Ray Yip

Iron deficiency : contemporary scientific issues and international programmatic approaches

Iron deficiency is a common nutritional disorder in developing countries and contributes significantly to reduced work productivity and economic output as well as to increased morbidity and mortality. There are well established biochemical tests for assessing iron status in developed countries. However, cost and interference from infectious conditions make it difficult to assess iron status in many developing country settings. Examination of the hemoglobin distribution in the population and assessment of the hemoglobin response to supplementation are alternative approaches to defining iron status and the nature of anemia. Prevention and control of iron deficiency requires the combined approach of dietary improvement, fortification of a common staple food when feasible, and appropriate iron supplementation for infants and pregnant women. In all these intervention activities, operational research is needed to improve effectiveness. In addition, controlling iron deficiency requires coordination with other nutrition and primary health care programs as part of an integrated approach to improved health and nutrition of the population.

A survey of 2,851 patients with hemochromatosis:: Symptoms and response to treatment

PURPOSE Hemochromatosis is a genetic disorder of iron absorption that affects 5 per 1,000 persons and is associated with reduced health and quality of life. We sought to determine the type and frequency of symptoms that patients experienced before the diagnosis and the treatments that they received. METHODS We mailed a questionnaire to 3,562 patients with hemochromatosis who were located using patient advocacy groups, physicians, blood centers, newsletters, and the Internet. RESULTS Of the 2,851 respondents, 99% were white and 62% were men. Circumstances that led to diagnosis of hemochromatosis included symptoms (35%), an abnormal laboratory test (45%), and diagnosis of a family member with hemochromatosis (20%). The mean (+/- SD) age of symptom onset was 41 +/- 14 years. Symptoms had been present for an average of 10 +/- 10 years before the diagnosis was made. Among the 58% of patients with symptoms, 65% had physician-diagnosed arthritis and 52% had liver disease. The most common and troublesome symptoms were extreme fatigue (46%), arthralgia (44%), and loss of libido (26%). Physician instructions to patients included treatment with phlebotomy (90%), testing family members (75%), and avoiding iron supplements (65%). CONCLUSIONS The diagnosis of hemochromatosis in most patients was delayed. Physician education is needed to increase the detection of patients with the disease and to improve its management.

Gestational weight gain among average-weight and overweight women — What is excessive?

OBJECTIVE Our purpose was to determine the association between increased gestational weight gain and birth weight outcomes for low-income women. STUDY DESIGN A total of 53,541 single, live infants delivered from 1990 to 1991 to white, black, and Hispanic women in eight states were evaluated. Multiple logistic regression was used to calculate risk of low and high (> 4500 gm) birth weight, adjusting for selected factors. RESULTS The association between gestational weight gain and birth weight varied by prepregnancy body mass index. Risk for low birth weight decreased with increasing weight gain for average-weight women. There was no reduction in risk for low birth weight, however, beyond weight gains of 30 to 34 pounds for overweight women and 15 to 19 pounds for very-overweight women. Risk for high birth weight, however, increased with increasing weight gain in all three groups. CONCLUSION Very-overweight women (body mass index > 29 kg/m2) may benefit from an upper guideline of 25 pounds of weight gain to help reduce risk for high birth weight.

The influence of fetal and maternal factors on the distribution of birthweight

This review of common risk factors for low birthweight emphasizes the usefulness of examining the entire distribution of birthweight. Of the factors we examined, only short gestational age seemed to affect the low end of the birthweight distribution in the form of skewness. Most factors, such as maternal race, infant sex, plurality, altitude, education, and smoking seem to affect the entire birthweight distribution, indicating a generalized effect. With the exceptions of race, infant sex, parity, and altitude, these factors seemed to have similar associations with both low birthweight and infant mortality. However, only the effects of race and sex on mortality have been repeatedly studied in detail for different combinations of gestational age and birthweight. A few of the factors examined, notably infant sex and parity, have opposite associations with birthweight and infant mortality. Female infants and firstborn infants have lower birthweights than their counterparts, but are more likely to survive. For factors that significantly affect the birthweight distribution, but do not affect mortality equally across the birthweight distribution, the development and use of population-based standards may result in less misclassification of IUGR. Separate standards by infant sex, altitude, and perhaps race may lead to more accurate classification of intrauterine growth. Last, the majority of risk factors have differential effects on birthweight depending on the level of the associated factors. For example, low maternal age and low prepregnancy BMI are associated with both increased risk of low birthweight and poor infant survival. Older maternal age and high prepregnancy BMI are associated with reduced risk of low birthweight, but with increased risk of infant mortality. One possible explanation is that young maternal age and low prepregnancy BMI are associated with adverse behavioral risk factors such as cigarette smoking, whereas increased age and high prepregnancy BMI are associated with gestational diabetes, multiparity, and genetic defects. It is possible that the greater variation in birthweight at the high end of the scale is indicative of increased risk of mortality. Thus, higher birthweight does not always equal better birth outcomes.

