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BACKGROUND: Effective treatment and prevention of obesity and its co-morbidities requires the recognition and understanding of cultural and social aspects of eating practices. The objective of the present study was to identify social factors and beliefs that may explain undesirable eating practices among women with high body mass index (HBMI) compared with normal-weight (NW) women from rural and urban areas classified as middle-low socioeconomic status (SES) in the State of Querétaro, Mexico. METHODS: A qualitative technique with individual in-depth interviews was used. Fifty-five women with either NW or HBMI from rural and urban areas participated in the study. The responses were analyzed by coding and grouping text fragments into categories in a data matrix, in order to make comparisons between BMI groups and between rural and urban women. RESULTS: The habit of skipping breakfast prevailed among women with HBMI who also reported childhood food deprivation. Feelings related to eating seemed to be more important than losing weight among women with HBMI from urban and rural areas. Thus, overweight might be interpreted as a social symbol of the enjoyment of a good life, primarily in rural areas. Overweight was socially accepted when it occurred in children and in married woman, mainly because it is a symbol of the good life that the head of the household provides, and also because women may feel more relaxed about their weight when they already have a partner. The study also revealed that women with HBMI were not sufficiently motivated to lose weight unless they experience a physical indication of poor health. CONCLUSION: The findings from this study are helpful in the understanding of the reasons why strategies for the prevention and treatment of obesity may not be as effective as expected. The belief system of particular social groups within different SESs should be considered in order to understand the etiology of obesity and develop effective strategies.
RESUMEN
A randomised, double-blind, placebo-controlled trial was carried out among Mexico children aged 6-15 months to determine how household characteristics modify vitamin A and zinc supplementation efficacy on Ascaris lumbricoides, Giardia intestinalis and Entamoeba histolytica/E. dispar infection durations. Children assigned to receive vitamin A every 2 months, a daily zinc supplement, a combined vitamin A-zinc supplement or a placebo were followed for 1 year. Parametric hazard models were fit to infection durations stratified by personal and household factors. Children supplemented with vitamin A and zinc combined from households lacking piped water and children in all three treatment arms from households with dirt floors had longer G. intestinalis and A. lumbricoides infection durations than their counterparts, respectively. Shorter E. histolytica/E.dispar durations were found among zinc-supplemented children of mothers who had <6 years of education and no indoor bathrooms. Heterogeneity in supplementation efficacy among children may reflect differences in exposure risk and baseline immune responses.
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Suplementos Dietéticos , Parasitosis Intestinales/tratamiento farmacológico , Vitamina A/administración & dosificación , Vitaminas/administración & dosificación , Zinc/administración & dosificación , Animales , Ascariasis/tratamiento farmacológico , Ascaris lumbricoides/patogenicidad , Método Doble Ciego , Composición Familiar , Heces/parasitología , Femenino , Giardia lamblia/patogenicidad , Giardiasis/tratamiento farmacológico , Vivienda/normas , Humanos , Lactante , Masculino , México , Recuento de Huevos de Parásitos , Padres/educación , Estudios ProspectivosRESUMEN
BACKGROUND: Micronutrient status may be a contributing factor to the development of childhood obesity in many industrializing countries passing the nutritional transition. The few studies investigating associations between serum concentrations of vitamin B and intake of B vitamins with adiposity, however, have reported inconsistent findings. OBJECTIVE: The aim of the study was to examine associations between serum vitamin B-12 and folate concentrations and intakes of B vitamins with body fat by using data on 1131 Mexican American children 8-15 y of age included in NHANES 2001-2004. METHODS: Children's body mass index (BMI), trunk fat mass (TrFM), and total body fat mass (TBFM) were used as body adiposity (BA) measures. Serum concentrations of folate and vitamin B-12 were measured in blood samples collected from children. Intake of B vitamins was collected according to 24-h dietary recall. Associations of BA with serum concentrations of vitamin B-12 and folate and intake of B vitamins were determined by using linear and multinomial regression models. RESULTS: Serum concentrations of vitamin B-12 and folate were inversely associated with BMI (ß: -2.68, P < 0.01; ß = -1.33, P < 0.01), TrFM (ß:-3.32, P < 0.01; ß: -0.14, P < 0.05), and TBFM (ß:-1.93, P < 0.01; ß: -3.19; P < 0.01). Higher serum concentrations of vitamin B-12 were associated with a reduced risk of obesity (OR: 0.48; 95% CI: 0.31, 0.77; P < 0.001). Thiamin and riboflavin intakes were inversely associated with BMI (ß:-1.35, P < 0.05; ß: -1.11, P < 0.05) and TrFM (ß:-1.26, P < 0.05; ß: -1.37, P < 0.05). CONCLUSION: Similar inverse associations between BA and status of both vitamin B-12 and folate and intake of thiamin and riboflavin suggest that these micronutrients may play a role in adipogenesis and risk of childhood obesity.
