Migration at early age from a high to a lower coronary heart disease risk country lowers the risk of subclinical atherosclerosis in middle-aged men.

BACKGROUND: Study of migrants offers a natural model to assess environmental risk of coronary heart disease (CHD) in countries differing in CHD occurrence. In Sweden, CHD risk has been markedly lower than in Finland from where a large migration occurred in the 1970s. OBJECTIVES: To study the structural and functional markers of subclinical atherosclerosis in twin pairs discordant for migration with the main focus on age at migration, length of residence and integration into Swedish society after migration from a high to a lower CHD risk country. METHODS: Carotid intima-media thickness (IMT) and brachial artery endothelial function (EF) were assessed with high-resolution ultrasound and a set of cardiovascular, socio-economic and psychosocial risk factors were estimated in 76 middle-aged male twin pairs discordant for migration from Finland to Sweden. RESULTS: Men who had migrated in adolescence had lower IMT values compared with their co-twins living in Finland (0.665 +/- 0.114 vs. 0.802 +/- 0.167 mm, P = 0.009). Also men who integrated well to Swedish society had lower (0.720 +/- 0.154 vs. 0.799 +/- 0.207 mm, P = 0.013) IMT values than their twin brothers living in Finland. Associations between IMT and migration age and between IMT and integration remained significant in multivariate analyses of several CHD risk factors. The intrapair difference in IMT was significantly associated with immigration age and integration (ANOVA, P = 0.0082), the difference being greatest among pairs where the brother living in Sweden had migrated at early age and integrated well to Swedish society. EF was better in men who had migrated to Sweden before the age of 21 years, but not later, compared with their co-twins in Finland (6.4 +/- 4.6% vs. 3.8 +/- 3.6%, P = 0.025). CONCLUSIONS: Migration at an early age and good integration are beneficial to vascular health associated with moving from a high to a lower CHD risk country, suggesting that an environment-sensitive period influences atherogenesis before adulthood.

Obesity, adipokines and asthma.

BACKGROUND: The prevalence of asthma and obesity is increasing concomitantly, but many aspects of this link are unclear. Our objective was to examine whether obesity is associated with asthma in three time points of life, and whether immunomodulatory adipokines, leptin and adiponectin are linked to overweight-associated asthma. METHODS: We studied the association between obesity and asthma at ages 3-18 years [mean (SD), 10 years (5), n = 3582, year 1980], 9-24 years [16 years (5), n = 2764, 1986] and 24-39 years [32 years (5), n = 2620, 2001] in a prospective cohort study and further tested for associations with serum leptin and adiponectin concentrations. Data on allergy status, smoking and other laboratory values (serum insulin, plasma C-reactive protein and serum lipid values) were also analyzed. RESULTS: Allergy and parental asthma were significantly associated with asthma at all ages. At ages 24-39 years, but not earlier, body mass index (BMI) (odds ratio, OR 1.05; P = 0.019) and female gender (OR 1.56; P = 0.031) were independently associated with asthma. Increase in BMI was also associated with incident asthma during adulthood (OR 1.08; P = 0.030). Levels of leptin, adiponectin or any other obesity-related biomarker were not independently associated with asthma. CONCLUSIONS: Asthma is linked with obesity in adults, but our results do not support a significant role for leptin, adiponectin or any other obesity-related biomarker studied in this association. Other factors should be sought for better understanding the connection between obesity and asthma.

Increased aortic intima-media thickness: a marker of preclinical atherosclerosis in high-risk children.

BACKGROUND: Autopsy studies in children have shown that atherosclerotic lesions begin to develop first in the intima of the aorta. Recent developments in ultrasound techniques have made it possible to visualize the intima-medial thickness of the abdominal aorta directly (aIMT). Therefore, we examined the feasibility of measuring aIMT in children and studied its value in distinguishing high-risk children from healthy controls compared with a more established marker of subclinical atherosclerosis, the common carotid artery intima-medial thickness (cIMT). METHODS AND RESULTS: IMTs were measured using high-resolution (13 MHz) ultrasound in 88 children (aged 11+/-2 years); 16 had hypercholesterolemia (LDL cholesterol, 5.1+/-1.2 mmol/L), 44 had type 1 diabetes (mean duration, 4.4+/-3.1 years; LDL cholesterol, 2.3+/-0.7 mmol/L), and 28 were healthy (controls; LDL cholesterol, 2.5+/-0.8 mmol/L). High-risk children had significantly increased aIMTs and cIMTs (both P<0.001) compared with controls. In controls, aIMT was similar to cIMT (P=NS), but aIMT was higher than cIMT in the children with hypercholesterolemia and diabetes (both P<0.01). Both markers showed excellent and approximately equal between-observer (<4%) and between-subject variation (<5%). CONCLUSIONS: Children with hypercholesterolemia and diabetes show increased IMTs compared with healthy controls, with a relatively greater increase in the aIMT than in the cIMT. Because atherosclerosis begins first in the intima of the aorta, these data suggest that the aIMT might provide the best currently available noninvasive marker of preclinical atherosclerosis in children.

