Is it true what my teacher told me, about black women and our rather large s?

We were learning African studies right before summer break, and she said that many docotors are volunteering to head to Africa to help black women with back problems they develope from having oddly shaped, large s. I guess they require back braces and some even get reduced to wheel chairs from carrying all that extra weight on their backside. I ask because this scared me. I have always had a that is too large for my body, like man black women in America. I dont want to end up in a wheelchair or have to wear a brace. Is this true and what can I do to avoid this terrible fate?