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R Fagard

Publications and source records attributed to R Fagard.

506 records · Page 29Linked to original sources
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Lead exposure and conventional and ambulatory blood pressure: a prospective population study. PheeCad Investigators.

OBJECTIVE: - To evaluate in a prospective fashion the association between low-level lead exposure and blood pressure. DESIGN: - Prospective cohort study. SETTING: - General population. PARTICIPANTS: - A random population sample (N=728; 49% men; age range, 20-82 years) was studied in Belgium for 1985 through 1989 and reexamined for 1991 through 1995. MEAN OUTCOME MEASURES: - At baseline and follow-up, blood pressure was measured by conventional sphygmomanometry (15 total readings) and at follow-up also by 24-hour ambulatory monitoring. Lead exposure was estimated from blood lead and zinc protoporphyrin concentrations. Multivariate analyses controlled for sex, age, body mass index, smoking and drinking habits, physical activity, exposure at work, social class, menopausal status, use of medications (antihypertensive medication, oral contraceptives, hormonal replacement therapy), hematocrit or hemoglobin, serum total calcium concentration, 24-hour urinary sodium and potassium excretion, and gamma-glutamyltransferase activity. RESULTS: - At baseline, mean (SD) systolic/diastolic conventional blood pressure was 130 (17)/77 (9) mm Hg. The mean blood lead concentration was 0.42 micromol/L (8.7 microgram/dL), and the mean zinc protoporphyrin concentration was 1.0 microgram per gram of hemoglobin. Over the 5.2-year median follow-up, the mean blood lead concentration dropped by 32% (0.14 micromol/L [2.9 microgram/dL]) (P<.001). Small but significant (P<.01) changes occurred in systolic (-1.5 mm Hg) and diastolic (+1.7 mm Hg) conventional blood pressure and in zinc protoporphyrin concentration (+0.5 microgram per gram of hemoglobin). Over the follow-up period, no consistent associations emerged between the changes in conventional blood pressure and in blood lead or zinc protoporphyrin concentrations. In addition, after adjustment for sex, age, and body mass index, blood lead and zinc protoporphyrin concentrations at baseline did not predict the development of hypertension in 47 patients (risk ratio for doubling of the initial lead concentration, 1.2; 95% confidence interval, 0.7-2.0). In a time-integrated analysis in which each person was characterized by all available measurements, conventional blood pressure did not correlate with blood lead or zinc protoporphyrin concentrations in a consistent manner. Similarly, the mean (SD) 24-hour blood pressure at follow-up (119 [11]/71 [8] mm Hg; N=684) did not show a consistent relationship with blood lead or zinc protoporphyrin concentrations at baseline or at follow-up. CONCLUSIONS: - Lead exposure at the intensity studied (<l.45 micromol/L [<30 microgram/dL]) was not consistently associated with increased conventional or 24-hour blood pressure in the general population or with increased risk of hypertension. These findings argue against the hypothesis that current lead exposure levels are associated with excess cardiovascular morbidity and mortality caused by hypertension.

Adult↗
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Genetic variability in the renin-angiotensin system: prevalence of alleles and genotypes.

BACKGROUND: Variants of the human genes coding for renin, angiotensin-converting enzyme (ACE), angiotensinogen (AGT) and the angiotensin II type-I receptor (AT1R) are inconsistently associated with cardiovascular-renal disease, possibly because of genetic differences in the background populations. METHODS: This systematic review of the literature investigated genetic variation in the renin system according to race, sex and age. Across studies with relevant information, multivariate analyses also accounted for the methods of genotyping and the enrollment of subjects as controls, cases or groups studied cross-sectionally. RESULTS: The 185 reviewed reports included 64978 subjects. In five studies (n=989) on the renin gene, the Hind III and Taq I polymorphisms varied with the groups' average age, whereas the Bg I, Bg II and Hind III but not Taq I sites differed according to race. Among 135 studies (n=44697) on the deletion/insertion (D/I) polymorphism of the ACE gene, the frequency of the D allele was 54.0%. Its prevalence was not related to sex and black race, was 49.9% lower in Asians, 10.0% lower in studies relying on I-specific primers, 4.9% higher for each 25-year increment in the average age of the groups studied, and 16.7% higher in cases than controls. Among 12 studies (n=4952) on the T174-->M variant of the AGT gene, the M174 frequency was 11.0%, did not vary according to sex and enrollment group, was 56.7% lower in blacks and 39.5% lower for each 25-year increase in the groups' mean age. Across 44 studies (n=16713) on the M235-->T substitution in the AGT gene, the T235 prevalence was 51.6%. Its frequency was not related to sex and the method of genotyping, tended to be 7.5% lower for each 25-year increase in average age, was from 4.6 to 6.6 times higher in nonwhites than whites and 13.2% higher in cases than controls. Among 13 studies (n=4332) on the A1166-->C variant of the AT1R gene, the C1166 allelic frequency was 25.7%. Its prevalence was independent of the enrollment group, 77.4% lower in Asians, and nearly doubled for each 25-year increment in age. CONCLUSION: With adjustments applied for the subjects' enrollment group and the methods of genotyping, genetic polymorphism in the renin system varies according to race and age, but not sex. One possible application of the present results is to provide allelic and genotypic frequencies, which could be used to assess power, to perform sample size calculations, or to predict selection bias in future studies.

Age Factors↗