Red meat consumption and metabolic syndrome in the Costa Rica Heart Study.

PURPOSE: Several epidemiologic investigations have found associations between the consumption of red meat and the metabolic syndrome (MetS). Very few studies have looked at populations undergoing the nutrition transition with smaller levels of red meat consumption than those in Westernized countries. In this population-based cross-sectional study, we examined the association between red meat consumption and MetS in Costa Rican adults, a population with comparably lower consumption of red meat. METHODS: Prevalence ratios (PRs) of MetS across quintiles of total, unprocessed, and processed red meat consumption were estimated with log-binomial regression models among 2058 adults from the Costa Rican Heart Study. Least-squares mean values of individual components of MetS across quintiles of red meat consumption were estimated with linear regression models. RESULTS: We observed a significant positive association between total red meat consumption and MetS (PR for highest compared to lowest quintile: 1.21; 95% CI: 1.03, 1.42; P for trend = 0.0113) but not for unprocessed or processed red meat consumption when analyzed separately after mutual adjustments. We additionally observed a significant positive association between total, unprocessed, and processed red meat consumption and abdominal obesity. CONCLUSION: In this Hispanic population undergoing the nutrition transition, total red meat intake may have an impact on MetS. Based on the relatively low consumption of red meat in Costa Rica compared to other Westernized countries, we hypothesize that a "threshold effect" may exist for unprocessed and processed red meat.

Adipose tissue palmitoleic acid is inversely associated with nonfatal acute myocardial infarction in Costa Rican adults.

BACKGROUND AND AIMS: Animal models have shown that adipose-derived palmitoleic acid may act as a lipokine by conferring resistance to diet-induced obesity; however, human epidemiologic studies investigating this relationship thus far have not provided data in support of this hypothesis. Because metabolic syndrome and cardiovascular disease are intricately linked with the former being a major risk factor for the latter, we hypothesized that adipose-derived palmitoleic acid may be inversely associated with myocardial infarction. We examined whether adipose tissue palmitoleic acid was associated with nonfatal acute myocardial infarction in a representative population of Costa Rican adults. METHODS AND RESULTS: Odds ratios of nonfatal acute myocardial infarction by quintiles of adipose tissue palmitoleic acid were calculated using conditional logistic regression in a case-control study of 1828 cases and 1828 controls matched by age, sex, and area of residence. We observed an inverse relationship between nonfatal acute myocardial infarction and adipose tissue palmitoleic acid (OR for highest quintile compared to lowest quintile of palmitoleic acid: 0.55; 95% CI: 0.41, 0.75; P for trend: <0.0001). We additionally observed a significant positive association between adipose tissue palmitoleic acid and high-density lipoprotein cholesterol. CONCLUSION: These data demonstrate an inverse association between adipose tissue palmitoleic acid and nonfatal acute myocardial infarction; however, further research is required in order to better understand the opposing associations between palmitoleic acid and high-density lipoprotein cholesterol and systolic blood pressure.

Invited Commentary: Physical Exertion and Placental Abruption-Public Health Implications and Future Directions.

Chahal et al. (Am J Epidemiol. 2018;187(10):2073-2079) assessed the risk of placental abruption due to physical exertion using a case-crossover design. The authors found an increased risk of placental abruption following increased physical exertion in the hour prior to the abruption. The risk was greater among women who were primarily sedentary during pregnancy or prior to becoming pregnant compared with those who were more physically active. The authors used a case-crossover design to assess the association of an intermittent exposure on an acute event. Chahal et al. address the limitations of the study, including the inability to control for time-varying confounders as well as the potential for recall bias. The public health implications of the study must be carefully evaluated given that physical activity prior to and during pregnancy can lead to healthy outcomes and is likely recommended. While the current study is unable to determine the type of physical exertion associated with placental abruption, future studies are recommended to determine the type of activity that presents increased risk. Additionally, studies among larger samples and in other countries will help determine the generalizability of the results.

