Mario Murcia

Reproducibility and validity of a food frequency questionnaire among pregnant women in a Mediterranean area

BackgroundStudies exploring the role of diet during pregnancy are still scarce, in part due to the complexity of measuring diet and to the lack of valid instruments. The aim of this study was to examine the reproducibility and validity (against biochemical biomarkers) of a semi-quantitative food frequency questionnaire (FFQ) in pregnant women.MethodsParticipants were 740 pregnant women from a population-based birth cohort study in Valencia (INMA Study). We compared nutrient and food intakes from FFQs estimated for two periods of pregnancy (reproducibility), and compared energy-adjusted intake of several carotenoids, folate, vitamin B12, vitamin C and α-tocopherol of the FFQ in the first trimester with their concentration in blood specimens (validity).ResultsSignificant correlations for reproducibility were found for major food groups and nutrients but not for lycopene (r=0.06); the average correlation coefficients for daily intake were 0.51 for food groups and 0.61 for nutrients. For validity, statistically significant correlations were observed for vitamin C (0.18), α-carotene (0.32), β-carotene (0.22), lutein-zeaxantin (0.29) and β-cryptoxantin(0.26); non-significant correlations were observed for retinol, lycopene, α-tocopherol, vitamin B12 and folate (r≤0.12). When dietary supplement use was considered, correlations were substantially improved for folate (0.53) and to a lesser extent for vitamin B12 (0.12) and vitamin C (0.20).ConclusionThis study supports that the FFQ has a good reproducibility for nutrient and food intake, and can provide a valid estimate of several important nutrients during pregnancy.

Thyroxine levels during pregnancy in healthy women and early child neurodevelopment.

Background: The fetus depends on maternal thyroid hormones during pregnancy for normal brain development. Little is known about the effects of subclinical hypothyroidism and mild hypothyroxinemia during pregnancy on neurodevelopment of the child. Methods: We evaluated a population-based birth cohort in Spain. A total of 1761 children and their mothers were included in the main analyses. Serum levels of free thyroxine and thyrotropin were measured in pregnant women. Mental and psychomotor development of their children was assessed using the Bayley Scales of Infant Development during the second year of life. Results: Low free thyroxine levels (<5th percentile) and self-reported prepregnancy thyroid disorder without medical treatment were associated with a decrease of mental scores (Beta = −3.4 [95% confidence interval= −6.7 to −0.2]) and −5.5 [−8.9 to −2.0], respectively). No association between thyrotropin levels and mental scores or psychomotor scores was observed. Conclusions: Low free thyroxine levels in healthy pregnant women are related to a moderate delay in child neurodevelopment. The impairment is similar in magnitude to that observed in mothers with untreated prepregnancy thyroid disorder. The value of screening pregnant women for thyroid function requires further assessment, particularly in mildly iodine-deficient areas.

Fish consumption during pregnancy, prenatal mercury exposure, and anthropometric measures at birth in a prospective mother-infant cohort study in Spain

BACKGROUND Birth size has been shown to be related to maternal fish intake, although the results are inconsistent. OBJECTIVE The objective was to assess the association of consumption of different types of fish and prenatal mercury exposure with birth weight, birth length, and classification as small for gestational age (SGA) in newborns. DESIGN Cord blood total mercury was measured in 554 newborns in a population-based cohort born from 2004 to 2006. Fish consumption was classified in 4 frequency categories (<1 portion/mo, 1-3 portions/mo, 1 portion/wk, and > or =2 portions/wk). RESULTS When multivariate models were adjusted, newborns in the higher quartile of total mercury weighed 143.7 g less (95% CI: -251.8, -35.6; P for trend = 0.02) and had higher odds of being SGA for length (odds ratio: 5.3; 95% CI: 1.2, 23.9; P from likelihood ratio test = 0.03) without a linear relation (P for trend = 0.13) compared with those in the lowest quartile. Mothers consuming >/=2 portions/wk of canned tuna had newborns who weighed more than those who consumed <1 portion/mo (P for trend = 0.03) and a lower risk of having infants who were SGA for weight (P for trend = 0.01). Consumption of > or =2 portions/wk of large oily fish was associated with a higher risk of being SGA for weight and consumption of lean fish with a lower risk of being SGA for length compared with the consumption of <1 portion/mo, but in neither case was there a linear relation (P for trend >0.05). CONCLUSIONS The role of fish in fetal growth depends on the amount and type of fish consumed. The findings for mercury warrant further investigation in other settings.

