N Thibult's research while affiliated with French Institute of Health and Medical Research and other places

The aim of this study was to evaluate the changes in height, weight and in the prevalence of overweight and obesity between 1992 and 2000 in children living in two towns of northern France. Two cross-sectional studies were performed in every pre-school (last section) and primary schools of the two towns in 1992 (383 girls and 421 boys enrolled) and 2000 (296 girls and 305 boys). Children were 5 to 12 year old in both studies. Body height and weight were measured, and BMI was calculated (weight/height(2)). Prevalence of overweight and obesity was determined according to the gender- and age- specific cut-offs of the new international reference (IOTF). We also used the 90(th) and the 97(th) percentiles of the French reference gender- and age-specific BMI curves to define two grades of overweight. After adjustment for age, boys were on average 1.5 cm taller in 2000 than in 1992 (p<0.001), and the same trend was observed in girls (+ 0.9 cm, p<0.075). Height-adjusted or age-adjusted weight and BMI were significantly higher in 2000 than in 1992. In girls, obesity defined by IOTF criteria increased from 1.6 to 4.4% (p<0.03) and overweight from 14.1 to 18.6% (p<0.11). In boys, the change in prevalences was significant only when the less stringent criteria (i.e. the 90(th) percentile of French references) was used (13.8% in 1992 vs 20% in 2000, p=0.03). Over an 8 years period, there was an increase in height and BMI in both boys and girls. These results show that the increase in the prevalence of obesity is accompanied by a global trend of accelerated growth.

The associations of different components of body mass with disease outcomes are not well defined. We investigated the effects of body composition on risk of death from cardiac causes and cancer in adult men. Middle-aged men (n = 7608) in the Paris Prospective Study were followed up for 15 y. At study entry, the following measurements were obtained: sagittal diameter, sum of midarm and midthigh circumferences, sum of 3 trunk skinfold thicknesses (estimate of trunk subcutaneous fat), and sum of 3 extremity skinfold thicknesses (estimate of extremity subcutaneous fat). To assess their relative contributions to cardiac and cancer mortality, we used multivariate Cox models in which the sagittal diameter adjusted for trunk skinfold thicknesses was used as an estimate of intraabdominal fat and the sum of midarm and midthigh circumferences adjusted for extremity skinfold thicknesses was used as an estimate of muscle mass. In multivariate analyses in both smokers and nonsmokers, the sagittal diameter was the only significant predictor of cardiac death. The sum of midarm and midthigh circumferences was negatively associated and sagittal diameter was positively associated with cancer death, whereas extremity skinfold thicknesses exhibited a U-shape relation. Exclusion of subjects who died from cancer in the first 5 y of follow-up did not change these results. Intraabdominal fat appears to be the main body compartment involved in risk of cardiac death, whereas increased risk of cancer death is associated with lower muscle mass and lower subcutaneous fat, independent of smoking and after the exclusion of early mortality. Increased central fat distribution may confer additional risk of death from cancer.

In men, an association between lower plasma total testosterone (PTT) and insulin resistance has been found in cross-sectional studies (1,2) and in one nested case-control study (3) without any possible conclusion in terms of causality or direction of the relationship. Indeed, to obtain such information, randomized controlled trials are needed. Until now, only one clinical trial has suggested that testosterone therapy improves insulin sensitivity in obese men (4). Cross-sectional studies concerning leptin regulation by androgens have provided no definitive conclusions as to whether the negative association between androgens and leptin level is independent (5) or dependent (6). This randomized controlled trial was designed to assess the role of androgens on insulin sensitivity and leptin regulation in healthy adult men. This study was a randomized, double-blind, unicentric, controlled, clinical trial. Three treatments (testosterone, dihydrotestosterone [DHT], and placebo) were compared in parallel groups during a 3-month period. All of the examinations were performed by only two physicians, using a standardized protocol. Blood was drawn between 8:00 a.m. and 9:30 a.m. after an overnight fast to determine fasting plasma glucose, insulin, leptin, sex hormones, lipids, coagulation and fibrinolysis parameters, hepatic enzymes, and prostate-specific antigen (PSA) and blood cell count. Then, a standard 75-g oral glucose tolerance test and a digital rectal examination were performed. In addition, between days 10 and 20, all of the subjects were monitored to measure sex hormones in order to adapt the treatment dose. The study protocol was approved by the Henri Mondor Hospital Ethics Committee. All of the included subjects gave written informed consent. Men with low levels of PTT (confirmed by two measurements) were selected from a large occupation-based population. The inclusion criteria were as follows: 1 ) either PTT ≤3.4 ng/ml [5th percentile value of PTT distribution in the 1,718 men of the TELECOM …

