I did discuss my WHR with my doctor when it was in the unhealthy range (but I was well within the normal BMI range). He wasn't happy about it, but he didn't offer any constructive suggestions for changing it.
I've seen lots of references to WHR being a health concern independent of weight. In general, a woman with *either* an absolute waist measurement of > 35 inches or a high WHR (defined as > .85 or .8, depending on the agency) is considered at higher risk for a host of health problems. You can be thin and still have a high WHR.
I just googled up an example of a high WHR being a better indicator of potential heart problems than BMI (this is a specific example, but I've seen others over time bc I've paid a lot of attention to this topic).
http://www.aarp.org/health/condition...n_bmi_for.html
Here's the most relevant sentence ("central obesity" means a high WHR, not an obese person):
"The study found that central obesity is associated with higher mortality even in individuals with normal BMI scores. That finding could prompt changes in how doctors care for heart disease patients."
ETA: and here's a similar study:
http://heartdisease.about.com/od/die...waisttohip.htm
"For one thing, it means that people who are not particularly overweight are still at increased risk if their waist size is increased. On the other hand, it means that some overweight people (the pear-shaped ones) may not have greatly increased risk, as long as their other risk factors are under control, and their extra weight is distributed so as to pad their thighs and butts."