René Gueguen

Objectives, Design and Recruitment of a Familial and Longitudinal Cohort for Studying Gene-Environment Interactions in the Field of Cardiovascular Risk: The Stanislas Cohort

Abstract The main objective of the Stanislas cohort is to study the role and the contribution of genetic and environmental factors to cardiovascular status. We plan: a) to describe the degree of association of a large number of cardiovascular risk indicators with cardiovascular endpoints, b) to evaluate the contribution of genetic and that of environmental factors to this association, c) to follow the evolution of these risk indicators during a period of at least ten years, d) to search for the determinants influencing this evolution. The principal variables studied are: a) to describe the degree of association of a large number of cardiovascular risk indicators with cardiovascular endpoints, b) to evaluate the contribution of genetic and that of environmental factors to this association, c) to follow the evolution of these risk indicators during a period of at least ten years, d) to search for the determinants influencing this evolution. a) blood pressure, cardiac mass, and wall thickness of carotid and femoral arteries, b) obesity and fat mass, c) indicators of lipid metabolism, d) genetic polymorphisms of several cardiovascular risk candidate genes, e) food, tobacco and alcohol consumption, f) consumption of drugs and anti-oxidant vitamins. Between September 1993 and August 1995, 1006 families consisting of the two biological parents with at least two children were recruited totalling 4295 individuals. This cohort will be followed up until 2004. There will be two health examinations five and ten years after the initial examination. A bank of blood samples (serum and plasma) in liquid nitrogen and DNA (−80 °C) has been established.

Determination of Serum Cystatin C: Biological Variation and Reference Values

Abstract Human cystatin C is a low molecular weight protein which has been proposed as a better marker of glomerular filtration rate than creatinine. To be able to interpret results obtained in different patient populations it is necessary to define cystatin C reference values. We measured serum concentration of cystatin C in 1223 subjects using a particle-enhanced nephelometric assay. Subjects were aged 4 to 79 years and were selected among apparently healthy individuals who came to the Centre for Preventive Medicine in Vandoeuvre-Lès-Nancy, France. We observed a Gaussian distribution of cystatin C concentration in serum. We did not find any effect of age or gender in children, hormonal status in women (puberty, menopause, oral contraceptives or hormone replacement therapy) or alcohol intake. Cystatin C concentration was slightly lower in female than in male adults below the age of 60 years. Cystatin C levels significantly increased above the age of 60 in both males and females, probably due to physiological aging of renal function. No other significant differences were observed between males and females. Using multiple regression analysis, moderate correlations were observed between body mass index and cystatin C, and between smoking and cystatin C, but these were not biologically significant. According to the literature, only methylprednisolone and cyclosporin A increased and decreased cystatin C levels, respectively. The reference values for cystatin C obtained in a carefully selected population were 0.75±0.089 mg/l for children aged 4–19 years, 0.74±0.100 mg/l for males and 0.65±0.085 mg/l for females (aged 20–59 years), and 0.83±0.103 mg/l for older individuals (≥60 years).

Trends of the potentially inappropriate medication consumption over 10 years in older adults in the East of France

To describe the trends of potentially inappropriate medication (PIM) use in older adults from 1995 to 2004 in the East of France, by using the 1997 Beers criteria and its French update, and to assess risk factors for this PIM use.

Determinants of hormonal replacement therapy in recently postmenopausal women

Although the efficacy of hormonal replacement therapy (HRT) on the consequences of the menopause is not questioned, it appears that in Europe and in the USA only a small proportion of women are users of HRT. In this study, we examined the prevalence and the determinants of HRT among 1986 French menopausal women, aged 45 to 55 years, presenting to a preventive medicine centre. Overall, 8.1% of women reported current use of HRT. The estrogen preparation most commonly reported was transcutaneous 17 beta-oestradiol. The first determinant of current HRT was birth-place. Women born in France were nearly four times more likely to be on treatment than foreign-born women. A surgical menopause multiplied the probability of current HRT by 2, as did a high level of education. An age at first pregnancy of more than 20 and less than 4 children were also positively linked with HRT use. Even in this population of recently menopausal women, volunteering to undergo health evaluation, the prevalence of HRT was low. The reservations towards HRT may be partly due to the women themselves, and partly due to the physicians. It seems very important to inform the medical profession about the risks and benefits of HRT, and to understand more precisely the reasons why so few women use HRT.

Alcohol and mortality from all causes.

