Paul Preziosi

Prevalence of Vitamin D Insufficiency in an Adult Normal Population

Abstract: The vitamin D status of a general adult urban population was estimated between November and April in 1569 subjects selected from 20 French cities grouped in nine geographical regions (between latitude 43° and 51° N). Major differences in 25-hydroxyvitamin D (25(OH)D) concentration were found between regions, the lowest values being seen in the North and the greatest in the South, with a significant ‘sun’ effect (r = 0.72; p = 0.03) and latitude effect (r = -0.79; p = 0.01). In this healthy adult population, 14% of subjects exhibited 25(OH)D values ≤ 30 nmol/l (12 ng/ml), which represents the lower limit (< 2 SD) for a normal adult population measured in winter with the same method (RIA Incstar). A significant negative correlation was found between serum intact parathyroid hormone (iPTH) and serum 25(OH)D values (p < 0.01). Serum iPTH held a stable plateau level at 36 pg/ml as long as serum 25(OH)D values were higher than 78 nmol/l (31 ng/ml), but increased when the serum 25(OH)D value fell below this. When the 25(OH)D concentration became equal to or lower than 11.3 nmol/l (4.6 ng/ml), the PTH values reached the upper limit of normal values (55 pg/ml) found in vitamin D replete subjects. These results showed that in French normal adults living in an urban environment with a lack of direct exposure to sunshine, diet failed to provide an adequate amount of vitamin D. It is important to pay attention to this rather high prevalence of vitamin D insufficiency in the general adult population and to discuss the clinical utility of winter supplementation with low doses of vitamin D.

A Primary Prevention Trial Using Nutritional Doses of Antioxidant Vitamins and Minerals in Cardiovascular Diseases and Cancers in a General Population: The SU.VI.MAX Study—Design, Methods, and Participant Characteristics

The SUpplementation en VItamines et Minéraux AntioXydants (SU.VI.MAX) Study is a randomized, double-blind, placebo-controlled, primary-prevention trial designed to test the efficacy of daily supplementation with antioxidant vitamins (vitamin C, 120 mg; vitamin E, 30 mg; and beta-carotene, 6 mg) and minerals (selenium, 100 microg; and zinc, 20 mg) at nutrition-level doses (one to three times the daily recommended dietary allowances) in reducing several major health problems in industrialized countries, especially the main causes of premature death, cancers and cardiovascular diseases. The present report describes the design, implementation, and baseline characteristics of participants in this 8-year cohort study, which started in 1994 in France; 12,735 eligible subjects (women aged 35-60, and men aged 45-60) were included in 1994 and will be followed for 8 years. Participants undergo a yearly visit consisting, every other year, of either biological sampling or clinical examination. They also regularly provide information on health events and dietary intake by filling out computerized questionnaires using the Minitel Telematic Network. Data on baseline characteristics of the participants suggest that the present sample is close to the national population in terms of geographic density, socioeconomic status, and the distribution of various major risk factors for the diseases under study. The choice of the study population should allow the results of this trial to apply to adult populations of both sexes in France and other industrialized countries.

Iron deficiency in Europe.

In Europe, iron deficiency is considered to be one of the main nutritional deficiency disorders affecting large fractions of the population, particularly such physiological groups as children, menstruating women and pregnant women. Some factors such as type of contraception in women, blood donation or minor pathological blood loss (haemorrhoids, gynaecological bleeding...) considerably increase the difficulty of covering iron needs. Moreover, women, especially adolescents consuming low-energy diets, vegetarians and vegans are at high risk of iron deficiency. Although there is no evidence that an absence of iron stores has any adverse consequences, it does indicate that iron nutrition is borderline, since any further reduction in body iron is associated with a decrease in the level of functional compounds such as haemoglobin. The prevalence of iron-deficient anaemia has slightly decreased in infants and menstruating women. Some positive factors may have contributed to reducing the prevalence of iron-deficiency anaemia in some groups of population: the use of iron-fortified formulas and iron-fortified cereals; the use of oral contraceptives and increased enrichment of iron in several countries; and the use of iron supplements during pregnancy in some European countries. It is possible to prevent and control iron deficiency by counseling individuals and families about sound iron nutrition during infancy and beyond, and about iron supplementation during pregnancy, by screening persons on the basis of their risk for iron deficiency, and by treating and following up persons with presumptive iron deficiency. This may help to reduce manifestations of iron deficiency and thus improve public health. Evidence linking iron status with risk of cardiovascular disease or cancer is unconvincing and does not justify changes in food fortification or medical practice, particularly because the benefits of assuring adequate iron intake during growth and development are well established. But stronger evidence is needed before rejecting the hypothesis that greater iron stores increase the incidence of CVD or cancer. At present, currently available data do not support radical changes in dietary recommendations. They include all means for increasing the content of dietary factors enhancing iron absorption or reducing the content of factors inhibiting iron absorption. Increased knowledge and increased information about factors may be important tools in the prevention of iron deficiency in Europe.

