Arterial structure and function after recovery from the metabolic syndrome: the cardiovascular risk in Young Finns Study

BACKGROUND

The reversibility of ultrasonographic vascular changes associated with the metabolic syndrome (MetS) recovery is unknown. We examined whether spontaneous recovery from MetS (according to the International Diabetes Federation definition) has a favorable effect on vascular properties and evaluated the associations between lifestyle factors and MetS recovery.

METHODS AND RESULTS

We measured carotid artery intima-media thickness, distensibility, and brachial flow-mediated dilatation by ultrasound in 1673 subjects of the Young Finns Study cohort (age, 31.5+/-5.0 years in 2001) who participated in follow-up studies in 2001 and 2007. At baseline, no differences in intima-media thickness, carotid artery distensibility, or flow-mediated dilatation were observed between the recovery group (baseline-only MetS) and those with incident (only at follow-up) or persistent (both at baseline and follow-up) MetS. After 6 years, the recovery group had smaller intima-media thickness (mean+/-SEM, 0.62+/-0.01 versus 0.68+/-0.01 mm; P=0.0009) and higher carotid artery distensibility (1.98+/-0.07%/mm Hg versus 1.56+/-0.04%/mm Hg; P=0.001) compared with the persistent group and higher flow-mediated dilatation compared with the control group (9.91+/-0.51% versus 8.57+/-0.12%; P=0.03). The recovery group had reduced intima-media thickness progression compared with the persistent group (0.036+/-0.005 versus 0.079+/-0.010 mm; P=0.001) and reduced carotid artery distensibility change compared with the incident group (-0.12+/-0.05%/mm Hg versus -0.38+/-0.10%/mm Hg; P=0.03) over the 6-year follow-up. Differences in carotid artery distensibility levels were attenuated (P=0.11) after the inclusion of weight change in the models. MetS recovery was paralleled with significant reductions in waist circumference that independently correlated with increased physical activity and increased attention paid to health habits during the follow-up.

CONCLUSIONS

Recovery from the MetS was associated with positive effects on vascular properties during a 6-year follow-up period of young adults.

Autoimmunity and atherosclerosis: the presence of antinuclear antibodies is associated with decreased carotid elasticity in young women. The Cardiovascular Risk in Young Finns Study

OBJECTIVE

There is ample evidence demonstrating that accelerated atherosclerosis prevails in autoimmune rheumatic diseases, particularly in SLE, and that the risk is due not only to traditional cardiovascular risk factors but also to the disease itself. ANAs are a hallmark of SLE and are known even to antedate the development of SLE. Our aim was to investigate whether positive ANAs in young adults are associated with risk factors for atherosclerosis or subclinical markers of atherosclerosis.

METHODS

ANAs were examined by IIF using HEp-2 cells as substrate in 2278 participants in the Cardiovascular Risk in Young Finns Study for whom detailed data on cardiovascular risk factors and markers of subclinical atherosclerosis (including brachial flow-mediated dilatation, carotid compliance and carotid intima-media thickness) were available.

RESULTS

In multivariate analyses, adjusted for age, BMI, serum concentrations of CRP, triglycerides, high-density lipoprotein and low-density lipoprotein cholesterol, blood pressure and smoking habits, ANA positivity (titre > 160) was inversely associated (beta = -0.145; P = 0.034) with carotid compliance in women.

CONCLUSIONS

Our results indicate that ANA positivity is associated with decreased carotid elasticity in women, suggesting that mechanisms resulting in ANA production may be involved in the development of early atherosclerosis.

Conventional cardiovascular risk factors and metabolic syndrome in predicting carotid intima-media thickness progression in young adults: the cardiovascular risk in young Finns study

BACKGROUND

Conventional risk factors and metabolic syndrome (MetS) are cross-sectionally associated with subclinical atherosclerosis in young adults. We evaluated the relations of conventional risk factors and MetS to the 6-year progression of carotid intima-media thickness (IMT) in a population of young adults.

RESULTS AND METHODS

The study included 1809 subjects (aged 32+/-5 years) who had IMT measured in 2001 and 2007. Risk factor measurements included low-density lipoprotein cholesterol, body mass index, C-reactive protein, smoking, and family history of coronary disease in addition to MetS components. We used European Group for the Study of Insulin Resistance, revised National Cholesterol Education Program, and International Diabetes Federation definitions to diagnose MetS in 2001. Waist circumference (P<0.0001), low-density lipoprotein cholesterol (P=0.01), and insulin (P=0.003) were directly associated with IMT progression in a multivariable model adjusted for age, sex, and baseline IMT (model R(2)=24%). When the MetS/European Group for the Study of Insulin Resistance definition was included in the model, it was directly associated with IMT progression (P=0.03), but its inclusion did not improve the model's predictive value. IMT increased 79+/-7 mum (mean+/-SEM) in subjects with MetS according to the MetS/European Group for the Study of Insulin Resistance definition and 42+/-2 mum in subjects without MetS (P<0.0001). In addition, the number of MetS components was linearly associated with IMT progression (P<0.0001). Similar results were seen with MetS/revised National Cholesterol Education Program and MetS/International Diabetes Federation definitions.

