Malawi study may lead to new approach to improve health and survival of HIV-positive mothers and their infants

For more than 20 years, Peggy Bentley, Professor of Nutrition and Associate Dean of Global Health in the Gillings School of Global Public Health, has blended her background in medical anthropology, nutrition, and public health to examine influences of social and behavioral factors on maternal and child health and nutrition. Her early work at UNICEF in their South Asia Regional Office focused on causes of diarrheal diseases and how the family and community contexts contributed to changes in the populations of India, particularly morbidity and mortality of children.

More recent work has examined the role of various family structures on the health of children. In a longitudinal study that examined the role of behavioral and environmental factors on infant health outcomes in low-income African-American mothers and infants in North Carolina, Bentley determined that culture-specific features of parenting may either prevent or promote infant obesity development. A key result in this study is the protective role of grandmothers relative to fathers, meaning that the grandmothers had a stronger influence on improvements to infants’ health than did the fathers, primarily because of their financial support and their advice related to parenting and infant feeding.

Presently, Bentley is leading a study of approximately 2,400 HIV-positive mothers and their children in Malawi to examine how inexpensive nutritional supplements might result in improved health of mothers and their infants. This work expands Bentley’s long-standing interest in the social, nutritional, and behavioral components of child health and survival. The implications of this work may guide health programs for populations in which HIV is prevalent, in particular in low-resource settings. Support of breastfeeding mothers is a key component of this study. Although vertical HIV transmission is possible through breastfeeding, in resource-poor settings, infants are at greater risk of dying if they are not breastfed rather than if they are, even by an HIV-positive mother. Therefore, international guidelines on breastfeeding for this population recommend exclusive breastfeeding for the first six months.

Breastfeeding by itself increases nutrient demands on the mother, and breastfeeding coupled with HIV infection places women at risk of nutritional depletion. Therefore, this study examines the benefits of nutritional supplementation for HIV-positive women while they are breastfeeding their babies for the first six months of life. It also examines the health outcomes of babies provided with nutritional supplements as a replacement for breast milk to protect their own nutritional status between six months and one year. Improved nutritional status is a key determinant of survival in the short term and of health and human capital in the long term.

This study, MaMi: Malawi Mothers and Infants, is based at the Carolina Population Center (CPC). Bentley is a CPC Faculty Fellow and is Principal Investigator of MaMi. Linda Adair is co-Principal Investigator and the Director of Data Analysis of MaMi. Adair is also a Faculty Fellow at CPC. The three-year project is funded by the Bill and Melinda Gates Foundation. MaMi uses data that were collected as part of the Breastfeeding, Antiretroviral, and Nutrition (BAN) study.

A part of the MaMi study involves examining the participants’ different household types and how these influence maternal and child health outcomes. Maternal survival is key to household structures in sub-Saharan Africa where it is common to have intergenerational households that may support many children.

Bentley says, “Family structures can really have an impact on all of the issues that we’re looking at. For example, we know that a woman’s infant feeding practices may be influenced by whether she is supported by a grandmother or the father of the baby. In this setting, mothers usually breastfeed for at least two years, and there may be stigma associated with early cessation, which was the recommended practice during this study period. So one of the things we will look at is how household structure influences the behavioral and biological outcomes for both the mother and child.”

This project is unique because of the integration of varying forms of data collection including self-reports, dietary intake assessments, physical measures, and biomarkers to understand the complex factors that affect child survival and health outcomes. The amount of data contributes to the challenges and opportunities presented by such a study.

Adair describes the analysis of these data: “A unique aspect of the analysis will determine whether the nutritional supplement raised maternal blood nutrient levels, whether it got into her breast milk, and then whether that affected infant’s nutrient levels and their subsequent growth and health.”

Bentley’s work is interdisciplinary on many levels. Her collaboration with nutritionists, anthropologists, physicians, child development scholars, and epidemiologists has informed her research. Her long-standing collaboration with Linda Adair, Charles van der Horst, Anna Maria Siega-Riz, and many others has brought a variety of perspectives to her research and included both quantitative and qualitative data collection and analysis.

Bentley hopes that the MaMi study will inform policy recommendations for maternal and child health, in particular for those in resource-poor settings with high HIV prevalence. While the project focuses on the impact of nutritional supplements on both a mother’s postpartum health and on infant growth, weight, and general nutrition, the findings will inform strategies for improving maternal and child health and survival in Malawi and beyond.

Bentley says, “A lot of people are waiting for these data to be analyzed and to understand if, in fact, we can support the health of the mother, a mother who’s infected with HIV in a setting where food scarcity or seasonal fluctuations in access to food is a problem.”

“We’re still in the early phases of understanding what the impact of this is going to be on nutrition and growth,” she says, “but the small number of studies that have been done are very promising that this could be a real answer for us.”

Information about the BAN study is available at http://www.med.unc.edu/infdis/research/hiv-stds/ban-study/

Some initial findings from the BAN study have already been published. See:

Bentley, Margaret E., Amy L. Corneli, Ellen G. Piwoz, Agnes Moses, Jacqueline R. Nkhoma, Beth Carlton Tohill, Yusuf Ahmed, Linda S. Adair, Denise J. Jamieson, and Charles van der Horst. 2005. Perceptions of the Role of Maternal Nutrition in HIV-Positive Breast-Feeding Women in Malawi. Journal of Nutrition 135, no. 4: 945-9.

Chasela, Charles S., Hudgens, Michael G., Jamieson, Denise J., Kayira, Dumbani, Hosseinipour, Mina C., Kourtis, Athena P., Martinson, Francis, Tegha, Gerald, Knight, Rodney J., Ahmed, Yusuf I., et al, the BAN Study Group. 2010. Maternal or Infant Antiretroviral Drugs to Reduce HIV-1 Transmission. New England Journal of Medicine 362, no. 24: 2271-81