Iron status: prevalence of impairment in three Hispanic groups in the United States

Iron Deficiency and Iron Deficiency Anemia in Women with and without Obesity: NHANES 2001-2006

Obesity has been linked to numerous health and nutritional problems, including impaired iron metabolism, a common cause of anemia. We aimed to determine the prevalence of anemia, iron deficiency (ID), and iron deficiency anemia (IDA) among women aged 20-49 years based on body mass index (BMI) status. We used measures of iron status and body mass index from the 2001-2006 National Health and Nutrition Examination Survey (NHANES). Mean serum ferritin, erythrocyte protoporphyrin, and soluble transferrin receptor were higher, while those of serum iron, percent transferrin saturation, and mean cell volume (MCV) were lower in women with obesity than those with normal weight (all p < 0.016). ID based on the ferritin model was 12.5 ± 1.0% vs. 22.9 ± 1.6% (p < 0.001); 9.0 ± 0.9% vs. 20.0 ± 1.3% (p < 0.001) based on the MCV model; and 8.1 ± 1.0% vs. 10.5 ± 1.2% (p > 0.05) based on the BII model for women with normal weight and women with obesity, respectively. Anemia prevalence was 5.5 ± 0.8% (normal) vs. 9.3 ± 1.0% (obese) (p = 0.005). The IDA estimates based on the ferritin and MCV models were similar but higher than that from the BII model (p < 0.001). Generally, the prevalence rates of ID and anemia (and IDA) were higher for women with obesity, but the method used to define deficiency mattered. The choice of iron indices is important for estimating ID and IDA in populations with obesity.

Prevalence of iron deficiency in 62,685 women of seven race/ethnicity groups: The HEIRS Study

Background

Few cross-sectional studies report iron deficiency (ID) prevalence in women of different race/ethnicity and ages in US or Canada.

Materials and methods

We evaluated screening observations on women who participated between 2001–2003 in a cross-sectional, primary care-based sample of adults ages ≥25 y whose observations were complete: race/ethnicity; age; transferrin saturation; serum ferritin; and HFE p.C282Y and p.H63D alleles. We defined ID using a stringent criterion: combined transferrin saturation <10% and serum ferritin <33.7 pmol/L (<15 μg/L). We compared ID prevalence in women of different race/ethnicity subgrouped by age and determined associations of p.C282Y and p.H63D to ID overall, and to ID in women ages 25–44 y with or without self-reported pregnancy.

Results

These 62,685 women included 27,079 whites, 17,272 blacks, 8,566 Hispanics, 7,615 Asians, 449 Pacific Islanders, 441 Native Americans, and 1,263 participants of other race/ethnicity. Proportions of women with ID were higher in Hispanics and blacks than whites and Asians. Prevalence of ID was significantly greater in women ages 25–54 y of all race/ethnicity groups than women ages ≥55 y of corresponding race/ethnicity. In women ages ≥55 y, ID prevalence did not differ significantly across race/ethnicity. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.

Conclusions

ID prevalence was greater in Hispanic and black than white and Asian women ages 25–54 y. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.

Maternal anaemia after delivery: prevalence and risk factors

The purpose of this study was to assess the prevalence of postpartum anaemia and determine the clinical risk factors for this condition to provide a viable alternative to postpartum haemoglobin measurement. In total, 1415 patients at Hospital Universitario del Tajo, Madrid, who underwent postpartum haemoglobin testing were included, and risk factors for having an Hb level <10 g/dl were determined. We found that 29% of the mothers were anaemic, and birth canal lacerations, caesarean delivery, episiotomy and South American origin were identified as the main risk factors for this condition. When we examined the performance of each risk factor alone in the prediction of postpartum anaemia, none of them achieved a sensitivity of 30%. Selective screening of women who had any of these five risk factors resulted in 23% of cases remaining unidentified. Despite the high incidence and disease burden of this condition, the management of puerperal anaemia is not standardised, and this condition is not easy to predict. Universal screening should be considered in high-prevalence settings. Impact statement The World Health Organisation (WHO) describes the postnatal period as the most critical and yet most neglected phase in the lives of mothers and infants. It is a common knowledge that a woman's adjustment to life with her new infant is very difficult. This period, known as the puerperium, often involves poor sleep quality, pain and fatigue, if not other major complications. In this context, we must face the challenge of increasing breastfeeding rates, which is why health care providers should be aware of the medical and psychological needs of the new mother. This work reports that postpartum anaemia, a potentially preventable or treatable condition that can make it more difficult to resume everyday activities, is highly prevalent. It remains to be seen whether ensuring the appropriate diagnosis and treatment of anaemia after delivery will result in improvements in the physical and psychological well-being of obstetric patients.

