Association between exclusive breastfeeding and childhood morbidity outcomes

Despite recent advancements, diarrhoea and respiratory infections continue to be the one of main causes of mortality in children under the age of five worldwide. Multiple studies have recommended that optimal breastfeeding practices, including exclusive breastfeeding during the first six months of life are one of the most effective interventions for decreasing the prevalence of diarrhoea and acute respiratory infections in infants. However, the preventive effect of exclusive breastfeeding on diarrhoea and acute respiratory infections on infants 0-6 months of age have remained under-investigated in South Asia.

This thesis is divided into two individual studies. The first study (narrative review) aimed to critically analyze the literature on the association between exclusive breastfeeding and childhood infections in children under the age of five. The second study (secondary analysis of cross-sectional data) explored the association between exclusive breastfeeding and other infant and young child feeding indicators (namely early initiation of breastfeeding and bottle feeding) and diarrhoea, acute respiratory infection, and fever in infants (0-6 months) in South Asian countries. This used data derived from the most recent Demographic and Health Surveys for the following countries and survey years: Afghanistan (2015), Bangladesh (2017-2018), India (2019-2021), Nepal (2016), Pakistan (2017-2018).

Results from the narrative review of 70 studies concluded that 85% of the included studies overall found a positive association between exclusive breastfeeding and reduced risk of infections and several studies reported that longer duration of exclusive breastfeeding was protective against many infectious diseases. It further noted that some papers used a different definition to measure exclusive breastfeeding from the World Health Organization’s definition. The second study found that exclusive breastfeeding was associated with lower odds of diarrhoea and fever in Afghanistan (aOR: 0.49, 95% CI 0.35, 0.70), (aOR: 0.36, 95% CI 0.26, 0.50) and India (aOR: 0.80, 95% CI 0.70, 0.91), (aOR: 0.75, 95% CI 0.67, 0.84) respectively. Exclusive breastfeeding was also associated with lower odds of acute respiratory infection in Afghanistan (aOR: 0.57, 95% CI 0.39, 0.83). Results from the other South Asian countries indicated the protective effect of EBF, however these results did not provide evidence of an association. Bottle feeding was associated with higher risk of acute respiratory infection in Afghanistan. Bottle fed infants also had a higher risk of diarrhoea in India and Nepal. Bottle feeding was significantly associated with higher risk of fever in Afghanistan and India. Early initiation of breastfeeding was significantly associated with a lower risk of diarrhoea in India.