It's not just for breakfast any more. While the play on words may be initially amusing, osteoporosis is not. Alcohol consumption is known to be a significant contributing factor to bone loss, and is believed to be a risk factor for osteoporosis.
Alcoholics often have bones that are less dense than normal.
Less bone density means less bone strength, which can increase an individual's risk of bone fracture. This indicates that alcohol is directly responsible for at least some detrimental effects on bone health. This may mean that alcohol has an irreversible toxic effect on bone cells, or that alcohol interferes with the normal communication between bone cells which governs the delicate balance between how much bone is formed and how much bone is resorbed. The animals were the human equivalent of young adults. So the fact that PTH can, under certain conditions, actually stimulate bone growth is a little bit unusual.