Hi Micaela,
There's not a lot. Simply not enough studies done with older babies and young children. As you mention the dose response is clearest for breast cancer. That's not to say that there may not be an impact, the below is from a paper of mine. The references cited may assist.
"Breastfeeding assists children to fight infection via immunological components that are present in breastmilk, the concentrations of which remain stable from six months to beyond the second year of lactation (Goldman, Goldblum & Garza 1983). Breastfeeding provides breastfed children with immunological factors that would otherwise be unavailable to them.  In some contexts, two and three year old children who have been weaned have higher morbidity and mortality rates than children of the same age who continue to be breastfed (Briend & Bari 1989; Feachem & Koblinsky 1984; Lepage, Munyakazi & Hennart 1981; Molbak et al 1994; WHO Collaborative Study Team on the Role of Breastfeeding on the Prevention of Infant Mortality 2000; World Health Organization 1998). "
Karleen Gribble
Australia
On 12/09/2013, at 2:49 AM, Micaela Notarangelo wrote:

> I am looking for health outcomes brought on by breastfeeding for longer
> than 12 months (both mother and child).
> 
> I remember that some of the health outcome of breastfeeding have a dose
> response effect, but a part from breast cancer (the longer the woman
> breastfed the lower the chances of breast cancer) I cannot find other
> dose-related effects that are not controversial.
> Most of the studies actually look at breastfeeding up to a year.
> 
> Can anyone point me to studies that report this kind of dose-response
> effect for breastfeeding, especially for more than 12 months of bf?
> 
> Additionally, I am interested in the composition of BM after 12 months:
> this is also very difficult to find.
> 
> Thanks to you all.
> 
> Micaela
> Italy
> 
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