Maternal intake of omega-3 and omega-6 polyunsaturated fatty acids during mid-pregnancy is inversely associated with linear growth.

This study investigates relations of maternal N-3 and N-6 polyunsaturated fatty acids (PUFA) intake during pregnancy with offspring body mass index (BMI), height z-score and metabolic risk (fasting glucose, C-peptide, leptin, lipid profile) during peripuberty (8-14 years) among 236 mother-child pairs in Mexico. We used food frequency questionnaire data to quantify trimester-specific intake of N-3 alpha-linolenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); N-6 linoleic acid and arachidonic acid (AA); and N-6:N-3 (AA:EPA+DHA), which accounts for the fact that the two PUFA families have opposing effects on physiology. Next, we used multivariable linear regression models that accounted for maternal education and parity, and child's age, sex and pubertal status, to examine associations of PUFA intake with the offspring outcomes. In models where BMI z-score was the outcome, we also adjusted for height z-score. We found that higher second trimester intake of EPA, DHA and AA were associated with lower offspring BMI and height z-score. For example, each 1-s.d. increment in second trimester EPA intake corresponded with 0.25 (95% CI: 0.03, 0.47) z-scores lower BMI and 0.20 (0.05, 0.36) z-scores lower height. Accounting for height z-score in models where BMI z-score was the outcome attenuated estimates [e.g., EPA: -0.16 (-0.37, 0.05)], suggesting that this relationship was driven by slower linear growth rather than excess adiposity. Maternal PUFA intake was not associated with the offspring metabolic biomarkers. Our findings suggest that higher PUFA intake during mid-pregnancy is associated with lower attained height in offspring during peripuberty. Additional research is needed to elucidate mechanisms and to confirm findings in other populations.

Association of plasma phospholipid polyunsaturated and trans fatty acids with body mass index: results from the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND/OBJECTIVE: Previous research has focused on associations between dietary fat and body mass index (BMI), but the contributions of different types of fat to BMI remain unclear. The purpose of this study is to estimate whether plasma phospholipid omega-3 (n-3), omega-6 (n-6) or trans fatty acids are associated with BMI at baseline and with subsequent BMI changes over time; and whether total phospholipid n-6 or trans fatty acids modify any association between phospholipid n-3 and BMI. METHODS: Cross-sectional and longitudinal linear mixed models include 6243 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort. Participants were 45-84 years old, had no history of cardiovascular disease at baseline (2000-2002) and were followed for up to 10 years. Plasma phospholipid fatty acids were measured using fasting plasma samples at baseline. Fully adjusted models include demographics, health behaviors and other fatty acids (n-3, n-6 and trans) as appropriate. RESULTS: In fully adjusted models, phospholipid n-3 fatty acid levels were inversely associated with baseline BMI (Ptrend <0.001). Baseline BMI was 1.14 (95% confidence interval (CI): 0.71, 1.57) kg m-2 lower among participants with total n-3 values in the highest vs the lowest quartiles, but was not associated with changes in BMI. Total phospholipid n-6 was positively associated with baseline BMI in partially adjusted but not fully adjusted models. No overall association was observed between fatty acid levels and changes in BMI. No clear association was observed between trans fatty acids and baseline BMI or BMI change. No effect modification in the association between phospholipid n-3 and baseline BMI or BMI change was observed by either phospholipid n-6 or trans fatty acids. CONCLUSIONS: Phospholipid total and specific n-3 fatty acid levels were inversely associated with BMI at baseline, whereas associations tended to be positive for total n-6 fatty acids. Significant associations between fatty acid levels and BMI changes were not observed.

Birth order and sibship composition as predictors of overweight or obesity among low-income 4- to 8-year-old children.

