Malaria infection confounds inflammation-adjusted micronutrient biomarker concentrations in children and women in Malawi: a secondary analysis of the 2015/2016 Malawi micronutrient survey

Abstract

Inflammation and infections such as malaria affect concentrations of many micronutrient biomarkers and hence estimates of nutritional status. We aimed to assess the relationship between malaria infection and micronutrient biomarker concentrations in pre-school children (PSC), school-age children (SAC) and women of reproductive age (WRA) in Malawi and examine the potential role of malarial immunity on the relationship between malaria and micronutrient biomarkers. Data from the 2015/2016 Malawi micronutrient survey were used. The associations between current or recent malaria infection, detected by rapid diagnostic test and concentration of serum ferritin, soluble transferrin receptor (sTfR), zinc, serum folate, red blood cell folate and vitamin B₁₂ were estimated using multivariable linear regression. Factors related to malarial immunity including age, altitude and presence of hemoglobinopathies were examined as effect modifiers. Serum ferritin, sTfR and zinc were adjusted for inflammation using the BRINDA method. Malaria infection was associated with 68 % (95 % CI 51, 86), 28 % (18, 40) and 34 % (13, 45) greater inflammation-adjusted ferritin in PSC, SAC and WRA, respectively (P < 0·001 for each). In PSC, the positive association was stronger in younger children, high altitude and children who were not carriers of the sickle cell trait. In PSC and SAC, sTfR was elevated (+ 25 % (16, 29) and + 15 % (9, 22) respectively, P < 0·001). Serum folate and erythrocyte folate were elevated in WRA with malaria (+ 18 % (3, 35) and + 11 % (1, 23), P = 0·01 and P = 0·003 respectively). Malaria affects the interpretation of micronutrient biomarker concentrations, and examining factors related to malarial immunity may be informative.

Keywords: Ferritin; Folate; Inflammation; Malaria; Micronutrient biomarkers.

Figure 1.

Identification of variables used to define malarial immunity in children and adults in the 2015 Malawi micronutrient survey. G6PD, glucose 6 phosphate dehydrogenase; ITTN, insecticide-treated nets; IRS, indoor residual spraying.

Figure 2.

Difference in ferritin concentration (on the log scale) between pre-school (PSC) children with and without malaria infection ((a) n 1084) and school-age children (SAC) with and without malaria infection ((b) n 743) in different sub-groups of interest in the 2015/2016 Malawi micronutrient survey.