Abstract: The Under-five mortality (U5M) rate is an important determinant of societal and national advancement- a key marker of wellbeing, value, and access. In spite of efforts to identify the predictors of U5M to reduce its high level in Nigeria, the problem remains a major cause for concern. This study estimated the potential role of unmeasured/unobserved factors at both family and community levels, using shared frailty models on the 2013 Nigeria Demographic and Health Survey (2013 NDHS) data. The Log-rank test was used to identify variables associated with U5M- hazard ratio estimates with P<0.05 were considered as statistically significant. Our findings suggested region, marital status, place of residence and place of delivery were significant determinants of U5M in both frailty models. We also found evidence of frailty effect on the risk, particularly at the community level- heterogeneity due to unmeasured/unobserved factors, which are generally ignored when we assess the risk using only observed variables. We, therefore, suggest that to achieve the sustainable development goals relating to child health in Nigeria, more significant efforts should be directed at identifying more determinants, such as to reduce the influence of unobserved factors and facilitate an extension of interventions to these factors.

Keywords:  Under-five mortality, Unobserved heterogeneity, Frailty model, Determinants, Nigeria.

Abstract: Context: Several decades of dietary research recommended the consumption of antioxidants and vitamins rich foods as a protective tool against a broad portfolio of diseases

Aims: This study aims to test if oral supplementation of natural antioxidants and vitamins before the winter season, may reduce the occurrence of upper respiratory tract infection (URTI) in adolescents.

Settings and Design: Natural antioxidants and vitamins supplements were given to 90 adolescents (45 males, and 45 females) from an orphanage against a placebo during three months in a double-blind fashion.

Methods and Material: Saliva was collected before and after supplementation. The antioxidant activity of saliva was determined in vitro using electrolysis as a free radical generating system. Additionally, total antioxidant activity, glutathione and ascorbic acid levels in the saliva were evaluated before and after supplementation. The URTI frequency was recorded throughout the winter season (3 months).

Statistical Analysis: All values were expressed as means ± SEM. Significance of the results was assessed using Student's t-test and Fisher’s test

Results: Data indicated that only five individuals from the group that received antioxidants and vitamins supplements manifested URTI while 14 adolescents from the non-supplemented group showed symptoms of URTI. Biochemical analysis revealed that the saliva in provenance from the supplemented group exhibited a higher capacity to scavenge free radicals compared to its capacity before supplementation. This supplementation also increased the total antioxidant activity and the levels of both ascorbic acid and glutathione in the saliva.

Conclusions: We concluded that oral intake of antioxidants and vitamins protects against URTI through increased antioxidant activity.

Keywords:  Antioxidants, vitamins, saliva, adolescents, upper respiratory tract infection (URTI).