CONCLUSIONS

Obesity, high low-density lipoprotein cholesterol, and high insulin level predicted IMT progression in young adults. All MetS definitions identified young adults with accelerated IMT progression, but we found no evidence that MetS would predict IMT progression more than expected from the sum of its risk components.

Cloninger's temperament traits and preclinical atherosclerosis: the Cardiovascular Risk in Young Finns Study

OBJECTIVE

Cloninger's psychobiological model of temperament has recently raised interest as a risk factor for CHD. However, there are no studies that have examined the associations of Cloninger's temperament traits with atherosclerosis.

METHODS

The subjects were 398 men and 657 women (mean age 31.7 years) participating in the Cardiovascular Risk in Young Finns Study. Linear regression analyses were used to examine the cross-sectional associations between temperament traits and preclinical atherosclerosis. Preclinical atherosclerosis was measured with carotid intima-media thickness ultrasound.

RESULTS

Higher novelty seeking (NS) and reward dependence (RD) and lower harm avoidance (HA) were associated with preclinical atherosclerosis. In NS and RD, associations remained significant after adjustments for various risk factors. The effect sizes of these associations were comparable to those of traditional risk factors of coronary heart disease, which is a major finding. No association for persistence (P) was found.

CONCLUSIONS

The present findings imply that examining a wider range of temperament and personality factors may offer new information that can help in explaining the between-individual variation in atherosclerosis and CHD morbidity.

Interactive effect of long-term mental stress and cardiac stress reactivity on carotid intima-media thickness: the Cardiovascular Risk in Young Finns study

The present study examined the interaction between vital exhaustion and cardiac reactivity and recovery on preclinical atherosclerosis assessed by carotid intima-media thickness (IMT) in young men and women. We measured heart rate (HR), respiratory sinus arrhythmia (RSA), and pre-ejection period (PEP) in response to mental arithmetic and speech tasks. Vital exhaustion and carotid IMT were also measured. Significant associations were observed for men aged 28-37 years, but not for men aged 22-25 years, nor for women in these age groups. It was shown that, among highly exhausted men in the older age group, lower HR reactivity was related to greater IMT. Our results also imply that, among non-exhausted men in this age group, slow HR and RSA recovery after acute stress predicted higher IMT. These results suggest that long-term stress as assessed by vital exhaustion is a risk only if it has resulted in ineffective cardiac stress reactivity. Autonomic imbalance resulting from chronic stress may be the common mechanism linking vital exhaustion and cardiac responsiveness to an increased risk of atherosclerosis.

Flow mediated vasodilation and circulating concentrations of high sensitive C-reactive protein, interleukin-6 and tumor necrosis factor-alpha in normal pregnancy--The Cardiovascular Risk in Young Finns Study

BACKGROUND

Traditional risk factors such as hyperlipidemia induce a state of inflammation that impairs vascular function. Despite marked maternal hyperlipidemia, endothelial function improves during pregnancy. In non-pregnant state increased circulating levels of pro-inflammatory cytokines and high sensitive C-reactive protein (hsCRP) lead to attenuated flow mediated vasodilation. Relation between endothelial function and pro-inflammatory cytokines has not been studied thoroughly in pregnancy. The aim of this study was to evaluate the effect of pregnancy on hsCRP and pro-inflammatory cytokines and their associations with vascular endothelial function.

METHODS

As part of population-based, prospective cohort Cardiovascular Risk in Young Finns study conducted in Finland we measured brachial artery flow mediated dilation (FMD) and serum concentrations of hsCRP, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in 57 pregnant Finnish women throughout gestation and 62 control women matched for age and smoking.

RESULTS

HsCRP-concentration was greater in pregnancy compared to non-pregnant controls (median hsCRP 2.52 mg l(-1) versus 1.21 mg l(-1), P<0.001). IL-6-concentration was slightly increased in pregnancy compared with the non-pregnant controls (median 1.66 versus 1.32 mg l(-1), non-significant [NS]) and TNF-alpha-concentration was slightly decreased in pregnant group (2.11 versus 2.38 pg ml(-1), NS). FMD increased during pregnancy and IL-6 had a positive correlation to the FMD in pregnancy (R = 0.288, P = 0.031).

