Validity of a food frequency questionnaire in assessing nutrient intakes of low-income pregnant women

Prenatal Fine Particulate Matter, Maternal Micronutrient Antioxidant Intake, and Early Childhood Repeated Wheeze: Effect Modification by Race/Ethnicity and Sex

Fine particulate matter (PM2.5) potentiates in utero oxidative stress influencing fetal development while antioxidants have potential protective effects. We examined associations among prenatal PM2.5, maternal antioxidant intake, and childhood wheeze in an urban pregnancy cohort (n = 530). Daily PM2.5 exposure over gestation was estimated using a satellite-based spatiotemporally resolved model. Mothers completed the modified Block98 food frequency questionnaire. Average energy-adjusted percentile intake of β-carotene, vitamins (A, C, E), and trace minerals (zinc, magnesium, selenium) constituted an antioxidant index (AI). Maternal-reported child wheeze was ascertained up to 4.1 ± 2.8 years. Bayesian distributed lag interaction models (BDLIMs) were used to examine time-varying associations between prenatal PM2.5 and repeated wheeze (≥2 episodes) and effect modification by AI, race/ethnicity, and child sex. Covariates included maternal age, education, asthma, and temperature. Women were 39% Black and 33% Hispanic, 36% with ≤high school education; 21% of children had repeated wheeze. Higher AI was associated with decreased wheeze in Blacks (OR = 0.37 (0.19-0.73), per IQR increase). BDLIMs identified a sensitive window for PM2.5 effects on wheeze among boys born to Black mothers with low AI (at 33-40 weeks gestation; OR = 1.74 (1.19-2.54), per µg/m3 increase in PM2.5). Relationships among prenatal PM2.5, antioxidant intake, and child wheeze were modified by race/ethnicity and sex.

Development of a Dietary Methyl Donor Food Frequency Questionnaire to Assess Folate and Vitamin B12 Status in Children with Chronic Hepatitis B Virus Infection

OBJECTIVE

To develop a dietary methyl donor food frequency questionnaire (DMD-FFQ) that is validated in a cohort of US children and to determine whether the consumption of folate and vitamin B₁₂, principal DMDs, correlates with HBV DNA levels and its methylation density.

STUDY DESIGN

We developed a semiquantitative DMD-FFQ to estimate intake of folate and vitamin B₁₂ and validated this instrument against a 24-hour dietary recall and biomarkers-red blood cell folate, serum vitamin B₁₂, and homocysteine-in 35 children with chronic HBV infection without other medical comorbidities. Estimates of DMD, as well as the serum biomarkers, were correlated with the methylation density of HBV CpG island 2 and HBV DNA levels.

RESULTS

Folate per kilogram of body weight by the DMD-FFQ correlated positively with 24-hour recall (r = 0.60; P < .001) and red blood cell folate (r = 0.40; P = .02), and negatively with homocysteine (r = -0.54; P < .001). Vitamin B₁₂ per kilogram by DMD-FFQ also correlated positively with 24-hour recall (r = 0.57; P < .001) and serum vitamin B₁₂ (r = 0.36, P = .04), and negatively with homocysteine (r = -0.44; P = .008). Neither DMD intake (from DMD-FFQ or 24-hour recall) nor serum biomarkers correlated with HBV DNA levels or its methylation density.

CONCLUSIONS

Our DMD-FFQ correlates well with a 24-hour recall and circulating biomarkers. Although little evidence existed that consumption of these micronutrients correlated with HBV replication, this tool could prove useful for investigating epigenetic modification by diet for several pediatric diseases.

Validation of a food frequency questionnaire for Japanese pregnant women with and without nausea and vomiting in early pregnancy

BACKGROUND

No previous study has shown the validity of a food frequency questionnaire (FFQ) in early pregnancy with consideration of nausea and vomiting during pregnancy (NVP). The aim of this study was to evaluate the validity of a FFQ in early pregnancy for Japanese pregnant women.

METHOD

We included 188 women before 15 weeks of gestation and compared estimated nutrient intake and food group intake based on a modified FFQ with that based on 3-day dietary records (DRs). Spearman's rank correlation coefficients, adjusting energy intake and attenuating within-person error, were calculated. Subgroup analysis for those with and without NVP was conducted. We also examined the degree of appropriate classification across categories between FFQ and DRs through division of consumption of nutrients and food groups into quintiles.

RESULTS

Crude Spearman's correlation coefficients of nutrients ranged from 0.098 (sodium) to 0.401 (vitamin C), and all of the 36 nutrients were statistically significant. In 27 food groups, correlation coefficients ranged from -0.015 (alcohol) to 0.572 (yogurt), and 81% were statistically significant. In subgroup analysis, correlation coefficients in 89% of nutrients and 70% of food groups in women with NVP and 97% of nutrients and 74% of food groups in women without NVP were statistically significant. On average, 63.7% of nutrients and 60.4% of food groups were classified into same or adjacent quintiles according to the FFQ and DRs.

CONCLUSIONS

The FFQ is a useful instrument, regardless of NVP, for assessing the diet of women in early pregnancy in Japan.

Development and Validation of a Mediterranean Oriented Culture-Specific Semi-Quantitative Food Frequency Questionnaire

The objectives were to develop a Mediterranean oriented semi-quantitative food frequency questionnaire (FFQ) and evaluate its validity in measuring energy and nutrient intakes. For FFQ development, the main challenge was to merge food items and practices reflecting cultural Mediterranean preferences with other food choices ensuing from diet transition to more westernized dietary patterns. FFQ validity was evaluated by comparing nutrient intakes against the average of two 24-h dietary recalls for 179 pregnant women. Although the mean intake values for most nutrients and energy tended to be higher when determined by the FFQ, the Cohen's d was below 0.3. Bland-Altman plots confirmed the agreement between the two methods. Positive significant correlations ranged from 0.35 to 0.77. The proportion of women classified correctly was between 73.2% and 92.2%, whereas gross misclassification was low. Weighted kappa values were between 0.31 and 0.78, while intraclass correlation coefficients were between 0.49 and 0.89. Our methodological approach for the development and validation of this FFQ provides reliable measurements of energy, macro- and micronutrient intakes. Overall, our culture-specific FFQ could serve as a useful assessment tool in studies aiming at monitoring dietary intakes, especially in the Mediterranean region, where countries share common cultural dietary habits.

