No evidence that breastfeeding makes maternal HIV worse

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Breastfeeding is not detrimental to the health of HIV-positive mothers, according to a study published in the April 30th edition of AIDS.

Investigators in Dar es Salaam, Tanzania, conducted a prospective cohort study involving 698 HIV-positive mothers between 1995 and 1997. The study was undertaken because earlier studies had produced conflicting evidence about the risk of maternal HIV disease progression after breastfeeding.

The investigators in Tanzania designed a prospective cohort study, and assessed whether breastfeeding was associated with maternal HIV disease progression by looking at the risk of death, low CD4 cell count, anaemia, and weight loss.

Glossary

disease progression

The worsening of a disease.

multivariate analysis

An extension of multivariable analysis that is used to model two or more outcomes at the same time.

anaemia

A shortage or change in the size or function of red blood cells. These cells carry oxygen to organs of the body. Symptoms can include shortness of breath, fatigue and lack of concentration.

prospective study

A type of longitudinal study in which people join the study and information is then collected on them for several weeks, months or years. 

p-value

The result of a statistical test which tells us whether the results of a study are likely to be due to chance and would not be confirmed if the study was repeated. All p-values are between 0 and 1; the most reliable studies have p-values very close to 0. A p-value of 0.001 means that there is a 1 in 1000 probability that the results are due to chance and do not reflect a real difference. A p-value of 0.05 means there is a 1 in 20 probability that the results are due to chance. When a p-value is 0.05 or below, the result is considered to be ‘statistically significant’. Confidence intervals give similar information to p-values but are easier to interpret. 

Mean duration of breastfeeding was 18.2 months. However, women with a CD4 cell count below 200 cells/mm3 at baseline tended to breastfeed for a shorter period (mean 14.9 months), whereas women who had a CD4 cell count above 500 cells/mm3 breastfed for longer (mean 18.7 months, p=0.03). The investigators also found that women who were in their mid-thirties breastfed for significantly longer than teenage mothers (20 months versus 18 months, p=0.02).

Follow-up was provided every three months. Mothers who had breastfed in the previous six months were defined as breastfeeding. The investigators found that recent breastfeeding was not associated with a woman’s risk of death in multivariate analysis which controlled for HIV disease stage and CD4 cell count in the month before death (risk ratio 0.73; 95% CI, 0.29-1.83). The investigators also found that breastfeeding had no association with the risk of anaemia, a fall in CD4 cell count to below 200 cells/mm3, or a loss of 10% or more of body weight.

The investigators repeated their analysis, stratifying women according to their CD4 cell count (above or below 350 cells/mm3). Again, they failed to find any significant association; for women with both high and low CD4 cell counts, the investigators failed to find any significant association between breastfeeding and the risk of death, a fall in CD4 cell count to below 200 cells/mm3, low haemaglobin, or a loss of 10% or more of body weight.

Analyses were then conducted to see if the proportion of time women breastfed for was associated with an increased risk of HIV disease progression. The proportion of months women breastfed for was not associated with either an increased risk of death or disease progression.

“Neither breastfeeding status not the duration of breastfeeding was associated with maternal HIV disease progression represented by death, a low CD4 cell count, anaemia or excessive weight loss in multivariate analyses in this cohort of women,” note the investigators.

The investigators add that recent studies have found that breastfeeding may not deplete a woman’s energy reserves to the extent previously thought, and that a woman’s metabolic efficiency is improved during breastfeeding. They suggest that the association found between disease progression and breastfeeding in an earlier study could have been because it was observational in nature and failed to include adequate controls.

“Our findings indicate that breastfeeding is not detrimental to the health of HIV-1 infected women,” conclude the investigators. Although they call for further studies to confirm their findings, they add that their study suggests “that HIV-positive women should continue to base their decisions about breastfeeding on their assessment of the health and nutritional benefits of breastfeeding, the risks associated with not breastfeeding, and the risk of vertical transmission to their children.”

Further information on this website

Breastfeeding - overview

References

Sedgh G et al. Breastfeeding and maternal HIV-1 disease progression and mortality. AIDS 18: 1043-1049, 2004.