CONCLUSIONS

Improvement of FMD in normal pregnancy was not affected by increase in hsCRP concentration. We found an association with IL-6 and FMD but we believe that improvement in endothelial function during normal pregnancy is not caused by variation in hsCRP, IL-6 or TNF-alpha.

Associations of genetic lactase non-persistence and sex with bone loss in young adulthood

Some studies have reported that after attainment of peak bone mass (PBM), slow bone loss may occur in both men and women; however, findings are inconsistent. Genetic factors play a significant role in bone loss, but the available evidence is conflicting. Genetic lactase non-persistence (lactase C/C(-13910) genotype) is suggested to increase risk for inadequate calcium intake predisposing to poorer bone health. We investigated whether this genotype is associated with PBM and bone loss in young Finnish adults. Subjects belong to the Cardiovascular Risk in Young Finns Study that is an ongoing multi-centre follow-up of atherosclerosis risk factors. From the original cohort, randomly selected subjects aged 20-29 participated in baseline bone mineral density (BMD) measurements (n=358), and in follow-up measurements 12 years later (n=157). Bone mineral content (BMC) and BMD at lumbar spine (LS) and femoral neck (FN) were measured at baseline and follow-up with dual energy X-ray absorptiometry (DXA). Lactase C/T(-13910) polymorphism was determined by PCR and allele-specific fluorogenic probes. Information on lifestyle was elicited with questionnaires. During the follow-up, bone loss at both bone sites was greater in males (LS BMD: -1.1%, FN BMD: -5.2%) than in females (LS BMD: +2.1%, FN BMD: -0.7%) (both bone sites p=0.001). Younger age predicted greater loss of FN BMC and BMD in females (p=0.013 and p=0.001, respectively). Increased calcium intake predicted FN BMD gain in both sexes (in females B=0.007 g/cm(2)/mg, p=0.002; in males B=0.006, p=0.045), and increased physical activity LS BMD gain in females (B=0.091 g/cm(2)/physical activity point, p=0.023). PBM did not differ between the lactase genotypes, but males with the CC(-13910) genotype seemed to be prone to greater bone loss during the follow-up (LS BMD: C/C vs. T/T p=0.081). In conclusion, bone loss in young adulthood was more common in males than in females and seemed to occur mainly at the femoral neck. Young males with the lactase CC(-13910) genotype may be more susceptible to bone loss; however, calcium intake predicts changes in bone mass more than the lactase genotype.

The association of pediatric low- and high-density lipoprotein cholesterol dyslipidemia classifications and change in dyslipidemia status with carotid intima-media thickness in adulthood evidence from the cardiovascular risk in Young Finns study, the Bogalusa Heart study, and the CDAH (Childhood Determinants of Adult Health) study

OBJECTIVES

This study was designed to determine which of the National Cholesterol Education Program or National Health and Nutrition Examination Survey low- and high-density lipoprotein cholesterol classifications of dyslipidemia status in adolescents is most effective at predicting high common carotid artery intima-media thickness (IMT) in adulthood.

BACKGROUND

Two classifications of pediatric dyslipidemia status have been proposed. No study has assessed which of these is most effective for predicting adolescents who will develop preclinical atherosclerosis in adulthood.

METHODS

Three population-based, prospective cohort studies collected lipoprotein measurements on 1,711 adolescents age 12 to 18 years who were remeasured as young adults age 29 to 39 years. Lipoproteins in adolescence were classified according to National Cholesterol Education Program and National Health and Nutrition Examination Survey cut points, and high IMT in adulthood was defined as those at or above the age-, sex-, race-, and cohort-specific 90th percentile of IMT.

RESULTS

Independent of the classification employed, adolescents with dyslipidemia were at significantly increased risk of having high IMT in adulthood (relative risks from 1.6 to 2.5). Differences in predictive capacity between both classifications were minimal. Overweight or obese adolescents with dyslipidemia had increased carotid IMT (males: 0.11 mm; females: 0.08 mm) in adulthood compared with those who did not have both risk factors. Adolescent dyslipidemia status was more strongly associated with high IMT in adulthood than change in dyslipidemia status.

CONCLUSIONS

Pediatric dyslipidemia classifications perform equally in the prediction of adolescents who are at increased risk of high IMT in young adulthood. Our data suggest that dyslipidemia screening could be limited to overweight or obese adolescents.

