Glad you asked, that means you’re really looking at this question closely. (There are pages on this site for metabolic syndrome and PCOS, in case you came from somewhere else). A local and well respected endocrinologist told me — wrongly — that they
were the same thing. So there is plenty of confusion here, in case you were having some.
But a new article referred to me by Dr. F in Pennsylvania (thanks) clarifies this question. Here are some of the important details from this articleOvalle and Azziz, then the conclusion:
- Insulin resistance affects between 10% and 25% of the general population;
- PCOS affects 4% to 6% of reproductive-aged women;
- Only about 50% to 70% of women with PCOS have insulin resistance, not everyone, according to this review anyway;
- The risk of type 2 diabetes mellitus among PCOS patients is 5- to 10-fold higher than normal — but not everybody gets it (and that has been clear for years).
In their review, Drs. Ovalle and Azziz make it clear that insulin resistance is just one part of PCOS; not all women with insulin resistance will get PCOS symptoms. There must be some other factor that causes women to go from insulin resistance to PCOS. What is that factor? This is not known. My working hypothesis is “stress”, through the central nervous system effects of stress hormones called “glucocorticoids”. Try the section of this website on stress and mood for more on that relationship.