Doctor of Philosophy in Human Nutrition (PhD)
Folic acid supplementation in children with sickle cell disease
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Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.
The WHO recommends 12 weeks daily iron supplementation for women in countries where anemia prevalence is ≥40%, such as in Cambodia. However, if iron deficiency is not a major cause of anemia, then, at best, untargeted iron supplementation is a waste of resources; at worst, it could cause harm. My aim was to assess the non-inferiority of 12 weeks of ferrous sulfate and ferrous bisglycinate supplementation on ferritin concentrations and the effect on gut inflammation concentrations in Cambodian women, as compared to placebo. A double-blind, three-arm, randomized controlled trial was conducted in Kampong Thom province, Cambodia. Non-pregnant women (n=480, 18-45 years) were randomized to receive 60 mg ferrous sulfate, 18 mg ferrous bisglycinate, or placebo. Non-fasting blood and stool samples were collected at baseline and 12 weeks. Ferritin was measured with an ELISA, and values were adjusted for inflammation. Fecal calprotectin was measured as an indicator of gut inflammation with use of an ELISA kit (BÜHLMANN fCAL®). Mixed-effects generalized linear models were used to assess the effect of the two iron interventions on ferritin and fecal calprotectin concentration at 12 weeks, as compared to placebo. A total of 480 women were enrolled with 88% (n=421) trial retention at 12 weeks. Our non-inferiority analysis was inconclusive to determine if ferrous bisglycinate was non-inferior to ferrous sulfate, as the CI for our predicted mean difference in ferritin concentrations between the two iron interventions crossed our ‘a priori’ defined margin of non-inferiority (20 μg/L). In a secondary analysis with use of a superiority approach, mean ferritin concentration at 12 weeks was significantly higher in the ferrous sulfate group (98.6 [94.7,102.6] µg/L, P
In populations where the prevalence of anemia is >20% in women of reproductive age, the World Health Organization (WHO) recommends weekly supplementation with 60 mg iron and 2.8 mg folic acid as an anemia prevention strategy. Folic acid was included in this weekly supplement not only for anemia prevention, but also to reduce the risk of neural tube defects (NTD) should a woman become pregnant. The dose of folic acid is equivalent to seven times the daily dose of folic acid shown to reduce the risk of NTDs in controlled trials (0.4 mg x 7 days = 2.8 mg). However, the majority of currently-used weekly supplements contain 0.4 mg of folic acid (the daily recommended dose in pregnancy). There is a lack of evidence to support if a weekly 2.8 mg dose of folic acid is more effective at raising red blood cell (RBC) folate concentrations to a level associated with a reduced risk of NTD (>748 nmol/L) than the current practice of weekly 0.4 mg folic acid. In this three-arm randomized controlled trial, we randomized n=331 non-pregnant Malaysian women (18-45 y) to receive 60 mg iron and either 2.8, 0.4, or 0 mg folic acid. RBC and plasma folate were measured at baseline, 16 weeks, and 4 weeks after the discontinuation of the intervention. Following 16 weeks of intervention, the primary outcome of mean RBC folate in the 2.8 mg folic acid per week group was significantly higher than the 0.4 mg and 0 mg groups [mean difference (95% CI) 271 (234, 309) and 355 (316, 394) nmol/L, respectively (P
Background: There is limited evidence regarding the potential risk of untargeted daily oral iron supplementation in women of reproductive age, especially in countries where genetic hemoglobinopathies are common and iron deficiency is not the major cause of anemia. Excess iron exposure can cause increased production of reactive oxygen species (ROS), which can lead to cellular (e.g. lipid, DNA) damage. Objective: The aim of this research was to retrospectively assess the effect of daily oral iron supplementation with 60 mg of elemental iron for 12 weeks, compared to placebo, on relative leukocyte telomere length (LTL) and mitochondrial DNA (mtDNA) content. Methods: In a double-blind randomized controlled trial, non-pregnant Cambodian women aged 18–45 years received 60 mg of elemental iron as ferrous sulphate (n = 201) or a placebo (n = 200) for 12 weeks. Relative LTL and mtDNA content were quantified in buffy coat collected at baseline and endline by monochrome multiplex quantitative polymerase chain reaction (MMqPCR) and the change in relative LTL and mtDNA content was determined. Results: Iron supplementation was not associated with an adjusted absolute or percent change in relative LTL after 12 weeks, compared to placebo (ß-coefficient: −0.04 [95% CI: −0.16, 0.08]; P = 0.50 and ß-coefficient: −0.96 [95% CI: −2.69, 0.77]; P = 0.28, respectively). However, iron supplementation was associated with a significantly smaller adjusted absolute and percent increase in mtDNA content after 12 weeks, compared to placebo (ß-coefficient: −11 [95% CI: −20, −2]; P = 0.02 and ß-coefficient: −11 [95% CI: −20, −1]; P = 0.02, respectively). Conclusions: Our findings suggest that daily oral iron supplementation with 60 mg of elemental iron for 12 weeks, as per the World Health Organization (WHO) global policy, may be associated with altered mitochondrial homeostasis. This is concerning and more research is needed to ascertain if there is potential risk associated with untargeted daily oral iron supplementation, to ultimately inform the safety of the WHO policy.