Genetics of C-reactive protein and complement factor H have an epistatic effect on carotid artery compliance: the Cardiovascular Risk in Young Finns Study

Atherosclerosis is characterized by a prominent inflammatory component and C-reactive protein (CRP) has been implicated to modulate the complement activity in atherosclerotic arteries via complement factor H (CFH) binding. In this study, we examined whether the gene-gene interactions between CRP haplotypes and CFH Tyr402His functional polymorphism exerted an effect on early atherosclerosis. Single nucleotide polymorphisms (SNPs) in CFH (Tyr402His) and CRP (-717A>G, -286C >T>A, +1059G>C, +1444C>T and +1846G>A) were genotyped in the participants of the Cardiovascular Risk in Young Finns Study (n=1698, aged 24-39 years). The CRP SNPs were further constructed into haplotypes and their interactive effects with the CFH Tyr402His polymorphism on the early atherogenic vascular changes [i.e. carotid artery compliance (CAC) and intima-media thickness (IMT)] were examined. After risk factor adjustment, a significant gene-gene interaction (P=0.007) on CAC was observed between CRP haplotype ATGTG and CFH Tyr402His polymorphism in males. Furthermore, logistic regression analysis verified the risk-modifying interactive effect on CAC between these loci (OR 3.70, 95% CI 1.37-10.02, P=0.010). No effects on CAC were observed in females and no effects on IMT were detected in either sex. We conclude that the combined presence of CRP haplotype ATGTG and CFH 402His allele may be disadvantageous to carotid artery elasticity in males.

Common variation in NOS1AP and KCNH2 genes and QT interval duration in young adults. The Cardiovascular Risk in Young Finns Study

BACKGROUND

Common genetic variants in the nitric oxide synthase 1 adaptor protein gene (NOS1AP) and in the HERG potassium channel gene (KCNH2) have been associated with cardiac repolarization in middle-aged and elderly subjects.

AIM

We examined the relation between these variants and QT interval duration in a population of healthy young adults.

METHODS

We measured QT interval duration and genotyped rs10494366 T>G (NOS1AP gene, n=1,842) and rs1805123 A>C (KCNH2 gene, n=1,894) in subjects aged 24-39 years.

RESULTS

The NOS1AP variant was significantly related with heart rate-corrected QT interval duration (QTc). Additive regression model adjusting for age, sex, systolic blood pressure, body mass index, alcohol use, and smoking indicated that the G allele was associated with a 3.2 ms (95% confidence interval (CI) 1.7-4.6 ms, P<0.0001) increase in QTc interval duration for each additional copy. The KCNH2 variant was not significantly related with QTc interval duration in the study sample.

CONCLUSION

These findings provide evidence from a population of healthy young adults that a common variation in the NOS1AP gene influences cardiac repolarization within the normal physiological range. Further studies are warranted to investigate the effects of this variant on sudden cardiac death and ventricular arrhythmias.

Depressive symptoms and the metabolic syndrome in childhood and adulthood: a prospective cohort study

OBJECTIVE

To examine the reciprocal associations between depressive symptoms and clinical definitions of the metabolic syndrome in childhood and adulthood.

DESIGN

Population-based prospective cohort study of 921 participants (538 women and 383 men) in Finland. The components of the metabolic syndrome were measured in childhood (mean age 12 years) and again in adulthood (mean age 33 years). A revised version of the Beck Depression Inventory was used to assess depressive symptoms at the mean ages of 24 and 33.

MAIN OUTCOME MEASURES

Metabolic syndrome defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP), the European Group for the Study of Insulin Resistance, and the International Diabetes Federation criteria.

RESULTS

In women, depressive symptoms were associated with increased risk of the metabolic syndrome in adulthood (odds ratio for NCEP metabolic syndrome per 1 SD increase in depressive symptoms 1.40, 95% confidence interval 1.05-1.85). The metabolic syndrome in childhood, in turn, predicted higher levels of depressive symptoms in adulthood (p = .03). In men, no associations were found between depressive symptoms and the clinical definitions of the metabolic syndrome.

CONCLUSION

The process linking depressive symptoms with the metabolic syndrome may go into both directions and may begin early in life.

The longitudinal effects of physical activity history on metabolic syndrome

PURPOSE

To examine the relationship of physical activity and its changes over a 9-yr follow-up to the prevalence of metabolic syndrome (MetS) in 2060 young adults (24-39 yr) enrolled in the Cardiovascular Risk in Young Finns Study.

METHODS

Leisure-time physical activity (LTPA) was assessed using a self-report questionnaire completed in connection with a medical examination at two consecutive measurements in 1992 and 2001. By summing the LTPA items, a physical activity index (PAI) was formed for both measurement points according to which the participants were divided into tracking groups: persistently active, increasingly active, decreasingly active, and persistently inactive. MetS in 2001 was defined by the guidelines of the European Group for the Study of Insulin Resistance (EGIR), the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III), and the International Diabetes Federation (IDF). A continuous metabolic risk score was also calculated by summing the z-scores for the metabolic risk factors.

