Walking is related to bone density and rates of bone loss - PubMed - This one is post menopausal women.
Elsewhere
“A Dutch team found that fast (or brisk) walking, at a pace of 5 to 6 km/hr or 3.1 to 3.7 mph, produced compressive and tensile strains at a level similar to hopping or running at 5 to 9 km/hour or 3.1 to 5.6 mph.
The research team concluded that “our results suggest that a training program including fast [or brisk] walking (above 5 km/h) and running exercises may increase or preserve the BMD (bone mineral density) at the femoral neck”. In other words, to improve bone health you need to walk pretty fast.”
They say walk pretty fast but walking at 5km/h isn’t fast. In conclusion yes if it’s brisk enough and terrain can make a difference. There are significant differences waking up and down a mountain compared to level pavement