Cardiovascular risk factors of young adults in relation to parental socioeconomic status: the Cardiovascular Risk in Young Finns Study.

The socioeconomic status (SES) of the family influences the cardiovascular risk status of children and adolescents; however, it is not as well known whether parental SES has any effect on the risk factor profile of young adults. The aim of the present study was to investigate the relations of different aspects of parental SES, namely occupation, education, income and living area, to the common cardiovascular risk factors of their offspring (n = 919) aged 18, 21 and 24 years as a part of the Cardiovascular Risk in Young Finns Study in 1986. Subjects from farming families and rural areas had the highest serum total and low-density lipoprotein cholesterol values, and the lowest diastolic blood pressure compared with subjects from other occupational groups and subjects from urban regions. The diet of young adults from farming families and from rural areas contained more saturated fatty acids and less monounsaturated and polyunsaturated fatty acids. In addition, the body mass index was lower in subjects from urban regions compared with rural regions, and physical inactivity was less common in the urban group. Subjects with the highest parental occupational status smoked less compared with those with the lowest status. Parental education related inversely to physical inactivity and directly to dietary polyunsaturated fatty acids. The income level of the family associated positively with frequent inebriation by alcoholic beverages and inversely with the percentage of dietary energy from fat. In conclusion, there were modest inverse associations between different indicators of the SES of parents and some of the traditional risk factors of their offspring in young adulthood, which may contribute to the future risk of cardiovascular diseases.

Reduced hormone-sensitive lipase activity is not a major metabolic defect in Finnish FCHL families.

The pathogenetic mechanisms behind familial combined hyperlipidemia (FCHL) are unknown. However, exaggerated postprandial lipemia and excessive serum free fatty acid (FFA) concentrations have drawn attention to altered lipid storage and lipolysis in peripheral adipose tissue. Hormone-sensitive lipase (HSL) is the enzyme responsible for intracellular lipolysis in adipocytes and a decrease of adipocyte HSL activity has been demonstrated in Swedish FCHL subjects. The aim of the study was to investigate if adipose tissue HSL activity had any effect on lipid phenotype and if low HSL activity and FCHL were linked in Finnish FCHL families. A total of 48 family members from 13 well-characterized Finnish FCHL families and 12 unrelated spouses participated in the study. FCHL patients with different lipid phenotypes (IIA, IIB, IV) did not differ in adipose tissue HSL activity from each other or from the 12 normolipidemic spouses (P = 0.752). In parametric linkage analysis using an affecteds-only strategy the low adipose tissue HSL activity was not significantly linked with FCHL phenotype. However, we found a significant sibling-sibling correlation for the HSL trait (0.51, P < 0.01). Thus, a modifying or interacting role of HSL in the pathogenesis of FCHL could not be excluded.

Associations of education with cardiovascular risk factors in young adults: the Cardiovascular Risk in Young Finns Study.

BACKGROUND: Low educational level is associated with an increased risk of coronary heart disease. The aim of the present study was to examine the relationships between education and common cardiovascular risk factors in young adults. METHODS: Trends in conventional risk factors of young adults aged 21, 24, 27 and 30 years in 1992 (n = 443) were examined across the educational groups as part of a 12-year follow-up study, the Cardiovascular Risk in Young Finns Study. Education was determined as participants' own educational level and as parental years of schooling. RESULTS: In males, subject's own education was related inversely and independently of parental school years to serum total and low density lipoprotein (LDL) cholesterol concentration, smoking and body mass index. In females, participant's own educational level associated inversely with smoking and physical inactivity. Parental school years was associated inversely and independently of one's own educational level with serum total and LDL cholesterol values and waist-hip ratio in females. In both genders, parental education was a stronger determinant of diet (butter use) than one's own educational level. CONCLUSIONS: The least educated young adults have adopted a more adverse lifestyle than the more educated. The risk factor profile in young adulthood, especially in females, is still affected by parental education. The influences of one's own and parental educational level on vascular risk profile should be taken into consideration when planning public health campaigns among young adults.

