I'm not quite sure what the argument is here? Just a wee bit confused.....
There is no question that the relationship between bone loss and oestrogen is dose dependent.
That is to say - yes it has been shown that a small amount of oestrogen will prevent some bone loss, but the greater the dose ( up to a certain point) the greater that effect will be. A while ago I read the stats on it, in a published paper and as always it's down to percentages of women showing percentages of bone loss. Can't lay my hands on it at the moment.
So yes a menostar patch or smaller will likely have some beneficial effect, but not as much as a 50 mcg patch which you will see from the menu is the licensed dose for prevention of oesteoporosis.
Re the NICE guidelines - I haven't looked at these for a while but these do become outdated, and as new information becomes available, specialists, and some GPs use this knowledge to prescribe differently. The NICE menopause guidelines are a good example - they are way out of date and are being updated (due in 2015) right now.
To me the NOS guidelines extract quoted below imply that HRT is beneficial as a prevention for osteoporosis, for women under 60. Taking it for prevention surely does not require a prior investigation to determine bone density?
Hurdity x