Constanza Marin

Vitamin D deficiency and anthropometric indicators of adiposity in school-age children: a prospective study.

BACKGROUND Cross-sectional studies have indicated that vitamin D serostatus is inversely associated with adiposity. It is unknown whether vitamin D deficiency is a risk factor for the development of adiposity in children. OBJECTIVE We investigated the associations between vitamin D serostatus and changes in body mass index (BMI; in kg/m²), skinfold-thickness ratio (subscapular-to-triceps), waist circumference, and height in a longitudinal study in children from Bogota, Colombia. DESIGN We quantified plasma 25-hydroxyvitamin D [25(OH)D] concentrations in baseline samples of a randomly selected group of 479 schoolchildren aged 5-12 y and classified vitamin D status as deficient [25(OH)D concentrations < 50 nmol/L], insufficient [25(OH)D concentrations ≥ 50 and < 75 nmol/L], or sufficient [25(OH)D concentrations ≥ 75 nmol/L]. We measured anthropometric variables annually for a median of 30 mo. We estimated the average change in each anthropometric indicator according to baseline vitamin D status by using multivariate mixed linear regression models. RESULTS Vitamin D-deficient children had an adjusted 0.1/y greater change in BMI than did vitamin D-sufficient children (P for trend = 0.05). Similarly, vitamin D-deficient children had a 0.03/y (95% CI: 0.01, 0.05/y) greater change in subscapular-to-triceps skinfold-thickness ratio and a 0.8 cm/y (95% CI: 0.1, 1.6 cm/y) greater change in waist circumference than did vitamin D-sufficient children. Vitamin D deficiency was related to slower linear growth in girls (-0.6 cm/y, P = 0.04) but not in boys (0.3 cm/y, P = 0.34); however, an interaction with sex was not statistically significant. CONCLUSION Vitamin D serostatus was inversely associated with the development of adiposity in school-age children.

Vitamin D deficiency and age at menarche: a prospective study

BACKGROUND Early menarche is a risk factor for cardiometabolic disease and cancer. Latitude, which influences sun exposure, is inversely related to age at menarche. This association might be related to vitamin D, but to our knowledge it has not been investigated in prospective epidemiologic studies. OBJECTIVE We studied the association between vitamin D status and the occurrence of menarche in a prospective study in girls from Bogota, Colombia. DESIGN We measured plasma 25-hydroxyvitamin D [25(OH)D] concentrations in a random sample of 242 girls (mean ± SD age: 8.8 ± 1.6 y) and followed them for a median of 30 mo. Girls were asked periodically about the occurrence and date of menarche. Baseline 25(OH)D concentrations were categorized as <50 nmol/L (deficient), ≥50 and <75 nmol/L, or ≥75 nmol/L (sufficient). The incidence of menarche was compared between groups by using time-to-event analyses. RESULTS A total of 57% of girls in the vitamin D-deficient group reached menarche during follow-up compared with 23% of girls in the vitamin D-sufficient group (P-trend = 0.0004). The estimated mean (±SE) ages at menarche in the same groups were 11.8 ± 0.2 y and 12.6 ± 0.2 y, respectively (P = 0.0009). After adjustment for baseline age and BMI-for-age z score in a Cox proportional hazards model, the probability of menarche was twice as high in vitamin D-deficient girls than in girls who were vitamin D-sufficient (HR: 2.05; 95% CI: 1.03, 4.07; P = 0.04). Similar results were obtained in girls aged ≥9 y at baseline (HR: 2.39; 95% CI: 1.14, 5.00; P = 0.02). CONCLUSION Vitamin D deficiency is associated with earlier menarche.

Provision of a School Snack Is Associated with Vitamin B-12 Status, Linear Growth, and Morbidity in Children from Bogotá, Colombia