A large number of prospective studies have observed an inverse relationship between a moderate intake of alcohol and coronary heart disease morbidity and mortality. Concerning death from all-causes, results are not unanimous. Alcohol intake was associated with a protection of all-cause mortality in England and USA physicians and the large study of the American Cancer Society. None of these studies separated the effects of different alcoholic beverages. In our prospective studies in France on 35 000 middle-aged men, we observed that only wine at moderate intake, was associated with a protective effect on all-cause mortality. The reason was that in addition to the known effect on cardiovascular diseases, a very moderate intake of wine, protected also from cancer and other causes as confirmed by Gronbaek in Denmark. Our recent results also indicate that the protective effect of a moderate intake of wine on all-cause mortality is observed at all levels of blood pressure and serum cholesterol.

Effect of six candidate genes on early aging in a French population

Background and aims: The objective of this study was to examine the association between an aging indicator previously defined from a nationwide population study, and lipids and apolipoproteins, angiotensin converting enzyme, paraoxonase activities, and six candidate genes related to the aging process. Methods: Two hundred and fifty-six healthy Caucasian men (69.8±4.0 years) were included in the study. Total cholesterol, triglycerides, HDL-cholesterol, lipoprotein(a), apolipoprotein A1, B and E concentrations, and the activities of paraoxonase, arylesterase, and angiotensin-converting enzymes were determined by standardized laboratory methods. A multiplex assay was used to genotype the studied polymorphisms: apolipoprotein E, lipoprotein lipase, paraoxonase, methylenetetrahydrofolate reductase, cystathionine β-synthase and angiotensin-converting enzymes. Results: Paraoxonase polymorphism at codon 192 (Gln/Arg) was the only one significantly associated with the aging indicator, Gln homozygotes being more advanced in aging compared with Arg allele carriers. It was also observed that the aging indicator was positively correlated with serum concentrations of total cholesterol, triglycerides and apolipoprotein B, and negatively with the activities of basal and stimulated paraoxonase and arylesterase. Multiple regression analysis showed that triglycerides and basal paraoxonase activity explain 13.6% of the variance of the aging indicator. Conclusions: Triglyceride concentration and paraoxonase gene and activities may contribute to the aging process. Taking into account the smallness of the sample size, and the poor level of significance due to the implication of paraoxonase polymorphism at codon 192, these results need to be verified in further studies on a greater number of subjects.

Reference Limits of Plasma Fibrinogen

Fibrinogen is considered to be a strong predictor and independent factor of cardiovascular diseases. The data presented here describe the baseline measurements of fibrinogen in 1008 apparently healthy subjects, aged 4-60 years and their relationship to age, sex, body weight, smoking, alcohol, and use of oral contraceptives. Pearsons correlations and a linear multiple regression model were used. Plasma fibrinogen was measured kinetically in a photometer, the Behring Chromotimer, using the CTS-fibrinogen method. There were neither statistical difference between girls and boys aged 4-20 years nor correlation with variables related to cardiovascular diseases. In adults, we found an increase of plasma fibrinogen concentration with age and no statistical difference between men and women, except in subjects aged 40-50 years. There was a positive correlation between fibrinogen and ponderal index. In women aged 20-30, 30-40, 40-50 and 50-60 years, the mean fibrinogen concentrations increased of 0.009, 0.021, 0.010 and 0.015 g/l for one percent of overweight, in each subgroup respectively. In women aged 20-30 years using oral contraceptives, the mean fibrinogen concentration was 0.19 g/l higher than in women not using oral contraceptives. The smoking effect was observed only in 30-40 year-old men. Each cigarette smoked per day increases of the mean fibrinogen by 0.35 g/l after standardization for ponderal index and alcohol consumption. Alcohol consumption was negatively correlated to plasma fibrinogen in subjects 30-40 years old. In women, 1 g of alcohol per day induces a 0.008 g/l decrease in the mean fibrinogen while in men the decrease is 0.004 g/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Age- and sex-related reference values for serum insulin concentration and its biological determinants in a French healthy population. The STANISLAS cohort

