Changes in hemoglobin levels with age and altitude in preschool-aged children in Peru: the assessment of two individual-based national databases

Evaluation of dietary composition between hemoglobin categories, total body iron content and adherence to multi-micronutrients in preschooler residents of the highlands of Puno, Peru

BACKGROUND

The anemia prevalence is higher in highlands populations. It is assumed that iron deficiency anemia (IDA) in children is mainly due to low dietary intake. However, other suggest that high prevalence of anemia is due to an inappropriate hemoglobin (Hb) adjustment for altitude.

MATERIALS AND METHODS

Cross-sectional study conducted in 338 preschoolers (PSC) from Puno-Peru. Hb was measured in whole blood, and ferritin, Soluble transferrin receptor, and Interleukin 6 in serum.The dietary iron intake was assessed by 24-h dietary recall, using NutriCap Software. Hb concentration was assessed as adjusted or unadjusted for altitude.

RESULTS

With unadjusted Hb, the anemia prevalence was 4.7%, whereas after Hb correction, the prevalence raised-up to 65.6% (p < 0.001). Reciprocally, erythrocytosis proportion decreased from 20.35 to 0.30% (p < 0.001). Total Body Iron (TBI) showed that 7.44% had ID and 0.32% had IDA. PSC with normal unadjusted Hb levels have more protein and micronutrients intake than anemic ones. PSC with erythrocytosis consumed less fat, and more niacin and ascorbic acid than anemics. Total iron intake was lower in anemic than the other groups, but without statistical significance due to the standard deviation of the data in a small number of anemic PSC (n = 16). TBI, unadjusted Hb, and adjusted Hb were not different between groups consuming or not multimicronutrients.

CONCLUSIONS

The consumption of iron and iron status in children who live at high altitude is adequate, and that anemia could be due to other micronutrient deficiencies and/or that the adjustment of Hb by altitude is inappropriate.

Micronutrient Status and Other Correlates of Hemoglobin among Children with Stunting: A Cross-Sectional Study in Uganda

In low-income countries, undernutrition and infections play a major role in childhood anemia. Stunted children may be at particular risk of anemia. In a cross-sectional study nested in a nutrition trial among 12-59-month-old stunted children in eastern Uganda, we measured hemoglobin (Hb) and markers of iron, cobalamin, folate and vitamin A status. We assessed low micronutrient status, socio-demography, stunting severity, inflammation and malaria as correlates of Hb and anemia using linear and logistic regression analyses, respectively. Of 750 stunted children, the mean ± SD age was 32.0 ± 11.7 months and 55% (n = 412) were male. The mean Hb was 104 ± 15 g/L and 65% had anemia, Hb < 110 g/L. In a multivariable model with age, sex and inflammation, the following were associated with lower Hb: serum ferritin < 12 µg/L (-5.6 g/L, 95% CI: -8.6; -2.6), transferrin receptors > 8.3 mg/L (-6.2 g/L, 95% CI: -8.4; -4.0), plasma folate <20 nmol/L (-4.6 g/L, 95% CI: -8.1;-1.1), cobalamin < 222 pmol/L (-3.0 g/L, 95% CI: -5.4; -0.7) and serum retinol-binding protein < 0.7 µmol/L (-2.0 g/L, 95% CI: -4.1; 0.2). In addition, severe stunting, inflammation and malaria were negative correlates. Anemia is common among stunted children in eastern Uganda; micronutrient deficiencies, inflammation and malaria are associated with low Hb.

Association between hemoglobin and elevation among school-aged children: a verification of proposed adjustments

BACKGROUND

Anemia is defined by a hemoglobin (Hb) concentration lower than normal based on cutoffs specific to age, sex, and pregnancy status. Hemoglobin increases with elevation as an adaptive response to lower blood oxygen saturation, thus, adjusting Hb concentration for elevation is necessary before applying cutoffs.

OBJECTIVE

Recent evidence among preschool-aged children (PSC) and non-pregnant reproductive-aged women (WRA) suggests that current World Health Organization (WHO) recommended Hb adjustments for elevation need updating. To confirm these findings, we examined the cross-sectional association between Hb and elevation among non-pregnant school-age children (SAC).

METHODS

Using data from 9 population-based surveys, we examined 26,518 SAC 5-14 years (54.5% female) with data on Hb and elevation (-6 to 3,834 meters, m). We used generalized linear models to assess the association between Hb and elevation under varying conditions, including controlling for inflammation-corrected iron and vitamin A deficiency. Hemoglobin adjustments for each 500 m increase in elevation were estimated for SAC and compared to existing adjustments and those estimated for PSC and WRA. We evaluated the impact of adjustments on anemia prevalence.

RESULTS

Hemoglobin concentration (g/L) was positively associated with elevation (m). The SAC elevation adjustments were consistent with those reported among PSC and WRA and suggest current recommendations may under-adjust Hb for those residing at lower elevations (<3000 m) and over-adjust Hb for those residing at higher elevations (>3000 m). Among the surveys included, proposed elevation adjustments increased anemia prevalence among SAC by 0 (Ghana, United Kingdom) to 15 (Malawi) percentage points relative to current elevation adjustments.