Genetics of familial combined hyperlipidemia.

Complex disorders are caused by several environmental factors that interact with multiple genes. These diseases are common at the population level and constitute a major health problem in Western societies. Familial combined hyperlipidemia (FCHL) is characterized by elevated levels of serum total cholesterol, triglycerides, or both. This disorder is estimated to be common in Western populations with a prevalence of 1% to 2%. In addition, 14% of patients with premature coronary heart disease (CHD) have FCHL, making this disorder one of the most common genetic dyslipidemias underlying premature CHD. Both genetic and environmental factors are suggested to affect the complex FCHL phenotype, but no specific susceptibility genes to FCHL have been identified. It is hoped that further analysis of the first FCHL locus and other new loci obtained in genome-wide scans will guide us to genes predisposing to this complex disorder.

Linkage of familial combined hyperlipidaemia to chromosome 1q21-q23.

More than half of the patients with angiographically confirmed premature coronary heart disease (CHD) have a familial lipoprotein disorder. Familial combined hyperlipidaemia (FCHL) represents the most common genetic dyslipidemia with a prevalence of 1.0-2.0%. FCHL is estimated to cause 10-20% of premature CHD and is characterized by elevated levels of cholesterol, triglycerides, or both. Attempts to characterize genes predisposing to FCHL have been hampered by its equivocal phenotype definition, unknown mode of inheritance and genetic heterogeneity. In order to minimize genetic heterogeneity, we chose 31 extended FCHL families from the isolated Finnish population that fulfilled strictly defined criteria for the phenotype status. We performed linkage analyses with markers from ten chromosomal regions that contain lipid-metabolism candidate genes. One marker, D1S104, adjacent to the apolipoprotein A-II (APOA2) gene on chromosome 1, revealed a lod score of Z = 3.50 assuming a dominant mode of inheritance. Multipoint analysis combining information from D1S104 and the neighbouring marker D1S1677 resulted in a lod score of 5.93. Physical positioning of known genes in the area (APOA2 and three selectin genes) outside the linked region suggests a novel locus for FCHL on 1q21-q23. A second paper in this issue (Castellani et al.) reports the identification of a mouse combined hyperlipidaemia locus in the syntenic region of the mouse genome, thus further implicating a gene in this region in the aetiology of FCHL.

Glucose intolerance in familial combined hyperlipidaemia. EUFAM study group.

BACKGROUND: Familial combined hyperlipidaemia (FCHL) is a common hereditary disorder. Hypertriglyceridaemia is associated with glucose intolerance and insulin resistance. METHODS: To study glucose tolerance in FCHL patients with different lipid phenotypes [hypercholesterolaemia (IIA), mixed hyperlipidaemia (IIB), hypertriglyceridaemia (IV)], we investigated 253 family members and 92 spouses arising from 33 well-defined Finnish FCHL pedigrees. RESULTS: In oral glucose tolerance tests the affected family members had higher values for glucose area under the curve than did non-affected family members [673+/-127 min mmolL(-1), 754+/-145 min mmol L(-1), 846+/-180 min mmol L(-1) and 838+/-183 min mmol L(-1) for phenotypes normal, IIA, IIB and IV respectively; P < 0.001 after adjustment for body mass index, waist circumference and age]. Impaired glucose tolerance and diabetes were more common among affected than non-affected family members (prevalences of normal glucose tolerance 94.0%, 80.0%, 54.3% and 58.5% for phenotypes normal, IIA, IIB and IV). CONCLUSION: Affected FCHL family members were more glucose intolerant than non-affected family members. In men, this disturbance was not related to lipid phenotype nor was it explained by obesity.

Phenotype expression in familial combined hyperlipidemia.

