Iron-Containing Oral Contraceptives and Their Effect on Hemoglobin and Biomarkers of Iron Status: A Narrative Review

The concentration of hemoglobin is associated with the dietary iron availability, food insecurity and the use of oral contraceptives among women in socially vulnerable areas of a capital city in northeastern Brazil

This study aimed to assess hemoglobin concentration and its association with oral contraceptive (OC) use, food insecurity (FI) and dietary iron availability (DIA) in adult women of reproductive age (20-44 years). This is a population-based cross-sectional study that analysed 505 women living in favelas and urban communities in a capital city in northeastern Brazil. Hemoglobin concentration was determined using capillary blood samples. FI and DIA were assessed using the Brazilian Food Insecurity Scale and the 24-h food recall, respectively. Association analysis was carried out using logistic regression. A directed acyclic graph (DAG) was designed to illustrate the causal paths between hemoglobin concentration and DIA. A significance level of 5 % was adopted. Low hemoglobin concentrations (11·2 g/dl: (1·79)) and a high prevalence of anaemia (64·0 %) were observed; 28·7 % used OC (28·7 %) and 76·4 % were in FI. An average energetic intake of 1495 kcal/d (482·0) and 0·46 mg/d (0·27) of DIA were also observed. In the DAG-guided multivariable analysis, it was observed that hemoglobin concentrations ≥ 12 mg/dl were directly associated with higher DIA (OR: 1·67; 95 % CI (1. 08, 2·59)) and OC use (OR: 1·67; 95 % CI (1·10, 2·55)) and inversely associated with mild FI (OR: 0·60; 95 % CI (0·37, 0·96)) or severe FI (OR: 0·37; 95 % CI: (0·18, 0·76)). Women taking OC and with a higher DIA were less likely to have low hemoglobin concentrations, while those in the context of FI were in the opposite situation.

Determinants of anemia level among reproductive-age women in 29 Sub-Saharan African countries: A multilevel mixed-effects modelling with ordered logistic regression analysis

BACKGROUND

Despite the implementation of different nutritional and non-nutritional interventions, 43% of reproductive-age women in Africa suffer from anemia. Recent evidence also shows that none of the Sub-Saharan African (SSA) countries are on the track to achieve the nutrition target of 50% anemia reduction by 2030. To date, information on the level of anemia and its determinants among reproductive-age women at the SSA level is limited. Thus, this study aimed to estimate the pooled prevalence of anemia level and its determinants in SSA countries.

METHODS

We used a pooled data of 205,627 reproductive-age women from the recent demographic and health surveys of 29 SSA countries that were conducted between 2010-2021. A multilevel mixed-effects analysis with an ordered logistic regression model was fitted to identify determinants of anemia level and the deviance value was used to select the best-fitted model. First, bivariable ordinal logistic regression analysis was done and the proportional odds assumption was checked for each explanatory variable using a Brant test. Finally, in a multivariable multilevel ordinal logistic regression model, a p-value<0.05 and AOR with the corresponding 95% CI were used to identify determinants of anemia level. All analyses were done using Stata version 17 software.

RESULTS

The pooled prevalence of anemia among women of reproductive age in SSA was 40.5% [95% CI = 40.2%-40.7%], where 24.8% [95% CI: 24.6%-25.0%], 11.1% [95% CI = 10.9%-11.2%], and 0.8% [95% CI = 0.7%-0.8%] had mild, moderate, and severe anemia, respectively. The prevalence significantly varied from the lowest of 13% in Rwanda to the highest of 62% in Mali, and anemia was found as a severe public health problem (prevalence of ≥ 40%) in 18 countries. The regression result revealed that polygamous marriage, women and husband illiteracy, poor household wealth, shorter birth interval, non-attendance of antenatal care, underweight, unimproved toilet and water facilities, and low community-level women literacy were positively linked with high anemia level. Additionally, the likelihood of anemia was lower in women who were overweight and used modern contraception.

CONCLUSIONS

Overall results showed that anemia among women of reproductive age is a severe public health problem in SSA countries, affecting more than four in ten women. Thus, enhancing access to maternal health services (antenatal care and contraception) and improved sanitation facilities would supplement the existing interventions targeted to reduce anemia. Moreover, strengthening women's education and policies regulating the prohibition of polygamous marriage are important to address the operational constraints.

The role of iron metabolism in chronic diseases related to obesity

Obesity is one of the major public health problems threatening the world, as well as a potential risk factor for chronic metabolic diseases. There is growing evidence that iron metabolism is altered in obese people, however, the highly refined regulation of iron metabolism in obesity and obesity-related complications is still being investigated. Iron accumulation can affect the body’s sensitivity to insulin, Type 2 diabetes, liver disease and cardiovascular disease. This review summarized the changes and potential mechanisms of iron metabolism in several chronic diseases related to obesity, providing new clues for future research.