Authors introduced an interaction effect long COVID x gender into the model in order to test their third hypothesis (“(iii) whether gender moderated the associations between long 119 COVID status and the health outcomes”, page 3, line 119).
The authors admit that, line 367, younger people were overrepresented, but to me, it was that older persons, especially over age 70, who were somehow missed in the survey sampling process. The study offers little to say about long covid among the elderly.