Electronic nutritional intake assessment in patients with urolithiasis: A decision impact analysis

Purpose

To evaluate a physician's impression of a urinary stone patient's dietary intake and whether it was dependent on the medium through which the nutritional data were obtained. Furthermore, we sought to determine if using an electronic food frequency questionnaire (FFQ) impacted dietary recommendations for these patients.

Materials and Methods

Seventy-six patients attended the Stone Clinic over a period of 6 weeks. Seventy-five gave consent for enrollment in our study. Patients completed an office-based interview with a fellowship-trained endourologist, and a FFQ administered on an iPad. The FFQ assessed intake of various dietary components related to stone development, such as oxalate and calcium. The urologists were blinded to the identity of patients' FFQ results. Based on the office-based interview and the FFQ results, the urologists provided separate assessments of the impact of nutrition and hydration on the patient's stone disease (nutrition impact score and hydration impact score, respectively) and treatment recommendations. Multivariate logistic regressions were used to compare pre-FFQ data to post-FFQ data.

Results

Higher FFQ scores for sodium (odds ratio [OR], 1.02; p=0.02) and fluids (OR, 1.03, p=0.04) were associated with a higher nutritional impact score. None of the FFQ parameters impacted hydration impact score. A higher FFQ score for oxalate (OR, 1.07; p=0.02) was associated with the addition of at least one treatment recommendation.

Conclusions

Information derived from a FFQ can yield a significant impact on a physician's assessment of stone risks and decision for management of stone disease.

Validation of a Food Frequency Questionnaire for Estimating Micronutrient Intakes in an Urban US Sample of Multi-Ethnic Pregnant Women

OBJECTIVE(S)

To validate the Block98 food frequency questionnaire (FFQ) for estimating antioxidant, methyl-nutrient and polyunsaturated fatty acids (PUFA) intakes in a pregnant sample of ethnic/racial minority women in the United States (US).

METHODS

Participants (n = 42) were from the Programming of Intergenerational Stress Mechanisms study. Total micronutrient intakes from food and supplements was ascertained using the modified Block98 FFQ and two 24-h dietary recalls collected at random on nonconsecutive days subsequent to completion of the FFQ in mid-pregnancy. Correlation coefficients (r) corrected for attenuation from within-person variation in the recalls were calculated for antioxidants (n = 7), methyl-nutrients (n = 8), and PUFAs (n = 2).

RESULT(S)

The sample was largely ethnic minorities (38 % Black, 33 % Hispanic) with 21 % being foreign born and 41 % having less than or equal to a high school degree. Significant and adequate deattenuated correlations (r ≥ 0.40) for total dietary intakes of antioxidants were observed for vitamin C, vitamin E, magnesium, and zinc. Reasonable deattenuated correlations were also observed for methyl-nutrient intakes of vitamin B6, betaine, iron, and n:6 PUFAs; however, they did not reach significance. Most women were classified into the same or adjacent quartiles (≥70 %) for total (dietary + supplements) estimates of antioxidants (5 out of 7) and methyl-nutrients (4 out of 5).

CONCLUSIONS

The Block98 FFQ is an appropriate dietary method for evaluating antioxidants in pregnant ethnic/minorities in the US; it may be less efficient in measuring methyl-nutrient and PUFA intakes.

Deficient maternal zinc intake-but not folate-is associated with lower fetal heart rate variability

OBJECTIVE

Few studies of maternal prenatal diet and child development examine micronutrient status in relation to fetal assessment.

METHODS

Twenty-four-hour dietary recall of zinc and folate and 20min of fetal heart rate were collected from 3rd trimester pregnant adolescents.

RESULTS

Deficient zinc was associated with less fetal heart rate variability. Deficient folate had no associations with HRV. Neither deficient zinc nor deficient folate was related to fetal heart rate.

CONCLUSIONS

These findings, from naturalistic observation, are consistent with emerging data on prenatal zinc supplementation using a randomized control design.

PRACTICAL IMPLICATION

Taken together, the findings suggest that maternal prenatal zinc intake is an important and novel factor for understanding child ANS development.

Mediators and Moderators of the Effectiveness of a Community Health Worker Intervention That Improved Dietary Outcomes in Pregnant Latino Women

BACKGROUND

Pregnancy is an opportune time to initiate diabetes prevention strategies for minority and underserved women, using culturally tailored interventions delivered by community health workers. A community-partnered randomized controlled trial (RCT) with pregnant Latino women resulted in significantly improved vegetable, fiber, added sugar, and total fat consumption compared to a minimal intervention group. However, studying RCT intervention effects alone does not explain the mechanisms by which the intervention was successful or help identify which participants may have benefitted most.

PURPOSE

To improve the development and targeting of future community health worker interventions for high-risk pregnant women, we examined baseline characteristics (moderators) and potential mechanisms (mediators) associated with these dietary changes.

METHOD

Secondary analysis of data for 220 Latina RCT participants was conducted. A linear regression with effects for intervention group, moderator, and interaction between intervention group and moderator was used to test each hypothesized moderator of dietary changes. Sobel-Goodman mediation test was used to assess mediating effects on dietary outcomes.