OBJECTIVE: This study aimed to examine the association of birth order and number and sex of siblings with overweight or obesity among 4- to 8-year-olds. METHODS: This is a cross-sectional study involving 273 low-income mother-child dyads. Questionnaires and anthropometry were completed. Multiple logistic regression was used to examine the association of birth order, having younger siblings, having older siblings, having at least one brother and having at least one sister with odds of overweight or obesity. Analyses were repeated to additionally include non-biological siblings. Models were adjusted for potential confounders and intermediate variables. RESULTS: Prevalence of child overweight or obesity was 42.5%. Adjusting for covariates, only children and youngest siblings had higher odds of overweight or obesity compared with oldest siblings (odds ratio [OR]: 4.18, 95% confidence interval [CI]: 1.67, 10.46 and OR: 3.21, 95% CI: 1.41, 7.33, respectively). Having one or more younger siblings and having at least one brother were associated with lower odds (OR: 0.38, 95% CI: 0.21, 0.69 and OR: 0.47, 95% CI: 0.28, 0.81, respectively). Including non-biological siblings did not meaningfully change the associations. CONCLUSION: Birth order and sibship composition are associated with overweight or obesity among 4- to 8-year-olds. Future studies identifying the underlying behavioural mechanism can help inform family-based intervention programmes.

Adipose tissue n-3 fatty acids and metabolic syndrome.

BACKGROUND: Evidence regarding the relationship of n-3 fatty acids (FA) to type 2 diabetes and metabolic syndrome components (MetS) is inconsistent. OBJECTIVE: To examine associations of adipose tissue n-3 FA with MetS. DESIGN: We studied 1611 participants without prior history of diabetes or heart disease who were participants in a population-based case-control study of diet and heart disease (The Costa Rica Heart Study). We calculated prevalence ratios (PR) and 95% confidence intervals (CI) for MetS by quartile of n-3 FA in adipose tissue derived mainly from plants (α-Linolenic acid (ALA)), fish (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) or metabolism (docosapentaenoic acid (DPA), as well as the EPA:ALA ratio, a surrogate marker of delta-6 desaturase activity). RESULTS: N-3 FA levels in adipose tissue were associated with MetS prevalence in opposite directions. The PR (95% CI) for the highest compared with the lowest quartile adjusted for age, sex, body mass index (BMI), residence, lifestyle, diet and other FAs were 0.60 (0.44, 0.81) for ALA, 1.43 (1.12, 1.82) for EPA, 1.63 (1.22, 2.18) for DPA and 1.47 (1.14, 1.88) for EPA:ALA, all P for trend <0.05. Although these associations were no longer significant (except DPA) after adjustment for BMI, ALA and DPA were associated with lower glucose and higher triglyceride levels, P<0.05 (respectively). CONCLUSIONS: These results suggest that ALA could exert a modest protective benefit, whereas EPA and DHA are not implicated in MetS. The positive associations for DPA and MetS could reflect higher delta-6 desaturase activity caused by increased adiposity.

Alpha-linolenic acid (ALA) is inversely related to development of adiposity in school-age children.

BACKGROUND/OBJECTIVES: Studies in adults indicate that dietary polyunsaturated fatty acid (PUFA) composition may play a role in development of adiposity. Because adipocyte quantity is established between late childhood and early adolescence, understanding the impact of PUFAs on weight gain during the school-age years is crucial to developing effective interventions. SUBJECTS/METHODS: We quantified N-3 and N-6 PUFAs in serum samples of 668 Colombian schoolchildren aged 5-12 years at the time of recruitment into a cohort study, using gas-liquid chromatography. Serum concentrations of N-3 (alpha-linolenic acid (ALA), eicosapentaenoic acid, docosahexaenoic acid) and N-6 PUFAs (linoleic acid, gamma-linolenic acid, dihomo-gamma-linolenic acid, arachidonic acid) were determined as percentage total fatty acids. Children's anthropometry was measured annually for a median of 30 months. We used mixed-effects models with restricted cubic splines to construct population body mass index-for-age z-score (BAZ) growth curves for age- and sex-specific quartiles of each PUFA. RESULTS: N-3 ALA was inversely related to BAZ gain after adjustment for sex, baseline age and weight status, as well as household socioeconomic level. Estimated BAZ change between 6 and 14 years among children in the highest quartile of ALA compared with those in the lowest quartile was 0.45 (95% confidence interval: 0.07, 0.83) lower (P-trend=0.006). CONCLUSIONS: N-3 ALA may be protective against weight gain in school-age children. Whether improvement in PUFA status reduces adiposity in pediatric populations deserves evaluation in randomized trials.

