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Background: Risk factors in young adulthood may persist into later life and eventually lead to cardiovascular (CV) disease. The purpose of this study was to describe the prevalence of hypertension and other established CV risk factors in older adolescents., Methods: Study nurses examined 120 girls and 80 boys with a mean age of 17.4 (SD, 0.8; range 15.8-19.6 years). After 5 minutes of sitting rest, resting blood pressure (BP) of the participants was measured in triplicate by sphygmomanometry. Body height and weight were measured and body mass index (BMI) was calculated. Serum lipids, smoking and drinking status were assessed. Hypertension was diagnosed according to the criteria specified in the 1996 update of the Task Force on BP treatment in Children and Adolescents (Pediatrics 1996;98:649-58)., Results: Almost 25% of the subjects currently smoked with a median daily consumption of 6 (Interquartile 4-9) and 11 (6-16) cigarettes in girls and boys, respectively. Fourty-nine (41%) girls used oral contraceptives. Systolic (118 versus 109 mm Hg, p<0.001) and diastolic BPs (70.5 versus 68.0 mm Hg, p=0.033) were significantly higher in boys than in girls. Two (2%) girls and four (5%) boys had systolic hypertension; diastolic hypertension was found in six (5%) girls and one (1%) boy. Twelve (10%) girls and six (8%) boys were overweight (>25.0 kg/m2). Twenty (17%) girls and seven (9%) boys had hypercholesterolemia (total serum cholesterol > or =5.2 mmol/L). Overall, 50 (42%) girls and 31 (39%) boys had at least one CV risk factor, 12 (10%) girls and four (5%) boys had two risk factors, and three (3%) girls and one (1%) boy had more than two risk factors., Conclusions: In 17-year-olds living in an affluent society the prevalence of CV risk factors was high. These findings underscore the importance of health education and prevention at this age.

An increased pulse pressure suggests aortic stiffening. New evidence also suggests that pulse pressure is a more sensitive measure of risk than other indexes of blood pressure in middle-aged and older persons. The objective of the study was to relate pulse pressure to the risk of cardiovascular events in the general population, and to assess whether pulse pressure could improve the Framingham risk prediction. A total of 378 men and 391 women over the age of 50 years (mean 62.7 years) were followed. Sex-specific Framingham cardiovascular risk scores were derived from age, systolic pressure, diastolic pressure, total and HDL cholesterol, smoking status and the presence or absence of diabetes mellitus. The cutoff points used to develop a pulse pressure score were calculated by determining the percentile points corresponding to the blood pressure categories in the Framingham risk score. We calculated relative hazard rates by multiple Cox regression. After a median follow-up of 7.2 years (range: 11 months-15 years), a total of 148 cardiovascular events occurred. In Cox regression analysis, a 10 mmHg higher pulse pressure was associated with 31% (P<0.0001) increase in the risk for cardiovascular events (fatal and nonfatal) after adjustment for sex, age, total and HDL cholesterol, smoking and the presence of diabetes mellitus. After adjustment for the aforementioned risk factors, a one-point increment in the blood pressure and pulse pressure scores was associated with a 40 and 48% (both P<0.0001) increase in the risk of fatal and nonfatal cardiovascular events, respectively. When both the blood pressure and pulse pressure scores were forced into a Cox model, only the pulse pressure score remained statistically significant (P<0.0001) with a relative hazard rate of 1.37 (CI: 1.16-1.69). These prospective data suggest that pulse pressure may improve the Framingham risk prediction among middle-aged and older individuals. Further studies, especially in the Framingham cohort, are warranted.