RESULTS

Results varied by dietary outcome. Improvements in vegetable consumption were greatest for women who reported high spousal support at baseline. Women younger than age 30 were more likely to reduce added sugar consumption than older women. Participants who reported higher baseline perceived control were more likely to reduce fat consumption. No examined mediators were significantly associated with intervention effects.

CONCLUSION

Future interventions with pregnant Latinas may benefit from tailoring dietary goals to consider age, level of spousal support, and perceived control to eat healthy.

Maternal calcium metabolic stress and fetal growth

BACKGROUND

Suboptimal maternal calcium intake and vitamin D status may or may not adversely influence fetal growth.

OBJECTIVE

It was hypothesized that maternal calcium metabolic stress in early pregnancy, rather than suboptimal calcium intake or insufficient vitamin D, influences the risk of small-for-gestational-age (SGA) births and other aspects of fetal growth. Stress to calcium metabolism was defined as elevated intact parathyroid hormone (PTH) (>62 pg/mL) accompanied by a very low calcium intake [<60% of the Estimated Average Requirement (EAR)] or insufficient 25-hydroxyvitamin D [25(OH)D] (<20 ng/mL).

DESIGN

This was a prospective cohort study of 1116 low-income and minority gravidae at entry to care of 13.8 ± 5.6 wk (mean ± SD).

RESULTS

The PTH concentration depended on circulating 25(OH)D and total calcium intake. When 25(OH)D was insufficient, even a high calcium intake (which equaled or exceeded the Recommended Dietary Allowance) was unable to maintain PTH or to moderate the proportion of patients with an elevated PTH. When examined one at a time, very low calcium intake (<60% of EAR), very low 25(OH)D (<12 ng/mL), and elevated PTH (>62 pg/mL) each had a small but significant association with birth weight. Elevated PTH was also related to birth length and risk of SGA birth. Elevated PTH accompanied by insufficient 25(OH)D or very low calcium intake was associated with a 2- to 3-fold increased risk of SGA birth and a significantly lower birth weight, birth length, and head circumference, even after women who developed preeclampsia were excluded. Infants born to gravidae with insufficient 25(OH)D or very low calcium intake without elevated PTH or with elevated PTH alone were unaffected.

CONCLUSION

Maternal calcium metabolic stress, rather than low calcium intake or insufficient vitamin D, has an adverse influence on fetal growth. This trial was registered at clinicaltrials.gov as NIH 0320070046.

Dietary outcomes in a Spanish-language randomized controlled diabetes prevention trial with pregnant Latinas

OBJECTIVES

We evaluated the effectiveness of a community-based healthy lifestyle intervention in improving dietary behaviors of pregnant Latinas from 2004 to 2006 in Detroit, Michigan.

METHODS

The 11-week, culturally tailored, Spanish-language Healthy Mothers on the Move (MOMs) intervention offered home visits, group classes, related activities, and social support from trained community health workers (CHWs) and peers. Dietary behaviors were measured by food frequency questionnaire. Linear mixed models estimated pre- and post-intervention changes, within and between MOMs intervention and minimal intervention (MI) groups.

RESULTS

MOMs (n = 139) and MI (n = 139) participants had similar baseline characteristics and dietary intake. Post-intervention, MOMs participants showed significant improvement in all dietary behaviors, except fruit and fiber consumption. Compared with MI participants, MOMs participants had significantly decreased consumption of added sugar (P = .05), total fat (P < .05), saturated fat (P < .01), percentage of daily calories from saturated fat (P < .001), solid fats and added sugars (P < .001), and had increased vegetable consumption (P < .001). Their increase in fiber consumption (P < .05) was significant relative to MI participants' decrease in fiber intake.

CONCLUSIONS

We confirmed the hypothesis that a community-planned, CHW-led healthy lifestyle intervention could improve dietary behaviors of low-income Latina women during pregnancy.

Periconception diet does not vary by duration of US residence for Mexican immigrant women

This cross-sectional study assessed the influence of duration of residence in the United States on periconception dietary intake of pregnant Mexican immigrant women, using baseline data from Healthy Mothers on the Move, a randomized control trial conducted with 234 women from 2004 to 2006 in Detroit, MI. Average maternal age was 27.3±5.2 years (range=18 to 41 years) with 5.99±4.76 years of US residence (range=0 to 36 years). Women's usual dietary intake during the past 12 months was recorded on a validated food frequency questionnaire (17.3 weeks average gestation). Intakes of selected micronutrients, macronutrients, and food groups were compared by US residence categories (≤5, 6 to 10, or ≥11 years) using analysis of covariance. The percent of women with intakes below the Estimated Average Requirement and the percent not meeting US dietary guidelines were calculated. There was no association between dietary intake and duration of US residence in this population. Percentages of women with dietary intake below the Estimated Average Requirement were: 12.0% for folate, 7.7% for vitamin C, 23.9% for calcium, 11.2% for protein, and 5.1% for carbohydrates. US dietary guidelines were not met for fruit by 17.5% and for vegetables by 74.8% of women. Typical diets were high in saturated fat and cholesterol. Of the 2,195 kcal average daily energy intake, >25% came from saturated fats, trans fats, and added sugars that may replace nutrients important for healthy fetal growth and development and women's health. Interventions to improve intake before, during, and after pregnancy are important in this population, regardless of duration of US residence.

The effect of weight status, lifestyle, and body image perception on health-related quality of life in children: a quantile approach

PURPOSE

To evaluate the effect of excess weight, lifestyle factors, and body image on HRQoL in a sample of school-aged children.

METHODS

Cross-sectional data of 4,338 thirteen-year-old children were collected in 2007 as part of the So.N.I.A project, a nutritional surveillance study in a northern Italian region. A two-stage sampling design was used in order to gain a Health District representative sample of the regional population. HRQoL was assessed using the EQ-5D-Y questionnaire completed by the children at school. The association between weight categories, defined by means of the International Obesity Task Force cut points, physical exercise, and body image perception and HRQoL as measured by the EQ-Visual Analogue Scale was studied by means of a quantile regression analysis.

