Bone health and HIV

  • November 1, 2013
Bone health and HIV

Florence Nabwire is researching the possible effects of ante-retroviral drugs on the bone health of HIV positive mothers and their babies.

What are the short and long-term effects of exposure to ante-retroviral drugs on the bones of HIV infected mothers and the children they give birth to who do not go on to be positive?

Current scientific evidence shows that HIV infection, anti-retroviral drugs, pregnancy and lactation each independently reduce bone mineral density. However, there is little information about the the bone health of HIV infected pregnant and breastfeeding women who are taking antiretroviral drugs. There are also few studies on the impact of intrauterine and postnatal exposure to ARVs on infant bone accretion and growth.  This is an area where Florence Nabwire [2013] intends to provide much needed data and says the need for it is all the more urgent as the use of triple combinations of ARVs to eliminate mother to child transmission of HIV is rapidly scaling up especially in Sub-Saharan Africa.

Last year at an International Workshop on HIV Paediatrics in Washington, her abstract, “Effects of implementing WHO Prevention of Mother-To-Child Transmission of HIV (2010) guidelines on nutrition outcomes of HIV exposed infants at Mulago National Hospital – Uganda”, was accepted for a poster presentation.

The study reviewed clinical charts and reported that infants whose mothers followed WHO Preventing Mother To Child Transmission [PMTCT] (2010) guidelines had poor growth measures compared to infants whose mothers had followed the WHO PMTCT (2006) guidelines. This was contrary to anticipated outcomes because the WHO 2010 guidelines promote a longer period of breastfeeding than the 2006 guidelines.  As it was a retrospective study based on chart reviews, information was not available on other factors which might explain the differences in growth. However, the majority of infants following the WHO 2010 guidelines had a longer exposure to ARVS from 14 weeks gestation up to one week after cessation of breastfeeding. Infants following the 2006 guidelines were only exposed to ARVs at 28 weeks gestation and had only seven days of postnatal exposure to ARVs. This triggered a discussion on whether prolonged exposure to ARVs could have played a role or whether the difference was just the result of other factors such as poor feeding practices or increased infections.

Florence says: “The duration of exposure to antiretroviral drugs is now even longer with the roll-out of PMTC option B-plus guidelines in which all pregnant women are started on ARVs for life regardless of their CD4 levels [immunity levels]. This means that HIV-infected pregnant women with high CD4 levels will initiate ARVs earlier, not just for the sake of their own health but for the health of the infants. More research is needed to provide evidence about both the short and long term safety of ARVs on maternal and infant bone health in the wider context of osteoporosis and optimal infant growth to compliment the successful efforts to eliminate mother to child transmission of HIV.”

The study and subsequent discussion was the catalyst for Florence’s PhD , for which she has been awarded a Cambridge-Gates scholarship for a PhD at the University of Cambridge and Medical Research Council Human Nutrition Research Unit. She and her PhD supervisor Dr Gail Goldberg have already received funding from the Cambridge Alborada trust. They have been awarded £10,000 towards start-up costs for her PhD field research in Uganda.

The research relates to Florence’s previous work in Uganda, where she spent three and a half years working as a nutritionist at the National Paediatric HIV/AIDS Clinic. Florence is the first nutritionist to be awarded a Gates Cambridge Scholarship.

Early years
Florence was born in Busia in Kenya and both her parents are primary school teachers. Her father would bring home exam papers for Florence and her three brothers to sit so they would progress at the same level as children at private schools. Florence studied food science and technology under the government of Kenya scholarship programme at the University of Nairobi.  She fell in love with the subject and graduated with a first class degree and was sponsored by the University to do her Masters in uman Nutrition.

In addition to her academic work, Florence was a student representative for her hall of residence and was captain of her university netball team for two years, representing the university twice at the East Africa Inter-University Games. At secondary school level, she had represented her province at national level in both netball and athletics and was named best national centre netball player in her final year of secondary school. She stopped playing netball after her masters when she moved to Uganda for work, but she intends to join the Queens’ college netball team in Cambridge.

Her masters was on the prevalence of vitamin A deficiency among pregnant women and was part of a European Union-funded INSTAPA project which involved Florence conducting surveys in the Makindu, Kilifi and and Kisumu-East districts of Kenya with the aim of identifying an appropriate study site for a trial involving adding biofortified yellow cassava to the diet.

She was looking at dietary diversity and the prevalence of maternal night-blindness and found that Makindu had the highest vitamin A deficiency and lowest dietary diversity at that time. Having identified the problem areas, she then recommended Makindu for the trial which has since been successfully carried out. The preliminary results show that yellow cassava improves the vitamin A status of primary school children. The study is likely to lead to the introduction of yellow cassava in Kenya and other African countries who rely on cassava as a staple.

Florence had long been interested in the impact of HIV on maternal and child health nutrition so after finishing her masters, she approached an NGO in Uganda called Baylor Uganda which provides treatment for HIV-infected children. She says the nutrition programme for children with HIV had just started and she wanted to learn more about nutrition in HIV and, if possible, make a difference. She initially volunteered for three months and saw the health of many of the children with nutritional problems improve. She was then offered a full-time role to expand the nutrition programme out of the national centre to 72 rural government facilities supported by the organisation. By the time she left to come to the University of Cambridge she was head of the organisation’s nutrition programme which had six nutritionists and supported about 400 government health facilities in addition to the National Clinic in Kampala.

Florence is already thinking about post-doctoral work having only just begun her PhD! She hopes the cohorts she studies for her PhD will provide scientific evidence on long term effects of exposure to antiretroviral drugs on bone health in the context of pregnancy, lactation and bone accretion and growth in uninfected children born to HIV positive mothers in Uganda.

Picture credit: and renjith krishnan.

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