In this cohort of 2500 infants, 152 participants died with nearly two thirds of them dying in their first year of life. Severe anaemia, malaria, diarrhoeal disease and pneumonia were the top causes of death.
Mortality
The overall two year crude mortality and the study infant mortality rate for this cohort were 60.8/1000 and 40/1000 respectively. However, the study infant mortality rate was much lower than the infant mortality (IMR) of 74/1000 expected in the region because the study missed most of the neonatal deaths (the median cohort enrolment age was 19 days). Findings from previous studies done in Uganda have shown that neonatal deaths constitute 40% of all infant deaths [1]. This is supported by a situation analysis of newborn health in Uganda in which neonatal mortality rate was estimated at 29/1000 vis-à-vis an IMR of 76/1000 [5]. By extrapolation therefore, this would put the actual IMR (including neonatal deaths) for this cohort at about 69/1000 live births which though slightly lower, is not significantly different from the overall country and region rates of 76/1000 and 74/1000 respectively [1]. This probably indicates that the mortality reduction activities that were implemented in the study participants did not have much effect on the overall child mortality in this cohort. The 2 year crude mortality cannot be compared to under-five mortality rates, since we did not follow the infants until age of five.
Causes of mortality
Our results showed anaemia, malaria, diarrhoeal diseases and pneumonia to be the leading causes of death in this cohort. This follows a pattern similar to that observed nationally [2]. There were no deaths directly attributable to tuberculosis except for one death where TB was assigned as a probable underlying cause of death. This contrasts with findings from a hospital based descriptive necropsy study done in Zambia in which TB accounted for 11% of respiratory infection deaths in the HIV-infected and 17% in the HIV-negative children aged 0 – 17 months [6]. The higher number of TB cases identified in the Zambia study was probably because it was hospital based. Secondly, the difference could be in the method used to investigate the cause of death which included an autopsy in the Zambian study. It is possible that we under-diagnosed tuberculosis in our study cohort, although we did very thorough investigations that are usually not done in this setting.
Anaemia is common among Ugandan children as indicated by findings from a study done in Uganda which showed that 73% of children aged 6–59 months have anaemia. The study further indicated that in the eastern region of Uganda, 80% of children in this age group had anaemia [2]. These findings give an indication of the burden of anaemia among infants and children in our study area. Similar to what has been reported previously, anaemia was the top cause of death in our study cohort. The underlying cause of anaemia has largely been assumed to be malaria, since most of Uganda is malaria endemic. However, in another study done on iron deficiency anaemia in Uganda, iron deficiency was found to be a significant underlying cause for anaemia in this age group. It was estimated that nearly half of the anaemia in children is due to iron-deficiency and the other half due to other causes such as malaria and worm infestation [2, 7].
Health seeking behaviour
Most of the children who died sought care from a health facility for the sickness that immediately preceded their death. The first point of care for nearly half of them was a local private facility. This is consistent with findings from studies done in rural Kenya on health care seeking behaviour [8, 9]. In our study, the occurrence of private providers as first point of care may have been partly because the study ran follow-up clinics only once a week. In these settings, most of the local private providers are not sufficiently equipped to handle life threatening child conditions. Consequently, this practice creates delay in accessing appropriate care and increases risk of death.
With regard to child’s place of death, we found that most deaths did not happen in a health facility. This is in spite of the fact that about 90% of children who died had sought care from a health facility for the sickness that preceded their death. This is similar to findings of a prospective cohort study done in rural Malawi [10]. This has implications for child health services and for clinical research involving children. Among those who sought care, about half of them were referred to hospital by their first point of care. However, one third of those referred did not reach the referral care points. Clinical research studies intended for this setting need to take this into consideration as they plan for follow up.
Factors associated with mortality
The dead and surviving participants had similar baseline socio-demographic and clinical factors except for mother’s age, father’s education and place of birth. Children born to very young mothers (13–17 yrs) had the highest risk of dying. This is consistent with other reports and is related to the fact that younger mothers tend to have lower education and socio-economic characteristics which contribute to the higher infant mortality [11]. The risk of dying generally diminished with increasing maternal age. This decrease in risk of mortality with increase in maternal age is probably due to the expected accumulation of child-care experience with increasing maternal age. Available literature supports this finding, but other studies show that children born to mothers aged 40 years and above are also at higher risk of dying [12, 13]. However in our study, the likelihood of dying was lowest for children born to mothers aged 40 years and above. The relatively small number of children in this cohort born to mothers aged 40 years and above could explain this unusual finding.
Other risk factors for infant and child mortality reported elsewhere include mother’s death during infant’s first year of life, death of previous sibling, being a twin, parental education, birth spacing, distance to nearest health unit, season of birth, etc [14–16]. In our cohort parent’s education level was surprisingly insignificant although findings from previous studies have shown parental education to have significant and negative relationship with child mortality [17–19]. Fathers with higher education levels are likely to have skilled occupations that lead to lower child mortality rates because of their higher socio-economic conditions [19]. Concerning child’s place of birth, in our cohort children born in a health facility had a significantly lower risk of dying than those whose place of birth was outside a health facility. In other studies however, child’s place of birth has not been found to be of significant influence [12, 20, 21].
Limitations
Due to limitation in the scope of our study, we were unable to measure the effect that other known child mortality determinants had on our cohort. Analysis of risk factors for death was applied to the entire sub-cohort of the dead children without segregating between those who died in their first year of life and those who died after their first year of life, due to low numbers. This is a critical limitation because risk factors for death in the first year of life are different from those after the first year of life. We implemented child mortality reduction activities for all our participants but due to lack of a comparison group, we were unable to reasonably assess the effect of these activities on mortality measurements. A verbal autopsy was done at least six weeks after death of a participant. This could have affected the ability of a parent/guardian to recall events that led to the death of their child.