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Adiposidad , Ácido Fólico/sangre , Americanos Mexicanos , Riboflavina/sangre , Tiamina/sangre , Vitamina B 12/sangre , Adolescente , Índice de Masa Corporal , Niño , Estudios Transversales , Femenino , Ácido Fólico/administración & dosificación , Deficiencia de Ácido Fólico/sangre , Deficiencia de Ácido Fólico/epidemiología , Humanos , Modelos Lineales , Masculino , Recuerdo Mental , Micronutrientes/administración & dosificación , Micronutrientes/sangre , Micronutrientes/deficiencia , Análisis Multivariante , Encuestas Nutricionales , Obesidad Infantil/sangre , Obesidad Infantil/epidemiología , Riboflavina/administración & dosificación , Deficiencia de Riboflavina/sangre , Deficiencia de Riboflavina/epidemiología , Tiamina/administración & dosificación , Deficiencia de Tiamina/sangre , Deficiencia de Tiamina/epidemiología , Vitamina B 12/administración & dosificación , Deficiencia de Vitamina B 12/sangre , Deficiencia de Vitamina B 12/epidemiologíaRESUMEN
Mexican-American children have a high prevalence of overweight/obesity. Micronutrient deficiencies may be contributing to the development of greater adiposity in these children. This study investigated the relations between adiposity and serum concentrations of carotenoids, retinol, and vitamin E among Mexican-American children 8-15 y of age included in the 2001-2004 U.S. NHANES. Associations of the outcomes of children's body mass index (BMI), truncal fat mass (TrFM), and total body fat mass (TBFM) with serum concentrations of α-carotene, cis-ß-carotene, trans-ß-carotene, retinol, and α-tocopherol were determined by using linear, quantile, and multinomial regression models. BMI was inversely associated with serum concentrations of α-carotene (ß = -0.88, P < 0.05), trans-ß-carotene (ß = -2.21, P < 0.01), cis-ß-carotene (ß = -2.10, P < 0.01), and α-tocopherol adjusted for total cholesterol ratio (ß = -3.66, P < 0.01), respectively. Similar inverse associations were found with TrFM and TBFM. Higher cis-ß-carotene and α-tocopherol serum concentrations were associated with reduced probability of overweight (OR: 0.57; 95% CI: 0.37, 0.89; P < 0.05; and OR: 0.56; 95% CI: 0.37, 0.86; P < 0.05; respectively) and obesity (OR: 0.39; 95% CI: 0.26, 0.58; P < 0.01; and OR: 0.38; 95% CI: 0.24, 0.60; P < 0.01; respectively). Higher retinol serum concentrations were associated with increased probability of overweight and obesity (OR: 2.01; 95% CI: 1.26, 3.22; P < 0.01; and OR: 2.90; 95% CI: 1.65, 5.09; P < 0.01; respectively). Significant inverse associations were found between serum concentrations of carotenoids and vitamin E and adiposity among Mexican-American children, but serum retinol concentrations were positively associated with adiposity. Future research is needed to understand the causes and consequences of micronutrient status on adiposity and comorbidities.
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Adiposidad , Carotenoides/sangre , Obesidad/complicaciones , Sobrepeso/complicaciones , Deficiencia de Vitamina E/complicaciones , Vitamina E/sangre , Grasa Abdominal/patología , Adolescente , Biomarcadores/sangre , Índice de Masa Corporal , Carotenoides/deficiencia , Niño , Estudios Transversales , Femenino , Humanos , Masculino , Americanos Mexicanos , Encuestas Nutricionales , Obesidad/epidemiología , Obesidad/etiología , Obesidad/patología , Sobrepeso/epidemiología , Sobrepeso/etiología , Sobrepeso/patología , Prevalencia , Estados Unidos/epidemiología , Vitamina A/efectos adversos , Vitamina A/sangre , Deficiencia de Vitamina E/sangreRESUMEN
Qualitative research using semi-structured interviews and key informant interviews were used to explore how women from low socioeconomic rural households in Queretaro State, Mexico perceived and reacted to their obesogenic environment. Reduced availability of healthy food options and household financial constraints along with reduced agency of women in this setting were factors that limited women's ability to access and consume diets consistent with the promotion of good health. The cultural values that emphasised obesity as a desirable state for women and the women's social networks that promoted these values were also identified as playing a role in reinforcing certain behaviours. Public health advocates wanting to design interventions in such settings need to be sensitive to the cultural as well as the environmental context described for rural Mexican women.