INSIG2 variants, dietary patterns and metabolic risk in Samoa.

BACKGROUND/OBJECTIVES: Association of insulin-induced gene 2 (INSIG2) variants with obesity has been confirmed in several but not all follow-up studies. Differences in environmental factors across populations may mask some genetic associations and therefore gene-environment interactions should be explored. We hypothesized that the association between dietary patterns and components of the metabolic syndrome could be modified by INSIG2 variants. SUBJECTS/METHODS: We conducted a longitudinal study of adiposity and cardiovascular disease risk among 427 and 290 adults from Samoa and American Samoa (1990-1995). Principal component analysis on food items from a validated food frequency questionnaire was used to identify neotraditional and modern dietary patterns. We explored gene-dietary pattern interactions with the INSIG2 variants rs9308762 and rs7566605. RESULTS: Results for American Samoans were mostly nonsignificant. In Samoa, the neotraditional dietary pattern was associated with lower triglycerides, body mass index (BMI), waist circumference, systolic and diastolic blood pressure and fasting glucose (all P-for-trend<0.05). The modern pattern was significantly associated with higher triglycerides, BMI, waist circumference and lower high-density lipoprotein-cholesterol (all P-for-trend<0.05). A significant interaction for triglycerides was found between the modern pattern and the rs9308762 polymorphism (P=0.04). Those from Samoa consuming the modern pattern have higher triglycerides if they are homozygous for the rs9308762 C allele. CONCLUSIONS: The common INSIG2 variant rs9308762 was associated with poorer metabolic control and a greater sensitivity of trigylcerides to a modern dietary pattern. Environmental factors need to be taken into account when assessing genetic associations across and within populations.

Fatty Acid desaturase gene variants, cardiovascular risk factors, and myocardial infarction in the costa rica study.

Genetic variation in fatty acid desaturases (FADS) has previously been linked to long-chain polyunsaturated fatty acids (PUFAs) in adipose tissue and cardiovascular risk. The goal of our study was to test associations between six common FADS polymorphisms (rs174556, rs3834458, rs174570, rs2524299, rs174589, rs174627), intermediate cardiovascular risk factors, and non-fatal myocardial infarction (MI) in a matched population based case-control study of Costa Rican adults (n = 1756). Generalized linear models and multiple conditional logistic regression models were used to assess the associations of interest. Analyses involving intermediate cardiovascular risk factors and MI were also conducted in two replication cohorts, The Nurses' Health Study (n = 1200) and The Health Professionals Follow-Up Study (n = 1295). In the Costa Rica Study, genetic variation in the FADS cluster was associated with a robust linear decrease in adipose gamma-linolenic, arachidonic, and eicosapentaenoic fatty acids, and significant or borderline significant increases in the eicosadienoic, eicosatrienoic, and dihomo-gamma-linolenic fatty acids. However, the associations with adipose tissue fatty acids did not translate into changes in inflammatory biomarkers, blood lipids, or the risk of MI in the discovery or the replication cohorts. In conclusion, fatty acid desaturase polymorphisms impact long-chain PUFA biosynthesis, but their overall effect on cardiovascular health likely involves multiple pathways and merits further investigation.

Genetic variation in fatty acid elongases is not associated with intermediate cardiovascular phenotypes or myocardial infarction.

