HIV-1 transmission through breast-milk: appraisal of risk according to duration of feeding.
OBJECTIVE
To estimate the risk of HIV-1 transmission through breast-milk in children born to infected mothers, and to determine the relationship between duration of breast-feeding and risk.


METHODS
The study population included 168 breast-fed and 793 bottle-fed children born to seropositive mothers. All subjects were enrolled and followed-up in the Italian Register for HIV Infection in Children; HIV sero-status was defined in all children. Multivariate analysis was performed using a logistic regression model. Independent variables included biological factors (duration of breast-feeding, gestational age, clinical condition of mother at delivery, mode of delivery, birth-weight and sex). Year of birth and age when HIV infection was diagnosed were also considered in the analysis attempting to control for possible selection biases.


RESULTS
Breast-feeding increased the risk of HIV-1 transmission. The estimated adjusted odds ratio for 1 day of breast- versus bottle-feeding was 1.19 (95% confidence interval, 1.10-1.28). The infection odds ratio of breast- versus bottle-feeding increased with the natural logarithm of the duration of practice.


CONCLUSIONS
These results are the first to provide an appraisal of the additional risk of HIV-1 transmission associated with a seropositive mother breast-feeding her child. Biological significance of this route of transmission was supported by demonstration of a relationship between duration of breast-feeding and risk of HIV-1 transmission.
de Martino
M
M
Italian Register for HIV infection in Children, Florence.
Tovo
P A
PA
Tozzi
A E
AE
Pezzotti
P
P
Galli
L
L
Livadiotti
S
S
Caselli
D
D
Massironi
E
E
Ruga
E
E
Fioredda
F
F
D001942:Breast Feeding; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission*; D015497:HIV-1; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007558:Italy / Q000453:epidemiology; D008297:Male; D008895:Milk, Human / Q000382:microbiology*; D012307:Risk Factors; D013997:Time Factors