CONCLUSION

Results confirm that current recommended Hb adjustments for elevation may need updating, and anemia prevalence in SAC may be higher than currently estimated. Findings will inform the WHO reexamination of global guidelines on the use of Hb adjustments for anemia assessment and may result in improved identification and treatment of anemia.

High prevalence of malnutrition and vitamin A deficiency among schoolchildren of rural areas in Malaysia using a multi-school assessment approach

Childhood malnutrition is known as a public health concern globally. The present study aims to assess the anthropometry and blood biochemical status of rural primary schoolchildren in Malaysia. A total of 776 children (7-11 years old) from ten rural primary schools from five states were included in this study. Nutritional outcomes were assessed based on sex, age group and school categories among the children (median age: 9 years (P25:8, P75:10)). The overall prevalence of malnutrition was 53·4 %. Vitamin A deficiency (VAD) was recorded at 20·6 and 39·8 % based on retinol and retinol-binding protein (RBP) levels, respectively. Anaemia, iron deficiency (ID), iron-deficiency anaemia (IDA) and elevated inflammation were found at 14·9, 17·9, 9·1 and 11·5 %, respectively. Malnutrition, VAD, anaemia, ID, IDA and elevated inflammation were more prevalent among Orang Asli (OA) schoolchildren compared with Non-Orang Asli schoolchildren. Higher occurrences of VAD and anaemia were also found among children aged <10 years. Retinol, RBP, α-carotene, ferritin and haemoglobin levels were lower among undernourished children. Besides, overweight/obese children exhibited a higher level of high-sensitivity C-reactive protein. Multivariate analysis demonstrated that OA school children (adjusted OR (AOR): 6·1; 95 % CI 4·1, 9·0) and IDA (AOR: 3·6; 95 % CI 1·9, 6·6) were associated with stunting among this population. The present study revealed that malnutrition, micronutrient deficiencies and anaemia are prevalent among rural primary schoolchildren in Malaysia, especially those from OA schools and younger age children (<10 years). Hence, more appropriate and targeted measures are needed to improve the nutritional status of these children.

A Critical Analysis of the Automated Hematology Assessment in Pregnant Women at Low and at High Altitude: Association between Red Blood Cells, Platelet Parameters, and Iron Status

The objectives of the study were to determine differences in the parameters of red blood cells (RBC), white blood cells (WBC), and platelets at low altitude (LA) and at high altitude (HA) and with the gestation being advanced, and to determine correlations between parameters of RBC and platelets. We also studied the association of RBC and platelets with markers of iron status. In addition, markers of iron status and inflammation were measured and compared at each trimester of gestation in pregnant women at LA and HA. A cross-sectional comparative study was conducted at Lima (150 m above sea level) and Cusco at 3400 m above sea level from May to December 2019. Hematological parameters in pregnant women (233 at LA and 211 at HA) were analyzed using an automated hematology analyzer. Serum ferritin levels, soluble transferrin receptor (sTfR), hepcidin, erythropoietin, testosterone, estradiol, and interleukin-6 (IL6) levels were measured by ELISA. One-way ANOVA supplemented with post hoc test, chi-square test, and Pearson correlation test statistical analyses were performed. p < 0.05 was considered significant. Pregnant woman at HA compared to LA had significantly lower WBC (p < 0.01), associated with higher parameters of the RBC, except for the mean corpuscular volume (MCV) that was no different (p > 0.05). Platelets and mean platelet volume (MPV) were higher (p < 0.01), and platelet distribution width (PDW) was lower at HA than at LA (p < 0.01). A higher value of serum ferritin (p < 0.01), testosterone (p < 0.05), and hepcidin (p < 0.01) was observed at HA, while the concentration of sTfR was lower at HA than at LA (p < 0.01). At LA, neutrophils increased in the third trimester (p < 0.05). RBC parameters decreased with the progress of the gestation, except RDW-CV, which increased. The platelet count decreased and the MPV and PDW were significantly higher in the third trimester. Serum ferritin, hepcidin, and serum testosterone decreased, while sTfR and serum estradiol increased during gestation. At HA, the WBC and red blood cell distribution width- coefficient of variation (RDW-CV), PCT, and serum IL-6 did not change with gestational trimesters. RBC, hemoglobin (Hb), hematocrit (Hct), mean corpuscular hemoglobin concentration (MCHC), and platelet count were lower as gestation advanced. MCV, MPV, and PDW increased in the third trimester. Serum ferritin, testosterone, and hepcidin were lower in the third trimester. Serum estradiol, erythropoietin, and sTfR increased as gestation progressed. Direct or inverse correlations were observed between RBC and platelet parameters and LA and HA. A better number of significant correlations were observed at HA. Hb, Hct, and RDW-CV showed a significant correlation with serum ferritin at LA and HA. Of these parameters, RDW-CV and PDW showed an inversely significant association with ferritin (p < 0.05). In conclusion, a different pattern was observed in hematological markers as well as in iron status markers between pregnant women at LA and HA. In pregnant women a significant correlation between several RBC parameters with platelet marker parameters was also observed. Data suggest that pregnant women at HA have adequate iron status during pregnancy as reflected by higher serum ferritin levels, lower sTfR levels, and higher hepcidin values than pregnant women at LA.