Iron status with different infant feeding regimens : relevance to screening and prevention of iron deficiency

The objective of this study was to evaluate the benefit of screening for anemia in infants in relation to their previous diet. The iron status of 854 nine-month-old infants on three different feeding regimens and on a regimen including iron dextran injection was determined by analysis of hemoglobin, serum ferritin, and erythrocyte protoporphyrin levels and of serum transferrin saturation. Infants were categorized as having iron deficiency if two or three of the three biochemical test results were abnormal and as having iron deficiency anemia if, in addition, the hemoglobin level was less than 110 gm/L. The prevalence of iron deficiency was highest in infants fed cow milk formula without added iron (37.5%), intermediate in the group fed human milk (26.5%), much lower in those fed cow milk formula with added iron (8.0%), and virtually absent in those injected with iron dextran (1.3%). The corresponding values for iron deficiency anemia were 20.2%, 14.7%, 0.6%, and 0%, respectively. The use of iron supplements is therefore justified in infants fed cow milk formula without added iron, even when there is no biochemical evidence of iron deficiency. The low prevalence of iron deficiency in the group fed iron-fortified formula appears to make it unnecessary to screen routinely for anemia in such infants. These results also support the recommendation that infants who are exclusively fed human milk for 9 months need an additional source of iron after about 6 months of age.

Increasing trends in plural births in the united states

Objective To determine the nature and posssible reasons for the increasing trend in plural in the United States during the 1980s. Methods We performed a descriptive analysis of births in the united States for five recial and ethnic groups from 1980–1989, using the United States vital records natality files. Results The rates of twin and triplet births rose 19 and 100%, respectively, during the 1980s. Approximately one-fourth of the observed increases can be attributed to rising maternal age. The increases in twin and triplet births occurred mainly among more educated and older white women. Conclusion The association of high education status with rising rates of plural births, independent of maternal age, suggests that the observed increase is the result of increasing use of fertility-stimulating therapy among a subset of the childbearing population.

Influence of maternal birth weight on rate of fetal growth and duration of gestation

Birth certificates of infants born in Tennessee during 1979 to 1984 were linked with the birth certificates of their mothers, who were born in Tennessee during 1959 to 1966 (n = 43,891) to study the association between maternal and infant birth weights. A highly significant association (P less than 0.0001) between maternal and infant birth weights was found for both blacks and whites. Women who weighed 4000 to 4499 g at birth were at lowest risk for delivery of a small for gestational age (SGA) infant (5.9% for whites, 4.8% for blacks). The risk of giving birth to an SGA infant increased with decreasing maternal birth weight, reaching a maximum of 19.8% for white mothers who weighed 2000 to 2499 g at birth, and 20.0% for black mothers who weighed 1000 to 1499 g at birth. In contrast, the rate of preterm birth varied much less by maternal birth weight for both whites and blacks. These data suggest that maternal birth weight exerts a stronger influence on intrauterine growth than on the duration of gestation. Women who were smaller than average at birth should be considered at high risk for delivery of an SGA infant.

Continuation of the decline in prevalence of anemia in low-income infants and children in five states.

Objective. To examine whether there is a continuation of the decline in prevalence of anemia among low-income infants and children 6.0 to 59.9 months old from the early 1980s to the mid-1990s. Study Design. Cross-sectional trend analysis of data from the Centers for Disease Control and Preventions Pediatric Nutrition Surveillance System from the 5 states (Colorado, New Mexico, Oklahoma, Utah, and Vermont) that have been using the same laboratory method for anemia screening since 1984 or earlier. Results. The overall prevalence of anemia decreased substantially in each state from the early 1980s to the mid-1990s as follows: Colorado by 52%; New Mexico by 75%; Oklahoma by 67%; Utah by 57%; and Vermont by 48%. In each state, the prevalence of anemia declined for children of different age groups, birth weights, genders, type of pediatric care visit (screening or follow-up), and most race/ethnic groups. Conclusions. The decline in the prevalence of anemia initially observed in the 1980s continued well into the 1990s. This decline is likely attributable to better iron nutrition related to greater usage of iron-fortified products and possibly better iron bioavailability in some of the food products.

Developmental changes in erythrocyte protoporphyrin: Roles of iron deficiency and lead toxicity

Iron deficiency and lead toxicity both result in increased erythrocyte protoporphyrin. The purpose of this study was to determine the differences in EP concentration, according to age and sex, obtained in the 2nd National Health and Nutrition Examination Survey of the United States and to determine the extent to which EP differences might be related to iron deficiency or lead toxicity. The highest EP concentrations were found in infants and children. Among adults, women had higher EP values than men. Lead toxicity (blood lead greater than 30 micrograms/dl) and low serum iron concentration/total iron binding capacity (Fe/TIBC less than 16%), often in combination, were associated with elevated EP values in infants and children. In women, elevated EP concentration were related primarily to low Fe/TIBC values, whereas in men there was only a weak association with elevated blood lead concentration. Age/sex differences in EP values diminished markedly when the influences of lead toxicity and iron deficiency were excluded by the above criteria.

Coordinated Strategies for Controlling Micronutrient Malnutrition: A Technical Workshop

Participants in a November 1991 workshop concluded that coordinated strategies for controlling malnutrition due to iodine, iron, vitamin A and other micronutrients deficiencies are technically feasible and should be given consideration in planning control efforts. Coordinated surveys involving clinical, biochemical and dietary assessment of multiple micronutrients are feasible. Multiple fortification is also possible using such vehicles as salt, processed rice or sugar. Supplementation efforts can be integrated with existing health care programs. Food-based strategies are also effective. The best examples have been community-based and have included a strong nutrition and health education component designed to change food consumption patterns, improve food preservation and preparation practices, and link income-generating activities with food production activities. Successful coordinated efforts will require a strong political commitment and a supportive infrastructure. Specific recommendations include the formation of national coordinating bodies for micronutrient deficiency control, establishment of a micronutrient information network and expansion of technical exchange and training.