To describe the change in diabetic status over 30 months. Cohort study of 5,400 Caucasian men from the Paris Prospective Study, aged 44-55 years, who were not known as having diabetes at baseline. Oral glucose tolerance tests were performed at baseline and after 30 months. At baseline, diabetes was diagnosed in 2.9% of the men by fasting plasma glucose (FPG) > or =7.0 mmol/l and in 0.9% by isolated postchallenge hyperglycemia (IPH) (FPG <7.0 mmol/l and 2-h plasma glucose concentration > or =11.1 mmol/l), i.e., one in four of all men with newly diagnosed diabetes. Thirty months later, 42% of the men with diabetes diagnosed by FPG reverted to nondiabetic status, compared with 72% of those with diabetes diagnosed by IPH (P < 0.0001). For the men with diabetes diagnosed by FPG at baseline, diabetes had been diagnosed by a physician at 30 months in 11.5%, in contrast to only 3.9% of those with diabetes diagnosed by IPH (P < 0.05). For the 51 men with diabetes diagnosed by IPH at baseline, those who reverted to nondiabetic status had a lower frequency of family history of diabetes (P < 0.1), a higher mean corpuscular volume (P < 0.08), and a significantly higher total cholesterol concentration (P < 0.006) at baseline; in contrast, for the 156 men with diabetes diagnosed by FPG at baseline, the men who reverted to nondiabetic status and those who remained diabetic had similar characteristics. In this epidemiological study, diabetes diagnosed by one FPG concentration was more stable than diabetes diagnosed by one IPH; in clinical practice, the diagnosis of diabetes requires confirmation of the hyperglycemia.

To describe the characteristics and vital prognosis of men with diabetes diagnosed by one fasting plasma glucose (FPG) concentration > or =7.0 mmol/l, with diabetes diagnosed by one isolated postchallenge hyperglycemia (IPH) (FPG <7.0 mmol/l and a 2-h plasma glucose concentration > or =11.1 mmol/l), or with impaired glucose tolerance (IGT). This study involved a cohort of 6,881 Caucasian nondiabetic men from the Paris Prospective Study, aged 44-55 years, who were followed for cause of death for 20 years. Diabetes was diagnosed in 4.3% of the men (1.0% diabetes diagnosed by IPH), and IGT was diagnosed in 9% of the men. At baseline, the men with diabetes diagnosed by IPH had a lower cardiovascular risk profile than those with diabetes diagnosed by FPG, as did the men with IGT and a normal fasting glucose level (<6.1 mmol/l, IGT and normal fasting glucose), compared with men with impaired fasting glucose (6.1-6.9 mmol/l, IGT and impaired fasting glucose [IFG]). At 20 years of follow-up, all-cause and cancer death rates were higher in men with diabetes diagnosed by IPH than in men with diabetes diagnosed by FPG (55 vs. 44%, P < 0.1 and 31 vs. 17%, P < 0.01, respectively) but were not significantly different for coronary causes (6 vs. 11%). Men with IGT and normal fasting glucose also had significantly higher cancer death rates than men with IGT and IFG. The most likely explanation for the high cancer and low coronary death rates is that men with diabetes diagnosed by IPH consumed alcohol; the men in this study drank 49 g of pure alcohol on average per day, equivalent to 0.6 l of wine. If these results are confirmed by other prospective studies, screening subjects for isolated postchallenge hyperglycemia may not be worthwhile.

To assess the association of fasting plasma nonesterified fatty acid (NEFA) concentration with the risk of death from coronary heart disease and cancer, the authors computed 15-year mortality rates for the 4,589 working men aged 43-53 years who were included in the Paris Prospective Study between 1967 and 1972. A total of 251 and 126 men died from cancer and coronary heart disease, respectively. For coronary heart disease death, the age- and tobacco-adjusted relative risk for men in the highest 20% of the fasting plasma NEFA concentrations compared with those in the lowest 80% was 1.54 (95% confidence interval (CI): 1.01, 2.34). It became nonsignificant after further adjustment for blood pressure, iliac/thigh ratio, and plasma insulin and cholesterol concentrations. In contrast, a high fasting plasma NEFA concentration exhibited a strong independent relation with cancer mortality (relative risk = 1.66, 95% CI: 1.25, 2.21, after adjustment for age, cigarette consumption, heart rate, and body mass index). Despite pathophysiologic mechanisms linking NEFA metabolism with visceral fat and plasma glucose, insulin, and triglyceride concentrations, the plasma NEFA concentration does not appear to be a good marker for coronary heart disease risk. In contrast, an unexpected association with cancer mortality was found that may point to the need for further investigation.

