease in family members. Parents of 381 girls and 375 boys age 8-12 y completed family history questionnaires. Nonfasting serum lipid and lipoproteins and plasma tHcy and cysteine levels were measured in the children. Serum folate and vitamin B12 levels were determined in a random subsample of 23% of the children, who participated in a food frequency interview. Children whose parents reported hypercholesterolemia had higher total and non-HDL cholesterol and apo B levels than the rest, but these levels were not associated with cardiovascular disease. tHcy levels were similar in girls and boys. tHcy was higher in children whose father, grandfather, or uncle died at age < or = 55 y of myocardial infarction or sudden cardiac arrest (n = 42) than in control children [5.92 mumol/L (95% confidence interval [CI] of 5.47-6.36) versus 5.25 mumol/L (95% CI, 5.16-5.34)], also after adjustment for socioeconomic group. Intake and serum levels of vitamin B12 and folate were within recommended or reference ranges. In a stepwise multiple regression analysis, serum folate (negative correlation), plasma creatinine, and sugar intake as percent of dietary energy (positive correlations) were significantly associated with tHcy (multiple r = 0.44, adjusted r2 = 18%; 95% CI, 5-30%). Our data show that a modest elevation in tHcy in children was related to premature cardiovascular death in their male relatives and may partly account for the contribution of family history to risk of cardiovascular disease. tHcy may be modifiable through the diet, even in children with apparently adequate vitamin nutriture.