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Imagen Corporal/psicología , Conducta Alimentaria/psicología , Adulto , Actitud Frente a la Salud , Índice de Masa Corporal , Conducta Alimentaria/etnología , Femenino , Alimentos , Humanos , México , Obesidad/etnología , Obesidad/psicología , Pobreza/etnología , Pobreza/psicología , Población Rural , Conducta Sedentaria/etnología , Adulto JovenRESUMEN
It has been recognised recently that obese individuals have lower concentrations of micronutrients and this may affect the concentrations of inflammatory cytokines. A cross-sectional study was carried out to evaluate the association of specific micronutrients' status with chronic inflammation caused by obesity in 280 women (36·1 (SD 7·5) years) from seven rural communities in Mexico. Measurements of weight, height and waist circumference were made on all women and body composition was determined by dual-energy X-ray absorptiometry. Concentrations of the cytokines IL-1, TNF-α, IL-6, IL-10 and IL-12, lipid profile, and the micronutrients Zn and vitamins A, C and E were determined in fasting blood samples. Ordered logistic regression models were used to determine associations between categorised cytokine levels and micronutrients. It was found that 80% of women were overweight or obese, and had significantly higher concentrations of C-reactive protein than normal-weight women (P= 0·05). The risk of higher levels of TNF-α, IL-6, IL-10 and IL-12 was reduced significantly among women with higher Zn concentrations (OR 0·63, 95% CI 0·42, 0·96, P= 0·03; OR 0·57, 95% CI 0·39, 0·86, P= 0·025; OR 0·63, 95% CI 0·41, 0·96, P= 0·04; OR 0·62, 95% CI 0·41, 0·95, P= 0·03, respectively). Higher concentrations of vitamin A were slightly associated with reduced risks of higher levels of IL-1 and IL-12 (OR 0·97, 95% CI 0·95, 0·99, P= 0·03; OR 0·97, 95% CI 0·94, 0·99, P= 0·03, respectively); when adjusting for BMI, this association was lost. No associations were found between vitamin C or vitamin E:lipids concentrations and inflammatory cytokines. In conclusion, higher Zn concentrations are associated with reduced risks of higher concentration of inflammation markers in a population of women with a high prevalence of obesity.
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Citocinas/sangre , Inflamación/sangre , Micronutrientes/sangre , Obesidad/epidemiología , Absorciometría de Fotón , Adulto , Composición Corporal , Estatura , Índice de Masa Corporal , Peso Corporal , Proteína C-Reactiva/metabolismo , Estudios Transversales , Femenino , Humanos , Modelos Logísticos , México/epidemiología , Persona de Mediana Edad , Prevalencia , Población Rural , Circunferencia de la CinturaRESUMEN
Vitamin A supplementation is associated with divergent clinical norovirus (NoV) outcomes in Mexican children. Fecal cytokine concentrations following NoV genogroup infections among 127 Mexican children 5-15 mo old enrolled in a randomized, double-blind, placebo-controlled, vitamin A supplementation trial were determined to clarify the role the gut immune response plays in these associations. Stools collected from supplemented children [20,000 IU retinol (3.3 IU = 1 µg retinol) for children < 12 mo of age; 45,000 iu for children ≥ 12 mo] or children in the placebo group were screened for NoV genogroups I (GI) and II (GII). Monocyte chemoattractant protein-1 (MCP-1), TNFα, IL-5, IL-6, IL-8, IL-4, IFNγ, and IL-10 fecal concentrations were also determined. Differences in cytokine levels between the 2 groups following GI and GII infections were determined using ordered logistic regression models. MCP-1 and IL-8 levels were greater among GI- and GII-infected children, respectively, compared with uninfected children, whereas IL-5 levels were greater following both genogroup infections. MCP-1, IL-8, and IL-6 fecal levels were reduced among supplemented children with GII-associated diarrhea compared with the placebo group. Vitamin A-supplemented, GII-infected children had reduced MCP-1 and TNFα levels compared with GII-infected children in the placebo group (P-interaction = 0.02 and 0.03, respectively). Supplemented children with GI-associated diarrhea had higher TNFα and IL-4 levels compared with children in the placebo group with diarrhea (P-interaction = 0.02 and 0.02, respectively). The divergent effects of supplementation on NoV outcomes may result from the different effects vitamin A has on the genogroup-specific immune responses.