Familial combined hyperlipidaemia (FCHL) is one of the most common hereditary disorders predisposing to early coronary death. The affected family members have elevations of serum total cholesterol, triglycerides or both. Despite intensive research efforts the genetic and metabolic defects underlying this complex disorder are still unknown. To dissect the metabolism and genetics of FCHL the phenotype of an individual must be precisely defined. We assessed the influence of different diagnostic criteria on the phenotype definition and studied factors affecting the phenotype expression in 16 large Finnish families (n = 255) with FCHL. The fractile cut-points used to define abnormal lipid values had a profound influence on the diagnosis of FCHL. If the 90th percentile cut-point was used, approximately 45% of the family members were affected, in concord with the presumed dominant mode of transmission for FCHL. If the 95th percentile was used only 22% of study subjects were affected. To characterize the metabolic differences or similarities between the different lipid phenotypes, we determined very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) particles separated by ultracentrifugation. In linkage analysis no single ultracentrifugation variable could discriminate reliably affected family members from non-affected family members. Our data emphasizes the need for re-evaluation of FCHL diagnostic criteria. Preferably, the diagnosis should be based on a single, reliable metabolic marker.

Associations between physical activity and risk factors for coronary heart disease: the Cardiovascular Risk in Young Finns Study.

Risk factors such as high serum cholesterol concentration measured in young adulthood predict premature coronary heart disease (CHD) in the middle-aged. The objective of this study was to analyze the associations between physical activity and CHD risk factors--body composition, blood pressure, serum lipids, apolipoproteins, and insulin--in children and young adults. The design was a cross-sectional study of atherosclerosis precursors in children and young adults using a cohort of children and young adults (N = 2,358) aged 9 to 24 years to determine indices of physical activity, measurements of anthropometric characteristics, blood pressure, serum lipids, apolipoproteins A-I and B, and insulin. The results show that a high level of physical activity was associated with high serum high density lipoprotein cholesterol (HDL-C) and HDL2-C concentrations, and low levels of serum triglycerides (TG), apolipoprotein B and insulin in males. However, in females, the influence of physical activity was evident only on TG level. In both genders, physical activity was inversely associated with obesity. In all these associations, a significant dose-related relationship was observed. We found no association between physical activity and blood pressure. In conclusion, physical activity is associated with a favorable serum lipid profile already during childhood and early adulthood in a dose-related manner, particularly in males. The promotion of physical activity is important in childhood in preventing obesity and premature cardiovascular disease.

Trends in serum lipid levels during 1980-1992 in children and young adults. The Cardiovascular Risk in Young Finns Study.

To assess secular trends in serum lipid levels in Finnish children and young adults, the authors examined a total of 3,517, 2,769, 2,392, 352, and 880 subjects who had complete data on serum lipids in 1980, 1983, 1986, 1989, and 1992, respectively, in a longitudinal follow-up study. Trend analyses were carried out among subjects aged 15 (n = 1,835) or 18 (n = 1,562) years to exclude the confounding effect of age on the study variables. Data on obesity, physical activity, smoking, and alcohol use were available from each study year, and data on diet were available for the study years 1980, 1986, and 1992. Between 1980 and 1992, mean total cholesterol levels decreased from 4.88 to 4.47 mmol/liter (from 189 to 173 mg/dl), and low density lipoprotein cholesterol levels decreased from 3.06 to 2.85 mmol/liter (from 119 to 110 mg/dl). The mean high density lipoprotein cholesterol levels decreased by 19%, from 1.43 to 1.15 mmol/liter (55.2 to 44.6 mg/dl). During 1986-1992, triglyceride levels increased by 15%, from 0.88 to 1.01 mmol/liter (78.2 to 89.9 mg/dl). During 1980-1992, body mass index values increased from 20.8 to 21.8 kg/m2, parallel to increases in skinfold thickness. In the diet, the ratio of polyunsaturated to saturated fatty acids increased from 0.26 to 0.39. Alcohol and oral contraceptive use became more frequent, and the subjects tended to become less physically active. In conclusion, a change in the lipid profile in Finnish adolescents aged 15 and 18 years and young adults during 1980-1992 was observed, characterized by a decrease in low density lipoprotein cholesterol and high density lipoprotein cholesterol levels and an increase in triglyceride level. Possible determinants for these changes include alterations in diet and a trend toward increased obesity.