In 2004, Bogotás Secretary of Education (SED) initiated a snack program in public primary schools. A midmorning food ration was provided free of charge to children to supplement 30 and 50% of their daily requirements of energy and iron, respectively. The purpose of this study, an observational investigation of 3202 children ages 5-12 y, was to examine whether the snack program improved childrens nutritional and health status. We measured micronutrient levels (plasma ferritin and vitamin B-12, and erythrocyte folate), anthropometry, and reported morbidity during the first semester of the 2006 school year. After adjusting for socioeconomic status and other school interventions, children at schools receiving the snack (n = 1803) had greater increases in plasma vitamin B-12 (42 pmol/L; P < 0.0001) from baseline to 3 mo of follow-up than children at schools not receiving the snack (n = 1399). They also experienced a smaller decrease in height-for-age Z-scores than children who did not receive the snack (P = 0.001). Provision of the SED snack was associated with significantly fewer reported days with morbidity symptoms (e.g. cough with fever, diarrhea with vomiting), 44% fewer doctor visits (P = 0.02), and 23% fewer days of school absenteeism (P = 0.03). The snack was not related to ferritin or folate levels. In conclusion, provision of a school-administered snack was related to improved vitamin B-12 status and linear growth and decreased reported morbidity. Although provision of the snack was not related to BMI changes over a 4-mo period, snack components such as candy and sugar-sweetened beverages should be replaced with healthier options, as the rates of child overweight in Colombia are not negligible.

Stunting Associated with Poor Socioeconomic and Maternal Nutrition Status and Respiratory Morbidity in Colombian Schoolchildren

Background There are few recent reports on the prevalence and risk factors of stunting and thinness among schoolchildren in Latin America. Objective To determine the prevalence and sociodemographic correlates of stunting and thinness among school-age children in Bogotá, Colombia, and to examine whether these nutritional indices are associated with the risk of respiratory and diarrheal morbidity symptoms, visits to the doctor, and school absenteeism during the school year in a prospective study. Methods We obtained information on anthropometric and maternal sociodemographic characteristics of 3,100 children 5 to 12 years of age who attended public primary schools in 2006 and who came from low- and middle-income households. Data on the incidence of common gastrointestinal and respiratory symptoms were collected prospectively on morbidity diaries throughout the year. Results The prevalence rates of stunting and thinness were 9.9% and 8.7%, respectively. There were inverse, statistically significant trends in the prevalence of stunting by categories of childs birth and current weight; maternal education level, height, and body mass index (BMI); and household socioeconomic stratum. A strong positive association was found with maternal parity (p for trend < .0001). Thinness was positively associated with the childs and the mothers age and inversely associated with birthweight and maternal BMI. Stunting was associated with a 44% increase in the incidence of cough with fever during the school year (p = .04). Conclusions Child stunting in Bogotá is associated with poor socioeconomic and maternal nutritional status and predicts symptoms of respiratory infection.

Adherence to a snacking dietary pattern and soda intake are related to the development of adiposity: a prospective study in school-age children.

OBJECTIVE Snacking has been related to increased prevalence of overweight among school-age children in cross-sectional studies. It is uncertain, however, whether snacking influences the development of adiposity over time. DESIGN We examined whether adherence to a snacking dietary pattern was associated with greater increases in childrens BMI, subscapular:triceps skinfold thickness ratio and waist circumference over a median 2·5-year follow-up. Dietary patterns were identified through principal component analysis of an FFQ administered at recruitment in 2006. Anthropometric follow-up was conducted annually. Linear mixed-effects models were used to estimate rates of change in each indicator according to quartiles of adherence to the snacking pattern. We also examined change in BMI, subscapular:triceps skinfold thickness ratio and waist circumference in relation to intake of the food items in the snacking pattern. SUBJECTS Children (n 961) 5-12 years of age. SETTING Public schools in Bogotá, Colombia. RESULTS After adjustment for age, sex, total energy intake and socio-economic status, children in the highest quartile of adherence to the snacking pattern had a 0·09 kg/m2 per year higher BMI gain than children in the lowest quartile (P trend = 0·05). A similar association was observed for mean change in subscapular:triceps skinfold thickness ratio (highest v. lowest quartile difference = 0·012/year; P = 0·03). Of the food items in the snacking pattern, soda intake was positively and significantly associated with change in BMI (P trend = 0·01) and waist circumference (P trend = 0·04) in multivariable analysis. CONCLUSIONS Our results indicate that snacking and soda intake are associated with development of adiposity in school-age children.

Vitamin D deficiency associated with increased incidence of gastrointestinal and ear infections in school-age children.