BACKGROUND/OBJECTIVES: Elongases 2, 4 and 5, encoded by genes ELOVL2, ELOVL4 and ELOVL5, have a key role in the biosynthesis of very long chain polyunsaturated fatty acids (PUFAs). To date, few studies have investigated the associations between elongase polymorphisms and cardiovascular health. We investigated whether ELOVL polymorphisms are associated with adipose tissue fatty acids, serum lipids, inflammation and ultimately with nonfatal myocardial infarction (MI) in a Costa Rican population. SUBJECTS/METHODS: MI cases (n=1650) were matched to population-based controls (n=1650) on age, sex and area of residence. Generalized linear and multiple conditional logistic regression models were used to assess the associations between seven common ELOVL polymorphisms and cardiometabolic outcomes. Analyses were replicated in The Nurses' Health Study (n=1200) and The Health Professionals Follow-Up Study (n=1295). RESULTS: Variation in ELOVL2, ELOVL4 and ELOVL5 was not associated with adipose tissue fatty acids, intermediate cardiovascular risk factors or MI. In the Costa Rica study, the number of the minor allele copies at rs2294867, located in the ELOVL5 gene, was associated with an increase in total and LDL cholesterol (adjusted P-values=0.001 and <0.0001 respectively). Additionally, the number of the minor allele copies at rs761179, also located in the ELOVL5 gene, was significantly associated with an increase in total cholesterol (adjusted P-value=0.04). However, the observed associations were not replicated in independent populations. CONCLUSION: Common genetic variants in elongases are not associated with adipose tissue fatty acids, serum lipids, biomarkers of systemic inflammation, or the risk of MI.

Biomarkers of dairy intake and the risk of heart disease.

BACKGROUND AND AIMS: Despite their relatively high content of saturated fat, studies of dairy product intake and the risk of cardiovascular disease have often yielded null or inverse results. The use of fatty acid biomarkers to reflect dairy intake could elucidate this association. This study aims to evaluate the association between dairy intake, assessed by adipose pentadecanoic (15:0) and heptadecanoic (17:0) fatty acids and food frequency questionnaire (FFQ), and the risk of nonfatal myocardial infarction (MI), in a matched case-control study of Costa Rican adults (n=3630). METHODS AND RESULTS: The association was examined using conditional logistic regression, adjusted for potential confounders. The associations of adipose tissue 15:0 and 17:0 with the risk of MI were not statistically significant (for 15:0: multivariate-adjusted OR for 5th quintile vs. 1st=1.14 (95% CI=0.85, 1.53), p-value for linear trend=0.77; for 17:0: multivariate-adjusted OR for 5th quintile vs. 1st=1.15 (95% CI=0.88, 1.51), p-value for linear trend=0.18). The association between the FFQ measure of dairy intake and MI showed evidence of a possible threshold effect, with a protective association observed for all but the top quintile of the exposure distribution. CONCLUSION: Dairy product intake as assessed by adipose tissue 15:0, 17:0, and by FFQ is not associated with a linear increase in the risk of MI in the study population. It is possible that the adverse effect of saturated fat in dairy products on cardiovascular health is offset by presence of beneficial nutrients.

Chronic inflammation is associated with overweight in Colombian school children.

BACKGROUND AND AIMS: To examine the cross-sectional associations of inflammatory markers in plasma including C-reactive protein (CRP) and ferritin, and white blood cell (WBC) count, with overweight, skinfold sum (subscapular + triceps), and skinfold ratio (subscapular/triceps) among children from Bogotá, Colombia. METHODS AND RESULTS: The sample (n = 2614) represented low- and middle-income children, aged 5-12 years, from Bogotá. We assessed their anthropometry, sociodemographic characteristics, and circulating inflammatory markers. We defined overweight, including obesity, according to the International Obesity Task Force BMI criteria. After adjustment for potential confounders, children in the fourth quartile of the CRP distribution had a 37% higher prevalence of overweight compared to those in the first quartile (P for trend = 0.03); and children in the fourth quartile of ferritin had a 67% greater prevalence of overweight compared to children in the first quartile (P for trend <0.001). Children in the highest 3 quartiles of the WBC distribution had a 35% higher prevalence of overweight than those in the first quartile (P = 0.03). Ferritin was significantly and positively associated with skinfold sum (P for trend < 0.001), while WBC was significantly and positively associated with skinfold ratio (P for trend < 0.001). There was a significant interaction between CRP and ferritin; children in the highest quartiles of CRP and ferritin had twice the prevalence of overweight compared to those below the highest quartiles (P = 0.001). CONCLUSION: Biomarkers of chronic inflammation are positively associated with child overweight. WBC is positively related to skinfold ratio, a proxy for truncal adiposity.