Background: Because telomeres are eroded during mitosis, telomere length indicates the replicative history of human somatic cells. Clinical markers of ageing--such as pulse pressure and survival--are associated with telomere length. On the basis of findings of studies in twins, telomere length seems to be familial, but little is known about its mode of inheritance. We aimed to investigate the inheritance of telomere length., Methods: We measured terminal restriction fragment (TRF) length in white-blood-cell DNA taken from individuals from the family-based cohort of the Flemish Study on Environment, Genes, and Health Outcomes., Findings: We recorded no correlation in sex and age adjusted TRF length between spouses (r=-0.05; p=0.70) nor between fathers and sons (r=-0.16; p=0.35). By contrast, we noted robust correlations in TRF length between fathers and daughters (r=0.60; p<0.0001); between mothers and sons (r=0.41; p=0.0017) and daughters (r=0.59; p<0.0001); and among siblings (r> or =0.61; p< or =0.0004)., Interpretation: X-linked inheritance of TRF length is the most probable explanation for our findings. Pending confirmation, our observations suggest that the process of ageing might be an X-linked trait.

Background: Many studies have analysed the relation between cardiovascular risk factors and oral contraceptive use in adult women, whereas information on the possible health effects of oral contraceptive use during adolescence is lacking., Design: The effect of current contraceptive pill use on blood pressure and serum total cholesterol concentration was studied in a cross-sectional sample of 120 adolescent girls with a mean age of 17.4 years., Methods: After the girls had rested for 5 minutes in the sitting position, trained study nurses measured blood pressure three times consecutively using a mercury sphygmomanometer. The nurses also administered a questionnaire gathering information on the use of oral contraceptives, smoking and parental social class. In the morning blood samples were taken for the measurement of serum total cholesterol., Results: Mean age (+/-SD) was 17.4+/-0.8 years. Blood pressure averaged (+/-SD) 108.7+/-9.9 systolic and 68.0+/-8.2 mmHg diastolic. Serum total cholesterol was 4.5+/-0.7 mmol/l. Forty-nine girls (41%) were taking the contraceptive pill. Of these, 44 (90%) were on a combination of ethinyloestradiol (20-35 microg) and a progestogen, four (8%) on anti-androgens (35 microg) and one (2%) only on a progestogen. After adjustment for age, body mass index, smoking and alcohol status systolic blood pressure was 4.6 mmHg higher (95% CI 1.2-8.1; P<0.001) in current pill users than in girls not currently on the pill (111.4 versus 106.8 mmHg). Adjusted for the aforementioned covariates, diastolic blood pressure was not related to pill use (68.2 versus 67.8 mmHg; P=0.7). Serum total cholesterol was 0.43 mmol/l (95% CI 0.18-0.60; P=0.001) higher among girls using oral contraceptives (4.7 versus 4.3 mmol/l), irrespective of whether or not the model was adjusted for age, body mass index, smoking and alcohol status., Conclusions: In 17-year-old girls, the use of oral contraceptives was associated with a nearly 5 mmHg higher systolic blood pressure and a 0.4 mmol/l higher level of serum total cholesterol. The long-term prognostic implications of our findings remain to be elucidated.

In this study, we investigated 17- to 18-year-old boys and girls to determine whether changes in humoral or cellular immunity or respiratory complaints were related to blood serum levels of polychlorinated biphenyls (PCBs) and dioxin-like compounds after lifetime exposure in Flanders (Belgium). We obtained blood samples from and administered questionnaires to 200 adolescents recruited from a rural area and two urban suburbs. Physicians recorded medical history and respiratory diseases. We measured immunologic biomarkers such as differential blood cell counts, lymphocyte phenotypes, and serum immunoglobulins. As biomarkers of exposure, we determined the serum concentrations of PCBs (PCB 138, PCB 153, and PCB 180) and dioxin-like compounds [chemical-activated luciferase expression (CALUX) bioassay]. The percentages of eosinophils and natural killer cells in blood were negatively correlated with CALUX toxic equivalents (TEQs) in serum (p = 0.009 and p = 0.05, respectively). Increased serum CALUX TEQs resulted in an increase in serum IgA levels (p = 0.05). Furthermore, levels of specific IgEs (measured by radioallergosorbent tests) of cat dander, house dust mite, and grass pollen were also significantly and negatively associated with the CALUX TEQ, with odds ratios (ORs) equal to 0.63 [95% confidence interval (CI), 0.42-0.96], 0.68 (0.5-0.93), and 0.70 (0.52-0.95), respectively. In addition, reported allergies of the upper airways and past use of antiallergic drugs were negatively associated with CALUX TEQs, with ORs equal to 0.66 (0.47-0.93) and 0.58 (0.39-0.85), respectively. We found a negative association between IgGs and marker PCBs in serum (p = 0.009). This study shows that immunologic measurements and respiratory complaints in adolescents were associated with environmental exposure to polyhalogenated aromatic hydrocarbons (PHAHs). The negative correlation between PHAHs and allergic responses in adolescents suggested that exposure may entail alterations in the immune status.