RESULTS

Of the participants, 891 (20.5 %) and 210 (4.84 %) were overweight and obese, respectively, with 1,922 (44.3 %) children exercising <2 h per week. Results from the quantile regression showed a decreased HRQoL for girls compared with boys, overweight or obese children who do little weekly exercise, and body image dissatisfaction, especially in the lower tail of the VAS distribution.

CONCLUSIONS

Excess weight, sedentary behavior, and an unsatisfactory self-perception are associated with reduced HRQoL in this population-based sample. Quantile regression can help to highlight differences in the effects along all of the outcome distribution.

Validation of a novel method for retrospectively estimating nutrient intake during pregnancy using a semi-quantitative food frequency questionnaire

Case control studies evaluating the relationship between dietary intake of specific nutrients and risk of congenital, neonatal or early childhood disease require the ability to rank relative maternal dietary intake during pregnancy. Such studies are limited by the lack of validated instruments for assessing gestational dietary intake several years post-partum. This study aims to validate a semi-quantitative interview-administered food frequency questionnaire (FFQ) for retrospectively estimating nutrient intake at two critical time points during pregnancy. The FFQ was administered to women (N = 84), who 4-6 years earlier had participated in a prospective study to evaluate dietary intake during pregnancy. The FFQ queried participants about intake during the previous month (FFQ-month). This was then used as a reference point to estimate consumption by trimester (FFQ-pregnancy). The resulting data were compared to data collected during the original study from two 24-h recalls (24 h-original) using Spearman correlation and Wilcoxon sign-rank-test. Total energy intake as estimated by the retrospective and original instruments did not differ and was only weakly correlated in the trimesters (1st and 3rd) as a whole (r = 0.18-32), though more strongly correlated when restricted to the first half of the 1st trimester (r = 0.32) and later half of the 3rd trimester (r = 0.87). After energy adjustment, correlation between the 24hR-original and FFQ-pregnancy in the 3rd trimester were r = 0.25 (P < 0.05) for dietary intake of vitamin A, and r = 0.26 (P < 0.05) for folate, and r = 0.23-0.77 (P < 0.005) for folate, and vitamins A, B6 and B12 in the 1st and 3rd trimester after including vitamin supplement intake. The FFQ-pregnancy provides a consistent estimate of maternal intake of key micronutrients during pregnancy and permits accurate ranking of intake 4-6 years post-partum.

Dietary assessment methods for micronutrient intake in pregnant women: a systematic review

The EURopean micronutrient RECommendations Aligned (EURRECA) Network of Excellence needs clear guidelines for assessing the validity of reported micronutrient intakes among vulnerable population groups. A systematic literature search identified studies validating the methodology used for measuring usual dietary intake during pregnancy. The quality of each validation study selected was assessed using a EURRECA-developed scoring system. The validation studies were categorised according to whether the study used a reference method that reflected short-term intake ( < 7 d) long-term intake ( > or = 7 d) or used biomarkers (BM). A correlation coefficient for each micronutrient was calculated from the mean of the correlation coefficients from each study weighted by the quality of the study. Seventeen papers were selected, which included the validation of fifteen FFQ, two dietary records (DR), one diet history and a Fe intake checklist. Estimates of twenty-six micronutrients by six FFQ were validated against 24-h recalls indicating good correlation for six micronutrients. Estimates of twenty-four micronutrients by two FFQ were validated against estimated DR and all had good or acceptable correlations. Estimates of fourteen micronutrients by three FFQ were validated against weighed DR indicating good correlations for five. Six FFQ were validated against BM, presenting good correlations only for folic acid. FFQ appear to be most reliable for measuring short-term intakes of vitamins E and B6 and long-term intakes of thiamin. Apart from folic acid, BM do not add any more certainty in terms of intake method reliability. When frequency methods are used, the inclusion of dietary supplements improves their reliability for most micronutrients.

Relative validation of a quantitative FFQ for use in Brazilian pregnant women

OBJECTIVE

To evaluate the ability of an FFQ, designed for use in Brazilian pregnant women, to estimate nutrient intakes during pregnancy.

DESIGN

A prospective study was conducted among 103 pregnant women attended by the Brazilian national health-care service. Food intake during pregnancy was evaluated by three 24 h dietary recalls (24hR), one per trimester of pregnancy, and also by two FFQ. The FFQ with eighty-five food items included questions about frequency of intake and portion sizes during two periods: the first 24 weeks of pregnancy and the pregnancy period as a whole. Deattenuated Pearson’s correlation coefficients and joint classification into quartiles of nutrient intake were applied.

SETTING

Ribeira˜o Preto, Sa˜o Paulo State, Brazil.

SUBJECTS

One hundred and three pregnant women, aged 18–35 years.

RESULTS

Acceptable correlation coefficients (r > 0.35) were found for Ca, K, Zn, Mg, fibre, vitamin C, niacin and folic acid for intake for the first 24 weeks; and for energy, lipids, protein, carbohydrate, Fe, K, Zn, fibre, vitamin B6, riboflavin and niacin for the gestational period as a whole. A high proportion of study participants (≥ 70 %) were categorized into the same or adjacent quartiles for estimated energy, carbohydrate, Ca, K, fibre, Zn, cholesterol, vitamin A, riboflavin, niacin, vitamin C, vitamin E and folic acid. Gross misclassification ranged from 2.3% (dietary fibre) to 12.5% (vitamin A, thiamin and SFA).

CONCLUSIONS

The FFQ is a useful tool for assessing categories of nutrient intake during pregnancy, since a high proportion of women were classified into the same or adjacent quartiles.

