Cough mixture abuse as a novel cause of folate deficiency: a prospective, community-based, controlled study.

Cough mixture abuse has been reported to cause severe folate deficiency and neurological defects. We carried out a prospective case-controlled survey to confirm this association and define the incidence and severity of the problem. A total of 57 cough mixture abusers and 47 other substance abusers (controls) were studied. When compared with controls, cough mixture abusers had a high incidence of low folate levels that could only be detected by screening.