INTERRELATION BETWEEN PLASMA TESTOSTERONE AND PLASMA INSULIN IN HEALTHY ADULT MEN: THE TELECOM STUDY

SummaryPlasma insulin is a risk factor for diabetes mellitus and cardiovascular disease in men. We investigated the association between plasma testosterone and plasma insulin in an occupational sample of 1292 healthy adult men. Total plasma testosterone decreased with each decade of age and insulin increased with each decade of age. In these cross-sectional data, this significant graded inverse association between testosterone and insulin was independent of age. The association was reduced but not explained by the addition of obesity and subscapular skinfold to the model. Adjustment for alcohol consumption, cigarette smoking and plasma glucose did not materially alter the association. These results are the reverse of the positive association of androgens with insulin in women and suggest alternative possible explanations for the effect of hyperinsulinaemia on cardiovascular disease risk. Prospective studies will be necessary to determine the direction and causal nature of this association.

Diet Quality and Dietary Diversity in France: Implications for the French Paradox

OBJECTIVES Assessing the quality of the total diet is a relatively new focus of studies in nutritional epidemiology. New indexes of healthful eating patterns have been largely limited to US populations. This study used evaluative criteria developed in the United States to assess diet quality and dietary diversity of French adults. METHODS Habitual dietary intakes of a representative sample of 837 adults (361 men and 476 women) in the Val-de-Marne Dèpartement were evaluated. Evaluative measures of diet quality included a modified diet quality index (DQI), a dietary diversity (DD) score, and a dietary variety score (DVS). The 5-point DQI assessed compliance with the key guidelines of the US Department of Agriculture (USDA) for healthy people. The DD score counted the number of major food groups consumed whereas the DVS counted the total number of foods consumed on a regular basis. RESULTS Few French adults consumed diets consistent with the USDA dietary recommendations. Only 14% of respondents derived less than 30% of energy from fat and only 4% derived less than 10% of energy from saturated fat. As a result, 63% of the sample had DQI scores of either 0 or I. In contrast, close to 90% of respondents scored a maximum of 5 in DD. Persons whose diets met US dietary recommendations also had the lowest DVSs. CONCLUSIONS Methodologic factors and cultural biases may account for some of the observed differences between French and US data. Nevertheless, studies of diet quality and diversity are a promising new approach to the study of the total diet and associated health outcomes and may provide new insight into the French paradox.

The potential role of antioxidant vitamins in preventing cardiovascular diseases and cancers

Cardiovascular diseases and cancers constitute major public health problems in all industrialized countries, where they are the main causes of premature mortality. There is a large body of evidence suggesting that free-radical production can directly or indirectly play a major role in cellular processes implicated in atherosclerosis and carcinogenesis. Here we present mechanistic data and results of epidemiologic studies on the relationship between antioxidant vitamin intake or biochemical status and the risk of cancer and cardiovascular diseases. Most epidemiologic data obtained on this topic were based on an observational approach, i.e., ecologic, case-control, or prospective studies. All these studies indicate that a high dietary intake or high blood concentrations of antioxidant vitamins are associated with a reduced risk of cardiovascular diseases and cancer at several common sites. Although the results of these studies are convergent, they merely suggest a relationship at the population and individual level but do not affirm a causality link. Only intervention studies (randomized trials), by specifically changing antioxidant vitamin intake, can provide conclusive answers. The apparent discrepancies between the results of four recently published trials may be explained by the type of population (general or high-risk subjects), the differing doses of supplementation (nutritional levels or higher), the number of antioxidants tested (one, two, or more), and the type of administration (alone or in balanced association). It thus appears that a low risk of pathologies may be related to multiple nutrients consumed at nutritional doses and in combination. Optimal effects may be expected with a combination of nutrients at levels similar to those found in a healthy diet. A single antioxidant vitamin given at high doses in subjects with high risk of pathologies (smokers, asbestos-exposed subjects) may not have substantial benefits and could even have negative consequences.

Determining factors in the iron status of adult women in the SU.VI.MAX study

The iron status of a national sample of adults living in France and participating in the SU.VI.MAX cohort, was assessed using serum ferritin and hemoglobin concentrations. Complete data were obtained for 6648 women 35–60 y old and for 3283 men 45–60 y old. Assessment of iron dietary intakes was realized on a subsample of 3111 women and 2337 men who reported six 24 h dietary records during a one-year period; 22.7% of menstruating women and 5.3% of post-menopausal women presented a total depletion of iron stores (serum ferritin <15 μg/l). Iron-deficient anemias were found in, respectively, 4.4% and less than 1% of these women. Three-quarters of the anemias were related to iron deficiency in menstruating women. In men, iron depletion and iron deficiency anemia were very rare. Post-menopausal women had much higher serum ferritin levels than menstruating women. In menstruating women, those using intrauterine devices had significantly lower serum ferritin levels than those without contraception, and much lower than those using oral contraception. The frequency of iron depletion reached 28.1% in women using intrauterine devices, but only 13.6% in those using oral contraceptives.The mean iron intake was 16.7±5.7 mg/d in men and 12.3±3.4 mg/d in women. Heme iron represented respectively, 11.1 and 10.4% of iron intake. Ninety-three percent of menstruating women had dietary iron intakes lower than recommended dietary allowances (RDA); 52.6% consumed less than two thirds of these RDA. In post-menopausal women and men, respectively 27.7% and 3.6% had dietary intakes lower than RDA. Serum ferritin was positively correlated with meat, fish and total iron intake, and negatively correlated with dietary products consumption, calcium and fiber intake.