Associations between diet and the hyperapobetalipoproteinemia phenotype expression in children and young adults: the Cardiovascular Risk in Young Finns Study.

The effect of diet on blood lipids has been under intensive study during recent decades. However, diet in the context of the hyperapobetalipoproteinemia (hyperapoB) phenotype has received less attention. The hyperapoB phenotype is commonly encountered in patients with premature coronary heart disease. It is defined as a combination of an increased concentration of apolipoprotein B (apo B), a normal concentration of LDL cholesterol (LDL-C), and as a result, a low LDL-C/apo B ratio. We studied the associations between diet and blood lipids in a cohort of 534 children and young adults 9 to 24 years old. The ratio of polyunsaturated to saturated fats (P/S ratio) correlated (r=-0.19, P<.001) with the LDL-C/apo B ratio. This association was also found when the model was adjusted with triglycerides (r=-0.24, P<.001). A change in the P/S ratio from 0.10 to 0.60 corresponded to a decrease of 0.12 in the LDL-C/apo B ratio, and in the highest apo B decile, the P/S value was higher in hyperapoB individuals (0.33) than in others (0.28, P=.019). Our results imply that the fatty acid composition of the diet may be one of the environmental factors that influence the hyperapoB phenotype expression.

No evidence of linkage between familial combined hyperlipidemia and genes encoding lipolytic enzymes in Finnish families.

Familial combined hyperlipidemia (FCHL) is characterized by different lipid phenotypes (IIa, IIb, IV) and elevated apolipoprotein B (apo B) levels in affected family members. Despite intensive research, the genes involved in the expression of this complex disorder have not been identified, probably because of problems associated with phenotype definition, unknown mode of inheritance, and most probably genetic heterogeneity. To explore the genetics of FCHL in the genetically homogeneous Finnish population, we collected 14 well-documented Finnish pedigrees with premature coronary heart disease and FCHL-like dyslipidemia. The lipolytic enzymes lipoprotein lipase (LPL), hepatic lipase (HL), and hormone-sensitive lipase (HSL) were selected as initial candidate genes because of their central roles in apo B and triglyceride metabolism. On the basis of the pedigree structures, a dominant mode of inheritance was adopted for linkage analyses, and serum total cholesterol and/or triglyceride levels exceeding the 90th percentile level were set as diagnostic criteria (criterion 1). In pairwise linkage analyses with intragenic markers, no evidence for linkage was found. Instead, the significantly negative LOD scores suggested exclusion of all three loci for single major gene effect. LOD scores were -14.63, -5.03, and -5.70 for the three LPL polymorphisms (theta=0.00); -9.40, -6.30, and -4.74 for the three HL polymorphisms (theta=0.00); and -15.29 for the HSL polymorphism (theta=0.00). The results were very similar when apo B levels over the 90th percentile were used as criteria for affected status (criterion 2). Also, when linkage calculations were carried out using an intermediate or recessive mode of inheritance, the results of pairwise linkage analysis remained negative. Furthermore, when haplotypes were constructed from multiple polymorphisms of the LPL and HL genes, no segregation with the FCHL phenotype could be observed in the 14 Finnish families. Data obtained by the affected sib-pair method supported these findings, suggesting that the LPL, HL, or HSL genes do not represent major loci influencing the expression of the FCHL phenotype.

Serum complement and familial combined hyperlipidemia.