A pilot study to increase fruit and vegetable intake in pregnant latina women

Previous studies have suggested that women have low dietary intake of fruits and vegetables. This study's objective was to test the effectiveness of a novel nutrition intervention (education about prenatal flavor learning) on increasing fruit and vegetable intake in a group of primarily Latina women at an urban prenatal clinic.

METHODS

The Harvard Service Food Frequency Questionnaire (HSFFQ) was administered to 2 groups at the same clinic at 2 time points for each group. The first group was a nonintervention, comparison group. The second (intervention) group received specific information about how a pregnant woman's food choices can influence subsequent solid food preferences of her infant, with encouragement given to increase fruit and vegetable choices. The HSFFQ was administered pre- and post-intervention for this group.

RESULTS

Combined fruit and vegetable intake declined from the administration of Q#1 to Q#2 in both the comparison (n = 28) and intervention (n = 31) groups. The decline was primarily the result of a decrease in vegetable intake, but it was not statistically significant. In the comparison group, only 23.3-36.6% of women were eating adequate daily servings of vegetables, and in the intervention group 32.3%-38.7%. In both the comparison and intervention groups, over 74% of the women were eating adequate daily servings of fruit at both time points.

CONCLUSIONS

In this Latina population of pregnant women, there was no difference in fruit and vegetable intake after receiving education about prenatal flavor learning. These findings suggest that education alone may not be sufficient to change health behaviors.

Reproducibility and validity of a food frequency questionnaire in assessing dietary intakes of low-income Caucasian postpartum women living in Sheffield, United Kingdom

The aim of this study was to examine the reproducibility and validity of a semi-quantitative food frequency questionnaire (FFQ) for assessing dietary intakes of low-income, Caucasian, English-speaking, postpartum women living in Sheffield, United Kingdom. Data was obtained from a cross-sectional sample of the 'Healthy Start' study; a population-based survey of mothers and infants. Participants completed two FFQs at 4 and 8 weeks postpartum. Measures from 24-hour dietary recalls (24HDRs) were collected at 4, 6, 8 and 12 weeks postpartum. In the reproducibility study, crude Pearson's correlation coefficients ranged from 0.40 (riboflavin) to 0.73 (thiamine), mean value 0.54. In the validation study, crude Pearson correlation coefficients between the FFQ and the measures from the 24HDRs ranged from 0.10 (B12) to 0.55 (manganese), mean value 0.34. Energy-adjustments and corrections for attenuation had no significant effect on the strength of the correlation both observed in the reproducibility and validity study. On average, 68% of the participants were classified correctly, and 3% were misclassified into the extreme opposite quintile of the distribution. The authors conclude that the questionnaire performed well for the majority of nutrients examined and that is a valid tool for ranking individuals according to nutrient distribution.

Predictors of measurement error in energy intake during pregnancy

Nutrition plays a critical role in maternal and fetal health; however, research on error in the measurement of energy intake during pregnancy is limited. The authors analyzed data on 998 women living in central North Carolina with singleton pregnancies during 2001-2005. Second-trimester diet was assessed by food frequency questionnaire. Estimated energy requirements were calculated using Institute of Medicine prediction equations, with adjustment for energy costs during the second trimester. Implausible values for daily energy intake were determined using confidence limits of agreement for energy intake/estimated energy requirements. Prevalences of low energy reporting (LER) and high energy reporting (HER) were 32.8% and 12.9%, respectively. In a multivariable analysis, pregravid body mass index was related to both LER and HER; LER was higher in both overweight (odds ratio = 1.96, 95% confidence interval: 1.26, 3.02; P = 0.031) and obese (odds ratio = 3.29, 95% confidence interval: 2.33, 4.65; P < 0.001) women than in normal-weight counterparts. Other predictors of LER included marriage and higher levels of physical activity. HER was higher among subjects who were underweight, African-American, and less educated and subjects who had higher depressive symptom scores. LER and HER are prevalent during pregnancy. Identifying their predictors may improve data collection and analytic methods for reducing systematic bias in the study of diet and reproductive outcomes.

Validity and reproducibility of a semi-quantitative food frequency questionnaire for use among Portuguese pregnant women

This study aimed to evaluate the validity and reproducibility of a semi-quantitative food frequency questionnaire (FFQ) to estimate nutrient intake among Portuguese pregnant women. A sample of 101 pregnant women completed a 3-day food diary (FD) in each pregnancy trimester (reference method) and an interviewer-administered FFQ in the immediate post-partum period. Ranking women according to their usual intake showed that, on average, 65% were classified into the same +/-1 quintile and 2.4% into opposite quintiles by the two methods. Energy-adjusted and de-attenuated correlation coefficients ranged from 0.20 (protein) to 0.58 (riboflavin). Similar results were obtained when the FFQ was compared to each trimester-specific FD. To assess the FFQ reproducibility, 70 women in their third pregnancy trimester were interviewed twice within a 2-week interval. The level of agreement was high, with > or = 75% of the participants being classified into the same +/-1 quintile by the two administrations for 13 of the 15 nutrients examined. A review of the published literature revealed that this is the first FFQ to take the whole pregnancy as its reference time window. Our findings showed that a single administration of this FFQ in the immediate post-partum period is a valid tool to rank Portuguese pregnant women according to their intakes.

Assessing diet in longitudinal birth cohort studies

Diet is an important component of a person's environment. It is important for adults and particularly for mothers during pregnancy and while breast feeding, and for children in utero and during later growth and development. Measurement of the type and amount of foods consumed is complex. Here we describe the different methods that can be used, when and when not to use each one, and the importance of validation studies.

Dietary intake and nutritional adequacy prior to conception and during pregnancy: a follow-up study in the north of Portugal

Objective

To assess maternal diet and nutritional adequacy prior to conception and during pregnancy.

Design

Follow-up of a cohort of pregnant women with collection of questionnaire data throughout pregnancy and after delivery.