Effect of Iodine Supplementation During Pregnancy on Infant Neurodevelopment at 1 Year of Age

Iodine is the main constituent of thyroid hormones, which in turn are required for fetal brain development. However, the relation between iodine intake during pregnancy, thyroid function, and child neurodevelopment needs further evaluation. The authors assessed the association of maternal iodine intake from diet and supplements during pregnancy and of maternal and neonatal thyroid function with infant neurodevelopment. The Mental Development Index and Psychomotor Development Index (PDI) for 691 children were obtained between 2005 and 2007 using the Bayley Scales of Infant Development at age 1 year in a prebirth cohort in Valencia, Spain. In multivariate analyses, a maternal thyrotropin level >4 μU/mL was associated with an increased risk of a PDI <85 (odds ratio = 3.5, P = 0.02). Maternal intake of ≥150 μg/day, compared with <100 μg/day, of iodine from supplements was associated with a 5.2-point decrease in PDI (95% confidence interval: -8.1, -2.2) and a 1.8-fold increase in the odds of a PDI <85 (95% confidence interval: 1.0, 3.3). When analyses were stratified by sex, this association was intensified for girls but was not observed for boys. Further evidence on the safety and effectiveness of iodine supplementation during pregnancy is needed before it is systematically recommended in iodine-sufficient or mildly deficient areas.

Iodine Intake and Maternal Thyroid Function During Pregnancy

Background: An adequate iodine intake during pregnancy is essential for the synthesis of maternal thyroid hormones and normal brain development in the fetus. Scant evidence is available on the effects and safety of iodine supplementation during pregnancy in areas with adequate or mildly deficient iodine intake. We examined the association of maternal iodine intake and supplementation with thyroid function before 24 weeks of gestation in population-based samples from 3 different areas in Spain. Methods: A cross-sectional study of 1844 pregnant women (gestational age range 8–23 weeks) was carried out in 3 areas in Spain (Guipúzcoa, Sabadell, Valencia), during the period 2004–2008. We measured levels of free thyroxine and thyroid-stimulating hormone (TSH) in serum, iodine in a spot urine sample, and questionnaire estimates of iodine intake from diet, iodized salt and supplements. Adjusted associations were assessed by multiple linear regression and logistic regression analyses. Results: There was an increased risk of TSH above 3 &mgr;U/mL in women who consumed 200 &mgr;g or more of iodine supplements daily compared with those who consumed less than 100 &mgr;g/day (adjusted odds ratio = 2.5 [95% confidence interval = 1.2 to 5.4]). We observed no association between urinary iodine and TSH levels. Pregnant women from the area with the highest median urinary iodine (168 &mgr;g/L) and highest supplement coverage (93%) showed the lowest values of serum free thyroxine. (geometric mean = 10.09 pmol/L [9.98 to 10.19]). Conclusions: Iodine supplement intake in the first half of pregnancy may lead to maternal thyroid dysfunction in iodine-sufficient or mildly iodine-deficient populations.

Prenatal Exposure to Mercury and Infant Neurodevelopment in a Multicenter Cohort in Spain: Study of Potential Modifiers

Vulnerability of the central nervous system to mercury is increased during early development. This study aimed to evaluate whether cord blood total mercury levels may have a negative effect on both mental and psychomotor development in a maternal-birth cohort from moderate-high fish consumption areas. Study subjects were 1,683 child participants in the INMA (Environment and Childhood) Project from 4 areas of Spain between 2003 and 2010. Cord blood total mercury levels were analyzed by atomic absorption spectrometry. Infant neurodevelopment was assessed around age 14 months by the Bayley Scales of Infant Development. Sociodemographic, lifestyle, and dietary information was obtained by questionnaire during pregnancy. The geometric mean of total mercury levels was 8.4 μg/L (95% confidence interval (CI): 8.1, 8.7). In multivariate analysis, a doubling in total mercury levels did not show an association with mental (β = 0.1, 95% CI: -0.68, 0.88) or psychomotor (β = -0.05, 95% CI: -0.79, 0.68) developmental delay; however, stratified findings by sex suggest a negative association between prenatal exposure to total mercury and psychomotor development among female infants (β = -1.09, 95% CI: -2.21, 0.03), although follow-up is required to confirm these results.

Diet quality in early pregnancy and its effects on fetal growth outcomes: the Infancia y Medio Ambiente (Childhood and Environment) Mother and Child Cohort Study in Spain

BACKGROUND Maternal diet has been associated with fetal growth outcomes; however, evidence is scarce on the role of dietary quality. OBJECTIVE The objective was to assess the effect of diet quality during the first trimester of pregnancy, as measured by the Alternate Healthy Eating Index (AHEI) adapted for pregnancy, on fetal growth. DESIGN We studied 787 women and their newborns from a Spanish cohort study. Diet quality was assessed by using a modification of the AHEI. Adjusted birth weight, birth length, and head circumference were used as continuous outcomes. We used a customized model to define fetal growth restriction in weight, length, and head circumference. RESULTS After adjustment of multivariate models, a positive association was observed between diet quality and adjusted birth weight and adjusted birth length. The greatest differences were found between the fourth and first quintiles of the AHEI. Newborns of women in the fourth quintile were on average 126.3 g (95% CI: 38.5, 213.9 g) heavier and 0.47 cm (95% CI: 0.08, 0.86 cm) longer than those in the lowest quintile (P for trend = 0.009 and 0.013, respectively). Women with the highest AHEI scores had a significantly lower risk of delivering a fetal growth-restricted infant for weight (odds ratio: 0.24; 95% CI: 0.10, 0.55; P for trend = 0.001) than did women in the lowest quintile, but this was not the case for fetal growth restriction in length (P for trend = 0.538) or head circumference (P for trend = 0.070). CONCLUSION A high-quality diet in the first trimester of pregnancy is associated with birth size and the risk of fetal growth restriction.