Association between hepatic lipase -514 C/T promoter polymorphism and myocardial infarction is modified by history of hypercholesterolemia and waist circumference.

BACKGROUND AND AIMS: To examine whether the association between the -514 C/T polymorphism of the hepatic lipase gene and myocardial infarction (MI) is modified by history of hypercholesterolemia and increased waist circumference. METHODS AND RESULTS: A total of 1940 pairs of nonfatal MI cases and population-based controls were genotyped. Multiple conditional logistic regression was used for data analyses. The -514T variant was not associated with MI in the whole population. However, among people with history of hypercholesterolemia the T allele increased MI risk for heterozygous and homozygous carriers, respectively [OR=1.25 (95%CI=0.92-1.70) and OR=1.59 (95%CI=1.09-2.32). In contrast, the T allele decreased MI risk among people with no history of hypercholesterolemia [OR=0.85 (95%CI=0.70-1.03) and OR=0.76 (95%CI=0.60-0.97)], p for interaction=0.004. Among subjects with normal waist circumference there was no association between the -514T allele and MI for heterozygous and homozygous carriers, respectively [OR=1.04 (95%CI=0.86-1.25) and OR=0.96 (95%CI=0.77-1.21)], while among subjects with waist circumference above the limits of the metabolic syndrome definition there was a protective association [OR=0.63 (95%CI=0.45-0.90) and OR=0.81 (95%CI=0.53-1.25) p for interaction=0.04]. CONCLUSION: The -514T allele is associated with MI in opposite directions depending on the background of the studied population. This could explain what seem like inconsistent results across studies.

Hemoglobin concentration is inversely associated with erythrocyte folate concentrations in Colombian school-age children, especially among children with low vitamin B12 status.

BACKGROUND: While the majority of cases of nutritional anemia in developing countries are caused by iron deficiency, other micronutrient deficiencies may also be involved. In Colombia, it was recently reported that 38% of school children were anemic; yet, the rate of iron deficiency was only 3.6%. OBJECTIVE: To determine if micronutrients other than iron were responsible for low hemoglobin concentrations in Colombian school children. METHODS: We examined hemoglobin concentrations in relation to plasma ferritin, vitamin A, vitamin B12, and erythrocyte folate levels in a representative sample of 2812 low- and middle-income children (5-12 years) from Bogotá, Colombia. RESULTS: In multivariate analysis, hemoglobin concentration was positively associated with child's age, mother's age, household's socioeconomic stratum, and family income. Low ferritin was related to 3.6 g/l lower hemoglobin concentration (95% confidence interval=-6.0, -1.3). Unexpectedly, we found an inverse trend in hemoglobin concentration by quartiles of erythrocyte folate; the adjusted hemoglobin concentration difference between the highest and lowest folate quartiles was -6.0 g/l (95% confidence interval=-7.2, -4.9; P for trend <0.0001). This difference was greatest among children with vitamin B12 concentration <148 pmol/l (-11.5 g/l), followed by children with vitamin B12 concentration 148-221 pmol/l (-7.7 g/l), and smallest in children with vitamin B12 concentration >221 pmol/l (-5.7 g/l); P for interaction=0.04. CONCLUSIONS: Hemoglobin concentration is inversely related to erythrocyte folate concentrations in a setting where folate fortification was adopted more than a decade ago. The impact of improving vitamin B12 status on this inverse relationship should be examined.

Dietary patterns and risk of nonfatal acute myocardial infarction in Costa Rican adults.