RESULTS

There was a significant linear relationship between MetS and LTPA at baseline in men and at follow-up in both sexes according to all three definitions. Persistent physical activity during 9 yr was associated with a lower prevalence of MetS than persistent physical inactivity on all definitions (all P < 0.05). Similar results were found for increasingly active women (all P < 0.05). All of these associations remained significant after adjustment for potential confounders. In both men and women, the 9-yr change in LTPA was related to the metabolic risk score after adjustments for baseline LTPA, age, smoking, and education.

CONCLUSIONS

A physically active lifestyle across the lifespan may prevent or delay the onset of metabolic syndrome in young male and female adults.

Alcohol consumption is directly associated with carotid intima-media thickness in Finnish young adults: the Cardiovascular Risk in Young Finns Study

OBJECTIVES

There is substantial epidemiological data suggesting a J- or U-shaped association between alcohol consumption and coronary events. However, some studies in experimental animals suggest that alcohol may increase atherosclerosis. Therefore, our aim was to study whether alcohol consumption is associated with carotid intima-media thickness (IMT), marker of subclinical atherosclerosis, in young, healthy adults.

METHODS

Alcohol consumption, carotid IMT and conventional cardiovascular risk factors were investigated in 2074 subjects, aged 24-39 years.

RESULTS

In subjects consuming none, >0 to <2, 2 to <4 or >or=4 units of alcohol per day, the respective carotid IMT values were 0.57+/-0.004, 0.59+/-0.003, 0.59+/-0.006, and 0.60+/-0.012 mm (mean+/-S.E.M., P<0.0001 for increasing IMT trend across alcohol consumption categories). This direct association between alcohol consumption and IMT was independent of age, sex and several cardiovascular risk factors, e.g. blood pressure, LDL-cholesterol, HDL-cholesterol, BMI, smoking, CRP and insulin (P=0.008 in multivariable regression model). The frequencies of drinking wine or strong alcohol beverages (respective P-values 0.03 and 0.01 for increasing IMT trend across beverage consuming frequency) were directly correlated with carotid IMT in models adjusted for age, sex and risk factors.

CONCLUSIONS

We found a direct relationship between alcohol consumption and carotid IMT in young adults. This association was independent of cardiovascular risk factors suggesting that in young healthy adults alcohol consumption may have pro-atherogenic effects.

Vascular endothelial function and leisure-time physical activity in adolescents

BACKGROUND

Exercise training improves endothelial function in high-risk adolescents, but the influence of habitual leisure-time physical activity on endothelial function in healthy adolescents is unknown.

METHODS AND RESULTS

Brachial artery flow-mediated endothelial function and physical activity habits were assessed in 483 adolescents (13 years of age) participating in an atherosclerosis prevention study (Special Turku Coronary Risk Factor Intervention Project for Children [STRIP]). Endothelial function was examined with ultrasound; physical activity was assessed with self-administered questionnaires. A leisure-time physical activity index was calculated by multiplying mean weekly leisure-time exercise intensity, duration, and frequency [boys, 31.2 +/- 23.0 MET h/wk (mean +/- SD); girls, 24.0 +/- 20.9 MET h/wk; P for gender difference=0.0003]. Maximum flow-mediated dilatation (FMD) and total FMD response (the area under the dilatation curve 40 to 180 seconds after hyperemia) were calculated. In boys, maximum FMD and area under the dilatation curve 40 to 180 seconds after hyperemia were directly associated with leisure-time physical activity index in regression analyses adjusted for brachial artery diameter (maximum FMD, P=0.020; area under the dilatation curve 40 to 180 seconds after hyperemia, P=0.0055). These associations remained significant after further adjustments for body mass index, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein, and systolic blood pressure. A difference of approximately 50 MET h/wk corresponding to approximately 10 hours of moderate intensity activity weekly between sedentary and active boys was associated with an approximately 1% unit difference in maximum FMD.

CONCLUSIONS

Leisure-time physical activity is directly associated with brachial artery FMD responses in 13-year-old boys, providing evidence that physical activity beneficially influences endothelial function in healthy male adolescents. Lack of association in girls may reflect their overall lower physical activity level.

Allelic variants of upstream transcription factor 1 associate with carotid artery intima-media thickness: the Cardiovascular Risk in Young Finns study

BACKGROUND

Polymorphisms of the upstream transcription factor 1 (USF1) have been associated with familial combined hyperlipidemia and coronary heart disease. The impact of this gene on subclinical atherosclerosis is unknown. Associations of 3 allelic variants of the USF1 gene and their haplotypes with carotid artery intima - media thickness (IMT), carotid artery compliance (CAC) and brachial artery flow mediated dilatation (FMD) were studied in a population of Finnish healthy young adults.

