manners: an example of a bad insertion of a factoid into polite dinner party conversation

The conversation, for whatever reason, turns to the topic of the lives of truck drivers.

"My uncle and brother are truckers and it seems like it is so unhealthy. You know, it's really hard on your back and knees to sit like that all day."
"I have a bunch of relatives who are truckers, too, and the lifestyle also seems really unhealthy. It seems like it's really easy to develop obesity and a drinking problem when you are on the road that much."
"Did you know truckers have the lowest IQs of any common occupation?"

"Are your relatives all really stupid?" the person did not add. Nor: "Are they blood relatives?"