09 Apr 2019

The “Children of 1997” birth cohort research team at the LKS Faculty of Medicine, The University of Hong Kong (HKUMed) found that exclusive breastfeeding in early infancy promoted a healthier lipid profile, specifically lower low density lipoprotein (LDL)-cholesterol, (the “bad” cholesterol associated with heart disease), in late adolescence. The finding demonstrates another benefit of breastfeeding, the most natural food for infants, by showing how breastfeeding might help prevent cardiovascular disease in later life.

Background

The World Health Organization recommends babies should be exclusively breastfed for the first six months because of the benefits for infant and maternal health. However, how these benefits extend from infancy into adulthood has not been fully delineated. Specifically, the long-term effects of breastfeeding on cardiovascular risk factors, such as LDL-cholesterol, are not well-established.

Breast milk contains more cholesterol than infant formula. Breast-fed infants have higher blood cholesterol but generate less cholesterol than formula-fed infants. To investigate the long-term effects of breastfeeding, a research team from HKUMed and The Chinese University of Hong Kong (CUHK) assessed the impact of breastfeeding on lipid profile in late adolescence.

Research method and findings

The team used Hong Kong’s “Children of 1997” birth cohort, one of Asia’s largest birth cohorts, for this study. Breastfeeding was recorded in 1997, and then 3,265 participants had lipids measured in 2013-2016 at ~17.5 years of age. Back in 1997, breastfeeding was not very common in Hong Kong and was not clearly related to the education of the mothers. As such, this study is much more suitable to assess effects of breastfeeding than studies from most other places where more highly educated mothers are more likely to breastfeed, making it difficult to know whether any health benefits are due to other attributes of educated mothers (for example, health consciousness) or to breastfeeding itself.

The research team found that exclusive breastfeeding for the first three months was associated with lower LDL-cholesterol at about 17.5 years, regardless of body mass index and fat percentage. Further studies are needed to clarify the exact mechanism and the full effects on lipid profile.¹

The team suggested that “breastfeeding is potentially important in cardiovascular disease prevention by promoting lower cholesterol for the population as a whole.”

These findings support the existing public health policies in promoting breastfeeding in Hong Kong and globally by highlighting an additional benefit. From 1997 to 2016, the proportion of mothers starting breastfeeding in Hong Kong increased from 33% to 85%. This study also provides evidence supportive of public health policies to increase the duration and exclusivity of breastfeeding.

1. Hui LL, Kwok MK, Nelson EAS, Lee SL, Leung GM, Schooling CM. Breastfeeding in infancy and lipid profile in adolescence. Pediatrics, 2019. [in press]

About the research team

The research was conducted by HKU Birth Cohort Study team led by Professor Gabriel Leung, Dean of Medicine, HKUMed and Dr C Mary Schooling, Associate Professor and Cluster Leader (Non-communicable Diseases in Global Health), School of Public Health, HKUMed; together with Dr Kwok Man Ki, Assistant Professor, School of Public Health, HKUMed; and Dr Lee So Lun, Honorary Clinical Associate Professor, Department of Paediatrics and Adolescent Medicine, HKUMed. The research was jointly conducted by CUHK collaborators, Dr Hui Lai Ling, Scientific Officer, the lead author of this study; and Professor Tony Nelson, Professor, Department of Paediatrics, Faculty of Medicine, CUHK. This study was supported by the Health and Medical Research Fund (10111491) and the WYNG Foundation.

About the School of Public Health, HKUMed

The School of Public Health, LKS Faculty of Medicine of The University of Hong Kong has a long and distinguished history in public health education and high impact research. With world leading research in infectious diseases as well as on non-communicable diseases of both local and global importance, the School has made significant contributions through its research and advocacy to improve the health of populations and individuals, both locally and globally. The School is a leading research and teaching hub in public health on influenza and other emerging viruses, control of non-communicable and infectious diseases, tobacco control, air pollution, psycho-oncology, behavioural sciences, exercise science, life-course epidemiology, and health economics, health services planning and management. These works have informed international (e.g. the World Health Organization, the US Food and Drug Administration and the Health Canada), national and local public health policies. Specifically, the “Children of 1997” Birth Cohort Study has generated new information about key public health issues, including the role of breastfeeding and second-hand smoke exposure in child and adolescent health.

The HKU and CUHK collaborative research team announces their findings on the association of breastfeeding with adolescent lipid profile. The research was conducted by HKU Birth Cohort Study team led by Professor Gabriel Leung, Dean of Medicine, HKUMed and Dr C Mary Schooling, Associate Professor and Cluster Leader (Non-communicable Diseases in Global Health), School of Public Health, HKUMed.