Prevalence of iron deficiency and iron deficiency anemia among three populations of female military personnel in the US Army

BACKGROUND

Iron deficiency is the most prevalent micronutrient deficiency disease in the world and occurs in young women in the United States. Female military personnel represent a unique population faced with intense physical and cognitive demands.

OBJECTIVE

The objective of this study was to determine the prevalence of iron deficiency and iron deficiency anemia among three populations of female military personnel in the US Army.

METHODS

Iron status was assessed in 1216 volunteers. Volunteers were recruited from three groups: immediately following initial entry to the Army (IET), immediately following basic combat training (AIT), or following at least six months of permanent assignment (PP). Iron deficiency was determined using a three variable model, including cut-off values for serum ferritin, transferrin saturation, and red cell distribution width (RDW). Iron deficiency anemia was categorized by iron deficiency and a hemoglobin (Hgb) value of <12 g/dL.

RESULTS

The prevalence of iron deficiency was greater in women in the AIT group (32.8%) than in the IET and PP groups (13.4 and 9.6%, respectively). The prevalence of iron deficiency anemia was greater in the AIT group (20.9%) than in the IET and PP groups (5.8 and 4.8%, respectively). Furthermore, the prevalence of iron deficiency anemia was greater in Hispanic (21.9%) and African-American military personnel (22.9%) than in Caucasian military personnel (10.5%).

CONCLUSIONS

These data indicate that female military personnel experience diminished iron status following training, and that iron nutriture is an important issue facing females in the military.

Hemoglobin and ferritin are currently the most efficient indicators of population response to iron interventions: an analysis of nine randomized controlled trials

Governments and donor agencies have implemented pilot and large-scale iron fortification programs, but there has been no consensus on the best choice of indicators to monitor population response to these interventions. We analyzed data from 9 randomized iron intervention trials to determine which of the following indicator(s) of iron status show the largest response in a population: hemoglobin (Hb), ferritin, transferrin receptor (TfR), zinc protoporphyrin (ZPP), mean cell volume (MCV), transferrin saturation (TS), and total body-iron store. We expressed the change in each indicator in response to the iron intervention in SD units (SDU) for the intervention group compared with the control group. Ferritin increased by > or =0.2 SDU in all trials and was significant in 7. Hb changed by > or =0.2 SDU in 6 and was significant in 5. TfR increased by > or =0.2 SDU in 5 of 8 interventions in which it was measured and was significant in 4. ZPP increased by > or =0.2 SDU and was significant in 3 of 6 interventions. Excluding Hb, the indicator with the largest change in SDU was ferritin in 4 trials, TS in 2 trials, body-iron store in 2 trials, and TfR in 1. In the 2 cases in which body-iron stores showed the largest change, the change in ferritin was nearly as large. Our results suggest that with currently available technologies, ferritin shows larger and more consistent response to iron interventions than ZPP or TfR. We cannot make confident inference about MCV or TS, which were included in only 4 and 2 trials, respectively. It is possible that the optimal indicator(s) may differ with age, sex, and pregnancy. There were too few trials in each age and sex group to allow us to explore this question.

Iron stores and cardiovascular disease risk factors in women of reproductive age in the United States

BACKGROUND

The increasing proportion of iron-replete individuals in industrialized countries and the possible increased risk of cardiovascular disease (CVD) among men with high iron stores raise concerns regarding improved iron status in women of reproductive age.

OBJECTIVE

This study examined the association between iron stores and a set of established CVD risk factors among nonpregnant women aged 20-49 y.

DESIGN

Data from the third National Health and Nutrition Examination Survey (1988-1994) were used to examine the relation between race-ethnicity-specific quartiles of serum ferritin (SF) and a set of CVD risk factors [body mass index (BMI), total cholesterol, triacylglycerol, HDL cholesterol, plasma glucose, and blood pressure (BP)]. Women with a history of CVD or liver disease were excluded. We controlled for age, session of measurement, prevalent infection, recent blood donation, and treatment with iron for anemia.

