[surferjoe2007]

Besides very high IGF and HGF in macromastia cases, moderately higher IGF is found in women with large boobs too.  I also read about large chested women exercising their back, using good posture and so on to avoid any back pain.  Plus 32H's are only 2 pounds a boob, so even they aren't a major concern.  5-6 lbs each is 32O (or 36M, etc.):
http://kdwb.iheart.com/onair/the-dave-ry...-12418095/

A radio station? that's what we're using for scientific information?, um ok, whatever. Even using their information (which doesn't measure extended cup size DD/DDD - GG/ HHH etc.......is as follows). If you had large breasts you'd might think twice about saying it's not a major concern, all breasts aren't (and weigh) the same. 

Ha it didn't seem like a subject of much difficulty or controversy, so it's not like it needs a good source.  Is this better?
https://en.wikipedia.org/wiki/Bra_size#C...ast_weight
Probably where that radio station got it from.  It seems like they calculated it.
So they assumed 34J or 32K is the cutoff in that discussion.  That sounds reasonable.  Keep in mind they said 1.5 kg per breast, so 3 kg total.  The chart uses the total.  Still even the flat chested have back problems and exercise, stretching and posture can benefit everyone.  And the torso in general and stomach are much heavier.  In fact obesity is a much greater contributor to back trouble than a couple pounds of boobs.  Even if the stomach has a little less leverage, it has way more weight.

Half your weight is in your torso in fact and not being upright makes a big difference.  Let's assume for simplicity a pair of 34J's are sticking out 5 inches from the torso, or 2.5 inches in their middle, with a weight of 6.2 lbs.  And let's say that person has a 62 lb. torso with a center of gravity half as high as the breasts, measured from where the back bends at the bottom.  That's 10x1/2=5 times the effect, so if that person leaned forward even 0.5 inch (2.5/5) at the middle her torso would put more strain on her back than her breasts do.  The average torso is about 18.75", or 9.375" at the center.  ATAN(0.5/9.375)=0.053 radians ~= 3 degrees.  A quick google suggested that you not slouch more than 20 degrees from vertical.  Posture information I found in general spoke in tens of degrees, not single digit degrees.  The weight of those breasts is not that much compared to, for example, a minor slouch.  Actually when a large chested woman hates her breasts and slouches to hide them, the slouching itself can do a lot of back damage.  Remember correct posture involves sticking out your chest.

Pullups have made an amazing difference for my back btw.  No more troubles.  I tried all these adjustments to my chair, fancy chair, correcting posture, and so on with mediocre success.  Then got a stronger back and poof zero discomfort.

Whoa, that turned into a bit of a crazy tangent.  Anyone can just stop or reduce NBE if they don't want to be over a certain size.  Same goes for IGF, it's not an all or nothing thing.  For the sake of good health it's probably best to use a low amount.  Macromastia merely illustrates its potential, in that it is not a minor factor and should perhaps be considered alongside major hormones.