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Infecciones por Caliciviridae/prevención & control , Quimiocinas/análisis , Citocinas/análisis , Interacciones Huésped-Patógeno , Intestinos/inmunología , Norovirus/fisiología , Vitamina A/uso terapéutico , Inmunidad Adaptativa , Infecciones por Caliciviridae/inmunología , Quimiocinas/inmunología , Citocinas/inmunología , Suplementos Dietéticos , Método Doble Ciego , Heces/química , Heces/microbiología , Femenino , Gastroenteritis/inmunología , Gastroenteritis/prevención & control , Humanos , Inmunidad Innata , Inmunomodulación , Lactante , Intestinos/microbiología , Masculino , México , Norovirus/clasificación , Norovirus/inmunología , Norovirus/aislamiento & purificación , Deficiencia de Vitamina A/inmunología , Deficiencia de Vitamina A/prevención & controlRESUMEN
BACKGROUND: The efficacy of vitamin A supplementation on diarrheal disease morbidity may reflect the divergent effects that supplementation has on pathogen-specific immune responses and pathogen-specific outcomes. OBJECTIVE: We examined how vitamin A supplementation modified associations between gut-cytokine immune responses and the resolution of different diarrheal pathogen infections. DESIGN: Stools collected from 127 Mexican children who were 5-15 mo old and enrolled in a randomized, placebo-controlled vitamin A supplementation trial were screened for enteropathogenic Escherichia coli (EPEC), enterotoxigenic E. coli (ETEC), and Giardia lamblia. Fecal concentrations of interleukin (IL)-6, IL-8, IL-4, IL-5, IL-10, monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) were measured by using an enzyme-linked immunosorbent assay. Hazard models that incorporated categorized cytokine variables (ie, nondetectable, less than the median of detectable concentrations, and at least the median of detectable concentrations) were fit to the length of pathogen infections stratified by treatment group. RESULTS: Vitamin A-supplemented children with fecal MCP-1 or IL-8 concentrations less than the median of detectable concentrations and IL-10 concentrations of at least median concentrations had longer durations of EPEC infection than did children in the placebo group. In supplemented children, detectable fecal TNF-α or IL-6 concentrations were associated with shorter ETEC infection durations, whereas MCP-1 concentrations of at least the median were associated with longer infection durations. Children in this group who had IL-4, IL-5, or IFN-γ concentrations of at least median detectable concentrations had shorter durations of G. lamblia infection. CONCLUSION: The effect of supplementation on associations between fecal cytokine concentrations and pathogen infection resolution depends on the role of inflammatory immune responses in resolving specific pathogen infections.
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Diarrea Infantil/tratamiento farmacológico , Diarrea Infantil/inmunología , Suplementos Dietéticos , Infecciones por Enterobacteriaceae/tratamiento farmacológico , Enterobacteriaceae/aislamiento & purificación , Inmunidad/efectos de los fármacos , Vitamina A/uso terapéutico , Inmunidad Adaptativa/efectos de los fármacos , Citocinas/análisis , Enterobacteriaceae/efectos de los fármacos , Infecciones por Enterobacteriaceae/microbiología , Escherichia coli Enteropatógena/efectos de los fármacos , Escherichia coli Enteropatógena/aislamiento & purificación , Escherichia coli Enterotoxigénica/efectos de los fármacos , Escherichia coli Enterotoxigénica/aislamiento & purificación , Heces/química , Heces/microbiología , Femenino , Giardia lamblia/efectos de los fármacos , Giardia lamblia/aislamiento & purificación , Humanos , Inmunidad Innata/efectos de los fármacos , Inmunidad Mucosa/efectos de los fármacos , Lactante , Masculino , México , Modelos de Riesgos ProporcionalesRESUMEN
The identification of immune response mechanisms that contribute to the control of diarrheal disease in developing countries remains an important priority. We addressed the role of fecal chemokines and cytokines in the resolution of diarrheal Escherichia coli and Giardia lamblia infections. Stools collected from 127 Mexican children 5 to 15 months of age enrolled in a randomized, double-blind, placebo-controlled, vitamin A supplementation trial were screened for enteropathogenic Escherichia coli (EPEC), enterotoxigenic E. coli (ETEC), and Giardia lamblia. Fecal concentrations of tumor necrosis factor alpha (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1), interleukin-4 (IL-4), IL-5, IL-6, IL-8, IL-10, and interferon-gamma (IFN-gamma) were determined. Hazard models incorporating cytokine variables were fit to durations of asymptomatic and symptomatic pathogen infections, controlling for treatment group. Increased levels of TNF-alpha and IL-6 were associated with decreased durations of EPEC infection and increased ETEC durations. Increased IL-4 and IFN-gamma levels were associated with decreased and increased durations, respectively, of both EPEC and ETEC infections. Increased IL-10 levels were associated with increased and decreased durations of asymptomatic and symptomatic EPEC infections, respectively, and increased durations of both asymptomatic and symptomatic ETEC infections. Increased levels of MCP-1, IFN-gamma, IL-4, and IL-5 were associated with increased G. lamblia infection duration, while increased IL-8 levels were associated with decreased durations. Differences in proinflammatory and Treg cytokine levels are associated with differences in the resolution of inflammatory and noninflammatory pathogen infections.