Familial combined hyperlipidemia (FCHL) is one of the most common inherited lipid disorders. Resistance of adipocytes to the effects of acylation stimulating protein (ASP) may contribute to ineffective triglyceride synthesis and thereby prolonged postprandial lipemia and increased fatty acid flux to the liver seen in FCHL patients. Interestingly, ASP is identical to C3a-desArg, fragment of the third component of complement. We examined the relationships between serum levels of complement components C3 and C4 and markers of lipid and glucose metabolism in 11 large FCHL families (n = 53). Median serum C3 levels were 38% higher in affected compared to non-affected male FCHL family members (1.90 g/l vs. 1.38, P = 0.0027). The strongest correlations were observed between serum complement C3 and apolipoprotein B levels, reaching 0.77 in males. These relations were not confounded by obesity or impaired glucose tolerance. In conclusion, serum levels of the main complement components C3 and C4 correlated significantly with serum lipid levels. Further studies are needed to clarify the importance of disturbances in the complement system on the pathogenesis of FCHL and other lipid disorders.

Influence of parental occupation on coronary heart disease risk factors in children. The Cardiovascular Risk in Young Finns Study.

BACKGROUND: The influence of parental occupation on selected coronary heart disease risk factors was studied in a cohort of Finnish children aged 9, 12 and 15 years (n = 1211) as part of the Cardiovascular Risk in Young Finns Study in 1986. METHODS: The relationships of parental occupation to serum lipid and apolipoprotein concentrations, blood pressure, obesity, smoking, physical activity, diet and birthweight were examined. The occupation of the parents was obtained by a questionnaire and classified as I: upper non-manual (22%), II: lower non-manual (26%), III: upper manual (32%), IV: lower manual (5%) and F: farmers (15%). RESULTS: Highest serum total and how density lipoprotein cholesterol concentrations were found in classes IV and F. Boys from class IV had 7.1% higher total cholesterol concentrations compared to class I (4.98 mmol/l versus 4.65 mmol/l, P = 0.0033), whereas farmers' girls had 10.4% higher concentrations than girls from class III (5.31 mmol/l versus 4.81 mmol/l, P = 0.0057). Blood pressure was related to parental occupation only in boys, and the values were highest in class F. Boys from class IV smoked most often, and they also had lowest values for physical activity index and highest obesity indices. Farmers' children consumed significantly more saturated fat and cholesterol than children from other classes. In boys, the percentage of subjects with a low birthweight (< or = 10th percentile) was smallest in class I and greatest in class IV (7.1% versus 20.7%, P = 0.0330). CONCLUSIONS: Socioeconomic status based on parental occupation is associated with several coronary heart disease risk factors already present in children. These differences should be taken into account in prevention programmes aimed at children at an increased risk for developing coronary heart disease as adults.

Serum lipoproteins in children and young adults: determinants and treatment strategies.

Serum lipoproteins are related to vascular atherosclerotic changes as seen in necropsy studies of child fatal accident victims; therefore, efforts have been made to reveal the determinants of lipoprotein metabolism in children and young adults. Recent data emphasize the adverse effects of obesity, insulin resistance and high fat intake on lipid profiles of children, and currently many lifestyle and dietary intervention studies are in progress. Detection of hereditary dyslipidemias in childhood is presently hampered by diagnostic problems. However, with the advent of efficient tools for genetic mapping, early diagnosis of common genetic dyslipidemias will probably be possible in the near future.

The effect of physical activity on serum total and low-density lipoprotein cholesterol concentrations varies with apolipoprotein E phenotype in male children and young adults: The Cardiovascular Risk in Young Finns Study.

