Dear Editor,

According to Wiklund et al. (1), mothers who breastfed for more than 33 months had greater bone strength than mothers who breastfed for less than 12 months (p < 0.05). These findings are in agreement with our results from a study of 1633 post-menopausal Hispanic women from Barranquilla, Colombia, where we did not find any long-term adverse effect of prolonged lactation (up to 48 months) on women’s bone health (2). In another study we found an increase in the bone mineral density and in the total bone and calcium content in all skeletal areas after each delivery and a reduced risk of bone fractures (OR 0.41; 95 % CI 0.28̶0.61; p < 0.00002) in women with two or more deliveries compared with nulliparous women (3). This “gestational bone mass peak” is analogous to the bone mass peak observed during puberty. One important question that remains to be answered by the study by Wiklund et al. is whether greater maternal bone size and bone strength are also associated with a reduced risk of bone fractures in the long run.