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Diarrea/inmunología , Enteritis/inmunología , Infecciones por Escherichia coli/inmunología , Escherichia coli/inmunología , Giardia lamblia/inmunología , Giardiasis/inmunología , Inmunidad Mucosa , Inmunidad Adaptativa , Animales , Citocinas/análisis , Heces/química , Humanos , Inmunidad Innata , Lactante , México , Ensayos Clínicos Controlados Aleatorios como Asunto , Linfocitos T/inmunología , Linfocitos T Reguladores/inmunología , Vitamina A/administración & dosificaciónRESUMEN
Micronutrient deficiencies have been found in obese individuals across age groups worldwide. While the effects of micronutrient deficiencies on human functions have been studied widely in different populations, there is limited information on how these micronutrient deficiencies affect obese populations. An examination of the available literature suggests associations exist between micronutrient deficiencies and obesity in different populations. These associations and possible mechanisms of the deficiencies' metabolic effects, such as their influence on leptin and insulin metabolism, are discussed here. Further studies are needed to clarify the roles of the different micronutrient deficiencies with respect to obesity and its comorbid conditions.
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Micronutrientes/deficiencia , Estado Nutricional , Obesidad/metabolismo , Tejido Adiposo/metabolismo , Animales , Antioxidantes/metabolismo , Calcio/deficiencia , Calcio/metabolismo , Femenino , Humanos , Insulina/metabolismo , Hierro/metabolismo , Deficiencias de Hierro , Leptina/metabolismo , Masculino , Micronutrientes/metabolismo , Obesidad/complicaciones , Vitamina A/metabolismo , Deficiencia de Vitamina A/metabolismo , Vitamina D/sangre , Deficiencia de Vitamina D/metabolismo , Zinc/deficiencia , Zinc/metabolismoRESUMEN
Seventy-six children < or =2 years old were prospectively followed for 1 year in a peri-urban community of Mexico City to determine asymptomatic infection and acute diarrhea associated with diarrheagenic Escherichia coli pathotypes (DEPs). By use of a pathogen-specific multiplex PCR, DEPs were sought in 795 stool samples, of which 125 (16%) were positive for DEP; of these, 4 represented shedding episodes and 4 parasite coinfections. Most single-DEP infections (85/117) were asymptomatic (P < 0.001), and of the 32 DEP diarrhea episodes, 41% were associated with atypical enteropathogenic E. coli (aEPEC), 37.5% with enterotoxigenic E. coli, 9% with typical EPEC, 9% with enteroinvasive E. coli, and 3% with Shiga toxin-producing E. coli strains. Among the 76 children, 54 had at least one stool positive for DEP, of which 23 experienced a DEP-associated diarrhea episode. In the last group of children, DEP infection was significantly associated with a diarrhea episode (relative risk [RR] = 2.5; 95% confidence interval [CI], 1.79 to 3.57; P < 0.001), with ETEC (RR = 2.30; 95% CI, 1.49 to 3.54; P = 0.003) and aEPEC (RR = 1.92; 95% CI, 1.23 to 3.0; P = 0.019) being the pathotypes associated with diarrhea. aEPEC-associated diarrhea episodes were frequently in the <12-month age group (RR = 2.57; 95% CI, 1.05 to 6.27; P = 0.04). aEPEC infections were distributed all year round, but associated diarrheal episodes were identified from April to October, with a May-June peak (rainy season). Most ETEC infections and diarrhea episodes characteristically occurred during the summer (rainy season), with a diarrhea peak in August. Of all DEPs, only aEPEC was associated with acute diarrhea episodes lasting 7 to 12 days (P = 0.019). DEPs are important causes of community-acquired enteric infection and diarrhea in Mexican children.