RESULTS

Mean SF values were 53.22 +/- 2.08 micro g/L (n = 1178), 58.93 +/- 2.39 micro g/L (n = 1093), and 43.33 +/- 1.39 micro g/L (n = 1075) among non-Hispanic white, non-Hispanic black, and Mexican American women, respectively. Iron stores were positively associated with CVD risk factors only among non-Hispanic black and Mexican American women after adjustment for confounding variables. The strongest associations were seen among Mexican American women: compared with the middle 2 quartiles, the lowest and highest quartiles of SF had lower and higher values, respectively, for BMI, total cholesterol, triacylglycerol, glucose, and diastolic BP.

CONCLUSION

These findings suggest that CVD risk factors, especially those related to glucose and lipid metabolism, are positively associated with iron status in women.

Dietary intake does not account for differences in low iron stores among Mexican American and non-Hispanic white women: Third National Health and Nutrition Examination Survey, 1988-1994

We used nationally representative data from the third National Health and Nutrition Examination Survey (NHANES III) to examine the relationship between low iron stores (serum ferritin < 12 microg/L) and dietary patterns that might affect iron status among Mexican American (MA) and non-Hispanic white (NHW) girls and women of reproductive age (12-39 y). Dietary data from the qualitative food-frequency questionnaire were used to classify subjects into three categories (using the 25th and 75th quartile values for NHW) for intake of heme iron, nonheme iron, iron absorption enhancers, and iron absorption inhibitors. The prevalence of low iron stores was 17.4% among MA (n = 1368) and 7.9% among NHW (n = 1473). Compared with high intake, the adjusted odds ratio (OR) for low iron stores was 1.80 [95% confidence interval (CI), 1.24-2.62] for medium intake of heme iron and 0.48 (95% CI, 0.25-0.91) for low intake of nonheme iron (plus iron supplement). Compared with no use, use of vitamin C supplements was associated with half the risk of low iron stores (OR = 0.50; 95% CI, 0.29-0.87). Similar results were found after income and parity were controlled for, except that the protective effect of vitamin C supplements was no longer significant. Even after adjustment for sociodemographic and dietary factors, MA women remained at increased risk for low iron stores (OR = 1.80; 95% CI, 1.30-2.49) indicating that the reasons for the higher prevalence of iron deficiency in MA women warrants further investigation.

Factors that predict low hematocrit levels in the postpartum patient after vaginal delivery

OBJECTIVE

The purpose of this study was to provide a viable alternative to routine postpartum hematocrit measurement, by a determination of the clinical risk factors that identify patients with anemia and an examination of the resulting cost savings.

STUDY DESIGN

In this retrospective review, cases (postpartum hematocrit level, <26%; subgroup hematocrit level, <23%) and control subjects were culled from the records of all vaginal deliveries from February 1997 to July 1998. Charts were reviewed for demographic characteristics, medical history, nursing assessments, and postpartum hematocrit measurements. Logistic regression modeling determined the best set of risk factors for the identification of low postpartum hematocrit levels.

RESULTS

From 1484 vaginal deliveries, 117 of the women (8%) had postpartum hematocrit levels of <26%. Estimated blood loss of >500 mL, Hispanic ethnicity, dizziness, or third- or fourth-degree laceration were the factors that identified 82.9% of the women with hematocrit levels of <26% and identified 97.4% of the women with hematocrit levels of <23%. Only 39.3% of the women would have required postpartum hematocrit measurement to obtain these detection rates.

CONCLUSION

Four risk factors (estimated blood loss of >500 mL, Hispanic ethnicity, dizziness, and third- or fourth-degree laceration) can safely determine the necessity of a postpartum hematocrit measurement.

Iron deficiency anemia: higher prevalence in Mexican American than in non-Hispanic white females in the third National Health and Nutrition Examination Survey, 1988-1994

BACKGROUND

Mexican American females have a higher prevalence of iron deficiency than do non-Hispanic white females.

OBJECTIVE

The objective was to estimate the prevalence of iron deficiency anemia and examine potential reasons for this difference between Mexican American (n = 1194) and non-Hispanic white (n = 1183) females aged 12-39 y.

DESIGN

We used data from the third National Health and Nutrition Examination Survey (1988-1994). Iron deficiency anemia was defined as abnormal results from >/=2 of 3 tests (erythrocyte protoporphyrin, transferrin saturation, and serum ferritin) and a low hemoglobin concentration. We used multiple logistic regression to adjust for factors that were more prevalent in Mexican American females and significantly associated with iron deficiency anemia.