This study investigated host factors and environmental factors as potential determinants of polychlorinated aromatic hydrocarbons (PCAHs) in serum of adolescents. We recruited 200 participants (80 boys and 120 girls), with a mean age of 17.4 years (SD, 0.8), in Belgium from a rural control area (Peer) and from two polluted suburbs of Antwerp where a nonferrous smelter (Hoboken) and waste incinerators (Wilrijk) are located. We quantified polychlorinated biphenyls (PCBs; congeners 138, 153, and 180) in serum by gas chromatography and obtained the toxic equivalents (TEQs) of PCAHs in serum with the chemically activated luciferase gene expression bioassay (CALUX). Serum PCB concentration was higher in boys than in girls (1.67 vs. 1.02 nmol/L or 377 vs. 210 pmol/g serum lipids; p< 0.001). In the whole adolescent group, multiple regression showed that serum PCB concentration decreased 0.06 nmol/L per 1% increase in body fat content (p< 0.001) and increased 0.39 nmol/L and 0.14 nmol/L per 1 mmol/L increase in serum concentrations of triglycerides (p < 0.001) and cholesterol (p = 0.002), respectively. Host factors explained 44% of the serum PCB variance. In the same model, serum PCB concentration increased 0.14 nmol/L with 10 weeks of breast-feeding (p< 0.001) and 0.06 nmol/L with intake of 10 g animal fat per day (p < 0.001), and was associated with residence in the waste incinerator area (9% higher; p = 0.04); 11% of the variance could be explained by these environmental factors. The geometric mean of the serum TEQ value was similar in boys and girls (0.15 TEQ ng/L or 33.0 pg/g serum lipids). In multiple regression, TEQ in serum decreased 0.03 ng/L per centimeter increase in triceps skinfold (p = 0.006) and was 29% higher in subjects living close to the nonferrous smelter (p < 0.001). This study showed that in 16- to 18-year-old teenagers host factors are important determinants of serum concentrations of PCAHs, whereas environmentally related determinants may to some extent contribute independently to human exposure to these persistent chemicals in the environment.

Studies on the possible association between blood pressure and blood lead have reached divergent conclusions. In a previous meta-analysis, a doubling of the blood lead concentration was associated with a 1.0/0.6 mm Hg increase in systolic and diastolic blood pressure (BP). This meta-analysis updates the analysis originally performed in 1994. Articles on the association between BP and blood lead were identified from computer searches from January 1980 to February 2001 using the Medical Literature Analysis and Retrieval System. Of the studies reviewed, 31 provided sufficient details to be considered. The meta-analysis included 58518 subjects recruited from the general population in 19 surveys and from occupationally exposed groups in 12 studies. In all but four studies, the results were adjusted for age, and most studies took into account additional confounding factors such as body mass index and the use of alcohol and medication. Weighted joint P-values were calculated using Stouffer's procedure. The association between BP and blood lead was similar in both men and women. In the combined studies, a two-fold increase in blood lead concentration was associated with a 1.0 mm Hg rise in the systolic pressure (95% CI +0.5 to +1.4 mm Hg; P < 0.001) and with a 0.6 mm Hg increase in the diastolic pressure (95% CI +0.4 to +0.8 mm Hg; P < 0.001). On balance, this meta-analysis suggests that there can only be a weak association between BP and blood lead.