Abstract Insulin is involved in coronary heart disease through diabetes and metabolic syndrome. A great deal is known about insulin and its correlates, as well as factors related to changes in insulin. However, few studies consider the broad variety of correlates simultaneously. Therefore, the aims of the present study were to characterize the main factors of biological variation affecting serum insulin concentration and to establish reference limits of insulinemia in a presumably healthy French population. Insulin was measured using a microparticular enzymatic immunoassay. A total of 646 subjects aged 11–58 years from the STANISLAS cohort and divided into four groups of 162 males, 157 females, 163 boys and 164 girls, were included in the statistical analyses. In the whole population, serum insulin concentration varied from 0.80 to 54.60 µU/ml. Significant factors affecting insulin were age, gender, body mass index and glucose, in addition to alanine aminotransferase and high-density lipoprotein cholesterol in men, triglycerides and oral contraceptive use in women, and alkaline phosphatase in girls. In summary, we presented biological correlates of insulin in both healthy French male and female adults and children/adolescents and determined reference limits for insulin for each group. These results will contribute to a better interpretation of insulin data in further studies and laboratory investigations.

Acetylation phenotypes and biological variation in a French Caucasian population

Factors affecting the caffeine acetylation phenotype were investigated in a French Caucasian population of 150 unrelated supposedly healthy subjects, aged 18 to 63 years. This population, including 75 men and 75 women, was used to determine whether the acetylation polymorphism is related to environmental influences such as smoking habits, intake of alcohol, use of oral contraceptives, use of certain drugs. The acetylation phenotype was assessed from the molar ratio of two caffeine metabolites: 5-acetylamino-6-formylamino-3-methyluracil/1-methylxanthine. For values less than 0.85, the subjects were classified as poor acetylators (frequency, mean +/- SD: 61.3 +/- 7.9%) in this study. Dose recoveries of 5-acetylamino-6-formylamino-3-methyluracil (mean +/- SD) were 1.26 +/- 0.85% and 3.58 +/- 1.64% in slow and rapid acetylators, respectively. The recovery (mean +/- SD) of 1-methylxanthine in the 3 hour-urine was 2.86 +/- 1.51% in slow acetylators and 2.36 +/- 1.27% in rapid acetylators. The mean value (and SD) of the molar ratio was 0.437 (0.177) and 1.669 (0.651) for slow and rapid acetylators. Three other metabolite ratios can also provide an acetylation index: 5-acetylamino-6-formylamino-3-methyluracil/5-acetylamino-6-formylamino-3 - methyluracil + 1-methylxanthine + 1-methyluric acid; 5-acetylamino-6-formylamino-3-methyluracil/1-methylxanthine + 1-methyluric acid + 1,7-dimethyluric acid; and 5-acetylamino-6-formylamino-3-methyluracil/1-methylxanthine + 1-methyluric acid + 1,7-dimethyluric acid + 1,7-dimethylxanthine with a bimodal distribution for the former and a trimodal distribution for the two latter ratios, both showing about 95% concordance with the 5-acetylamino-6-formylamino-3-methyluracil/1-methylxanthine ratio. Age did not influence the excretion of caffeine and its five major metabolites. A marked influence of sex was observed only on the unchanged caffeine excretion, and the effect was greater in slow acetylators than in rapid acetylators. The 5-acetylamino-6-formylamino-3-methyluracil excretion was about three times higher in rapid acetylators than in slow acetylators in both sexes.

Stepwise strategies in analysing haematuria and leukocyturia in screening

Abstract The aim of the present work was to compare in a supposed healthy population of 680 subjects several algorithms for positive selection of urine samples requiring microscopic examination for erythrocytes and leukocytes after screening by automated test-strip measurement and particle counting on a Sysmex UF-50™ flow cytometer. Four strategies have been formulated and the sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate, and microscopic review rate were measured. The strategy combining test strip analysis and automated counting on all samples, followed by microscopic examination of only discordant samples gave the best results. When the two methods of haematuria screening were in agreement (91% of samples), the false negative rate for microscopy was 1.1%, with a false positive rate of 0.8%, sensitivity of 66% and specificity of 99%, and the results are acceptable without any other examination. When the two methods of haematuria screening were discrepant, visual microscopic analysis was necessary to obtain definitive results. For leukocyturia screening, 80% of results were in agreement by test strip and automatic sediment urinalysis, with only ten results considered as false negatives (1.8%) and four as false positives (0.7%). Agreement was good and the other criteria were good (sensitivity 79%, specificity 99%). On conflicting samples, there was no agreement between methods and microscopic analysis was essential. The benefit of such an algorithm would be optimisation of the workflow without any loss of sensitivity and specificity at the expense of a two-fold increase in cost.