METHODS AND RESULTS

The study population comprised 2,281 individuals participating in the Cardiovascular Risk in Young Finns study. IMT, CAC and FMD values were measured by ultrasound examination. Genotypes were analysed using the 5' nuclease assay. A significant difference in IMT was found for usf1s1 (rs3737787) and usf1s8 (rs2516838) genotypes (p-values 0.046 and 0.021, respectively). Moreover, there was a significant difference between groups in haplotype 1 and haplotype 2 for IMT (p-values 0.011 and 0.028 respectively). In multivariate stepwise linear regression models adjusted by age, sex, body mass index, systolic and diastolic blood pressures, smoking, C-reactive protein, glucose, high- and low-density lipoprotein-cholesterols and triglycerides there were significant associations for the usf1s1 minor genotype AA to predict low IMT (p=0.038) and usf1s8 minor genotype GG to predict high IMT (p=0.003). There was also a significant association for haplotype 2 to predict low IMT in the otherwise similar multivariate model (p=0.006). No associations were found for polymorphisms and CAC, FMD or serum lipids.

CONCLUSIONS

The rs2516838 and rs3737787 polymorphisms of USF1 influence the carotid artery IMT, which is a new finding.

Lifetime body mass index and later atherosclerosis risk in young adults: examining causal links using Mendelian randomization in the Cardiovascular Risk in Young Finns study

Aims

Mendelian randomization uses genetic variants related to environmentally modifiable risk factors in an attempt to improve causal inference from observational data. We examined the effect of lifetime body mass index (BMI) on adult carotid intima-media thickness (CIMT) and various atherosclerotic risk factors by using both Mendelian randomization and conventional analyses.

Methods and results

A total of 2230 individuals (1218 women), aged 3–18 at study induction, took part in clinical examinations in 1980, 1983, 1986, and, most recently, 2001 when they were aged 24–39. In these analyses we utilized the known relation between FTO polymorphism rs9939609 and BMI. The dose–response association between the number of A alleles in FTO and higher mean BMI from childhood to adulthood was confirmed, but no associations with potential confounding factors were observed. In standard regression models, lifetime BMI was associated with adult CIMT, lifetime systolic blood pressure, adult fasting glucose, and adult HOMA-index. When variation in FTO was used as an instrument for unconfounded BMI levels, similar or larger effects of lifetime BMI on all these phenotypes were found, although with wider confidence intervals.

Conclusion

Mutually supportive results from Mendelian randomization and standard regression models strengthen the evidence of the effect of lifetime BMI on atherosclerosis risk in young adults.

Association of age at menarche with cardiovascular risk factors, vascular structure, and function in adulthood: the Cardiovascular Risk in Young Finns study

BACKGROUND

It is unclear whether age at menarche is an independent determinant of future cardiovascular risk.

OBJECTIVE

We aimed to determine whether menarcheal age is an independent predictor of body mass index (BMI) and a wide range of cardiovascular risk factors in adolescence and adulthood.

DESIGN

We examined the associations of menarcheal age with BMI (in kg/m(2)) and other cardiovascular risk factors in adolescence and adulthood in a population-based sample of 794 female adolescents aged 9-18 y at baseline. Their age at first menstruation was requested at baseline and again 3 and 6 y later. Cardiovascular risk factors were assessed at baseline and at age 30-39 y.

RESULTS

A 1-y decrease in menarcheal age was associated with 0.81 (95% CI: 0.53, 1.08) higher adult BMI as well as greater waist circumference and waist-to-hip ratio, elevated systolic blood pressure, higher insulin resistance, and greater risk of metabolic syndrome (P < 0.05 for all). In multivariable analysis in which these adult risk factors were mutually adjusted for, only the inverse association between age at menarche and adult BMI remained. However, this inverse association was lost after adjustment for premenarcheal BMI (beta: -0.16; 95% CI -0.55, 0.23; P = 0.42). Higher premenarcheal BMI predicted earlier menarche, and the strong association between premenarcheal BMI and adult BMI was robust to adjustment for age at menarche.

CONCLUSIONS

These findings suggest that early menarche is only a risk marker. Greater childhood BMI seems to contribute to earlier age at menarche and, because of tracking, greater adult BMI and associated cardiovascular risk. An independent effect of early menarche on adult adiposity cannot be excluded, but it is likely to be small at best.