Setting

Antenatal clinics at two public hospitals in Porto, Portugal.

Subjects

Two hundred and forty-nine pregnant women who reported a gestational age below 13 weeks at the time they attended their first antenatal visit.

Results

Intakes of energy and macronutrients were within recommended levels for most women. Pregnancy was accompanied by increases in the dietary intake of vitamins A and E, riboflavin, folate, Ca and Mg, but declines in the intake of alcohol and caffeine. The micronutrients with higher inadequacy prevalences prior to pregnancy were vitamin E (83 %), folate (58 %) and Mg (19 %). These three micronutrients, together with Fe, were also those with the highest inadequacy prevalences during pregnancy (91 %, 88 %, 73 % and 21 %, respectively, for folate, Fe, vitamin E and Mg). Ninety-seven per cent of the women reported taking supplements of folic acid during the first trimester, but the median gestational age at initiation was 6·5 (interquartile range 5, 9) weeks. Self-reported prevalences of Fe and Mg supplementation were high, and increased throughout pregnancy.

Conclusion

The study identified low dietary intakes of vitamin E, folate and Mg both in the preconceptional period and during pregnancy, and low intake of Fe during pregnancy only. The low dietary intake of folate and the late initiation of supplementation indicate that current national guidelines are unlikely to be effective in preventing neural tube defects.

Validação relativa de Questionário de Freqüência Alimentar em gestantes usuárias de serviços do Sistema Único de Saúde em dois municípios no Rio Grande do Sul, Brasil

OBJETIVOS: avaliar o desempenho do Questionário de Frequência Alimentar (QFA), desenvolvido por Sichieri e Everhart, em medir o consumo alimentar de gestantes atendidas pelo Sistema Único de Saúde (SUS), comparando as estimativas de consumo de energia e nutrientes com as obtidas por recordatórios alimentares. MÉTODOS: foram realizadas duas entrevistas com gestantes em atendimento pré-natal em Bento Gonçalves e Porto Alegre, no Rio Grande do Sul, Brasil. Na primeira, foi aplicado o QFA e, depois, os recordatórios alimentares relativos aos dois dias prévios. Na segunda, foram obtidos novos recordatórios. Médias e limites de concordância para as diferenças entre as duas avaliações de ingestão alimentar foram calculadas conforme Bland-Altman. RESULTADOS: a diferença entre os métodos mostrou que o QFA superestimou o consumo de energia e nutrientes. O coeficiente de correlação ajustado para energia variou de 0,01 (gordura insaturada) a 0,47 (cálcio). Correlações maiores foram observadas para fibras, vitamina C, ácido fólico, cálcio e potássio. Em média, 30% das gestantes foram classificadas no mesmo quartil de consumo. CONCLUSÕES: o QFA pode ser uma ferramenta útil para avaliar consumo de gestantes em estudos epidemiológicos, contanto que sejam realizados esforços para melhorar seu desempenho. É necessário avaliar a influência de características sócio-demográficas e estado de saúde na validade do método.

Effect of the introduction of 'Healthy Start' on dietary behaviour during and after pregnancy: early results from the 'before and after' Sheffield study

The aim of the study was to examine the effect of the introduction of a new food-support benefit 'Healthy Start' (HS) on dietary intakes and eating patterns of low-income, Caucasian, pregnant and postpartum women living in Sheffield (UK). A before-and-after study comparing nutritional behaviour of participants, who were beneficiaries or eligible for the Welfare Food Scheme (WFS) (phase 1) or HS (phase 2), was conducted. Dietary intakes and eating patterns were assessed using a validated semi-quantified FFQ. In phase 1, 176 WFS subjects (ninety pregnant and eighty-six postpartum) were recruited and in phase 2, there were 160 HS subjects (ninety-six pregnant and sixty-four postpartum). The results suggested that pregnant and postpartum HS women significantly increased their daily intakes of energy, Fe, Ca, folate and vitamin C compared with the WFS women. Observed differences remained significant after controlling for potential confounding effects of known factors, i.e. education and age. HS women were more likely to meet the recommended nutrient intakes for Fe, folate, Ca and vitamin C. HS women ate significantly more mean portions of fruit and vegetables per d (P = 0.004 and P = 0.023) respectively. None of the HS recipients was receiving HS vitamin supplements. The present study showed that pregnant and postpartum HS women increased their food consumption, and a higher proportion of them than the earlier WFS scheme met the recommended intakes for Ca, folate, Fe and vitamin C.

Prevalence of obesity in 6- and 9-year-old children living in Central-North Italy. Analysis of determinants and indicators of risk of overweight

The objective of our article is to survey the prevalence of overweight and obesity among 6- and 9-year-old children in Emilia-Romagna, a region of Central-North Italy, and to study the eating habits and behaviours of these children and their families. During 2003 and 2005, we analysed a stratified sample of the general population of children attending pre-school (2681 children aged 6 years) and primary school (2955 children aged 9 years). Their height and weight were measured by healthcare workers. In the 6-year-old children, information concerning their eating habits was collected by means of a questionnaire completed by their parents. The prevalence of overweight was 16.5% in 6-year-old children and 20.6% in 9-year-old children. The increase of overweight from 6- to 9-year-old children was observed in males (13.5% in 6-year-old/21.3% in 9-year-old boys), but not in females. The prevalence of obesity was 8.9% in children aged 6 years and 9.0% in those aged 9 years, and it was higher in comparison with Italian surveys carried out in 1993 and in 2001: 7.5% in 6-year-old and 7.8% in 9-year-old children in 1993, and 6.6% in 6-year-old and 7.2% in 9-year-old children in 2001. In pre-school children, overweight and obesity were closely influenced by the education level, occupation and nutritional status of the parents.

