Background: Lack of exclusive breastfeeding among infants 0-5 months of age and no breastfeeding among children 6-23 months of age are associated with increased diarrhea morbidity and mortality in developing countries. We estimate the protective effects conferred by varying levels of breastfeeding exposure against diarrhea incidence, diarrhea prevalence, diarrhea mortality, all-cause mortality, and hospitalization for diarrhea illness.Methods: We systematically reviewed all literature published from 1980 to 2009 assessing levels of suboptimal breastfeeding as a risk factor for selected diarrhea morbidity and mortality outcomes. We conducted random effects meta-analyses to generate pooled relative risks by outcome and age category.Results: We found a large body of evidence for the protective effects of breastfeeding against diarrhea incidence, prevalence, hospitalizations, diarrhea mortality, and all-cause mortality. The results of random effects meta-analyses of eighteen included studies indicated varying degrees of protection across levels of breastfeeding exposure with the greatest protection conferred by exclusive breastfeeding among infants 0-5 months of age and by any breastfeeding among infants and young children 6-23 months of age. Specifically, not breastfeeding resulted in an excess risk of diarrhea mortality in comparison to exclusive breastfeeding among infants 0-5 months of age (RR: 10.52) and to any breastfeeding among children aged 6-23 months (RR: 2.18).Conclusions: Our findings support the current WHO recommendation for exclusive breastfeeding during the first 6 months of life as a key child survival intervention. Our findings also highlight the importance of breastfeeding to protect against diarrhea-specific morbidity and mortality throughout the first 2 years of life.

Suboptimal breastfeeding practices among infants and young children <24 months of age are associated with elevated risk of pneumonia morbidity and mortality. We conducted a systematic review and meta-analysis to quantify the protective effects of breastfeeding exposure against pneumonia incidence, prevalence, hospitalizations and mortality. We conducted a systematic literature review of studies assessing the risk of selected pneumonia morbidity and mortality outcomes by varying levels of breastfeeding exposure among infants and young children <24 months of age. We used random effects meta-analyses to generate pooled effect estimates by outcome, age and exposure level. Suboptimal breastfeeding elevated the risk of pneumonia morbidity and mortality outcomes across age groups. In particular, pneumonia mortality was higher among not breastfed compared to exclusively breastfed infants 0-5 months of age (RR: 14.97; 95% CI: 0.67-332.74) and among not breastfed compared to breastfed infants and young children 6-23 months of age (RR: 1.92; 95% CI: 0.79-4.68). Our results highlight the importance of breastfeeding during the first 23 months of life as a key intervention for reducing pneumonia morbidity and mortality.

Diarrhea is a leading cause of morbidity and mortality globally; yet the overall burden of diarrhea in terms of duration and severity has not been quantified. As improvements in treatment lead to decreases in diarrhea mortality, it is important to understand the substantial impact of diarrhea morbidity on disability among children and adults worldwide.

Evidence supporting the impact of therapeutic zinc supplementation on the duration and severity of diarrhea among children under five is largely derived from studies conducted in South Asia. China experiences a substantial portion of the global burden of diarrhea, but the impact of zinc treatment among children under five has not been well documented by previously published systematic reviews on the topic. We therefore conducted a systematic literature review, which included an exhaustive search of the Chinese literature, in an effort to update previously published estimates of the effect of therapeutic zinc. We conducted systematic literature searches in various databases, including the China National Knowledge Infrastructure (CNKI), and abstracted relevant data from studies meeting our inclusion and exclusion criteria. We used STATA 12.0 to pool select outcomes and to generate estimates of percentage difference and relative risk comparing outcomes between zinc and control groups. We identified 89 Chinese and 15 non-Chinese studies for the review, including studies in 10 countries from all WHO geographic regions, and analyzed a total of 18,822 diarrhea cases (9469 zinc and 9353 control). None of the included Chinese studies had previously been included in published pooled effect estimates. Chinese and non-Chinese studies reported the effect of therapeutic zinc supplementation on decreased episode duration, stool output, stool frequency, hospitalization duration and proportion of episodes lasting beyond three and seven days. Pooling Chinese and non-Chinese studies yielded an overall 26% (95% CI: 20%−32%) reduction in the estimated relative risk of diarrhea lasting beyond three days among zinc-treated children. Studies conducted in and outside China report reductions in morbidity as a result of oral therapeutic zinc supplementation for acute diarrhea among children under five years of age. The WHO recommendation for zinc treatment of diarrhea episodes should be supported in all low- and middle-income countries.

After the publication of this work [1], we became aware that we had incorrectly cited the number of diarrhea cases for 2005 among individuals 5-15 years and [greater than or equal to] 16 years reported by Fischer Walker et al [2]. We estimate that of the 2.115 billion episodes of diarrhea among individuals [greater than or equal to] 16 years in 2005 [2], 2.009 billion episodes were mild (95%); 104.7 million were moderate (4.95%); and 1.1 million were severe (0.05%). Of the estimated 699.2 million diarrhea episodes among children 5-15 years of age in 2005 [2], an estimated 664.2 million were mild (95%); 34.6 million were moderate (4.95%); and 350,000 were severe (0.05%).