Apolipoprotein E (apo E) determines serum total (TC) and low-density lipoprotein (LDL-C) cholesterol concentrations and is thus associated with coronary heart disease (CHD) risk. We studied if the effect of physical activity (PA) on serum TC and LDL-C concentrations varies with apo E phenotype in a population-based sample of children and young adults with regular PA. The study cohort consisted of subjects aged 9, 12, 15, 18, 21, and 24 years in 1986 (N = 1,498) participating in a large multicenter study of cardiovascular risk factors in children and young adults. Serum lipid concentrations were determined enzymatically, and apo E phenotypes by isoelectric focusing and immunoblotting. The composition of the diet was determined by a 48-hour recall method, and a PA index was calculated on the basis of frequency, intensity, and duration of activity assessed by a questionnaire. LDL-C (P = .0082), TC (P = .014), and the high-density lipoprotein cholesterol (HDL-C)/TC ratio (P = .0004) responses to exercise varied with apo E phenotype. The effect of PA on LDL-C, TC, or HDL/TC was not found in apo E phenotype E4/4. A moderate inverse effect of PA on TC and LDL-C and a positive effect on HDL/TC was found in subjects with E4/3 and E3/3 phenotypes. Similar but stronger associations were found between these variables within the group of E3/2 males. The effect of PA on serum lipid levels was strongest within the phenotype E3/2. These associations were not explained by dietary habits. Apo E phenotype partly determines the effect of PA on serum TC and LDL-C in Finnish male children and young adults with regular PA.

Effect of leisure-time physical activity change on high-density lipoprotein cholesterol in adolescents and young adults.

In adults, the high-density lipoprotein cholesterol (HDL-C) level is higher among physically active subjects. However, the association of physical activity and HDL-C is less well studied in adolescents and young adults. Furthermore, it is not known whether the effect of physical activity on HDL-C levels is independent, or whether it is mediated by other physiological changes seen in exercise, such as weight loss or increased insulin sensitivity. In order to study the effects of leisure-time physical activity on the levels of serum HDL-C concentration, we analysed longitudinal data from a follow-up study of adolescents and young adults. The study subjects were participants of a large multicentre study of cardiovascular risk factors, aged 15-21 years at the beginning of the study (n = 714). HDL-C was measured from the serum supernatant after precipitation with dextran sulphate and MgCl2. A physical activity index was calculated on the basis of frequency, intensity, and duration of leisure-time activity assessed by a questionnaire. In males, an increase in the physical activity level predicted an increase in HDL-C concentration, and this association persisted after simultaneously controlling for changes in body mass index (kg/m2), subscapular skinfold thickness, serum insulin and triglyceride concentrations, and smoking. For example, an increase in the physical activity level corresponding to approximately 1 hour of intensive exercise weekly lead to an increase of 42 mumol/L in HDL-C as calculated from the regression equation. In conclusion, physical activity seems to have a direct effect on HDL-C levels among young male subjects within the usual range of physical activity levels.

Smoking, alcohol and lipoprotein metabolism.

Daily smoking and use of alcohol have a many-fold influence on lipid metabolism. The relations between HDL-cholesterol, alcohol use and smoking are well known. During recent years, the influence of smoking on postprandial lipid and glucose metabolism, and on insulin sensitivity in particular, has gained increasing attention. In addition, new data have emerged about the oxidative properties of alcohol use and smoking. As life habits tend to show clustering, isolating mechanisms responsible for the lipid changes induced by smoking or alcohol per se is difficult and is one factor causing contradiction in this study area.

Prevalence of hyperapobetalipoproteinemia and factors affecting the phenotype expression in children and young adults. The Cardiovascular Risk in Young Finns Study.