RESULTS

The prevalence of iron deficiency anemia was 6.2 +/- 0.8% (f1.gif" BORDER="0"> +/- SE) in Mexican American females and 2.3 +/- 0.4% in non-Hispanic white females. Mean dietary iron intake, mean serum vitamin C concentrations, and the proportion of females using oral contraceptives were similar in the 2 groups. Age <20 y and education were not associated with iron deficiency anemia. After adjustment for poverty level, parity, and iron supplement use, the prevalence of iron deficiency anemia was 2.3 times higher in Mexican American than in non-Hispanic white females (95% CI: 1.4, 3.9). In those with a poverty income ratio (based on household income) >3.0, however, the prevalence of iron deficiency anemia was 2.6 +/- 0.9% in Mexican American and 1.9 +/- 0.6% in non-Hispanic white females (NS).

CONCLUSION

Although much of the ethnic disparity in iron deficiency anemia remains unexplained, factors associated with household income may be involved.

Iron deficiency in Massachusetts communities: Socioeconomic and demographic risk factors among children

OBJECTIVES

This study examined the association between community rates of iron deficiency in children and sociodemographic characteristics of Massachusetts communities.

METHODS

Between April 1990 and March 1991, 238 273 Mssachusetts children 6 through 59 months of age were screened; iron deficiency was defined as an erythrocyte protopophyrin concentration of 0.62 micromol/L or higher and a blood lead level of less than 1.2 micromol/L. Sociodemographic data were obtained from the 1990 US Census.

RESULTS

Five percent of communities had iron deficiency rates greater than 13.9 per 100 children screened. Iron deficiency rate was positively associated with proportion of Southeast Asians (odds ratio [OR] = 1.10, 95% confidence interval [CI] = 1.08, 1.12), proportion of Hispanics (OR = 1.008, 95% CI = 1.002, 1.013), and high school incompletion (OR = 1.028, 95% CI = 1.020, 1.035). Similarly, an examination of three Massachusetts cities indicated that the iron deficiency rate was higher for children with Southeast Asian (relative risk [RR] = 3.6, 95% CI = 3.3, 3.8) and Hispanic (RR = 1.6, 95% CI = 1.5, 1.8) surnames than for all other children.

CONCLUSIONS

Wide variation exists in iron deficiency rates for children in Massachusetts communities. Community iron deficiency was associated with low socioeconomic status and high proportions of Southeast Asians and Hispanics.

Methods to assess iron status in various NHANES surveys

This paper summarizes iron status measurements included in the three cross-sectional National Health and Nutrition Examination Surveys (NHANES) completed to date, as well as a special study of Hispanics, known as the Hispanic Health and Nutrition Examination Survey (HHANES). Approaches for defining iron status in the population based on these measurements are also described as well as issues in comparing iron status data between surveys, using NHANES II and III data as an example.

Susceptibility to environmental pollutants among minorities

Susceptibility to environmental pollutants involves both biological and nonbiological factors. Individuals belonging to minority groups are much more likely to be subject to a number of these factors. This paper examines biological susceptibility of minorities to environmental pollutants and provides specific examples of susceptibility resulting from: genetic makeup; occupation; other factors such as compromised health status, exposure to mixtures of pollutants, substance abuse, and unemployment; and social inequality of access to health care, education, and communication skills. Recommendations are made for specific actions and for additional studies.

Health status by social class and/or minority status: implications for environmental equity research

Much of the epidemiologic research in the United States has been based only on the categories of age, sex and race; thus, race has often been used in health statistics as a surrogate for social and economic disadvantage. Few multivariate analyses distinguish effects of components of social class (such as economic level) from the relative, joint, and independent effects of sociocultural identifiers such as race or ethnicity. This paper reviews studies of social class and minority status differentials in health, with a particular emphasis on health status outcomes which are known or suspected to be related to environmental quality and conditions which increase susceptibility to environmental pollutants. Sociodemographic data are presented for the U.S. population, including blacks, Asian American/Pacific Islanders, American Indian/Alaska Natives, and Hispanics. Four areas of health status data are addressed: mortality, health of women of reproductive age, infant and child health, and adult morbidity. Conceptual and methodological issues surrounding various measures of position in the system of social strata are discussed, including the multidimensionality of social class, in the context of the importance of these issues to public health research. Whenever possible, multivariate studies that consider the role of socioeconomic status in explaining racial/ethnic disparities are discussed.