OBJECTIVE: To investigate the association between dietary patterns and risk of a first nonfatal acute myocardial infarction (MI) in Costa Rican adults. DESIGN: Population-based case-control study. SUBJECTS: A total of 496 incident MI cases and 518 population-based randomly selected controls matched to the cases by age (+/-5 years), gender, and county of residence. Subjects were interviewed with a validated food frequency questionnaire. Dietary patterns were identified by factor analysis. Odds ratios (OR) and 95% confidence intervals (CI) were obtained using multivariate conditional logistic regression adjusted for several recognized risk factors for MI. RESULTS: Two diet patterns were identified, 'vegetable' characterized by increased intake of vegetables and fruits, and 'staple', characterized by an increased use of palm oil for cooking, and intake of refined grains (mostly white rice and white bread), legumes, coffee, added sugar, and red meat. Compared to the lowest quintile of the staple diet pattern, the highest quintile was associated with an increased risk of MI (OR: 3.70, 95% CI: 2.30-5.97). Adjusting for potential confounders did not change the results (OR: 3.53, 95% CI: 1.98-6.31). Consistently, an increasing staple pattern score was associated with lower HDL cholesterol (P for trend <0.02) and alpha-linolenic acid in adipose tissue (P for trend <0.0001). The vegetable pattern was not associated with MI. CONCLUSIONS: The staple dietary pattern of Costa Rican adults is associated with low plasma HDL cholesterol, low alpha-linolenic acid in adipose tissue, and increased risk of MI.

Effect of vitamin supplementation to HIV-infected pregnant women on the micronutrient status of their infants.

OBJECTIVE: We examined whether supplementation with vitamin A and/or vitamins B, C, and E to HIV-infected women during pregnancy and lactation is related to increased concentrations of vitamins A, B12, and E in their infants during the first 6 months of life. DESIGN: We carried out a randomized clinical trial among 716 mother-infant pairs in Dar-es-Salaam, Tanzania. Women were randomly allocated to receive a daily oral dose of one of four regimens: vitamin A, multivitamins (B, C, and E), multivitamins including A, or placebo. Supplementation started at first prenatal visit and continued after delivery throughout the breastfeeding period. The serum concentration of vitamins A, E and B12 was measured in infants at 6 weeks and 6 months postpartum. RESULTS: Maternal vitamin A supplementation increased serum retinol in the infants at 6 weeks (mean difference=0.09 micromol/l, P<0.0001) and 6 months (mean difference=0.06 micromol/l, P=0.0002), and decreased the prevalence of vitamin A deficiency, but had no impact on serum vitamins E or B12. Multivitamins increased serum vitamin B12 at 6 weeks and 6 months (mean differences=176 pmol/l, P<0.0001 and 127 pmol/l, P<0.0001, respectively) and vitamin E (mean differences=1.8 micromol/l, P=0.0008 and 1.1 micromol/l, P=0.004, respectively) and decreased the prevalence of vitamin B12 deficiency. CONCLUSIONS: Vitamin supplementation to HIV-1-infected women is effective in improving the vitamin status of infants during the first 6 months of age.

Individual saturated fatty acids and nonfatal acute myocardial infarction in Costa Rica.

BACKGROUND: Epidemiological studies on the effect of individual saturated fatty acids (SFAs) on cardiovascular disease, especially in developing countries with different dietary patterns, are scarce. OBJECTIVE: To determine the risk of nonfatal acute myocardial infarction (MI) associated with consumption of individual SFAs and their food sources in Costa Rica. DESIGN: The cases (n=485) were survivors of a first acute MI and were matched by age, sex and area of residence to population controls (n=508). Data on anthropometrical measurements, lifestyle and diet were collected using interviewer-administered questionnaires. RESULTS: In analyses adjusted for confounders, consumption of total and individual SFAs was associated with an increased risk of MI. The odds ratio (OR) (95% confidence intervals) for 1% increase in energy from total saturated fat was 1.12 (1.03-1.21) while it was 1.51 (1.03-2.22) for lauric acid+myristic acid, 1.14 (1.01-1.30) for palmitic acid and 2.00 (1.34-3.00) for stearic acid. Although lauric and myristic acids were associated with increased risk of MI, they were consumed in small amounts and most of the saturated fat (87%) came from palmitic and stearic acids, which derived mainly from red meat and fried foods. Consumption of cheese (1-2 vs 0 servings/day) was associated with increased risk of MI (OR=3.07; 95% confidence interval: 1.74-5.39; P for trend <0.0001), while consumption of low-fat milk was not. CONCLUSION: Increased consumption of total and individual SFAs is associated with increased risk of MI. Lauric, myristic and stearic acids were more potent than palmitic acid.