Associations of dyslipidemias from childhood to adulthood with carotid intima-media thickness, elasticity, and brachial flow-mediated dilatation in adulthood: the Cardiovascular Risk in Young Finns Study

BACKGROUND

Dyslipidemias are the major cause for atherosclerosis. They may act synergistically with nonlipid risk factors to increase atherogenesis. In the present study, we examined the effects of dyslipidemias from childhood to adulthood and their interaction with nonlipid risk factors on markers of subclinical atherosclerosis.

METHODS AND RESULTS

Study subjects were participants of the longitudinal Cardiovascular Risk in Young Finns Study started in 1980 (n=2265, age 3 to 18 years). To phenotype type IIa, IIb, and IV dyslipidemias and hypoHDL-cholesterolemia, we calculated age and sex-specific z scores for lipid values for each subject in 1980, 1983, 1986, and 2001. Subjects with mean z score over 90th percentile for LDL-cholesterol or triglycerides were considered having type IIa or IV dyslipidemia. Subjects with mean z score over 90th percentile for LDL-cholesterol and triglycerides had type IIb dyslipidemia, and those with mean z score below 10th percentile for HDL-cholesterol had hypoHDL-cholesterolemia. Compared to controls, subjects with type IIb dyslipidemia had increased carotid IMT (P<0.01). This difference remained significant when adjusted with other risk factors (P<0.05). Carotid IMT also increased significantly more with increasing number of nonlipid risk factors (P<0.001) or presence of the metabolic syndrome (P<0.05) in subjects with type IIb than in controls. Subjects with type IIb or type IV dyslipidemia had decreased carotid elasticity (P<0.05), but these differences became nonsignificant (P>0.3) when adjusted with blood pressure.

CONCLUSIONS

Our findings suggest that type IIb dyslipidemia has deleterious effects on vasculature already since childhood. Subjects with type IIb dyslipidemia are more vulnerable to the effects of cardiovascular risk factors and metabolic syndrome.

The influence of smoking and homocysteine on subclinical atherosclerosis is modified by the connexin37 C1019T polymorphism - The Cardiovascular Risk in Young Finns Study

BACKGROUND

A polymorphism C1019T on the connexin37 (Cx37) gene has been found to associate with coronary artery disease. There are conflicting results on which allele confers risk, and the possibility of interactions between the polymorphism and risk factors has been raised. In this study, we examined interactions between the Cx37 polymorphism and common risk factors and their associations to early vascular parameters of atherosclerosis: carotid artery intima-media thickness (IMT), and carotid artery compliance (CAC) and brachial artery flow mediated dilatation (FMD).

METHODS

A population of 1440 healthy young adults from the Cardiovascular Risk in Young Finns Study was studied. The subjects were genotyped and their cardiovascular risk factor and ultrasound data gathered in 2001 were used for the statistical analyses.

RESULTS

In the whole population, homocysteine in subjects with the TT genotype was found to be associated with higher FMD values (p for interaction 0.038) and remained so in three different adjusted models (p for interaction 0.022-0.038). In women with the CC genotype, smoking was found to be associated with higher FMD values and the smoking-by-genotype interaction remained significant in three adjusted models (p for interaction 0.001-0.041). In women with TT genotype, the effect of smoking was opposite, i.e., FMD values for smokers were lower compared to non-smokers. In men, physical activity interacted with Cx37 on CAC in the CT and TT genotypes (p for interaction 0.011). No significant interactions were found to predict IMT.

CONCLUSIONS

The effect of smoking and homocysteine levels on arterial endothelial functions and elasticity were modified by the allelic variation of the Cx37 gene. These data suggest that variation in the connexin gene may modify effects risk factors have on vascular function.

Childhood predictors of the metabolic syndrome in adulthood. The Cardiovascular Risk in Young Finns Study

BACKGROUND

Obese youths may be susceptible to develop the metabolic syndrome (MS) later in life.

AIM

To study childhood predictors of MS in adulthood.

METHOD

Prospective cohort study including 2,195 subjects, aged 3-18 years at base-line in 1980, who were re-examined in 1983, 1986, and 2001.

RESULTS

In adults (aged 24-39 years) in 2001, the prevalence of MS (using the International Diabetes Federation criteria) was 19% in men and 12% in women. Multivariable logistic regression model selected obesity, male sex, high triglycerides, high insulin, high C-reactive protein (CRP), and family history of hypertension and type 2 diabetes, as independent predictors of adult MS. Youth obesity (body mass index (BMI)>80th age- and sex-specific percentile) was the strongest risk factor for MS. During the 21-year follow-up, there was an increasing trend in BMI, insulin, systolic blood pressure, and triglycerides, and a decreasing trend in high-density lipoprotein cholesterol in obese subjects who developed MS in adulthood compared to those obese subjects who did not develop MS.

