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Welcome to the NWU Repository, the open access Institutional Repository of the North-West University (NWU-IR). This is a digital archive that collects, preserves and distributes research material created by members of NWU. The aim of the NWU-IR is to increase the visibility, availability and impact of the research output of the North-West University through Open Access, search engine indexing and harvesting by several initiatives.

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Predictors of vitamin D status in undernourished and well-nourished children 6–59 months old, in the JB Marks Municipality of South Africa.
(Taylor and Francis Ltd., 2024) Carbooa, J.A; Malana , L; Lombarda , M; Malekaa, N; Malekaa, N; Claire Dolman-Macleoda, R
Objective: to investigate the predictors of vitamin D (vitD) status of undernourished and well-nourished children aged under five years in the North West Province of South Africa. Design: this cross-sectional study assessed sociodemographic data, nutritional supplement intake, vitD-rich food consumption, and sunlight exposure via a structured questionnaire. Venous blood samples were collected to evaluate vitD, iron, and inflammatory markers. Setting: the maternal and child wellness departments of six community clinics in the JB Marks Municipality. Participants: 121 undernourished and 51 well-nourished children, 6–59 months old. Results: The prevalence of serum 25 (OH) D< 30 ng/ml was 20.3%, 19.9%, and 21.6% in the total, undernourished, and wellnourished groups, respectively. The total mean 25 (OH) D concentration was 38.41±9.64 ng/ml. Age showed a negative association trend with 25 (OH) D in the well-nourished group (β:− 0.172, 95% CI− 0.353, 0.010, p= 0.063), while household income was inversely associated with 25 (OH) D (β=− 1.86, 95% CI=− 2.99,− 0.733, p= 0.001) in the total group. Among the undernourished children, iron-deficiency anaemia (IDA) was associated with almost five times greater odds for 25 (OH) D< 30 ng/ml (OR: 4.646, 95% CI 1.339, 16.123, p= 0.016). Intake of vitD supplements, therapeutic foods, multivitamins, and formula milk was associated with significantly higher 25 (OH) D concentrations and was adjusted for in subsequent analyses. Additionally, consumption of eggs more than once a month was associated with higher 25 (OH) D levels in the wellnourished children aged 24–59 months. Nutritional status, inflammation, and sunlight exposure were not associated with 25 (OH) D concentrations. Conclusion: vitD insufficiency exists in both the undernourished and the well-nourished. Age, egg consumption, and IDA should be considered in the correction of vitD insufficiency in children.
Regular moderate physical activity potentially accelerates and strengthens both the pro-inflammatory and pro-resolving lipid mediator response after acute exercise stress.
(Churchill Livingstone, 2024) Malan, Linda; Zandberg, Lizelle; Pienaar, Cindy; Nienaber, Arista; Havemann-Nel, Lize
The PUFA-derived lipid mediator response shifts from pro-inflammatory to inflammation resolution over time and may be modified by regular moderate exercise. This pre-post-test study aimed to compare the expression of PTGES2 (COX2) and ALOX15 in leucocytes and the plasma 5- and 15-HETE, 18-HEPE and 17-HDHA responses after unaccustomed resistance exercise between 18–35-year-old male recreational runners (n = 18) and lessactive controls (n = 15). One repetition maximum (1RM) was determined for squats, 45◦ leg presses and leg extensions. Subsequently three sets of 8–10 repetitions were performed at 80 % 1RM and blood collected over 72hours. PTGES2 and ALOX15 expression changed over time in runners (P = 0.016, P = 0.007) but not controls (P= 0.631, P = 0.539). 5- and 15-HETE changed over time in runners (P < 0.001, P = 0.022), but not controls (P =0.457, P = 0.985). 18-HEPE changed in runners and controls (P < 0.001, P = 0.024), 17-HDHA changed borderline in runners (P = 0.076). In conclusion, pro-inflammatory and inflammation-resolving lipid mediators may respond sooner and more robust in recreational runners than less-active controls after strenuous resistance exercise.
Relationships between Iron Status and Selected Physical Fitness Components of South African Adolescents: The PAHL-Study.
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Monyeki, Makama Andries; Veldsman, Tamrin; Coetzee, Ben; Sparks, Martinique; Moss, Sarah Johanna; Pienaar, Cindy; Swanepoel, Mariette; Malan, Linda; Kruger, Herculina Salome
Poor iron status is detrimental to physical and cognitive performance in adolescents. Due to the limited studies investigating the association between iron status and physical fitness components in adolescents from low- and middle-income countries, we aimed to determine the association of iron status with selected physical fitness components in South African adolescents. A cross-sectional study design, including 178 adolescents (102 girls and 76 boys) from the Physical Activity and Health Longitudinal Study (PAHLS), was followed. Height and weight were measured to calculate the body mass index (BMI). Subsequently, WHO BMI-for-age-specific categorised body fatness. Cardiorespiratory fitness was determined with a 20-m shuttle run test (V˙O2max), and lower-body explosive power by the standing broad jump (SBJ). Fasting haemoglobin (Hb) and ferritin were analysed from blood samples. Correlation analyses determine the association between iron status, explosive power and cardiorespiratory fitness. Of the 178 participants, 18.5% (n = 33) had low Hb, and 14% (n = 25) iron deficiency without anaemia. Significant positive correlations were found between the selected physical fitness components, ferritin, and Hb. In boys, a positive association was found between Hb and SBJ (r = 0.30, p = 0.006), whilst in girls, positive associations were found between ferritin (r = 0.25, p = 0.04) and SBJ, and Hb with both SBJ (r = 0.21, p = 0.03) and V˙O2max (r = 0.32, p = 0.001). Hb concentration remained associated with V˙O2max and SBJ in girls after adjustment for age, whilst in boys, Hb concentration was associated with SBJ. Higher iron status in South African adolescents is associated with higher lower-limb explosive power and cardiorespiratory fitness. We suggest monitoring of haematological parameters, and interventions to improve the iron status of South African adolescents.