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Diarrea/epidemiología , Diarrea/microbiología , Escherichia coli Enteropatógena/aislamiento & purificación , Escherichia coli Enterotoxigénica/aislamiento & purificación , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Factores de Edad , ADN Bacteriano/genética , Escherichia coli Enteropatógena/clasificación , Escherichia coli Enterotoxigénica/clasificación , Proteínas de Escherichia coli/genética , Heces/microbiología , Femenino , Humanos , Lactante , Masculino , México/epidemiología , Reacción en Cadena de la Polimerasa/métodos , Estudios Prospectivos , Estaciones del Año , Factores de Virulencia/genéticaRESUMEN
OBJECTIVE: Gastrointestinal parasites continue to be an important cause of morbidity and stunting among children in developing countries. We evaluated the effect of vitamin A and zinc supplementation on infections by Giardia lamblia, Ascaris lumbricoides, and Entamoeba histolytica. METHODS: A randomized, double-blind, placebo-controlled trial was conducted among 707 children who were 6 to 15 months of age and from periurban areas of Mexico City, Mexico, between January 2000 and May 2002. Children, who were assigned to receive either vitamin A every 2 months, a daily zinc supplement, a combined vitamin A and zinc supplement, or a placebo, were followed for 1 year. The primary end points were the 12-month rates and durations of infection for the 3 parasites and rates of parasite-associated diarrheal disease as determined in stools collected once a month and after diarrheal episodes. RESULTS: G. lamblia infections were reduced and A. lumbricoides infections increased among children in the combined vitamin A and zinc group or the zinc alone group, respectively. Durations of Giardia infections were reduced among children in all 3 treatment arms, whereas Ascaris infections were reduced in the vitamin A and zinc group. In contrast, E. histolytica infection durations were longer among zinc-supplemented children. Finally, E. histolytica- and A. lumbricoides-associated diarrheal episodes were reduced among children who received zinc alone or a combined vitamin A and zinc supplement, respectively. CONCLUSIONS: We found that vitamin A and zinc supplementation was associated with distinct parasite-specific health outcomes. Vitamin A plus zinc reduces G. lamblia incidence, whereas zinc supplementation increases A. lumbricoides incidence but decreases E. histolytica-associated diarrhea.
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Parasitosis Intestinales/tratamiento farmacológico , Oligoelementos/uso terapéutico , Vitamina A/uso terapéutico , Vitaminas/uso terapéutico , Zinc/uso terapéutico , Animales , Ascariasis/tratamiento farmacológico , Ascaris lumbricoides , Niño , Diarrea/tratamiento farmacológico , Diarrea/parasitología , Suplementos Dietéticos , Método Doble Ciego , Quimioterapia Combinada , Entamebiasis/tratamiento farmacológico , Giardiasis/tratamiento farmacológico , Humanos , MéxicoRESUMEN
BACKGROUND: The effect of vitamin A supplementation on viral gastrointestinal infections among young children living in developing countries remains unclear. METHODS: The effect of vitamin A supplementation on norovirus (NoV) infection among 127 Mexican children 5-15 months of age was studied in a randomized, placebo-controlled trial during June-August 1998. Stool samples collected every 2 weeks and after diarrheal episodes were screened for NoV and characterized at the genogroup level (GI and GII). RESULTS: Of the stool samples collected, 29.9% were positive for NoV, and NoV GI and NoV GII were found in 55.4% and 46.4% of the positive samples, respectively. Vitamin A supplementation reduced the prevalence of NoV GII infections (rate ratio [RR], 0.60 [95% confidence interval {CI}, 0.20-0.82]), increased the length of both NoV GI and GII shedding, and decreased the prevalence of NoV-associated diarrhea (RR, 0.51 [95% CI, 0.26-0.97]). CONCLUSIONS: These findings suggest that NoV is an important cause of pediatric diarrhea in this study population and that vitamin A supplementation has divergent effects on specific outcomes of NoV infection.