Background: Vitamin D deficiency (VDD) is highly prevalent among children worldwide. The effects of VDD include alterations of the immune response and increased risk of infection but little evidence exists in school-age children. We investigated the association of vitamin D status with morbidity in a prospective study of school-age children from Bogotá, Colombia. Methods: We measured plasma 25-hydroxyvitamin D (25(OH)D) concentrations in a random sample of 475 children (mean ± standard deviation age: 8.9 ± 1.6 years) and followed them for an academic year. Caregivers were asked to record daily information on the incidence of morbidity episodes using pictorial diaries. Baseline vitamin D status was classified according to 25(OH)D concentrations as deficient (<50 nmol/L), insufficient (≥50 and <75 nmol/L) or sufficient (≥75 nmol/L). We used Poisson regression to estimate incidence rate ratios and 95% confidence intervals for days with diarrhea, vomiting, diarrhea with vomiting, cough with fever and earache or discharge with fever, comparing vitamin D-deficient with vitamin D-sufficient children. Estimates were adjusted for child’s age, sex and household socioeconomic status. Results: The prevalence of VDD was 10%; an additional 47% of children were vitamin D-insufficient. VDD was associated with increased rates of diarrhea with vomiting (adjusted incidence rate ratio: 2.05; 95% confidence interval: 1.19, 3.53) and earache/discharge with fever (adjusted incidence rate ratio: 2.36; 95% confidence interval: 1.26, 4.44). VDD was not significantly related to cough with fever. Conclusions: These results suggest that VDD is related to increased incidence of gastrointestinal and ear infections in school-age children. The effect of correcting VDD on reducing risk of these infections needs to be tested in supplementation trials.

Micronutrient status and global DNA methylation in school-age children.

Aberrations in global LINE-1 DNA methylation have been related to risk of cancer and cardiovascular disease. Micronutrients including methyl-donors and retinoids are involved in DNA methylation pathways. We investigated associations of micronutrient status and LINE-1 methylation in a cross-sectional study of school-age children from Bogotá, Colombia. Methylation of LINE-1 repetitive elements was quantified in 568 children 5–12 years of age using pyrosequencing technology. We examined the association of LINE-1 methylation with erythrocyte folate, plasma vitamin B12, vitamin A ferritin (an indicator of iron status) and serum zinc concentrations using multivariable linear regression. We also considered associations of LINE-1 methylation with socio-demographic and anthropometric characteristics. Mean (± SD) LINE-1 methylation was 80.25 (± 0.65) percentage of 5-mC (%5-mC). LINE-1 methylation was inversely related to plasma vitamin A. After adjustment for potential confounders, children with retinol levels higher than or equal to 1.05 µmol/L showed 0.19% 5-mC lower LINE-1 methylation than children with retinol levels lower than 0.70 µmol/L. LINE-1 methylation was also inversely associated with C-reactive protein, a marker of chronic inflammation, and female sex. We identified positive associations of maternal body mass index and socioeconomic status with LINE-1 methylation. These associations were not significantly different by sex. Whether modification of these exposures during school-age years leads to changes in global DNA methylation warrants further investigation.

A Prospective Study of LINE-1DNA Methylation and Development of Adiposity in School-Age Children

Background Repetitive element DNA methylation is related to prominent obesity-related chronic diseases including cancer and cardiovascular disease; yet, little is known of its relation with weight status. We examined associations of LINE-1 DNA methylation with changes in adiposity and linear growth in a longitudinal study of school-age children from Bogotá, Colombia. Methods We quantified methylation of LINE-1 elements from peripheral leukocytes of 553 children aged 5–12 years at baseline using pyrosequencing technology. Anthropometric characteristics were measured periodically for a median of 30 months. We estimated mean change in three age-and sex-standardized indicators of adiposity: body mass index (BMI)-for-age Z-score, waist circumference Z-score, and subscapular-to-triceps skinfold thickness ratio Z-score according to quartiles of LINE-1 methylation using mixed effects regression models. We also examined associations with height-for-age Z-score. Results There were non-linear, inverse relations of LINE-1 methylation with BMI-for-age Z-score and the skinfold thickness ratio Z-score. After adjustment for baseline age and socioeconomic status, boys in the lowest quartile of LINE-1 methylation experienced annual gains in BMI-for-age Z-score and skinfold thickness ratio Z-score that were 0.06 Z/year (P = 0.04) and 0.07 Z/year (P = 0.03), respectively, higher than those in the upper three quartiles. The relation of LINE-1 methylation and annual change in waist circumference followed a decreasing monotonic trend across the four quartiles (P trend = 0.02). DNA methylation was not related to any of the adiposity indicators in girls. There were no associations between LINE-1 methylation and linear growth in either sex. Conclusions Lower LINE-1 DNA methylation is related to development of adiposity in boys.