Population-based twin study of the effects of migration from Finland to Sweden on endothelial function and intima-media thickness.

Finnish men have higher coronary heart disease (CHD) mortality than Swedish men do. To assess the impact of migration to a country with lower CHD mortality on subclinical atherosclerosis, we measured early functional and structural atherosclerotic vascular changes in twins discordant for migration from Finland to Sweden. Conventional CHD risk factors, flow-mediated dilatation (FMD) of the brachial artery, carotid intima-media thickness, and carotid artery compliance were measured in 74 male twin pairs (20 monozygous, 54 dizygous), aged 42 to 69 years, in which co-one twin had migrated more than 20 years ago permanently to Sweden. There were no significant differences in CHD risk factors except for diastolic blood pressure and body fat percentage, which were higher in Sweden. In all subjects, mean FMD was non-significantly higher in Sweden (5.7+/-4.3% vs 4.9+/-4.2%, P=0.22), but in monozygous twins the difference in FMD was highly significant (7.2+/-4.4 vs 3.7+/-2.9%, P=0.003). There was no significant difference in intima-media thickness or carotid artery compliance between Sweden and Finland. We conclude that in Finnish monozygous twins the endothelial function is better among the twins that have migrated to a country with lower CHD prevalence.

Noninvasive assessment of brachial artery endothelial function with digital ultrasound and 13-MHz scanning frequency: feasibility of measuring the true inner luminal diameter using the intima-lumen interface.

Previous studies assessing endothelial function as flow-mediated changes in the brachial artery diameter have not been able to measure the true inner luminal diameter. This is due to the lack of image quality, which has hampered the visualisation of the lumen-intimal interface. Because increases in resolution and scanning frequency have recently led to improved ultrasound (US) image quality, we assessed the feasibility of measuring the true brachial artery diameter using digital US and 13-MHz scanning frequency. Satisfactory true inner diameter measurements were obtained in all subjects (n = 148, middle-aged men, mean age 54 +/- 7 y) participating in a risk factor study. At baseline flow, the intima to intima diameter was 4.03 +/- 0.49 and 4.67 +/- 0.52 mm measured conventionally from the anterior to the posterior media-adventitia interface (difference 0.64 +/- 0.10 mm). After hyperaemia, the intima to intima diameter was 4.23 +/- 0.46 mm and the adventitia to adventitia diameter 4.86 +/- 0.50 mm. Flow-mediated dilation (FMD) expressed as the percentage change from the baseline diameter measured 5.3 +/- 4.3% using the true inner diameters and 4.3 +/- 3.7% using the conventional outer diameters. The difference in FMD values was systematic, and there was a good linear correlation between them (r = 0.93, p < 0.0001). If FMD is presented as the percentage change from baseline to hyperaemia, this new method gives values that are approximately 1% unit higher, compared with values when brachial luminal diameter is measured in the conventional way between the adventitia-media interfaces.

Comparison of hand-to-leg and leg-to-leg bioelectric impedance devices in the assessment of body adiposity in prepubertal children. the STRIP study. Special Turku coronary Risk factor Intervention Project.

UNLABELLED: The body composition of 40 seven-year-old children and of 50 of their parents was measured using two bioelectric impedance devices, the Model 101, RJL Systems, USA (conventional hand-to-leg device) and TANITA body fat analyser, TBF 105, Tanita Co, Tokio, Japan (newer leg-to-leg device). There were strong correlations between impedances obtained by these two devices [r= 0.95, r = 0.93, r= 0.82, r = 0.81 for girls (n = 22), boys (n = 18), mothers (n = 27) and fathers (n = 23), respectively (p < 0.0001 for all)]. However, there was a clear difference in the absolute impedance values due to the fact that the devices measure different segments of the body. Fat percentages based on built-in equations of the two devices correlated in girls, mothers and fathers (r = 0.71, r = 0.94, r = 0.80, respectively; p < 0.001) but not in boys (r = 0.21, p = 0.41). Using the Bland-Altman comparison method, a large intraindividual difference was observed in the fat percentages by the two devices, independent of adiposity level. Both devices detected significant gender differences in fat percentages in 7-y-old girls and boys with similar BMIs. CONCLUSION: When using the Tanita 105 leg-to-leg bioelectric impedance device to assess adiposity in children there is an obvious need for revised equations. For this, comparative studies using more validated methods, i.e. densitometry or DEXA, as part of a multi-compartment model are needed.