Hyperapobetalipoproteinemia (hyperapoB) is one of the most common phenotypes in patients with premature coronary heart disease. In this study the factors that affect the expression of the hyperapoB phenotype were evaluated in young individuals. A cohort of 1125 children and young adults aged 9-24 years was classified into three groups by sex: (1) normal serum apolipoprotein B (apoB), (2) high apoB (> or = 90th percentile) and normal low density lipoprotein cholesterol (LDL-C < 90th), (3) high apoB and high LDL-C (> or = 90th percentile). In females, alcohol use (11, 33, 0%, in groups 1-3, P < 0.05) and oral contraceptive use (35, 83, 47%, P < 0.01) were significantly different between the groups and the highest frequencies were seen in the hyperapoB group (group 2). In both sexes smoking tended to be more common in the hyperapoB group (29, 43, 18%, P < 0.14). The two hyperapoB definition criteria (high apoB and low LDL-C/apoB ratio) were studied with multiple linear regression analyses. Oral contraceptive use correlated positively with apoB values (coefficient beta = 0.101, R2 = 2.1%, P < 0.01) and negatively with LDL-C/apoB ratio (beta = -0.134, R2 = 3.3%, P < 0.001). Alcohol use (beta = -0.072, R2 = 2.9%, P < 0.001) and smoking (beta = -0.050, R2 = 1.0%, P < 0.05) correlated negatively with LDL-C/apoB ratio. Prevalence of the hyperapoB phenotype was 4.4%. According to the results, the expression of the hyperapoB phenotype may be influenced by common lifestyle habits. This should be considered if high risk young individuals are identified through the expression of the hyperapoB phenotype.

Patterns of intense physical activity among 15- to 30-year-old Finns. The Cardiovascular Risk in Young Finns Study.

Previous studies have reported increasing trends in physical activity in the Finnish population. These reports have not, however, included the perspective of cardiorespiratory stress in adolescent and young adults. We examined the present patterns of physical activity among Finnish adolescents and young adults in 1992. We specifically assessed whether the young people experience the volume of physical activity that is believed to stress the cardiorespiratory system appropriately in order to increase the level of fitness. The subjects in the present study were participants of a large multicenter study of atherosclerosis precursors in children and young adults. Physical activity was measured with a self-administered questionnaire in 2255 adolescents and young adults (1015 males and 1240 females). The proportion of subjects undertaking the volume of physical activity believed to benefit the cardiorespiratory system appropriately was 19%. The proportion was higher in males than in females (26 vs 13%). The proportion of active subjects became smaller in older age groups in both sexes. Half the study population (51% of the males; 48% of the females) reported frequent leisure-time physical activity less than once a month. In conclusion, Finnish adolescents and young adults have low levels of physical activity on the average, and many young Finns seldom undertake the volume of physical activity believed to benefit the cardiopulmonary system. Young males seem to be physically more active than females.

The role of insulin in clustering of serum lipids and blood pressure in children and adolescents. The Cardiovascular Risk in Young Finns Study.

In adults hyperinsulinaemia is associated with an atherogenic risk profile including obesity, low levels of HDL-cholesterol, high levels of triglycerides and elevated blood pressure. To examine these associations in the young we studied the cross-sectional relationships of insulin with obesity indices (body mass index, subscapular skinfold thickness), serum lipids and blood pressure in 1,865 children, adolescents and young adults aged 6-24 years. We also used longitudinal data to study the value of a single insulin measurement to predict high risk factor levels and clustering of multiple risk factors after a 6-year follow-up. In cross-sectional analyses the levels of triglycerides, HDL-cholesterol, systolic blood pressure and obesity indices were usually significantly different across the quartiles of fasting insulin in both sexes among children, adolescents and young adults. In general, no associations were seen with total cholesterol or LDL-cholesterol. In prospective analysis elevated baseline insulin was related to the incidence of hypertriglyceridaemia (> or = 95th percentile) at the follow-up. This relationship persisted even after adjustments for baseline obesity or 6-year change in obesity status. Moreover, baseline insulin concentration was higher in subjects who subsequently showed clustering of high triglycerides, low HDL-cholesterol and high systolic blood pressure levels at the follow-up. We conclude that high fasting insulin levels measured in children and adolescents predict the development of hypertriglyceridaemia years later. In addition, high insulin levels seem to precede the development of a potentially atherogenic risk factor profile including low HDL-cholesterol, high triglycerides and high systolic blood pressure.