Vitamin A Deficiency Is Associated with Gastrointestinal and Respiratory Morbidity in School-Age Children

Infection is an important cause of morbidity throughout childhood. Poor micronutrient status is a risk factor for infection-related morbidity in young children, but it is not clear whether these associations persist during school-age years. We examined the relation between blood concentrations of micronutrient status biomarkers and risk of gastrointestinal and respiratory morbidity in a prospective study of 2774 children aged 5-12 y from public schools in Bogotá, Colombia. Retinol, zinc, ferritin, mean corpuscular volume, hemoglobin, erythrocyte folate, and vitamin B-12 concentrations were measured in blood at enrollment into the cohort. Children were followed for 1 academic year for incidence of morbidity, including diarrhea with vomiting, cough with fever, earache or ear discharge with fever, and doctor visits. Compared with adequate vitamin A status (≥30.0 μg/dL), vitamin A deficiency (<10.0 μg/dL) was associated with increased risk of diarrhea with vomiting [unadjusted incidence rate ratio (IRR): 2.17; 95% CI: 0.95, 4.96; P-trend = 0.03] and cough with fever (unadjusted IRR: 2.36; 95% CI: 1.30, 4.31; P-trend = 0.05). After adjustment for several sociodemographic characteristics and hemoglobin concentrations, every 10 μg/dL plasma retinol was associated with 18% fewer days of diarrhea with vomiting (P < 0.001), 10% fewer days of cough with fever (P < 0.001), and 6% fewer doctor visits (P = 0.01). Every 1 g/dL of hemoglobin was related to 17% fewer days with ear infection symptoms (P < 0.001) and 5% fewer doctor visits (P = 0.009) after controlling for sociodemographic factors and retinol concentrations. Zinc, ferritin, mean corpuscular volume, erythrocyte folate, and vitamin B-12 status were not associated with morbidity or doctor visits. Vitamin A and hemoglobin concentrations were inversely related to rates of morbidity in school-age children. Whether vitamin A supplementation reduces the risk or severity of infection in children over 5 y of age needs to be determined.

Vitamin B-12 Deficiency in Children Is Associated with Grade Repetition and School Absenteeism, Independent of Folate, Iron, Zinc, or Vitamin A Status Biomarkers

BACKGROUND Micronutrients are essential to neurocognitive development; yet their role in educational outcomes is unclear. OBJECTIVE We examined the associations of micronutrient status biomarkers with the risk of grade repetition and rates of school absenteeism in a cohort of school children. METHODS We recruited 3156 children aged 5-12 y from public schools in Bogota, Colombia. Circulating ferritin, hemoglobin, zinc, vitamin A, and vitamin B-12; erythrocyte folate; and mean corpuscular volume (MCV) were measured in blood samples obtained at the beginning of the year. Absenteeism was recorded weekly during the school year, and grade repetition was determined the next year. Risk ratios for grade repetition and rate ratios for absenteeism were estimated by categories of micronutrient status indicators with use of Poisson regression, adjusting for potential confounders. RESULTS The risk of grade repetition was 4.9%, and the absenteeism rate was 3.8 d per child-year of observation. Vitamin B-12 deficiency (<148 pmol/L) was associated with an adjusted 2.36-fold greater risk of grade repetition (95% CI: 1.03, 5.41; P = 0.04) compared with plasma concentrations ≥148 pmol/L. Other micronutrients were not related to grade repetition. Vitamin B-12 deficiency was also associated with school absenteeism rates. Compared with children with plasma vitamin B-12 concentrations ≥148 pmol/L, vitamin B-12-deficient children had a 1.89-times higher adjusted rate (95% CI: 1.53, 2.34; P < 0.0001). Anemia was related to a 72% higher rate (95% CI: 48%, 99%; P < 0.0001), whereas every 5-fL difference in MCV was associated with a 7% lower adjusted rate (95% CI: 4%, 10%; P < 0.0001). CONCLUSIONS Vitamin B-12 deficiency was associated with risk of grade repetition and school absenteeism rates in school children from Bogota, Colombia. The effects of correcting vitamin B-12 deficiency on educational outcomes and neurocognitive development of school children need to be determined in intervention studies.