Pierre Valeix

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.

Determinants of thyroid volume in healthy French adults participating in the SU.VI.MAX cohort

To study the relative importance of determinants of thyroid volume.

Effects of supplementation with a combination of antioxidant vitamins and trace elements, at nutritional doses, on biochemical indicators and markers of the antioxidant system in adult subjects.

OBJECTIVE To test the impact of supplementation with nutritional doses of antioxidant nutrients on biochemical indicators of vitamin and trace element levels. DESIGN A randomized double-blind trial was performed comparing two groups receiving daily either a combination of vitamins (beta-carotene, 6 mg; vitamin C, 120 mg; and vitamin E, 30 mg) and trace elements (zinc, 20 mg; and selenium, 100 micrograms); or a placebo. SUBJECTS 401 subjects (166 males aged 45 to 60 years and 235 females aged to 35 to 60 years). MEASURE OF OUTCOME: Biological markers of vitamin and trace element status and free radical parameters were measured initially, 3 months, and 6 months after supplemention. RESULTS Mean serum concentrations of alpha-tocopherol, vitamin C, beta-carotene, zinc and selenium increased significantly after 3 months of supplementation in the group receiving multivitamins associated with minerals. At baseline, 18.2% of the men and 5.1% of the women had low concentrations of serum vitamin C (< 20 mumol/l): 2.4% of the men and 17% of the women presented low concentrations of serum retinol (< 1.4 mumol/l): 18.7% of men and 10% of women had serum beta-carotene < 0.30 mumol/l. None of the study subjects had serum alpha-tocopherol concentrations below the limit cut-off point (< 9.3 mumol/l). Low serum zinc concentrations (< 10.7 mumol/l) were found in 15.1% of men and 23.8% of women. Low serum selenium concentrations (< 0.75 mumol/l) were found in 6% of men and 6.4% of women. A significant increase in plasma and red cell GPx activity was observed in groups receiving supplementation. No modifications were observed after 6 months of supplementation for malondyaldehyde. CONCLUSION This study demonstrates the efficacy of an intake of antioxidant vitamins and trace elements, given at nutritional doses, on biochemical indicators of vitamin and trace elements status.

Effects of light to moderate alcohol consumption on thyroid volume and thyroid function

Objective  To examine a possible relationship between alcohol consumption and thyroid volume and function.

Lifestyle factors related to iodine intakes in French adults.

OBJECTIVE To assess dietary iodine intakes among adults and to investigate the relationships of dietary, lifestyle, demographic and geographical characteristics with dietary iodine status. Adequacy of iodine intakes was also assessed. DESIGN Cross-sectional study. Linear regression analyses and logistic regression modelling were used to determine correlates of iodine intakes. Usual iodine mean intake was calculated by averaging six 24 h dietary records completed over a 2-year period. SUBJECTS Females aged 35-60 years (n 2962) and males aged 45-60 years (n 2117) living in France and who participated in the SU.VI.MAX study. RESULTS Iodine intakes ranged from 30.0 to 446.3 microg/d. The median iodine intake was 150.7 microg/d for males and 131.4 microg/d for females. High-level (97.5th percentile) intakes were 273.4 microg/d for males and 245.0 microg/d for females. Overall, 8.5 % of males and 20.3 % of females had intakes <100 microg/d (P < 0.001). Alcohol drinkers and smokers tended to have lower iodine intakes than abstainers or non-smokers. Regular physical activity and both intermediate and high education levels were associated with a lower risk of iodine intake of <150 microg/d. For both males and females there were significant overall regional differences (P < 0.001) in multivariate-adjusted iodine intakes, with higher adjusted iodine intakes in Brittany and Normandy than in the north-eastern region. CONCLUSIONS Our data show a borderline low iodine intake in this middle-aged French population. However, differences in iodine intakes may contribute to explaining only a small part of the effects of sex and age on thyroid disease incidence.

Iodine intakes assessed by urinary iodine concentrations in healthy children aged ten months, two years, and four years

Urinary iodine excretion was assessed in 642 healthy children aged 10 mo (n=243), 2 yr (n=183), and 4 yr (n=216) living in the Paris area and originating from continental France (60.3%), North Africa (13.8%), the West Indies (9.1%), West Africa (8.3%), Southeast Asia (4.8%), and southern Europe (3.8%). Mild impairment of neurological (reflexes, tone, audiometry) and intellectual development (Brunet-Lézine scale) was assessed in relation to iodine status. Iodine excretions (median values) were 18.4, 11.9, and 10.9 μg/100 mL at 10 mo, 2 yr, and 4 yr, respectively, and risk of mild iodine deficiency (5–10 μg/100 mL) was 18.1%, 34.8%, and 38.3% for the same age groups. No relationship was found between anthropometry, global development quotient, and iodine status. High hearing thresholds were more commonly associated with lower iodine excretion, suggesting mild hearing defects. In spite of iodine prophylaxis, the risk of mild to moderate iodine deficiency still exists in France and in a number of European countries. Evaluation of neurological sequels of borderline iodine status is a major public health problem in European communities.

Serum thyrotropin and free thyroxine reference ranges as defined in a disease-free sample of French middle-aged adults

Abstract Background: The goal of this study was to provide reference ranges for thyrotropin (TSH) and free thyroxine (fT4) based on data collected from a disease-free sample of French middle-aged adults. Methods: A total of 3218 subjects participating in the Supplémentation en Vitamines et Minéraux Antioxydants (SU.VI.MAX) study had measurements for TSH, fT4 and urinary iodine concentrations. Thyroid volume and structure were evaluated using standardized ultrasonography. We selected a disease-free sample which included 2338 subjects (1313 females aged 35–60 years and 1025 males aged 45–60 years) with normal thyroid imaging, no previously reported thyroid disease or use of thyroid medication, and no risk factors for thyroid dysfunction. Distribution of TSH and fT4 was estimated in males and females. Results: The median (central 95% range) TSH serum concentrations for females were 1.79 mU/L (0.29–5.21 mU/L) for ages 35–44 years and 1.98 mU/L (0.27–6.94 mU/L) for ages 45–60 years (p<0.0001, for age). The median (central 95% range) for males 45–60-year-old was 1.63 mU/L (0.28–4.54 mU/L) (p<0.0001, for sex). Sex- and age-specific mean fT4 concentrations did not differ significantly (p=0.06) between males and females and (p=0.08) between female age groups. However, median fT4 concentrations between 45–60-year-old males and females differed (p<0.001). Conclusions: In middle-aged adults, the TSH distribution was associated with gender and, among females, with age. Stratification according to gender and age should be considered when TSH ranges are used in the diagnosis, treatment and monitoring of thyroid disease. Clin Chem Lab Med 2009;47:1497–505.