To investigate associations between adiposity indices and food intake in nonobese prepubertal free-living children. Five-hundred and one children, 280 boys and 221 girls aged 5-11 y in two little towns in northern France. Cross-sectional survey. Height and weight, four skinfolds (biceps, triceps, subscapular, suprailiac), waist and hip girths, were measured. Sum of skinfolds (SSF), body mass index (BMI), and relative weight (RW) were calculated. Energy intake (EI), percentage of energy intake ascribed to carbohydrates (%EIC), complex carbohydrates (%EICC), fats (%EIF), saturated fats (%EISF) and proteins (%EIP) were assessed by a single 24 h record. Basal metabolic rate (BMRI was estimated according to Schofield's equations. Obese (RW > or = 120%), and underreporting children according to Goldberg's and Black's equations were excluded. In multiple linear regressions analyses performed with hierarchical mixed models, adiposity indices were significantly and inversely associated in girls with %EIC (all P-values < 0.02), and positively with %EIF (all P-values < 0.05, waist girth and BMI excepted). Similar but non-significant trends were observed in boys. The relationships were not linear, and thresholds close to current dietary recommendations were highlighted. When %EIF was low, a lower percentage of energy intake ascribed to %EISF was associated with thinness. These associations remained after the exclusion of children who had an EI/BMR > or = 1.50. In nonobese prepubertal children aged 5-11 y, a high %EIC, close to dietary recommendations (> or = 55%), was associated with thinness. A high %EIF, over the upper dietary recommendation (< or = 35%), was associated with a greater adiposity thickness. There was no further increase in adiposity beyond this threshold. Reasons for the absence of a linear relationship pattern between adiposity and macronutrient intake remain to be determined.

Objective: Several studies, mainly in animals, but also in humans, have shown that diet in infancy is associated with differences in blood cholesterol concentrations later in life. The objective was to examine this relationship in children aged 5-11 y after taking into account their current diet and parental hypercholesterolemia. Setting and subjects: 251 prepubertal boys and 223 prepubertal girls enrolled in the schools in two little towns in northern France. Design and methods: Cross-sectional evaluation including measurements of cholesterol concentrations on capillary blood and a single weekday food intake record. Infant feeding patterns were obtained by questionnaire given to the mothers. Results: 50% of the children had been breast-fed for a median duration of less than 2 months. Cow's milk was introduced in the diet as whole milk for 33% of the children. After adjustment for age, height, and sibship, capillary cholesterol concentration was lower in boys who had been breast fed (geometric mean: 4.4, 95% confidence interval of the mean: 4.2-4.6 mmol/L) than in those fed with formula (4.7, 4.5-4.8 mmol/L, P<0.03). In girls, breastfeeding had no significant effect on blood cholesterol concentration, which was associated with the type of cow's milk given in infancy: whole milk: 4.9 mmol/L (4.7-5. 2); totally or partially skimmed milk: 4.5 mmol/L (4.2-4.6), P<0.008. The current saturated fat and cholesterol intakes and parental hypercyholesterolemia were associated with current blood cholesterol concentration in children, but did not modify its relationship with infant feeding patterns. Conclusion: Results of the present study suggest that diet in infancy may have longstanding effect on lipid metabolism. Sponsorship: The study was supported by funds from Eridania Béghin-Say, Groupe Fournier, Lesieur and Nestlé France, Roche Diagnostic and of the MGEN (Mutuelle Générale de l'Education Nationale, contract INSERM-MGEN #9158) and a grant from the Association de Langue Française pour l'Etude du Diabète et du Métabolisme (ALFEDIAM). European Journal of Clinical Nutrition (2000) 54, 114-119

To determine changes in the prevalences of overweight and obesity between 1980 and 1991 in French adults. Two cross-sectional studies were performed in 1980 and 1991 by the French National Institute of Statistics and Economics Studies in representative samples of the non-institutionalized French population using a similar random sampling of households from the last available national population census. Overweight and obesity were defined, based on reported height and weight, by a body mass index (BMI)> or = 25 kg/m2 and > or = 30 kg/m2, respectively. As age and socio-economic class (SEC) distributions changed between 1980 and 1991, results were compared before and after a direct age class and SEC standardization of the 1991 data, according to the 1980 population distribution. 6792 men and 7150 women in 1980, 7250 men and 7856 women in 1991, aged at least 20y, about 1/2500th of the French non-institutionalized adult population. In women, between 1980 and 1991, there were slight increases in the prevalences of obesity (from 6.3% to 7.0%, P<0.08) and of overweight (26.8% and 27.5%, not statistically significant NS). These increases were most pronounced in women aged 20-29y (obesity: 1.4-2.1%, P<0.15; overweight: 8.0-11.5%, P<0.01). In men, the corresponding prevalences were 6.4% and 6.5%, (NS), and 39.4% and 40.8% (NS). After standardization, the increases in the prevalences of obesity and overweight were even higher between 1980 and 1991 in women (the standardized prevalences in 1991 were respectively: 7.8% and 28.9%), but were unchanged in men. There were slight overall increases in the prevalences of overweight and obesity between 1980 and 1991 in both genders, which were most pronounced among young women. Changes in the age and SEC distribution in the French population have limited the increase in the prevalences of overweight and obesity in women. These results, based on reported data, may underestimate the prevalences of overweight and obesity and their increase. Nevertheless, the prevalences of reported obesity are similar to those of other European countries, such as Sweden and The Netherlands, and lower than in the UK, USA and Canada.