CONCLUSIONS

Youth determinants of adult MS included obesity, high triglycerides, high insulin, high CRP, and family history of hypertension and type 2 diabetes. Identifying these risk factors at an early stage could help identifying children and adolescence at greater risk of developing MS later in life.

When do social inequalities in C-reactive protein start? A life course perspective from conception to adulthood in the Cardiovascular Risk in Young Finns Study

BACKGROUND

It is unclear when in the life course do social inequalities in inflammation emerge. We examined whether the association between socioeconomic position (SEP) and C-reactive protein (CRP) is determined at conception, in childhood, adolescence or adulthood in 1484 participants from the population-based Cardiovascular Risk in Young Finns Study.

METHODS

Five variants of the CRP gene were used to investigate whether SEP differences in CRP levels are determined at conception. SEP and serum CRP were assessed in childhood (age 3-9), adolescence (age 12-18) and in adulthood (age 24-39). SEP was measured using parental education and occupational status in childhood and adolescence, and participants' own education and occupational status in adulthood. Participants with CRP > 10 mg/l were excluded.

RESULTS

All CRP gene variants were associated with circulating CRP concentrations in childhood, but there were no differences in the distribution of these variants by SEP. No strong evidence was found of associations between parental SEP and CRP. A graded association between higher SEP and lower CRP was observed in adulthood for education (P = 0.0005) but not for occupational status. Trajectories that led to high educational achievement both in the participants and their parents were associated with lower (P <or= 0.047) CRP levels in adulthood. Excluding participants with infectious diseases, pregnant or lactating women and women using oral contraceptives did not change the findings.

CONCLUSION

In this cohort, SEP differences in CRP concentrations seen in adulthood appear not to be determined at conception or evident in childhood or adolescence.

Relationship between leptin and C-reactive protein in young Finnish adults

CONTEXT

Leptin and C-reactive protein (CRP) concentrations are increased in inflammation, and both have been linked to increased risk for cardiovascular diseases.

OBJECTIVE

The objective of the study was to explore in a population-based sample whether the relation between leptin and CRP is independent of obesity level and whether genetic causes of CRP elevation contribute to leptin levels.

DESIGN

This was a population-based study including 1862 young adults (971 women; 891 men) aged 24-39 yr.

SETTING

The study was conducted at five centers in Finland.

MAIN OUTCOME MEASURES

Associations between leptin and CRP adjusted for obesity indices, risk factors, genetic variables, and lifestyle variables were measured.

RESULTS

Women had 3.0-fold higher median concentrations of leptin (12.5 vs. 4.1 ng/ml) and 1.3-fold higher median concentrations of CRP (0.75 vs. 0.56 mg/liter) than men (P < 0.0001 in both comparisons). In univariate analyses, CRP and leptin were significantly intercorrelated (r = 0.47, P < 0.0001 for women; r = 0.46, P < 0.0001 for men). In multiple regression analysis including age, body mass index, waist circumference, insulin, lipids, systolic and diastolic blood pressures, smoking status, and use of oral contraceptives in women, leptin was the main determinant of CRP in men (P < 0.0001) and the second most important determinant in women (P < 0.0001). A Mendelian randomization test based on genetic variants in the CRP gene (five single nucleotide polymorphisms) provided no support for CRP as a causal agent for leptin.

CONCLUSIONS

Leptin, obesity, and oral contraceptive use in women were the main factors related to CRP. The relation between leptin and CRP was independent of obesity and cardiovascular risk factors.

Associations between connexin37 gene polymorphism and markers of subclinical atherosclerosis: the Cardiovascular Risk in Young Finns study

OBJECTIVE

Connexin37 (cx37) C1019T polymorphism has been shown to associate with coronary artery disease in different populations. We investigated whether this polymorphism associates with carotid artery intima-media thickness (IMT), carotid artery compliance (CAC) and brachial artery flow mediated dilatation (FMD) - i.e., early ultrasound markers of subclinical atherosclerosis - in a clinically healthy population of young Finnish adults.

METHODS AND RESULTS

1440 individuals from the Cardiovascular Risk in Young Finns study were genotyped and studied using cardiovascular risk factor and ultrasound data obtained in 2001. In linear regression models, no significant association between the cx37 polymorphism and carotid IMT, CAC or brachial artery FMD (ANOVA, p=0.159, 0.151 and 0.547), respectively, was found in the whole population or in women and men separately.

CONCLUSIONS

The connexin37 C1019T polymorphism is not related with markers of subclinical atherosclerosis in young adults.