The protective role of breastfeeding in this study was in agreement with previous reports.[12
] In the developing world, infectious diseases, in general and diarrhea, specifically are significant causes of childhood mortality. As we know, longer breastfeeding may diminish children mortality through its protective effect on infections. Although, the epidemiology of CMR in Shahroud is showing that of the developed world with congenital disorders and accidents as leading causes of deaths, our study suggests breastfeeding as an important protective factor consistently. It seems that Integrated Management of Children Illness (IMCI) strategies have been successful in providing health service units in the region. These strategies emphasize exclusive feeding with breast milk up to the age of six months, as recommended by the WHO.[15
In our study, LBW was reported as a significant risk factor for CMR. This finding is also in agreement with results of most previous studies.[13
] Many factors can cause LBW including poor maternal nutritional conditions and some underlying disorders. The wide CI of OR (1.37-39.67) itself speaks volumes for the uncertainty as regards to this.
The number of total child health care visits was related to under five year old mortality. In fact, late onset of child care and/or lack of care were significant risk factors for children death. This finding also agrees with findings of previous researches.[15
] Regular care visits are important in early diagnosis and treatment of children's acquired or congenital health problems.
Performing a population based nested case control design using risk set sampling of controls can be considered as a strength of our study. With risk set sampling of controls, a population member present for twice as long as another, will have twice the chance of being selected and this can be considered as an important advantage to an ordinary case-control study and reduces selection bias. In addition, cases (children who died) and controls are matched on age, and age is not considered as a confounder.
Our study has some potential limitations that should be consider of them when interpreting the results. Data was extracted from family health files recorded by health house staff. Thus, the impact of other important factors such as lifestyle, socio-economic status, underlying diseases and maternal stature on CMR needs to be further explored using more sophisticated studies. It is also suggested that other sources which could ordinary record all death events (such as cemeteries), as well as socio-economic data (such as hospitals, insurance organizations, and health care providing centers) be considered in data collection and even data be directly elicited from families if possible.
It was expected that parents’ low level of education would at least partly account as risk factor for the CMR, but based on our findings there were no statistically significant association between them. In fact, the parents had similar levels of education in our study population context and it was not possible for us to investigate the role of this factor on child death. However, in studies, where parents had various levels of education, the effect of this factor on child mortality rate has been observed.[13
In summary, it seems that complex and multiple factors may be involved in mortality of under 5-year-old children, so combined efforts would be necessary to improve child health indicators. Various types of intervention can be considered to prevent a majority of deaths in age group of interest. For instance, the importance of health care visits and breastfeeding should be declared, as far as possible and effective efforts must be performed to prevent LBW. More attention should be paid to health cares to prevent preterm births and congenital anomalies. Inappropriate management of services, lack of follow-up and the problems in the referral system are some of the factors that need to be addressed through careful planning to reduce CMR. Finally, reducing fatal accidents, especially traffic events, are another key step to further decreasing CMR.