High-dose oral vitamin D supplementation for prevention of infections in children aged 0 to 59 months: a systematic review and meta-analysis.
(Oxford University Press, 2024) Janet Adede Carboo; Robin Claire Dolman-Macleod; Linda Malan; Martani Johanni Lombard
Context Vitamin D plays an important role in immune function, and the deficiency thereof has been associated with several infections, most notably respiratory tract infections. However, data from intervention studies investigating the effect of high-dose vitamin D supplementation on infections have been inconclusive. Objective The aim of this study was to evaluate the level of evidence regarding the efficacy of vitamin D supplementation above the standard dose (400 IU) in preventing infections in apparently healthy children < 5 years of age. Data Sources PubMed, Scopus, Science Direct, Web of Science, Google Scholar, CINAHL, and MEDLINE electronic databases were searched between August 2022 and November 2022. Seven studies met the inclusion criteria. Data Extraction Meta-analyses of outcomes in more than one study were performed using Review Manager software. Heterogeneity was evaluated using the I2 statistic. Randomized controlled trials in which vitamin D was supplemented at > 400 IU compared with placebo, no treatment, or standard dose were included. Data Analysis Seven trials that enrolled a total of 5748 children were included. Odds ratios (ORs) with 95%CIs were calculated using random- and fixed-effects models. There was no significant effect of high-dose vitamin D supplementation on the incidence of upper respiratory tract infection (OR, 0.83; 95%CI, 0.62–1.10). There was a 57% (95%CI, 0.30–0.61), 56% (95%CI, 0.27–0.07), and 59% (95%CI, 0.26–0.65) reduction in the odds of influenza/cold, cough, and fever incidence, respectively, with daily supplementation of vitamin D > 1000 IU. No effect was found on bronchitis, otitis media, diarrhea/gastroenteritis, primary care visits for infections, hospitalizations, or mortality. Conclusion High-dose vitamin D supplementation provided no benefit in preventing upper respiratory tract infections (moderate certainty of evidence) but reduced the incidence influenza/cold (moderate certainty of evidence), cough, and fever (low certainty of evidence). These findings are based on a limited number of trials and should be interpreted with caution. Further research is needed.
Comparison of test performance of two commonly used multiplex assays to measure micronutrient and inflammatory markers in serum: results from a survey among pregnant women in South Africa.
(Cambridge University Press, 2024) Chimhashu, Tsitsi Letwin; Verhoef, Hans; Symington, Elizabeth A.; Zandberg, Lizelle; Baumgartner, Jeannine; Malan, Linda; Smuts, Cornelius Marius; Feskens, Edith J. M; Melse-Boonstra, Alida
The combined sandwich-ELISA (s-ELISA; VitMin Lab, Germany) and the Quansys Q-Plex™ Human Micronutrient Array (7-Plex) are multiplex serum assays that are used to assess population micronutrient status in low-income countries. We aimed to compare the agreement of five analytes, α-1-acid glycoprotein (AGP), C-reactive protein (CRP), ferritin, retinol-binding protein 4 (RBP4) and soluble transferrin receptor (sTfR) as measured by the 7-Plex and the s-ELISA. Serum samples were collected between March 2016 and December 2017. Pregnant women (n 249) were recruited at primary healthcare clinics in Johannesburg, and serum samples were collected between March 2016 and December 2017. Agreement between continuous measurements was assessed by Bland–Altman plots and concordance measures. Agreement in classifications of deficiency or inflammation was assessed by Cohen’s kappa. Strong correlations (r > 0·80) were observed between the 7-Plex and s-ELISA for CRP and ferritin. Except for CRP, the 7-Plex assay gave consistently higher measurements than the s-ELISA. With the exception of CRP (Lin’s ρ = 0·92), there was poor agreement between the two assays, with Lin’s ρ < 0·90. Discrepancies of test results difference between methods increased as the serum concentrations rose. Cohen’s kappa for all the five analytes was < 0·81 and ranged from slight agreement (vitamin A deficiency) to substantial (inflammation and Fe deficiency) agreement. The 7-Plex 1.0 is a research and or surveillance tool with potential for use in low-resource laboratories but cannot be used interchangeably with the s-ELISA. Further optimising and validation is required to establish its interchangeability with other validated methods.