Maternal pre-pregnancy overweight and obesity, and child neuropsychological development: two Southern European birth cohort studies

BACKGROUND Maternal pre-pregnancy obesity may be associated with impaired infant neuropsychological development; however, there are few studies and it is unclear if reported associations are due to intrauterine mechanisms. METHODS We assessed whether maternal pre-pregnancy overweight and obesity were associated with cognitive and psychomotor development scores (mean 100 ± 15) of children aged 11-22 months in two birth cohorts: Environment and Childhood (INMA, Spain; n = 1967) and Mother-Child (RHEA, Greece: n = 412). Paternal body mass index (BMI) was used as a negative control exposure. RESULTS The percentage of overweight and obese mothers was 18% and 8%, respectively, in INMA and 20% and 11% in RHEA, respectively. Maternal pre-pregnancy obesity was associated with reduced infant cognitive development scores in both INMA (score reduction: -2.72; 95% CI: -5.35, -0.10) and RHEA (score reduction: -3.71; 95% CI: -8.45, 1.02), after adjusting for socioeconomic variables and paternal BMI. There was evidence in both cohorts of a dose-response relationship with continuous maternal BMI. Paternal overweight/obesity was not associated with infant cognitive development. Associations with psychomotor scores were not consistent between cohorts, and were stronger for paternal than maternal BMI in RHEA. CONCLUSIONS This study in two birth cohorts with moderately high obesity prevalence suggests that maternal pre-pregnancy obesity is associated with reduced child cognitive development at early ages. This association appears more likely to be due to maternal than shared family and social mechanisms, but further research is needed to disentangle a direct intrauterine effect from other maternal confounding factors.

Fish intake during pregnancy, fetal growth, and gestational length in 19 European birth cohort studies.

BACKGROUND Fish is a rich source of essential nutrients for fetal development, but in contrast, it is also a well-known route of exposure to environmental pollutants. OBJECTIVE We assessed whether fish intake during pregnancy is associated with fetal growth and the length of gestation in a panel of European birth cohort studies. DESIGN The study sample of 151,880 mother-child pairs was derived from 19 population-based European birth cohort studies. Individual data from cohorts were pooled and harmonized. Adjusted cohort-specific effect estimates were combined by using a random- and fixed-effects meta-analysis. RESULTS Women who ate fish >1 time/wk during pregnancy had lower risk of preterm birth than did women who rarely ate fish (≤ 1 time/wk); the adjusted RR of fish intake >1 but <3 times/wk was 0.87 (95% CI: 0.82, 0.92), and for intake ≥ 3 times/wk, the adjusted RR was 0.89 (95% CI: 0.84, 0.96). Women with a higher intake of fish during pregnancy gave birth to neonates with a higher birth weight by 8.9 g (95% CI: 3.3, 14.6 g) for >1 but <3 times/wk and 15.2 g (95% CI: 8.9, 21.5 g) for ≥ 3 times/wk independent of gestational age. The association was greater in smokers and in overweight or obese women. Findings were consistent across cohorts. CONCLUSION This large, international study indicates that moderate fish intake during pregnancy is associated with lower risk of preterm birth and a small but significant increase in birth weight.

Air pollution during pregnancy and childhood cognitive and psychomotor development: six European birth cohorts.

Background: Accumulating evidence from laboratory animal and human studies suggests that air pollution exposure during pregnancy affects cognitive and psychomotor development in childhood. Methods: We analyzed data from 6 European population-based birth cohorts—GENERATION R (The Netherlands), DUISBURG (Germany), EDEN (France), GASPII (Italy), RHEA (Greece), and INMA (Spain)—that recruited mother–infant pairs from 1997 to 2008. Air pollution levels—nitrogen oxides (NO2, NOx) in all regions and particulate matter (PM) with diameters of <2.5, <10, and 2.5–10 &mgr;m (PM2.5, PM10, and PMcoarse, respectively) and PM2.5 absorbance in a subgroup—at birth addresses were estimated by land-use regression models, based on monitoring campaigns performed primarily between 2008 and 2011. Levels were back-extrapolated to exact pregnancy periods using background monitoring sites. Cognitive and psychomotor development was assessed between 1 and 6 years of age. Adjusted region-specific effect estimates were combined using random-effects meta-analysis. Results: A total of 9482 children were included. Air pollution exposure during pregnancy, particularly NO2, was associated with reduced psychomotor development (global psychomotor development score decreased by 0.68 points [95% confidence interval = −1.25 to −0.11] per increase of 10 &mgr;g/m3 in NO2). Similar trends were observed in most regions. No associations were found between any air pollutant and cognitive development. Conclusions: Air pollution exposure during pregnancy, particularly NO2 (for which motorized traffic is a major source), was associated with delayed psychomotor development during childhood. Due to the widespread nature of air pollution exposure, the public health impact of the small changes observed at an individual level could be considerable.