Maternal smoking is associated with decreased 5-methyltetrahydrofolate in cord plasma

BACKGROUND

Maternal-fetal folate transport via the placenta has been shown to be concentrative. Exposure to cigarette smoke is associated with decreased maternal folate status through altered dietary intakes and possibly through nondietary mechanisms such as increased folate turnover. The effect of maternal smoking on fetal folate status has not been documented.

OBJECTIVE

The objective was to determine the effect of maternal smoking on plasma 5-methyltetrahydrofolic acid (5-MTHFA) concentrations in umbilical cord blood.

DESIGN

African American women were recruited from an antenatal clinic in Detroit, MI. Plasma 5-MTHFA concentrations were measured in maternal-umbilical cord pairings (n = 58). The participants completed a structured interview to determine demographic characteristics, including smoking.

RESULTS

Concentrations of 5-MTHFA were significantly higher in venous cord plasma (16.8 +/- 7.5 ng/mL) than in maternal plasma (13.0 +/- 7.5 ng/mL) but remained associated (r = 0.60, P < 0.001) with each other. Cigarettes smoked by the mothers was negatively associated (r = -0.31, P = 0.019) with venous cord 5-MTHFA concentrations and remained so after control for maternal plasma 5-MTHFA and other variables. Venous cord plasma 5-MTHFA was significantly lower in smoking (15.1 +/- 7.6 ng/mL; n = 32) than in nonsmoking (19.0 +/- 7.0 ng/mL; n = 26) mothers.

CONCLUSIONS

Cord plasma 5-MTHFA concentrations were elevated relative to maternal blood, as expected, because the placenta is capable of concentrative folate transport to the fetus. The negative effect of maternal smoking on infant, but not on maternal, 5-MTHFA status indicates that maternal smoking may impair folate transport to the fetus.

Nutrient intake and food consumption among pregnant women from an agricultural region of Morocco

This study aimed to assess dietary intake and nutrient adequacy in pregnant women selected from an agricultural region of Morocco. On a sample of 172 pregnant women from rural and urban area, data on socio-demographic characteristics and dietary habits by a quantified food frequency were collected using questionnaires. Mean daily intakes of energy and nutrients were estimated and compared to reference nutrient intakes (RNI). The results show that the mean daily intakes of energy (3110.9 kcal in urban; 2707.5 kcal in rural) and some nutrients were adequate. However, iron, folate, zinc and calcium intakes were inadequate for the majority of women and more markedly in rural area. Education level appeared to affect nutrient intakes while no differences were registered across pregnancy stages or according to household size. The study suggests that an education program should be conducted to improve dietary intakes in order to prevent risks for pregnancy outcome in this population.

Validation of a food-frequency questionnaire for use in pregnancy

Objectives

As a part of an ongoing project to develop a nutritional screening tool, we evaluated the performance of a semi-quantitative food-frequency questionnaire (FFQ) in terms of validity in a Sheffield Caucasian pregnant population using two different statistical approaches – the correlation coefficient and the limits of agreement (LOA). The FFQ was designed specifically for pregnant women and previously used in a large-scale study.

Design

A validation study.

Setting

A community-based field study of a general population of pregnant women booked for their first antenatal appointment at the Jessop Wing, Royal Hallamshire Hospital, Sheffield, UK.

Subjects

One hundred and twenty-three women of different socio-economic status, aged between 17 and 43 years, provided complete dietary data.

Results

The validity of the FFQ was tested against a series of two 24-hour recalls. As expected, the intakes of all examined nutrients, except for iodine, carotene, vitamin E, biotin, vitamin C and alcohol, were higher when determined by the FFQ than when determined by 24-hour recall. Pearson's correlation coefficient between the two methods ranged from 0.19 (added sugar, zinc) to 0.47 (Englyst fibre). The LOA were broader for some of the nutrients, e.g. protein, Southgate fibre and alcohol, and an increasing lack of agreement between the two methods was identified with higher dietary intakes.

Conclusions

The FFQ gave useful estimates of the nutrient intakes of Caucasian pregnant women and appears to be a valid tool for categorising pregnant women according to dietary intake. The FFQ performed well for most nutrients and had acceptable agreement with the 24-hour recall.

Assessing diet quality in a population of low-income pregnant women: a comparison between Native Americans and whites

OBJECTIVE

To assess diet quality of pregnant women in the WIC program in North Dakota and to compare Native Americans with whites, we used a DQI-P (diet quality index for pregnancy) among low-income pregnant women enrolled in WIC, a special supplemental program for women, infants, and children.

METHODS

Dietary information was collected for all participants using the Harvard Service Food Frequency Questionnaire (HSFFQ). DQI-P scores were based on 10 components previously used in other diet quality indices: percent recommended intake of grains, vegetables, fruits, folate, calcium, and iron; total fat, saturated fat, and cholesterol; and dietary diversity. Each component contributed 10 points to the total possible DQI-P score of 100.

RESULTS

The mean DQI-P score was 53.9. Native Americans (51.8) had significantly lower DQI-P scores (51.8 vs. 54.2; p<0.0001); significantly higher scores for iron and folate; and significantly lower scores for cholesterol, total fat intake, and saturated fat components than did whites. As DQI-P scores increased, diet improved and scores for individual components increased.

CONCLUSION

While there were significant differences between the diet quality of Native American and white pregnant women, the differences were minimal. The DQI-P scores for all women in this population indicate that their diets are not meeting dietary recommendations. Interventions should focus on decreasing fat intake and increasing iron and folate intake to meet national dietary recommendations. More emphasis should be placed on eating whole fruit and vegetables.

Reliability and validity of a maternal food frequency questionnaire designed to estimate consumption of common food allergens

BACKGROUND

Maternal food intake during pregnancy may influence the development of food hypersensitivity (FHS) in the child. A food frequency questionnaire estimating the frequency with which some of the mains food allergens are consumed was designed and validated.

