L’obesite est definie par un exces de masse grasse de l’organisme, pouvant conduire a une alteration de l’etat de sante. Elle est mesuree par l’indice de masse corporelle (IMC), calcule a partir des mesures de poids et de taille de l’individu. Le seuil d’IMC superieur ou egal a 30 kg/m 2 definit l’obesite. L’augmentation de l’IMC est associee a la mortalite globale et par maladies cardiovasculaires, ainsi qu’a de nombreuses pathologies respiratoires et osteo-articulaires. La prevalence de l’obesite a ete estimee en France en 2006 a 16,1 % [intervalle de confiance a 95 %] [14,8-18,9] chez les hommes et a 17,6% [15,0-20,2] chez les femmes. Cette prevalence est en augmentation en France, comme dans la plupart des pays occidentaux. On constate une croissance extremement forte de la prevalence de l’obesite dans les pays en voie de developpement. La transformation rapide des modes de production agricole et la surabondance alimentaire qui en resultent ainsi que la sedentarisation de la population participent a la modification des comportements alimentaires et a l’augmentation de la prevalence de l’obesite.

Certain epidemiological and experimental studies suggest that n-3 fatty acids and folate can reduce blood pressure (BP). We investigated the effect of a daily supplementation with dietary doses of B-vitamins or n-3 fatty acids for 5 years on BP in patients with a history of CVD who participated in the Supplémentation en Folates et Omega-3 trial. The patients (n 2501; 1987 men and 514 women) were randomly assigned in a 2 × 2 factorial design to one of four groups: B-vitamins (5-methyl-THF (560 μg); vitamin B₆ (3 mg) and vitamin B₁₂ (20 μg)) and a placebo capsule for n-3 fatty acids; n-3 fatty acids (600 mg of EPA and DHA at a ratio of 2:1) and a placebo capsule for B-vitamins; both B-vitamins and n-3 fatty acids; or placebo capsules for both treatments. The patients took two capsules daily in a double-blind manner for a median duration of 4·7 years. At baseline and annual examination for 5 years, the patients underwent a clinical examination where BP and clinical and biological parameters were assessed. No effect of supplementation with either n-3 PUFA or B-vitamins on BP was observed in crude and adjusted multivariate models. Change in BP was not associated with change in homocysteine. In conclusion, the present results do not support the routine use of dietary supplements containing B-vitamins, or of n-3 fatty acids, to reduce BP in people with prior CVD.

The melanocortin-1 receptor (MC1R) gene is known to play a major role in skin and hair pigmentation and to be highly polymorphic in Caucasians. This study was performed to investigate the relationships between MC1R gene polymorphisms and skin color in a large sample of French middle-aged Caucasian women. The codons 60 to 265 and the codon 294 of the MC1R gene were sequenced in 488 women. The skin color was measured on the inner side of the forearm using a spectrophotometric instrument. Fifteen variants were identified: Arg151Cys, Arg160Trp, Arg142His, Asp294His, Ile155Thr, Asp84Glu, Val60Leu, Val92Met, Arg163Gln, Ser83Pro, Thr95Met, Pro256Ser, Val265Ile, Ala166Ala and Gln233Gln. Women carrying Arg151Cys, Asp294His, Arg160Trp and Asp84Glu variants had a significantly higher reflectance in the red region, which indicates a lower level of functional melanin. This association was the most pronounced for women carrying Asp84Glu. In contrast, no significant difference was observed for other variants. Moreover, associations between MC1R polymorphisms and the risks of experiencing sunburn and of having freckles were found independently of skin color. Our findings support the hypothesis that MC1R polymorphisms do not necessarily alter the skin color but should sensitize the skin to UV-induced DNA damage.

Left-and right-handers have coexisted since the Palaeolithic age. Hand preference is heritable. Moreover, there is extensive evidence of an association between left-handedness and several fitness costs. In this context, the persistence of the polymorphism is interesting. Here, we explore the associations between socio-economic status and handedness, analysing data from two large cohorts of adult men and women. Such associations are relevant to an evolutionary approach, as the socio-economic and the reproductive value are related. Our results partly support the hypothesis that left-handers have a socio-economic status advantage, countervailing the health issues. Although the models explain a small proportion of the variance observed, the frequency of left-handedness is significantly higher: (1) among women of higher educational level; (2) among categories of higher income; and (3) among individuals who have a higher position in the company. The importance of these findings for the evolution of the polymorphism of handedness is discussed.

The metabolic syndrome (MetS) is a common multi-component disorder resulting from genetic and environmental components (1) . Lowgrade inflammation also plays a role in the pathogenesis of the MetS and polymorphisms of several pro-inflammatory genes have been associated with type 2 diabetes and other phenotypes of the MetS (2) . Dietary fat is an important environmental factor that can modify the risk of the MetS (3) . However, limited data exist that indicate that an individual's genetic background interacts with their dietary fat exposure, affecting their risk of the MetS. The aim of the LIPGENE prospective case-control study was to examine the interaction between polymorphisms implicated in the pathogenesis of the MetS with biomarkers of habitual dietary fat composition. The LIPGENE cohort consists of 1754 matched case and control subjects. Plasma fatty acid composition (14: 0-22: 6n-3) was determined as a biomarker of habitual dietary fat intake.

The positive association between dietary sodium intake and PP observed in the present study provides further evidence for the current concept linking sodium to rise in BP through modification and stiffening of the arterial wall, whereas negative associations between dietary potassium intake and both SBP and DBP, hence MAP, support the vasodilator properties of this latter nutrient.