Asunto(s)
Infecciones por Caliciviridae , Gastroenteritis , Norovirus/efectos de los fármacos , Vitamina A , Infecciones por Caliciviridae/tratamiento farmacológico , Infecciones por Caliciviridae/epidemiología , Infecciones por Caliciviridae/fisiopatología , Heces/virología , Femenino , Gastroenteritis/tratamiento farmacológico , Gastroenteritis/epidemiología , Gastroenteritis/fisiopatología , Gastroenteritis/virología , Humanos , Lactante , Masculino , México/epidemiología , Norovirus/clasificación , Norovirus/aislamiento & purificación , Prevalencia , Resultado del Tratamiento , Vitamina A/administración & dosificación , Vitamina A/uso terapéutico , Vitaminas/administración & dosificación , Vitaminas/uso terapéuticoRESUMEN
Previous clinical vitamin A trials have found no consistent effect on diarrhoeal disease and respiratory tract infection. These inconsistent results may be due to the distinct effects vitamin A supplementation has among children stratified by factors related to socio-economic status, nutritional status and season. We evaluated the effect of supplementation on the overall incidence of diarrhoeal disease and respiratory tract infections and on the incidence among children stratified by these factors. A total of 188 children, aged 6-15 months, from periurban, marginalized communities of Mexico City were assigned to receive vitamin A ( < 12 months of age, 20,000 IU retinol; >or= 12 months, 45,000 IU retinol) or a placebo every 2 months, and were followed for up to 15 months. Project personnel visited households twice a week to determine the onset and duration of diarrhoeal disease and respiratory tract infections. Vitamin A supplementation had no significant effect on risk of overall diarrhoeal disease but reduced mild watery diarrhoea (incidence rate ratio (RR) 0.69; 95 % CI 0.50, 0.93) and cough with fever (RR 0.69; 95 % CI 0.48, 0.98). Vitamin A supplementation decreased diarrhoeal disease during the summer (RR 0.74; 95 % CI 0.57, 0.94), among non-stunted children (RR 0.69; 95 % CI 0.52, 0.93) and among children from households with better socio-economic measures. Heterogeneity in the response to vitamin A supplementation may reflect heterogeneity in the aetiology and epidemiology of diarrhoeal disease and respiratory tract infections and the impact that supplementation has on the immune response.
Asunto(s)
Diarrea Infantil/prevención & control , Suplementos Dietéticos , Infecciones del Sistema Respiratorio/prevención & control , Vitamina A/administración & dosificación , Diarrea Infantil/epidemiología , Femenino , Artículos Domésticos , Humanos , Incidencia , Lactante , Masculino , México/epidemiología , Estado Nutricional , Infecciones del Sistema Respiratorio/epidemiología , Estaciones del Año , Factores SocioeconómicosRESUMEN
BACKGROUND: The overall effect of vitamin A supplementation on diarrheal disease in community trials may result from its effect on specific diarrheal pathogens. METHODS: We conducted a placebo-controlled, double-blind trial of the prophylactic effect of vitamin A on gastrointestinal pathogen infections and clinical symptoms among 188 children in Mexico City, Mexico, from January 1998 to May 1999. Children 6-15 months of age were randomly assigned to receive either a vitamin A supplement (for children <12 months of age, 20,000 international units [IU] of retinol; for children > or =12 months of age, 45,000 IU of retinol) every 2 months or a placebo and were followed for up to 15 months. Stool samples, collected semimonthly, were screened for enteropathogenic Escherichia coli (EPEC), enterotoxigenic E. coli (ETEC), Shiga toxin-producing E. coli (STEC), enteroinvasive E. coli (EIEC), and Giardia lamblia. RESULTS: Vitamin A supplementation reduced the prevalence of EPEC infections (rate ratio [RR], 0.52 [95% confidence interval {CI}, 0.23-0.86]) and led to shorter durations of both EPEC and ETEC infections. Supplementation also reduced the prevalence of EPEC-associated diarrhea (RR, 0.41 [95% CI, 0.16-1.00]), EPEC-associated fever (RR, 0.15 [95% CI, 0.02-0.98]), and G. lamblia-associated fever (RR, 0.27 [95% CI, 0.13-0.80]). Finally, children who received vitamin A supplementation had shorter durations of EPEC-associated diarrhea than did children who did not receive supplementation but had longer durations of G. lamblia-associated diarrhea. CONCLUSIONS: These results suggest that the effect of vitamin A supplementation on clinical outcomes may be pathogen dependent.
