Calcium Intake and Iron Status in Human Studies: A Systematic Review and Dose-Response Meta-Analysis of Randomized Trials and Crossover Studies.

BACKGROUND: The interaction between dietary (and supplementary) divalent ions has been a long-standing issue in human nutrition research. Developing an optimal calcium and iron supplementation recommendation requires detailed knowledge of the potential trade-offs between: 1) the clinical effects of concurrent intake on iron absorption and hematological indices; and 2) the potentially negative effects of separated ingestion on adherence to iron and/or calcium supplements. Human clinical studies have examined the effects of calcium intake on iron status, but there are no meta-analyses or recent reviews summarizing the findings. OBJECTIVES: To synthesize peer-reviewed, human, randomized, and cross-over studies on effects of calcium consumption on iron indices without age, gender, or any other restrictions. METHODS: Weighted mean differences for total, heme, and nonheme iron absorption (%) and serum ferritin (µg/L) were obtained from pooled analysis of the highest daily calcium intake compared to the lowest daily calcium intake. RESULTS: The negative effect of calcium intake was statistically significant in short-term iron absorption studies, but the effect magnitude was low [weighted mean difference (WMD) = -5.57%; 95% CI: -7.09 to -4.04]. The effect of calcium on the iron status was mixed. The inverse dose-response association of calcium intake with the serum ferritin concentration was significant (P value = 0.0004). There was, however, no reduction in the hemoglobin concentration (WMD = 1.22g/L;  95% CI:  0.37-2.07). CONCLUSIONS: The existing body of studies is insufficient to make recommendations with high confidence due to heterogeneity in designs, limitations of ferritin as an iron biomarker, and a lack of intake studies in pregnant women. Prescribing separation of prenatal calcium and iron supplements in free-living individuals is unlikely to affect the anemia burden. There is a need for effectiveness trials comparing the effects of prescribing separated intake to concurrent intake, with functional endpoints as primary outcomes and adherence to each supplement as intermediate outcomes.

Will Africans take COVID-19 vaccination?

The economic and humanistic impact of COVID-19 pandemic is enormous globally. No definitive treatment exists, hence accelerated development and approval of COVID-19 vaccines, offers a unique opportunity for COVID-19 prevention and control. Vaccine hesitancy may limit the success of vaccine distribution in Africa, therefore we assessed the potentials for coronavirus vaccine hesitancy and its determinants among Africans. An online cross-sectional African-wide survey was administered in Arabic, English, and French languages. Questions on demographics, self-reported health status, vaccine literacy, knowledge and perception on vaccines, past experience, behavior, infection risk, willingness to receive and affordability of the SARS-COV-2 vaccine were asked. Data were subjected to descriptive and inferential statistics. A total of 5,416 individuals completed the survey. Approximately, 94% were residents of 34 African countries while the other Africans live in the Diaspora. Only 63% of all participants surveyed were willing to receive the COVID-19 vaccination as soon as possible and 79% were worried about its side effects. Thirty-nine percent expressed concerns of vaccine-associated infection. The odds of vaccine hesitancy was 0.28 (95% CI: 0.22, 0.30) among those who believed their risk of infection was very high, compared to those who believed otherwise. The odds of vaccine hesitancy was one-fifth (OR = 0.21, 95% CI: 0.16, 0.28) among those who believed their risk of falling sick was very high, compared to those who believed their risk of falling very sick was very low. The OR of vaccine hesitancy was 2.72 (95% CI: 2.24, 3.31) among those who have previously refused a vaccine for themselves or their child compared to counterparts with no self-reported history of vaccine hesitancy. Participants want the vaccines to be mandatory (40%), provided free of charge (78%) and distributed in homes and offices (44%). COVID-19 vaccine hesitancy is substantial among Africans based on perceived risk of coronavirus infection and past experiences.

Knowledge, attitude and Perception Regarding Risk Factors of Overweight and Obesity Among Secondary School Students in Ikeja Local Government Area, Nigeria.

CONTEXT: Childhood obesity has risen dramatically in the last four decades. Childhood obesity is likely to continue through adulthood and increases the risk of non-communicable diseases later in life. AIMS: This study assessed the knowledge, attitude, and perception of the secondary school students in Ikeja local government, Lagos state towards the risk factors of overweight and obesity. METHODS AND MATERIALS: This descriptive cross-sectional study was carried out using a structured questionnaire administered on consenting participants. The completed questionnaires collected from the participants was then analyzed. STATISTICAL ANALYSIS USED: Data were analyzed using SPSS version 22.0. RESULTS: The prevalence of overweight and obesity were 6.6% and 1.4%. Overall knowledge (<50%) of students regarding the risk factors of overweight and obesity was very low. Majority of the students (97.4%) do daily exercise, 48.4% spend at least 30 minutes doing exercise daily. However, 62.0% watching television, 18.7% play video games, and 35.8% sleep for more than 8 hours daily. Participants also showed negative perception towards the effects of overweight and obesity. There was a significant association between age, gender, class, and body mass with knowledge, attitude, and perception of respondents towards risk factors and effects of overweight and obesity (P < 0.05). CONCLUSIONS: Despite the low prevalence of overweight and obesity, low knowledge, poor attitude and negative perception regarding risk factors of overweight and obesity, the majority of the students perceived regular exercise as an important means of reducing overweight and obesity.