Application of the method of triads to evaluate the performance of food frequency questionnaires and biomarkers as indicators of long-term dietary intake.

Little is documented about the performance of the food frequency questionnaire (FFQ) in US minority groups and in populations in developing countries. The authors applied a novel technique, the method of triads, to assess the validity and reproducibility of the FFQ among Hispanics. The subjects were men (n = 78) and women (n = 42) living in Costa Rica. Seven 24-hour dietary recalls and two FFQ interviews (12 months apart) were conducted between 1995 and 1998 to estimate dietary intake during the past year. Plasma and adipose tissue samples were collected from all subjects. Validity coefficients, which measure the correlation between observed and "true" dietary intake, were also estimated. The median validity coefficients for tocopherols and carotenoids estimated by dietary recall, the average of the two FFQs, and plasma were 0.71, 0.60, and 0.52, respectively. Compared with adipose tissue, plasma was a superior biomarker for carotenoids and tocopherols. Adipose tissue was a poor biomarker for saturated and monounsaturated fatty acids but performed well for polyunsaturated fatty acids (validity coefficients, 0.45-1.01) and lycopene (validity coefficient, 0.51). This study also showed that biomarkers did not perform better than the FFQ and that they should be used to complement the FFQ rather than substitute for it.

Population-based study of alpha- and gamma-tocopherol in plasma and adipose tissue as biomarkers of intake in Costa Rican adults.

BACKGROUND: gamma-Tocopherol is the most abundant form of vitamin E in the US diet, but alpha-tocopherol concentrations are the highest in plasma and tissues. Although plasma and adipose tissue concentrations of alpha-tocopherol have been used as biomarkers of intake, the relation between gamma-tocopherol intake and concentrations in plasma and adipose tissue is unknown. OBJECTIVE: Our goal was to investigate in a randomly selected population from Costa Rica whether plasma or adipose tissue concentrations of alpha- and gamma-tocopherol are suitable biomarkers of intake. DESIGN: A total of 361 men (x +/- SD age: 55 +/- 11 y) and 121 women (aged 59 +/- 10 y) completed a 135-item food-frequency questionnaire and provided a fasting blood sample and adipose tissue biopsy sample. RESULTS: Dietary gamma-tocopherol correlated with adipose tissue (r = 0.37, P < 0.001) and plasma (r = 0.42, P < 0.001) concentrations, regardless of supplement use. Dietary alpha-tocopherol correlated poorly with adipose tissue (r = 0.15, P < 0.01) and plasma (r = 0.16, P < 0.001) concentrations, and these correlations were even lower when users of vitamin supplements (n = 24) were excluded (adipose tissue: r = 0.10, P < 0.05; plasma: r = 0.09, P < 0.05). Compared with subjects who reported palm shortening (36%) as the major type of fat used for cooking, subjects using soybean oil (52%) had higher amounts of both alpha- and gamma-tocopherol in their diets. However, only gamma-tocopherol concentrations were higher in the plasma and adipose tissue of soybean oil users. CONCLUSIONS: Plasma and adipose tissue concentrations of gamma-tocopherol are equally good biomarkers of intake. The weak associations between alpha-tocopherol intake and plasma or adipose tissue concentrations suggest that these biomarkers are influenced more by factors other than alpha-tocopherol intake.