Weber DR, et al. - Researchers assessed the impacts of type 1 diabetes (T1D) on calcium absorption and estimated calcium retention in adolescent females, using a dual-stable calcium isotope method. Negative estimated calcium retention was observed in one-quarter of girls, at a time when bone mineral accrual should be ongoing, possibly resulting from excess urinary calcium excretion as opposed to diminished gastrointestinal calcium absorption. Impaired bone mineral accrual and skeletal fragility could be attributed to insufficient calcium availability for bone deposition during adolescence.