Effect of Micronutrient Supplementation on Infection in Institutionalized Elderly Subjects: A Controlled Trial

To determine the impact of a trace element and vitamin supplementation on infectious morbidity, a double-blind controlled trial was performed on 81 elderly subjects in a geriatric center during a 2-year period. Subjects were randomly assigned to one of four treatment groups, and received daily: placebo; trace elements/zinc 20 mg; selenium 100 micrograms); vitamins (vitamin C 120 mg; beta-carotene 6 mg; alpha-tocopherol 15 mg); or a combination of trace elements and vitamins at equal doses. (1) Before supplementation, low serum values in vitamin C, folate, zinc and selenium were observed in more than two thirds of the patients. (2) After 6 months of supplementation, a significant increase in vitamin and trace element serum levels was obtained in the corresponding treatment groups: a plateau was then observed for the whole study. (3) Subjects who received trace elements (zinc and selenium) alone or associated with vitamins had significantly less infectious events during the 2 years of supplementation. These results indicate that supplementation with low doses of vitamins and trace elements is able to rapidly correct corresponding deficiencies in the institutionalized elderly. Moreover, zinc and selenium reduced infectious events.

Dietary patterns in six European populations: results from EURALIM, a collaborative European data harmonization and information campaign

Objective: To determine and describe the extent to which European dietary data collected in disparate surveys can be meaningfully compared.Design: Seven independent population-based surveys from six European countries were initially included. Differences in study designs and methodological approaches were examined. Risk factor data for 31, 289 adults aged 40–59 y were harmonized and pooled in a common, centralized database.Results: Direct comparisons of dietary measures across studies were not deemed appropriate due to methodological heterogeneity. Nonetheless, comparisons of intra-population contrasts by gender across sites were considered valid. Women consumed fruit and vegetables more often than men. Age-standardized gender differences in the prevalence of low fruit and vegetable consumption ranged from 7 to 18% and 5 to 15%, respectively. Data on energy intake showed good agreement across study populations. The proportion of total energy from macronutrients was similar for women and men. Gender differences for relative intakes of saturated fatty acids (percentage energy) were small and only in France were they significant. Dietary fibre density was significantly higher in women than in men. Overall, the participating Southern European populations from Italy and Spain exhibited more healthful food composition patterns.Conclusions: Contrasts in dietary patterns by gender across populations may provide the basis for health promotion campaigns. The most favourable patterns observed may serve as attainable goals for other populations. An international risk factor surveillance programme based upon locally run, good quality studies has the potential to provide the needed data.Sponsorship: European Community (DG V), project 96CVVF3-446-0; Swiss Federal Office for Education and Science, OFES 96.0089.European Journal of Clinical Nutrition (2000) 54, 253–262

Alcohol intake in relation to body mass index and waist-to-hip ratio : the importance of type of alcoholic beverage

OBJECTIVE Alcohol consumption may play a role in the development of obesity but the relationship between alcohol and weight is still unclear. The aim of our study was to assess the cross-sectional association of intakes of total alcohol and of specific alcoholic beverages (wine, beer and spirits) with waist-to-hip ratio (WHR) and body mass index (BMI) in a large sample of adults from all over France. DESIGN Cross-sectional. SETTING Participants were free-living healthy volunteers of the SU.VI.MAX study (an intervention study on the effects of antioxidant supplementation on chronic diseases). SUBJECTS For 1481 women aged 35-60 years and 1210 men aged 45-60 years, intakes of total alcohol and specific alcoholic beverages were assessed by six 24-hour dietary records. BMI and WHR were measured during a clinical examination the year after. RESULTS A J-shaped relationship was found between total alcohol consumption and WHR in both sexes and between total alcohol consumption and BMI in men only (P<0.05). The same relationships were observed with wine (P<0.05); men and women consuming less than 100 g day(-1) had a lower BMI (men only) and WHR than non-drinkers or those consuming more. Spirits consumption was positively associated with BMI (linear regression coefficient beta=0.21, 95% confidence interval (CI): 0.09-0.34 and beta=0.22, 95% CI: 0.06-0.39 for men and women, respectively) and WHR (beta=0.003, 95% CI: 0.001-0.005 and beta=0.003, 95%CI: 0.0002-0.006) in both sexes in a linear fashion. No relationship between beer consumption and BMI or WHR was found. CONCLUSION If confirmed in longitudinal studies, our results indicate that consumption of alcoholic beverages may be a risk factor for obesity.