The association between Thiamine status and stuttering: A comparative case‒control study

Stuttering is a complex neurodevelopmental speech disorder characterized by disruptions in fluency that can affect communication, social participation, and quality of life. While genetic, neurological, and environmental factors are well-established contributors, emerging evidence suggests that nutritional deficiencies, particularly thiamine (vitamin B1), may play a role in speech‒motor instability. Thiamine is essential for cerebral energy metabolism, neurotransmitter balance, and myelin integrity, all of which are critical for fluent speech. Populations in low-resource settings, such as Pakistan, face high rates of micronutrient deficiency, yet the potential association between thiamine status and stuttering remains underexplored. This study aimed to examine the association between plasma thiamine levels and stuttering in Pakistani adults and to assess whether thiamine deficiency is correlated with stuttering severity. A comparative cross-sectional case–control study recruited 26 adults with clinically diagnosed stuttering and 26 fluent controls (aged 19–40 years) from clinical and community sources. Stuttering severity was assessed via the Stuttering Severity Instrument–Fourth Edition (SSI-4). Venous blood samples were analyzed for their plasma thiamine concentration via HPLC/ELISA, with deficiency defined as