MATERIALS AND METHODS

Pregnant women were recruited at the ante-natal clinic of St. Mary's Hospital, Isle of Wight, UK. A food frequency questionnaire was developed and validated by comparing responses to information recorded in 7 days food diaries. The reliability of the food frequency questionnaire was evaluated by asking women to complete the questionnaire on two separate occasions at 30 and 36 weeks gestation.

RESULTS

Fifty-seven women completed the validity study and 91 women completed the reliability study. For both validity and reliability, questions with dichotomous response categories showed the highest level of agreement. Frequency of intake of foods commonly "hidden" in foods produced the lowest validity and reliability scores. In the validity study responses to the food frequency questionnaire identically matched information recorded in the food diaries 80% of the time, on average. In the reliability study, responses were identical on both questionnaires 85% of the time on average.

CONCLUSION

In this study a food frequency questionnaire estimating the frequency with which some of the main food allergens are consumed during pregnancy was designed and validated. This food frequency questionnaire could be used in future studies to assess the role of maternal food intake in the development of FHS in the infant.

Use of a food frequency questionnaire in American Indian and Caucasian pregnant women: a validation study

BACKGROUND

Food frequency questionnaires (FFQs) have been validated in pregnant women, but few studies have focused specifically on low-income women and minorities. The purpose of this study was to examine the validity of the Harvard Service FFQ (HSFFQ) among low-income American Indian and Caucasian pregnant women.

METHODS

The 100-item HSFFQ was administered three times to a sample of pregnant women, and two sets of 24-hour recalls (six total) were collected at approximately 12 and 28 weeks of gestation. The sample included a total of 283 pregnant women who completed Phase 1 of the study and 246 women who completed Phase 2 of the study. Deattenuated Pearson correlation coefficients were used to compare intakes of 24 nutrients estimated from the second and third FFQ to average intakes estimated from the week-12 and week-28 sets of diet recalls.

RESULTS

Deattenuated correlations ranged from 0.09 (polyunsaturated fat) to 0.67 (calcium) for Phase 1 and from 0.27 (sucrose) to 0.63 (total fat) for Phase 2. Average deattenuated correlations for the two phases were 0.48 and 0.47, similar to those reported among other groups of pregnant women.

CONCLUSION

The HSFFQ is a simple self-administered questionnaire that is useful in classifying low-income American Indian and Caucasian women according to relative dietary intake during pregnancy. Its use as a research tool in this population may provide important information about associations of nutrient intakes with pregnancy outcomes and may help to identify groups of women who would benefit most from nutritional interventions.

Validation of a semi-quantitative food-frequency questionnaire for use among adults in Guatemala

OBJECTIVE

The purpose of the study was to assess the validity of a 52-item semi-quantitative food-frequency questionnaire (FFQ) by comparing it with multiple 24-hour dietary recalls.

DESIGN

Three non-consecutive 24-hour dietary recalls and one FFQ were administered over a one-month period.

SETTING

Four communities of El Progreso, Guatemala.

SUBJECTS

Seventy-three individuals aged 22-55 years.

RESULTS

: Intakes of energy and other nutrients as measured by the FFQ were higher than intakes measured by 24-hour recalls. Energy was overestimated by 361 kcal, and nutrient overestimates were particularly great for vitamin C and iron. Pearson correlation coefficients for crude energy and nutrients intakes ranged from 0.64 for energy to 0.12 for vitamin C. Exact agreement for both methods (measured by the concordance correlation coefficient) ranged from 0.59 (fat) to 0.06 (vitamin C). Pearson correlation coefficients for energy-adjusted nutrients ranged from 0.59 (carbohydrates) to 0.11 (thiamin). Pearson correlation coefficients for the proportion of total energy derived from specific foods ranged from 0.59 (tortillas) to 0.01 (sugared beverages). Cross-classification of quartiles of crude nutrient intakes for both methods indicated that <11% were grossly misclassified; after adjusting for energy intake, <13% were grossly misclassified.

CONCLUSIONS

This FFQ provides good measures of energy and macronutrient intakes and a reasonably reliable measure of micronutrient intake, indicating its suitability for comparing exposures within a study population in reference to heath-related endpoints. Our results highlight the need to adapt any FFQ to specific cultural needs - in this case, the Guatemalan 'core foods' (tortilla, bread and beans), for which inter-individual variability in intake is high.

Validation of a food frequency questionnaire in Native American and Caucasian children 1 to 5 years of age

OBJECTIVE

To assess the validity of the Harvard Service Food Frequency Questionnaire (HFFQ) in the diet assessment of Native American and Caucasian children 1 to 5 years of age participating in the North Dakota WIC program.

METHODS

The 84-item HFFQ was administered twice to the parent or guardian of 131 Native American and 102 Caucasian children ages 1 to 5 years (total n = 233), first at the child's routine WIC visit and then following the completion of three 24-hr dietary recalls taken over approximately 1 month. Average nutrient intakes from the three 24-hr dietary recalls were compared to average nutrient intakes from the HFFQs by calculating Pearson correlation coefficients and adjusting for energy intake and within person variation.

RESULTS

Correlation coefficients ranged from 0.26 for dietary fiber to 0.63 for magnesium. The average correlation was 0.52, similar to that found in validation studies among adolescents and adults. The following nutrients had correlations of 0.50 or greater: carbohydrate, sucrose, total fat, vitamin C, vitamin E, vitamin B1, vitamin B2, niacin, folate, vitamin B6, calcium, magnesium, and iron.

CONCLUSIONS

The HFFQ is a simple self-administered questionnaire completed by the child's parent or guardian and is useful in assessing the diets of Native American and Caucasian children. It may also provide important nutritional information about this age group for future program planning, research, education, and intervention purposes.