Breastfeeding and Kawasaki Disease
by Anne Eglash MD, IBCLC, FABM
Kawasaki disease (KD) is an illness among young children involving inflammation of small and medium sized arteries (vasculitis), especially the arteries around the heart. Children with KD can develop aneurysms of the coronary (heart) arteries. According to authors of the study for this week’s CQW, which is set in China, the incidence of KD varies in different countries, ranging from 3-264 cases per 100,000 children, with more cases occurring in high-resource countries.
Kawasaki disease is thought to be a response to infections or environmental agents among individuals who are genetically susceptible. Treatment involved intravenous gamma globulin (IgG) infusions.
Some studies have already shown that the risk is for KD is higher among children not breastfed. Japan has the highest rate of KD, and in 2016 Japanese researchers published evidence that breastfeeding is protective of KD. A German study published in 2019 also found breastfeeding to be protective.
This week’s study is a case control study. The authors identified 426 children diagnosed with KD, who were hospitalized at a hospital in China between November 2013 and March 2019. They matched the cases with 479 healthy children who were seen for routine health exams at the same hospital, in order to compare breastfeeding rates.
Demographic data was collected about the birth, gestational age, weight, mode of delivery, etc. They interviewed each family regarding feeding history, and categorized infants as partially (mixed formula and breastfeeding) or exclusively breastfed during the first 6 months, or formula fed.
- Exclusive breastfeeding during the first 6 months of life was significantly protective of Kawasaki disease.
- Infants who received both breastmilk and formula in the first 6 months of life also had a significantly lower risk of Kawasaki disease.
- Children with Kawasaki disease who were exclusively breastfed during the first 6 months of life were more likely to respond well to treatment.
- Children with Kawasaki disease who were exclusively breastfed during the first 6 months of life were less likely to develop aneurysms of their heart (coronary) arteries.
See the Answer
The association between breastfeeding and Kawasaki disease is not fully understood. We performed a case–control study to examine the association between breastfeeding and Kawasaki disease. In this study, 389 children diagnosed with Kawasaki disease and 426 gender- and age-matched controls were identified at Renmin Hospital of Wuhan University between November 2013 and March 2019. Demographic and clinical data were collected from a structured telephone interview and medical record database. Odds ratio and 95% confidence interval for risk of Kawasaki disease were estimated. Children who were breastfed exclusively had a decrease in developing Kawasaki disease (adjusted odds ratios and 95% confidence intervals 0.53 (0.38–0.74).
Although the risk reduction was not statistically different, partial breastfeeding also provided a protective effect (adjusted odds ratios and 95%confidence intervals 0.70 (0.48–1.01). In the stratified analysis, we still observed that exclusive breastfeeding was inversely associated with the development of complete Kawasaki disease (adjusted odds ratios and 95%confidence intervals 0.52 (0.31–0.88) and incomplete Kawasaki disease (adjusted odds ratios and 95% confidence intervals 0.54 (0.38–0.77). However, there was no significant association between exclusive breastfeeding and the intravenous immunoglobulin treatment response (adjusted odds ratios and 95% confidence intervals 0.69 (0.27–1.69) and the risk of coronary artery lesions (adjusted odds ratios and 95% confidence intervals 0.79 (0.49–1.31) in Kawasaki disease.
Conclusion: Our analysis suggests that exclusive breastfeeding was inversely associated with the development of Kawasaki disease and that breastfeeding might be a potential protective factor against Kawasaki disease.
Partial (mixed breast and formula) breastfeeding in the first 6 months of life was associated with a trend of less KD, but the trend was not significant in this study.
Children who developed KD, who were exclusively breastfed in the first 6 months of life, were not likely to have milder cases or fewer complications such as coronary aneurysms.
According to the authors, breastfeeding has been shown to protect children from inflammation due to infectious diseases, such as respiratory syncytial virus (RSV), and gastroenteritis. Since KD is an inflammatory illness, it makes sense that the anti-inflammatory bioactive factors in breastmilk would help to protect the onset of the disease. The authors also hypothesize that the difference in the gut bacteria in breastfed vs formula fed infants may also play a role in the reduced risk of KD in exclusively breastfed infants, since the gut bacteria in breastfed infants tend to promote intestinal maturity, thereby strengthening the gut immune system.