Asunto(s)
Diarrea/tratamiento farmacológico , Diarrea/prevención & control , Enfermedades Gastrointestinales/prevención & control , Vitamina A/uso terapéutico , Diarrea/microbiología , Método Doble Ciego , Infecciones por Escherichia coli/tratamiento farmacológico , Infecciones por Escherichia coli/prevención & control , Femenino , Enfermedades Gastrointestinales/tratamiento farmacológico , Enfermedades Gastrointestinales/microbiología , Giardiasis/tratamiento farmacológico , Giardiasis/prevención & control , Humanos , Lactante , Masculino , México/epidemiología , PrevalenciaRESUMEN
The impact of vitamin A supplementation on childhood diarrhea may be determined by the regulatory effect supplementation has on the mucosal immune response in the gut. Previous studies have not addressed the impact of vitamin A supplementation on the production of monocyte chemoattractant protein 1 (MCP-1), an essential chemokine involved in pathogen-specific mucosal immune response. Fecal MCP-1 concentrations, determined by an enzyme-linked immuno absorption assay, were compared among 127 Mexican children 5-15 mo of age randomized to receive a vitamin A supplement (<12 mo of age, 20,000 IU of retinol; > or =12 mo, 45,000 iu) every 2 mo or a placebo as part of a larger vitamin A supplementation trial. Stools collected during the summer months were screened for MCP-1 and gastrointestinal pathogens. Values of MCP-1 were categorized into 3 levels (nondetectable,
Asunto(s)
Quimiocina CCL2/análisis , Quimiocina CCL2/inmunología , Diarrea/inmunología , Intestinos/inmunología , Vitamina A/administración & dosificación , Animales , Antiinflamatorios/administración & dosificación , Ascariasis/inmunología , Ascaris lumbricoides , Quimiocina CCL2/biosíntesis , Diarrea/microbiología , Diarrea/parasitología , Suplementos Dietéticos , Ensayo de Inmunoadsorción Enzimática , Infecciones por Escherichia coli/inmunología , Heces/química , Heces/microbiología , Heces/parasitología , Giardia lamblia , Giardiasis/inmunología , Humanos , Lactante , Intestinos/química , Modelos Logísticos , México , PlacebosRESUMEN
Sixty-three children in periurban Mexico City were examined for the occurrence of asymptomatic norovirus (NoV) infection from June to August 1998. NoV was detected in 48 of 161 stool specimens (29.8%), with 31 children (49.2%) having at least one positive stool. Asymptomatic NoV infection occurred commonly during summertime in a Mexican pediatric population.
Asunto(s)
Infecciones por Caliciviridae/fisiopatología , Infecciones por Caliciviridae/virología , Heces/virología , Norovirus/aislamiento & purificación , Humanos , Lactante , Recién Nacido , México , Datos de Secuencia Molecular , Norovirus/genética , Filogenia , ARN Viral/análisis , ARN Viral/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Homología de Secuencia , Población UrbanaRESUMEN
Vitamin A supplementation has consistently reduced infant mortality and the severity of pathogen-induced diarrhea. The mechanism by which vitamin A modulates the mucosal immune response to produce these effects remains poorly defined. To address this issue, stools collected during the summer months from 127 Mexican children 5-15 mo old enrolled in a larger, randomized, double-blind, placebo-controlled, vitamin A supplementation trial were screened for interleukin (IL)-4, IL-6, interferon-gamma (IFN-gamma), and gastrointestinal pathogens. Fecal cytokine values were categorized into 3 levels (undetectable,
Asunto(s)
Diarrea/inmunología , Suplementos Dietéticos , Inmunidad Mucosa/efectos de los fármacos , Vitamina A/farmacología , Animales , Ascariasis/inmunología , Ascaris/aislamiento & purificación , Estatura , Peso Corporal , Control de Enfermedades Transmisibles , Diarrea/parasitología , Heces/parasitología , Femenino , Humanos , Lactante , Masculino , México , Factores Socioeconómicos , Células TH1/microbiología , Células Th2/inmunologíaRESUMEN
BACKGROUND: The efficacy of micronutrient supplementation in improving childhood health and survival in developing countries may be specific to the micronutrient used and health outcome measured. OBJECTIVE: We evaluated the effect of vitamin A and zinc supplementation on overall rates of childhood diarrheal disease and respiratory tract infections and rates stratified by household and personal characteristics. DESIGN: A double-blind, randomized, placebo-controlled trial was carried out in which 736 children aged 6-15 mo living in a periurban area of Mexico City were assigned to receive vitamin A every 2 mo, zinc daily, vitamin A and zinc together, or placebo. Children were followed for 12 mo to determine overall counts of diarrheal episodes and respiratory tract infections. RESULTS: Vitamin A supplementation was associated with a 27% increase in diarrheal disease [risk ratio (RR): 1.27; 95% CI: 1.10, 1.45; P < 0.001] and a 23% increase in cough with fever (RR: 1.23; 95% CI: 1.02, 1.47; P = 0.02), whereas zinc had no effect on these outcomes. Vitamin A supplementation decreased diarrhea in children from households with dirt floors but increased diarrhea in children from households with nondirt floors, piped water, and indoor bathrooms. Zinc supplementation decreased diarrhea in children from households with dirt floors and whose mothers were more educated. Vitamin A supplementation increased cough with fever in children from less-crowded households that lacked indoor bathrooms and in children of less-educated mothers. CONCLUSIONS: Vitamin A increases diarrheal disease and respiratory tract infections in young children in periurban areas of Mexico City. Vitamin A and zinc have more heterogeneous effects in different subgroups of children.