Analysing the nutrition-disease nexus: the case of malaria

Does anthropometric status at 6 months predict the over-dispersion of malaria infections in children aged 6-18 months? A prospective cohort study

BACKGROUND

In malaria-endemic settings, a small proportion of children suffer repeated malaria infections, contributing to most of the malaria cases, yet underlying factors are not fully understood. This study was aimed to determine whether undernutrition predicts this over-dispersion of malaria infections in children aged 6-18 months in settings of high malaria and undernutrition prevalence.

METHODS

Prospective cohort study, conducted in Mangochi, Malawi. Six-months-old infants were enrolled and had length-for-age z-scores (LAZ), weight-for-age z-scores (WAZ), and weight-for-length z-scores (WLZ) assessed. Data were collected for 'presumed', clinical, and rapid diagnostic test (RDT)-confirmed malaria until 18 months. Malaria microscopy was done at 6 and 18 months. Negative binomial regression was used for malaria incidence and modified Poisson regression for malaria prevalence.

RESULTS

Of the 2723 children enrolled, 2561 (94%) had anthropometry and malaria data. The mean (standard deviation [SD]) of LAZ, WAZ, and WLZ at 6 months were - 1.4 (1.1), - 0.7 (1.2), and 0.3 (1.1), respectively. The mean (SD) incidences of 'presumed', clinical, and RDT-confirmed malaria from 6 to 18 months were: 1.1 (1.6), 0.4 (0.8), and 1.3 (2.0) episodes/year, respectively. Prevalence of malaria parasitaemia was 4.8% at 6 months and 9.6% at 18 months. Higher WLZ at 6 months was associated with lower prevalence of malaria parasitaemia at 18 months (prevalence ratio [PR] = 0.80, 95% confidence interval [CI] 0.67 to 0.94, p = 0.007), but not with incidences of 'presumed' malaria (incidence rate ratio [IRR] = 0.97, 95% CI 0.92 to 1.02, p = 0.190), clinical malaria (IRR = 1.03, 95% CI 0.94 to 1.12, p = 0.571), RDT-confirmed malaria (IRR = 1.00, 95% CI 0.94 to 1.06, p = 0.950). LAZ and WAZ at 6 months were not associated with malaria outcomes. Household assets, maternal education, and food insecurity were significantly associated with malaria. There were significant variations in hospital-diagnosed malaria by study site.

CONCLUSION

In children aged 6-18 months living in malaria-endemic settings, LAZ, WAZ, and WLZ do not predict malaria incidence. However, WLZ may be associated with prevalence of malaria. Socio-economic and micro-geographic factors may explain the variations in malaria, but these require further study. Trial registration NCT00945698. Registered July 24, 2009, https://clinicaltrials.gov/ct2/show/NCT00945698 , NCT01239693. Registered Nov 11, 2010, https://clinicaltrials.gov/ct2/show/NCT01239693.

Beyond causes of death: The social determinants of mortality among children aged 1-59 months in Nigeria from 2009 to 2013

Background

Millions of children worldwide suffer and die from conditions for which effective interventions exist. While there is ample evidence regarding these diseases, there is a dearth of information on the social factors associated with child mortality.

Methods

The 2014 Verbal and Social Autopsy Study was conducted based on a nationally representative sample of 3,254 deaths that occurred in children under the age of five and were reported on the birth history component of the 2013 Nigerian Demographic and Health Survey. We conducted a descriptive analysis of the preventive and curative care sought and obtained for the 2,057 children aged 1–59 months who died in Nigeria and performed regional (North vs. South) comparisons.

Results

A total of 1,616 children died in the northern region, while 441 children died in the South. The majority (72.5%) of deceased children in the northern region were born to mothers who had no education, married at a young age, and lived in the poorest two quintiles of households. When caregivers first noticed that their child was ill, a median of 2 days passed before they sought or attempted to seek healthcare for their children. The proportion of children who reached and departed from their first formal healthcare provider alive was greater in the North (30.6%) than in the South (17.9%) (p<0.001). A total of 548 children were moderately or severely sick at discharge from the first healthcare provider, yet only 3.9%-18.1% were referred to a second healthcare provider. Cost, lack of transportation, and distance from healthcare facilities were the most commonly reported barriers to formal care-seeking behavior.

Conclusions

Maternal, household, and healthcare system factors contributed to child mortality in Nigeria. Information regarding modifiable social factors may be useful in planning intervention programs to promote child survival in Nigeria and other low-income countries in sub-Saharan Africa.