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The authors suggest that the high energy demands
of breastfeeding in HIV-infected mothers may
accelerate the progression to HIV-related death.
If this is true then a higher death rate should
be apparent in women who breastfed their infants
exclusively compared with those who gave their
infants food supplements or avoided breastfeeding
altogether.
By contrast, Coutsoudis and colleagues have
published an analysis of morbidity and mortality
in mothers enrolled in a randomised study of
Vitamin A supplementation conducted in Durban,
South Africa, analysed according to their chosen
method of infant feeding.4 This secondary analysis
was conducted to specifically address the concerns
raised by the preliminary results from Nduati
and colleagues and showed that two of 410 (0.5%)
women who ever breastfed their infants died
compared with three of 156 (1.9%) who never
breastfed. In addition there was no excess of
any reported morbidity in mothers who breastfed
compared with those who did not (12.7% and 14.7%,
respectively). While these results are reassuring,
the limitations of the analysis must be recognised
- women chose whether or not to breastfeed their
infants, and the numbers of women involved was
small. The study had at most 50% power to exclude
a 3-fold increase in mortality in mothers who
breastfeed.
Neither of these studies provided detailed
information on the mode, duration and quantity
of breastfeeding and the associated mortality
risks. In addition the two groups of women enrolled
in the trials are not directly comparable. Those
in Durban were in general healthier, as evidenced
by a lower prevalence of anaemia and
better immune status at enrolment, than the
women in Nairobi. The overall mortality rate
in the Durban cohort was less than 1% with an
average follow-up of 10.5 months compared with
overall mortality rates over 4% at 1 year and
7% at 2 years in the Nairobi cohort.
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